ashfordeOU

@ashfordeou source repo

671 skills
0 followers
23 hours ago last updated

▌
Environmental Disturbance Torque Budget · ashfordeou bundle
Use when you must estimate the worst-case environmental disturbance torque budget for a spacecraft: compute gravity-gradient torque from orbit mean motion and principal moment spread at the attitude offset, solar pressure torque from area, incidence cosine and lever arm with reflectivity convention, residual magnetic dipole torque against the local field, and aero drag torque from the free-molecular relation at explicit density. Produces per-source worst-case torques, aligned-axis total with dominant source, per-orbit disturbance impulse and actuator torque margin. Trigger: disturbance torque budget, worst-case disturbance torque, gravity-gradient torque, solar pressure torque, residual magnetic dipole, aero drag torque, per-orbit impulse.

0
installs
▌
Unidirectional Lamina Micromechanics · ashfordeou bundle
Use when you must predict the engineering constants of a unidirectional composite lamina from the fiber and matrix constituent properties and the fiber volume fraction: compute the longitudinal modulus E1 and the major Poisson ratio nu12 by the rule of mixtures, the transverse modulus E2 by the Halpin-Tsai closed form with the xi equal to 2 shape factor on the fiber transverse modulus, the in-plane shear modulus G12 by the Halpin-Tsai closed form with the xi equal to 1 shape factor on the fiber shear modulus, and the density by the rule of mixtures. Produces the lamina engineering constants in the material axes and the Voigt-Reuss and Hashin-Shtrikman bound bands on E2 and G12 as the verification envelope predictions fall inside. Constituent properties are inputs; no property tables are reproduced. Trigger: unidirectional lamina micromechanics, fiber volume fraction, rule of mixtures, halpin tsai transverse and shear moduli, hashin shtrikman bounds.

0
installs
▌
Fmes Coverage Analysis · ashfordeou bundle
Use when you must verify the coverage of the failure-mode effect rows over the functional-hazard condition set: map every FMEA row to the failure condition it demonstrates through its condition_id, list the covered and the uncovered condition ids, flag the rows that carry no condition link as orphan rows, and report the coverage ratio of covered over total conditions. Breaks the coverage down per severity class when conditions carry severity, and suggests candidate condition ids for unlinked rows with a deterministic text-match score. Produces the covered and uncovered condition id lists, the orphan row list, the coverage ratio, the per-severity-class coverage dict and the match suggestions that gate the FMEA-to-FHA loop before the assessment closes. Trigger: fmes-coverage-analysis, fmea-fha-coverage, uncovered-failure-condition, orphan-row-flag, condition-match-score.

0
installs
▌
Reliability Allocation · ashfordeou bundle
Use when you must allocate a system reliability requirement down to the design items: flow one top-level failure rate per flight hour, or its MTBF equivalent, into per-item target rates by equal split or by complexity-weighted apportionment from design-team complexity weights, produce the per-item failure-rate and MTBF targets for the item development specifications, verify the series-sum closure of the item budgets against the system rate, and report each item capability margin against its predicted capability rate to flag overruns and slack for rebalancing. Produces the per-item failure-rate and MTBF targets, the closure result and the margin report. Trigger: reliability allocation, failure-rate budget, MTBF target flow-down, complexity weights, apportionment, item development specification, series-sum closure, capability margin.

0
installs
▌
Rotorcraft Hover Ground Effect · ashfordeou bundle
Use when you must compute the hover-in-ground-effect performance of a rotorcraft rotor: the Cheeseman-style ground-effect reduction factor for the rotor induced power from the height above the ground and the rotor radius, the in-ground-effect induced power, the in-ground-effect total hover power from the induced-power factor and the unchanged profile power, the power margin against an available power, and the maximum rotor height at which the rotorcraft can still hover with that available power. Produces the ground-effect factor, the IGE induced and total hover power, the IGE power margin and the maximum hover height that gate a rotorcraft hover check in ground effect. Trigger: rotorcraft-hover-ground-effect, hover-in-ground-effect, ige-power-reduction, ground-effect-factor, ige-hover-ceiling, rotor-height-ratio.

0
installs
▌
Accelerate Stop Distance · ashfordeou bundle
Use when you must compute the rejected takeoff accelerate stop distance for a flight test: accelerate the airplane to the decision speed V1, stop it with the braking deceleration, and check the total against the available runway length. Produces the accelerate distance, the stop distance, and the runway fits verdict that gate the rejected takeoff field length assessment. Trigger: rejected takeoff, V1 decision speed, braking deceleration, accelerate stop distance, runway length, balanced field length.

0
installs
▌
Flight Test Instrumentation · ashfordeou bundle
Use when you must design flight test instrumentation: select sensors for the measurement parameters (air data, accelerations, angular rates, strain, control positions, engine data) with the right range, accuracy, and bandwidth, size the data acquisition sample rate against the anti-aliasing and Nyquist limits, and verify the recording, telemetry, pre-test calibration, and measurement uncertainty chain before the test. Applies the Nyquist criterion, sensor range checks, ADC quantization, and calibration currency to release an instrumented channel for flight. Trigger: instrumentation design, sample rate, anti-aliasing, Nyquist, sensor selection, telemetry, calibration, measurement uncertainty.

0
installs
▌
Pcm Telemetry Decommutation · ashfordeou bundle
Use when you must decommutate a serial PCM telemetry stream: acquire frame sync by locating the sync word in the captured word stream, walk the locked minor frames and count sync misses, and demultiplex the recovered telemetry channels into time series, with fixed channels read from their word slot every frame, supercommutated channels read from their multiple word slots per frame, and subcommutated channels keyed by the subframe id into the per-subframe value lists. Produce the locked frame count, the sync miss report, the subframe id trace, and the recovered per-channel time series that feed data reduction. Trigger: pcm telemetry decommutation, pcm frame sync, supercommutated demux, subcommutated demux, minor frame decode.

0
installs
▌
Brayton Optimum Pressure Ratio · ashfordeou bundle
Use when you must select the pressure ratio of a simple gas-turbine-cycle that maximizes the net specific work at the cycle temperature limits: compute the max-work pressure ratio from x_opt = sqrt(tau) for the ideal cycle and x_opt = sqrt(tau*eta_c*eta_t) with component efficiencies; check the zero-work limiting ratio, exactly the max-work ratio squared; and judge the verdict that the max-efficiency ratio diverges from the max-work ratio. Produces the ideal and lossy max-work pressure ratios, the zero-work limit with the r_zero = r_opt**2 cross-check, the specific work at the optimum, and the efficiency-versus-work verdict in SI units. Trigger: maximum specific work, max-work pressure ratio, gas turbine cycle pressure ratio selection.

0
installs
▌
Hydrogen Peroxide Monopropellant Thruster · ashfordeou bundle
Use when you must size and assess a hydrogen peroxide monopropellant thruster for spacecraft reaction control: compute the decomposition heat release of H2O2 at a documented concentration with the water dilution, the adiabatic decomposition temperature from the peroxide decomposition energy balance, and the frozen composition isentropic nozzle expansion of the steam-oxygen product mixture to the vacuum exhaust velocity, the vacuum specific impulse and the propellant mass flow at the required thrust, with the advisory silver-catalyst-bed band check. Produces the steam-oxygen mixture composition and mass fractions, decomposition temperature, mixture gas constant, isentropic exponent, exhaust velocity, vacuum specific impulse, propellant mass flow and the silver-catalyst-bed band verdict that size a monopropellant RCS thruster. Trigger: hydrogen-peroxide-monopropellant-thruster, peroxide-decomposition, steam-oxygen-mixture, silver-catalyst-bed, concentration-limited-decomposition.

0
installs
▌
Geostationary Station Keeping · ashfordeou bundle
Use when you must compute geostationary station keeping quantities for a GEO satellite: the geosynchronous radius and orbital speed from the sidereal day, the annual north-south delta-v from the inclination drift with the two-burn-per-year model, the per-burn delta-v, the burn time from thrust and spacecraft mass, the annual propellant from the specific impulse, the east-west deadband drift-cycle period and maneuver cadence from the longitude acceleration and box half-width, and the uncontrolled drift time to the inclination tolerance. Produces the radius, speed, annual and per-burn delta-v, burn time, annual propellant, east-west cycle period and cadence, and the uncontrolled-drift verdict that gate a GEO propulsion budget. Trigger: geostationary station keeping, geosynchronous orbit radius, north-south station keeping, inclination drift control, east-west deadband cycle, longitude acceleration, station keeping delta-v, geo propellant budget, uncontrolled drift time.

0
installs
▌
Requirements Allocation · ashfordeou bundle
Use when you must allocate system requirements to items and functions per ARP4754A development planning: assign each system requirement to a design item or function, check the allocation coverage to find the unallocated requirements, detect a requirement allocated to more than one item, and group the allocated requirements per item for the item development handoff. Produces the allocation register, the unallocated list, and the double allocation verdict that gate the handoff of requirements to item level development. Trigger: requirements allocation, allocation coverage, item allocation, unallocated requirements, allocate system requirements to items.

0
installs
▌
Failure Rate Estimation · ashfordeou bundle
Use when you must estimate or demonstrate aircraft system failure-rates from test or service data per ARP4761A: compute the point failure-rate estimate from the number of failures and the test-hours, derive the exact poisson chi-square upper-bound on the failure-rate at a stated confidence, apply the zero-failure rule (1.609 million test-hours demonstrate a 1e-6 per hour rate at 80 percent confidence), size the test-hours needed to demonstrate a target rate with allowed failures, and bound the MTBF. Produces the failure-rate, confidence bound, and MTBF numbers that feed the FTA, Markov, and PSSA/SSA quantitative models. Trigger: failure-rate estimation, failure rate, test-hours, chi-square, MTBF, confidence upper-bound, zero-failure rule, reliability demonstration, poisson.

0
installs
▌
Pitch Bandwidth Criteria · ashfordeou bundle
Use when you must assess the pitch-axis flying qualities of an aircraft with the MIL-STD-1797A bandwidth and phase-delay criterion: model the pitch attitude response as a short period transfer function with a control anticipation numerator time constant and an actuator lag, evaluate the frequency response, find the bandwidth frequency omega_BW as the lower of the 45 degree phase margin frequency and the 6 dB gain margin frequency, read the -180 degree frequency, compute the phase delay tau_p from the phase at twice omega_180, and grade the Category A Level 1, 2 and 3 boundaries. Produces omega_BW, omega_180, tau_p, the flying qualities level and the limiting criterion. Trigger: pitch bandwidth criterion, phase delay tau, bandwidth frequency, phase margin 45 degrees, mil-std-1797a bandwidth, short period transfer function, actuator lag, flying qualities level.

0
installs
▌
Rotorcraft Autorotative Descent · ashfordeou bundle
Use when you must estimate the power-off autorotative descent performance of a single-rotor helicopter: the energy-method sink rate from the minimum level-flight power and the weight, the empirical minimum descent rate from the Talbot-Schoers correlation of NASA TM 78452 (public domain), its equivalent power-based entry, and the feet-per-minute conversion. Produces the energy-method sink rate, the empirical minimum descent rate and the power-to-weight ratio entry that gate an autorotative descent assessment after engine failure. Trigger: rotorcraft autorotative descent, autorotative descent rate, power-off descent, minimum descent rate, rotor energy balance, engine failure descent, descent rate estimate.

0
installs
▌
Stability Derivatives Avl · ashfordeou bundle
Use when you must estimate the aerodynamic stability derivatives of an aircraft from its geometry in AVL style: estimate the wing and tail lift curve slopes from the planform aspect ratio, the quarter-chord sweep, and the Mach number; estimate Cm_alpha from the tail volume coefficient and the downwash gradient; estimate the lateral-directional derivatives Cn_beta, Cl_beta, Cl_p, Cl_r, Cn_p, and Cn_r from the vertical tail geometry, the wing dihedral, and the sweep contribution; and derive the neutral point and the static margin from the longitudinal estimates. Produces the non-dimensional derivative table that feeds the longitudinal and dynamic stability leaves. Trigger: stability derivatives, lift curve slope, wing planform, aspect ratio, quarter chord sweep, Mach correction, Cn beta, neutral point, static margin, AVL.

0
installs
▌
High Angle Of Attack Testing · ashfordeou bundle
Use when the task is post-stall envelope definition, AoA instrumentation calibration, or deep stall testing. Plan and run the high angle of attack flight test: calibrate the angle of attack sensor position error against a tower fly-by or trailing cone reference, size the post-stall and deep stall test points across configurations and center of gravity conditions, estimate the stall warning margin against the required margin in the certification context, and judge the departure resistance and spin entry resistance in the post-stall envelope. Produces the corrected AoA calibration, the HiAOA test matrix, the stall margin verdict, and the departure and spin resistance assessment. Trigger: high angle of attack, AoA calibration, deep stall, departure resistance, post-stall, spin entry.

0
installs
▌
Fuel Jettison Flight Test · ashfordeou bundle
Use when you must reduce a fuel jettison flight test demonstration: least-squares fit the telemetered fuel-weight-vs-time samples taken while the dump runs, read the measured average dump rate from the fitted slope, extrapolate the time from the takeoff weight down to the landing weight at that measured rate, judge the PASS or FAIL verdict against the 900 s limit, and check the measured rate against the design-side required rate. Produces the fitted slope, intercept and R^2, the measured dump rate, the extrapolated landing-weight time, the verdict with margin in seconds, and the rate-requirement check with margin in kg/s. Trigger: fuel jettison flight test, measured dump rate, fuel-weight-vs-time samples, jettison demonstration.

0
installs
▌
Stall Speed Determination · ashfordeou bundle
Use when you must determine the reference stall speed Vs1g for a flight test: derive it from the wing loading and the maximum lift coefficient, correct it for a weight change, and check the stall margin against the current flight speed. Produces the Vs1g reference stall speed in m/s, the weight-corrected stall speed, and the stall margin verdict that gate the performance assessment. Trigger: Vs1g, stall speed, wing loading, stall margin, flight test, weight correction.

0
installs
▌
Fastener Installation Quality · ashfordeou bundle
Use when you must verify the installation quality of aerospace structural fasteners during assembly: select the grip length for the clamped stack from the available grip increments, check the thread protrusion against the typical protrusion band, compute the clamp load from the applied torque with the torque coefficient, verify the clamp load and the torque scatter band against the joint allowables, check the countersink flushness for flush head fasteners, confirm the swage collar engagement for lock-bolt fasteners, and classify the installation verdict as pass, rework, or scrap with the specific defect. Produces the selected grip, the protrusion check, the clamp-load estimate, the flushness and engagement checks, and the installation verdict that gate the assembly quality assessment. Trigger: fastener installation quality, grip length selection, thread protrusion, clamp load from torque, countersink flushness, collar engagement, Hi-Lok installation check.

0
installs
▌
Failure Mode Criticality · ashfordeou bundle
Use when you must quantify and rank the failure modes of an item by their rate-based criticality: split the item failure rate into per-mode rates with the mode ratios, compute the MIL-STD-1629A style criticality number C_m = beta * alpha * lambda_p * t for every mode with its failure-effect probability, sum the per-mode criticalities into the item criticality C_r, and rank the modes by C_m with each mode's share of item criticality and a dominant-mode flag. Produces the per-mode rate split, the C_m values, C_r and the sorted rank list that gates maintenance and redesign prioritization. Trigger: failure-mode criticality, fmeca criticality number, mode ratio, failure-effect probability, item criticality.

0
installs
▌
Particular Risk Analysis · ashfordeou bundle
Use when you must perform or review a particular risk analysis (PRA) per ARP4761A: quantify the probability of a single-event risk (rotor burst, tire burst, bird strike, fire, lightning), combine it with the conditional probability that the hazard leads to a failure condition, and assess hazard zone containment, separation, and redundant routing mitigations. Produces event-exposure probabilities, combined failure-condition probabilities, and zone verdicts for the safety assessment. Trigger: particular risk analysis, rotor burst, tire burst, bird strike, containment, hazard zone, arp4761a, pra.

0
installs
▌
Certification Basis · ashfordeou bundle
Use when you must determine the applicable certification regulations and the certification path for a civil aircraft or system: map the project type and aircraft category to the governing airworthiness parts (FAR-25 or CS-25 for transport airplanes, Part 23 or CS-23 for normal airplanes, Part 27 and Part 29 for rotorcraft, Part 33 for engines, Part 35 for propellers), identify special conditions when the design has a novel or unusual feature not covered by the regulation, and select the certification path (type certificate, amended TC, supplemental type certificate, TSO authorization) with the required finding types (compliance finding, means of compliance, certification program). Produces the certification basis list, the special condition flags, and the certification path recommendation. Trigger: certification basis, applicable regulations, FAR-25 applicability, CS-25, type certificate, supplemental type certificate, TSO authorization, special conditions, certification path, regulatory applicability.

0
installs
▌
Means Of Compliance · ashfordeou bundle
Use when you must select the means of compliance for each certification item in a civil aircraft certification program: assign the acceptable MOC class (moc-1 engineering analysis, moc-2 ground test, moc-3 flight test, moc-4 simulation tool, moc-5 similarity, moc-6 safety assessment) from deterministic suitability rules over item kind, severity class, DAL and a novelty screen, gate top-severity systems items on moc-6, and score the compliance matrix coverage per item kind. Produces the per-item MOC assignment, the coverage score, and a certification plan readiness verdict. Trigger: means of compliance, moc-1, moc-2, moc-3, moc-4, moc-5, moc-6, compliance matrix, certification item, coverage score, certification plan, novelty screening.

0
installs
▌
Fuselage Skin Stringer · ashfordeou bundle
Use when you must size a pressurized fuselage skin-stringer panel at the conceptual level: compute the hoop and longitudinal membrane stresses from the cabin differential pressure and the fuselage radius, derive the skin thickness from the governing hoop stress with the 1.5 factor of safety and the minimum gauge, bound the stringer spacing from the flat panel buckling allowable, set the frame pitch from the stringer column buckling length between frames, and size the stringer area from the compression strip load with the effective skin width. Produces the skin thickness, stringer spacing, frame pitch, and stringer area that gate the fuselage structure integration. Trigger: fuselage skin stringer, pressurized fuselage, hoop stress, stringer spacing, frame pitch, panel buckling.

0
installs
▌
Pilot Induced Oscillation · ashfordeou bundle
Use when you must assess pilot-induced oscillation (PIO) susceptibility and pilot-in-the-loop coupling for a piloted aircraft: categorize the oscillation into Category I (linear aircraft response), Category II (quasi-linear response with rate-limited actuators), or Category III (nonlinear response with mode transitions or control logic changes), identify the typical causes: excessive phase lag, high control sensitivity, actuator rate limiting, structural notch filters, run a phase-lag-at-crossover risk check that returns a low, medium, or high band with the equivalent time delay and phase margin, and select suppression measures such as phase compensation, gain reduction, notch filter retuning, and control logic changes. Supports flight test detection of divergent oscillation. Framed by FAR-25 and CS-25 flight characteristics requirements. Trigger: pilot-induced-oscillation, pio, phase lag, crossover frequency, equivalent time delay, actuator rate limiting, pilot-in-the-loop coupling, pio suppression.

0
installs
▌
Short Period Mode Analysis · ashfordeou bundle
Use when you must analyze the short-period longitudinal mode of an aircraft: convert the dimensionless stability derivatives C_m_alpha, C_m_q, C_m_alphadot, C_Z_alpha and C_Z_q to dimensional per-unit-mass derivatives with the aerodynamic timescale, compute the short-period natural frequency and damping ratio from the two-DOF pitch model, verify the phugoid separation assumption, and check the mode against the Level 1 flying qualities damping and frequency boundaries for the flight phase category. Produces the mode metrics and the Level 1, 2, or 3 verdict that feeds the dynamic stability assessment and complements the static longitudinal stability leaf. Trigger: short period, natural frequency, damping ratio, flying qualities, pitch oscillation, stability derivatives, mode analysis.

0
installs
▌
Stall Characteristics Testing · ashfordeou bundle
Use when you must plan and gate the stall characteristics flight test: build the stall test matrix across configurations and power settings, pick the entry technique (gradual deceleration at one knot per second, power-on, turning, accelerated), compare the natural stall with the accelerated stall at the entry load factor, verify the stall warning onset (buffet or stick shaker) against the required margin, and judge the recovery characteristics (altitude loss, pitch-up, roll-off, departure resistance) against the certification requirements. Produces the test matrix, the warning onset verdict, and the recovery verdict that gate the stall test program. Trigger: stall characteristics, buffet, stick shaker, accelerated stall, stall warning, natural stall, recovery.

0
installs
▌
Static Stability Flight Test · ashfordeou bundle
Use when the task is static stability flight testing, trim curve reduction, neutral point location, or static margin estimation. Evaluate the static stability flight test results: fit the trim curve to the elevator angle versus speed points, derive the trim curve slope, locate the stick fixed neutral point from the slope, estimate the static margin, and assess the elevator angle per g from the incremental elevator angle per load factor step. Produces the trim curve fit, the slope, the stick fixed neutral point, the static margin, and the stability verdict that gate the static stability demonstration. Trigger: static stability, trim curve, elevator angle, stick fixed, neutral point, static margin, elevator angle per g.

0
installs
▌
Welding Qualification · ashfordeou bundle
Use when you must build and check the engineering content of an aerospace weld procedure qualification record (WPS/PQR): compute the weld heat input in kJ per mm from voltage, current, travel speed, and process efficiency; verify heat input, preheat, and interpass temperature against the qualified procedure ranges; confirm the production weld thickness and joint configuration sit inside the qualified coverage; and list the qualification test coupons required for the process and joint type. Produces the heat input, the preheat and interpass margins, the thickness and variable coverage verdicts, and the coupon test matrix that gate the weld procedure qualification. Trigger: weld procedure qualification, WPS PQR, heat input, kJ per mm, preheat, interpass temperature, thickness coverage, coupon test matrix, GTAW, GMAW, qualification test coupons.

0
installs
▌
Requirements Traceability · ashfordeou bundle
Use when planning or auditing requirements traceability per ARP4754A: determine closure status across SRATS, high-level requirements (HLR), low-level requirements (LLR), code, and test levels, list traceability gaps for a level, flag derived requirements, and compute the verified-closure ratio of the trace matrix. Bidirectional closure (each level traces down and back up) and open verification items drive the closed/open verdict; all logic is deterministic, offline stdlib. Trigger: traceability, requirements, closure, SRATS, high-level requirements, low-level requirements, derived requirements, verification, trace matrix.

0
installs
▌
Fault Tree Quantification · ashfordeou bundle
Use when you must quantify a fault-tree top event from its minimal cut sets and basic-event probabilities: compute the rare-event approximation (sum of cut-set probabilities), the Esary-Proschan min-cut upper bound, and the exact inclusion-exclusion top probability when 2^n stays tractable; truncate the cut sets below an analyst probability threshold and keep the retained probability share; rank the cut sets by per-cut-set probability share to flag dominant failure combinations. Produces the quantified top-event probability, its bound chain, and the truncated cut-set mass picture, the predicted-probability input the SSA closure comparison consumes. Trigger: fault-tree quantification, rare-event approximation, min-cut upper bound, cut-set truncation, cut-set probability share, top-event probability.

0
installs
▌
Reliability Block Diagram · ashfordeou bundle
Use when you must analyze aircraft system reliability with a reliability block diagram (RBD) per ARP4761A: evaluate a structure of blocks in series from constant failure-rate components, compute component and system mission reliability R(t) = exp(-lambda t), combine series, active parallel, k-out-of-n voting and cold standby redundancy blocks, derive exact block and system MTBF, convert a non-exponential block to an equivalent failure rate -ln(R)/t, and identify the dominant component whose failure rate drives system reliability by one-at-a-time sensitivity analysis. Parses a block structure of rates and returns system reliability, MTBF, per-block reliabilities and the dominant component. Produces the quantitative series-parallel reliability view that complements the fault tree logic view. Trigger: reliability block diagram, RBD, series parallel reliability, redundancy, k-out-of-n, standby, MTBF, mission reliability, failure rate.

0
installs
▌
Dynamic Stability Flight Test · ashfordeou bundle
Use when the task is dynamic stability flight testing, mode damping estimation, log decrement analysis, or handling qualities assessment. Plan and analyze a dynamic stability flight test: select the excitation technique for each mode (elevator doublet for the short period, elevator pulse for the phugoid, rudder pulse for the Dutch roll, aileron step for roll subsidence, rudder step for the spiral), reduce the decaying oscillation records to the log decrement, damping ratio, damped and undamped frequencies, time to half amplitude, and cycles to half amplitude, and return a handling qualities verdict per band. Produces the mode identification summary and the acceptable, marginal, or inadequate verdict that gates the stability demonstration. Trigger: dynamic stability, short period, phugoid, Dutch roll, log decrement, damping ratio, handling qualities.

0
installs
▌
Process Noise Discretization · ashfordeou bundle
Use when you must discretize the continuous white noise of a linear system into the discrete-time process noise covariance for a Kalman filter with the van-loan method: given the continuous plant matrices F and G and the continuous-spectral-density Qc, compute the discrete-noise-covariance Qd as the exact integral of the propagated noise strength over the filter step and the state transition matrix from the matrix exponential of F times the step. Produces the discrete noise covariance Qd, the exact transition matrix, and the closed forms of the discrete white noise acceleration, random walk and INS velocity random walk models, in SI units, that gate the filter propagation of every estimation-filtering leaf that consumes a given Q. Trigger: van loan discretization, continuous spectral density, process-noise-discretization, discrete noise covariance, continuous white noise to discrete Q, discrete white noise acceleration, velocity random walk.

0
installs
▌
Maintainability Prediction · ashfordeou bundle
Use when you must roll LRU-level failure rates and repair-task times into a system maintainability prediction: compute the failure-rate-weighted MTTR as the lambda-weighted mean of the per-LRU mean repair times, build the lognormal repair-time model on the failure-rate-weighted median t50, derive the t50 and t95 repair-time percentiles with the Acklam inverse normal quantile, and pass or fail the predicted t95 against the maximum-repair-time requirement with the margin. Produces the weighted MTTR, the t50 and t95 repair times with the lognormal sigma, the verdict and margin, and the per-LRU expected-downtime rollup. Trigger: maintainability prediction, failure-rate-weighted mttr, mttr rollup, mean time to repair, lognormal repair-time model, repair-time percentile, t95 repair time, maximum-repair-time requirement.

0
installs
▌
Rotorcraft Blade Flapping Dynamics · ashfordeou bundle
Use when you must compute the blade-flapping dynamics of a helicopter main rotor: the blade Lock number from the air density, the section lift-curve slope, the blade chord, the rotor radius and the blade flap moment of inertia, the steady hover coning angle from the Lock number, the collective pitch and the uniform inflow ratio, and the rotating flap natural frequency ratio for a flap hinge offset. Produces the Lock number, the coning angle in radians and degrees and the flap frequency ratio per revolution that gate a rotor-dynamics assessment. Trigger: rotorcraft blade flapping, Lock number, coning angle, flap frequency ratio, rotor dynamics, hinge offset, helicopter main rotor, articulated blade.

0
installs
▌
Rotorcraft Forward Flight Flapping · ashfordeou bundle
Use when you must compute the steady first-harmonic (1/rev) flapping equilibrium of a helicopter main rotor blade in forward flight under uniform inflow: the longitudinal flapping angle a1s (the tip-path-plane aft tilt, negative few degrees at cruise) and the lateral flapping angle b1s of the idealized centrally hinged untwisted blade from the advance ratio, the inflow ratio, the collective pitch and the blade Lock number gamma, with the forward-flight coning angle a0 that reduces to the hover coning value at zero advance ratio. Produces the longitudinal and lateral flapping angles and the coning angle in radians and degrees and the first-harmonic flap summary that gates rotorcraft trim assessments and tip-path-plane checks. Trigger: rotorcraft forward flight flapping, tip path plane tilt, first harmonic flap response, longitudinal flapping angle, lateral flapping angle, advance ratio flapping, flap equilibrium tilt.

0
installs
▌
Individuals And Moving Range Chart · ashfordeou bundle
Use when you must run an individuals and moving range control chart: compute the moving ranges between successive measurements and the average moving range, build the individuals chart limits from the mean plus and minus E2 times the average moving range (E2 = 2.66), estimate the process standard deviation from the average moving range over the d2 constant (d2 = 1.128), set the moving range chart upper limit at 3.267 times the average moving range, flag the individual values and moving ranges outside their limits, and return the in-control or out-of-control verdict for one-measurement-per-lot processes (destructive testing, single unit per batch, bond or coating lots). Produces the central lines, limits, flagged points, and the stability verdict that gate lot-to-lot process control without subgroups. Trigger: moving range chart, individuals chart, I-MR chart, single measurement per lot, destructive testing, lot monitoring.

0
installs
▌
Solid Rivet Installation Quality · ashfordeou bundle
Use when you must verify the installation quality of solid rivets during assembly: select the rivet length from the stack thickness plus a head-style allowance (protruding heads 1.5 diameters, countersunk heads 0.8 diameters), judge the driven shop head geometry against the workmanship bands (driven diameter 1.4 to 1.5 d, driven height 0.4 to 0.5 d), compute the squeeze force needed to upset the rivet against the material flow stress over the shank area, and check the hole fill clearance against the 0.1 mm limit. Produces the selected rivet length, the shop head verdict, the required squeeze force and the hole fill verdict that gate the assembly quality assessment. Trigger: solid rivet length selection, shop head dimensions, driven head formation, rivet squeeze force, hole fill check.

0
installs
▌
Reliability Growth Analysis · ashfordeou bundle
Use when you must determine whether a system failure rate is improving over development or field test time: fit the Duane growth slope by ordinary least squares of the log cumulative failure rate on log cumulative time, fit the Crow-AMSAA power-law process shape beta by deterministic MLE bisection, and read the growth verdict off the fitted shape against the 1.0 boundary. Produces the duane-growth-slope, the amsaa-shape-beta with the lambda scale, the fitted current-mtbf under both estimators, the projected-mtbf at a target cumulative test time, and the improving, hpp-constant or degrading verdict that decides whether continued testing or a corrective redesign is warranted. Trigger: reliability growth analysis, duane-growth-slope, amsaa-shape-beta, growth-verdict, test-time-projection, fitted current-mtbf, power-law process, cumulative test time.

0
installs
▌
Control Surface Effectiveness · ashfordeou bundle
Use when you must size and verify the elevator authority and hinge moment requirements of a transport-category airplane: compute the dynamic pressure and the hinge moment coefficient from the tab and angle derivative terms, the hinge moment from the elevator area and chord, the stick force from the gearing arm, the tail volume coefficient and the elevator pitching moment derivative, the elevator deflection needed to trim and to reach a maneuver load factor, the authority margin against the maximum deflection, and the net pitch-up moment about the main gear needed to rotate at the takeoff lift off speed. Produces the hinge moment, stick force, trim and maneuver deflections, authority margin, and controllability verdict that gate the control surface sizing check. Trigger: elevator authority, hinge moment, stick force, elevator deflection, tail volume coefficient, rotation authority, controllability limit.

0
installs
▌
Lateral Directional Stability · ashfordeou bundle
Use when you must assess the lateral-directional stability of an aircraft: compute the directional stability derivative Cn beta from the vertical tail volume coefficient, fin efficiency, and fin lift slope; compute the dihedral contribution to the roll stability derivative Cl beta from the wing dihedral angle and lift coefficient; and characterize the lateral-directional modes: Dutch roll frequency and damping ratio from the simplified yaw sideslip model, the roll mode time constant from the roll damping derivative, and the spiral mode stability classification. Produces the stability derivatives, the mode metrics, and the stable or unstable verdicts that gate the lateral-directional stability assessment. Trigger: lateral directional stability, dihedral effect, directional stability, vertical tail volume, Dutch roll, roll mode, spiral mode, sideslip, yaw stability.

0
installs
▌
Climb Performance Flight Test · ashfordeou bundle
Use when you must run a climb performance flight test on a fixed-wing aircraft: measure the rate of climb in feet per minute from the pressure altitude change over a timed steady climb segment, correct the measured rate of climb for the test weight and the density altitude to the reference condition, convert the pressure altitude rate to the geometric rate with the outside air temperature, determine the service ceiling and the absolute ceiling where the best rate of climb decays to the threshold, integrate the time to climb between altitudes, and check the climb gradient in percent against the certification requirement. Produces the corrected rate of climb, the ceiling altitudes, the time to climb, and the gradient margin that gate the climb test assessment. Trigger: climb flight test, rate of climb, pressure altitude, service ceiling, climb gradient, time to climb, steady climb.

0
installs
▌
In Flight Engine Relight Test · ashfordeou bundle
Use when you must reduce an in-flight engine restart demonstration: fit the least-squares windmill N2 regression against true airspeed from the windmill survey, read the minimum relight airspeed where the fitted N2 line crosses the required relight threshold, summarize the starter-assisted relight time-to-idle samples against the type-data limit per altitude band, and combine the band verdicts with the airspeed into the overall restart-demonstration verdict. Produces the regression slope, intercept and R-squared, the minimum relight airspeed in m/s, per-band time-to-idle statistics and verdicts, and the combined PASS or FAIL verdict. Trigger: in-flight relight test, engine restart demonstration, windmill N2 survey, relight airspeed, time-to-idle limit.

0
installs
▌
Development Assurance Levels · ashfordeou bundle
Use when you must assign development assurance levels per ARP4754A development assurance: rate the failure condition severity into catastrophic, hazardous, major, minor, and no safety effect, map the severity onto the DAL scale A through E, assign the FDAL to each function and the IDAL to each item, and check that no item DAL is lower than its function DAL. Independence between redundant items is evaluated as the alternative to raising the item DAL, and the ARP4761A FHA severity rating feeds the assignment. Trigger: development-assurance-levels, DAL, FDAL, IDAL, severity to DAL mapping, catastrophic failure condition, DAL propagation, independence alternative.

0
installs
▌
Functional Hazard Assessment · ashfordeou bundle
Use when the safety assessment starts with functional hazard assessment or an FHA worksheet must be produced. Identify and rate the failure conditions of a functional hazard assessment (FHA) per ARP4761A: derive the A-FHA and S-FHA failure conditions from each aircraft or system function, rate severity into the categories catastrophic, hazardous, major, minor, and no safety effect, map each severity to its quantitative probability target (extremely improbable below 1e-9/flight-hour, extremely remote below 1e-7, remote below 1e-5, probable below 1e-3), and populate the FHA worksheet rows with phase, effects, and the safety objective that feeds the PSSA and SSA. Trigger: functional hazard assessment, failure condition, severity category, probability target, FHA worksheet, A-FHA, S-FHA.

0
installs
▌
Requirements Elicitation · ashfordeou bundle
Use when you must capture the system requirements from stakeholder needs and operational scenarios per ARP4754A: document the stakeholder needs, convert each operational scenario into candidate requirement statements, and record every candidate in the requirements elicitation log with its source. Assess each requirement statement against the quality criteria: atomicity (one shall clause), verifiability (measurable acceptance bound and an assigned method), unambiguity (no weasel words such as approximately, etc, suitable, and/or), single-verb structure, and traceability to its source; then run the elicitation completeness checklist that flags missing needs, uncovered scenarios, and unlogged candidates before the requirement enters the requirements baseline. Produces the populated elicitation log, the per-statement quality assessment, and the completeness verdict. Trigger: requirements elicitation, stakeholder needs, needs capture, operational scenarios, elicitation log, requirement statement quality.

0
installs
▌
Goal Structuring Notation · ashfordeou bundle
Use when you must build or validate a Goal Structuring Notation (GSN) safety argument for a certification claim: decompose the top goal into sub-goals through a strategy, attach safety assessment evidence as solution nodes, record context, assumptions and justifications, and run the argument validity checks (acyclicity, exactly one top goal, every leaf goal supported by a solution, no dangling references, strategies decomposed, away-goal justification). Produces the validated argument graph with the support coverage score and issue list, and the metrics that gate the safety-case submission. Trigger: goal structuring notation, GSN, safety argument, safety case, claim decomposition, strategy, solution node, away goal, argument validation, support coverage.

0
installs
▌
Rotorcraft Axial Descent Flow States · ashfordeou bundle
Use when you must classify the axial flow state of a rotor in vertical descent: hover at zero rate, the vortex-ring band from zero to twice the hover induced velocity, and the windmill-brake momentum state at and above that boundary. Computes the band limits, the windmill-brake induced velocity from the momentum-theory closed form, the signed rotor power and torque in descent (negative when the rotor absorbs power from the airstream), and the torque-reversal condition c = P_profile over k T versus v_h that decides whether the zero-shaft-power autorotative equilibrium is reachable on the momentum branch. Produces the flow-state verdict, the descent induced velocity, signed power and torque, and the momentum reachability verdict. Trigger: vortex-ring state, windmill-brake state, axial descent, descent induced velocity, torque reversal, rotor descent power.

0
installs
▌
Cruise Performance Flight Test · ashfordeou bundle
Use when you must plan and reduce a cruise performance flight test: schedule level cruise points across a Mach sweep at constant altitude with stabilized fuel flow runs, correct measured fuel flow from the test weight to the reference weight with the square-root weight correction, convert corrected fuel flow and true airspeed into range performance, fit a quadratic range performance curve versus Mach, and read off the maximum range cruise Mach at the vertex and the long range cruise speed at the 99 percent point. Produces the corrected fuel flow table, the fitted curve, the maximum range cruise Mach, the long range cruise Mach, and verdicts gating the cruise fuel economy flight test assessment. Trigger: cruise performance flight test, fuel flow versus Mach, Mach sweep at altitude, maximum range cruise speed, long range cruise speed.

0
installs
▌
Landing Distance Determination · ashfordeou bundle
Use when you must determine the landing distance for a flight test: derive the approach speed Vref from the reference stall speed with the 1.23 factor, add the airborne flare segment and the braking ground roll, apply the 1.67 certification field length factor, and check the result against the available runway length. Produces the airborne and ground roll legs, the total demonstrated landing distance, the certified field length, and the runway fits verdict that gate the FAR 25.125 landing performance assessment. Trigger: landing distance, Vref approach speed, flare distance, braking ground roll, field length factor, runway length.

0
installs
▌
Takeoff Distance Determination · ashfordeou bundle
Use when you must determine the takeoff distance for a flight test: integrate the measured ground speed samples over the ground roll, add the rotation distance at the rotation speed, and close the airborne climb segment to the 35 ft obstacle height with the climb rate. Produces the ground roll distance, rotation distance, climb distance, and total takeoff distance that gate the takeoff field length assessment. Trigger: takeoff distance, ground roll, rotation speed, 35 ft obstacle, climb segment, flight test.

0
installs
▌
Added Mass Coefficients Potential Flow · ashfordeou bundle
Use when you must determine the added-mass-coefficients-potential-flow virtual mass (apparent mass) of a body accelerating through an inviscid irrotational fluid from the kinetic energy of the irrotational flow it sets up: the 2-D circular cylinder rho pi R^2 and normal flat plate rho pi a^2 per unit span, the 3-D sphere two-thirds rho pi R^3, the elliptic cylinder and the prolate and oblate spheroid coefficients, plus the kinetic-energy and acceleration-reaction relations. Produces the added mass of the requested shape, its ratio to the displaced fluid mass, the fluid kinetic energy at a translation speed, the virtual mass with the body mass, and the acceleration-reaction force for the fluid inertia of unsteady motion. Trigger: added mass coefficients, virtual mass, apparent mass, acceleration reaction force, kinetic energy of irrotational flow, body accelerating in fluid, airship hull added mass, ditching float added mass, spheroid added mass.

0
installs
▌
Rotorcraft Forward Flight Performance · ashfordeou bundle
Use when you must compute the forward-flight power required of a rotorcraft rotor with momentum-theory inflow: the Glauert induced velocity at a given flight speed, the induced power, the parasite power from the equivalent flat-plate drag area, the profile power from rotor blade solidity and tip speed, and the total power, then find the best endurance speed (minimum total power) and the best range speed (minimum power per unit speed) over a speed sweep. Produces the forward induced velocity, the three power components, the total power curve, and the two characteristic speeds that gate a rotorcraft cruise performance assessment. Trigger: rotorcraft forward flight, glauert inflow, induced power model, parasite power, equivalent flat plate area, best endurance speed, best range speed, rotor profile drag.

0
installs
▌
Rotorcraft Vertical Climb Performance · ashfordeou bundle
Use when you must compute the vertical climb performance of a rotorcraft rotor with axial momentum theory: the climb induced velocity from the hover induced velocity and the climb rate, the induced power through an induced power factor, the total rotor power required in a vertical climb as induced plus profile power, and the maximum vertical rate of climb for an available shaft power. Produces the induced velocity in climb, the climb power required, the climb power margin and the maximum vertical rate of climb that gate a rotorcraft climb check at a chosen density altitude. Momentum theory only: uniform inflow, no ground effect, climb only. Trigger: rotorcraft vertical climb performance, axial momentum theory, climb induced velocity, rotorcraft climb power, vertical rate of climb, available shaft power, climb power margin.

0
installs
▌
Fault Tree Importance Measures · ashfordeou bundle
Use when you must rank basic events of a fault tree by importance: compute the Birnbaum measure, the Fussell-Vesely measure, the risk achievement worth (RAW) and the risk reduction worth (RRW) of each basic event from the minimal cut sets and the basic-event probabilities, sort the events by each measure, and flag the dominant contributors above a Fussell-Vesely threshold. Produces the per-event measure dict, the sorted rank list and the dominance list that gate risk-reduction prioritization. Trigger: basic event ranking, birnbaum importance, fussell-vesely importance, risk achievement worth, risk reduction worth, top event sensitivity, dominant contributor.

0
installs
▌
Interacting Multiple Model Filter · ashfordeou bundle
Use when you must track a maneuvering target with an interacting multiple model filter: run a two-mode IMM bank of constant velocity (CV) and constant acceleration (CA) Kalman filters per planar axis, mix the mode-conditioned estimates through the Markov mode-transition probabilities, refresh mode probabilities from innovation likelihoods, and combine the per-mode estimates into the mixed state estimate. Produces mode probabilities that gate maneuver detection, per-mode estimates, the combined estimate and position error history on a scripted maneuvering track. Hand-coded stdlib matrices, deterministic, offline. Trigger: interacting multiple model filter, imm filter, mode probability, Markov mode switching, maneuvering target tracking.

0
installs
▌
Additive Manufacturing Qualification · ashfordeou bundle
Use when qualifying a powder bed fusion or directed energy deposition build, when a build parameter change needs energy density re-verification, or when preparing the AM qualification record and witness coupon plan. Define and validate the additive manufacturing process parameter set for aerospace parts: record the layer height, laser power, scan speed, and hatch spacing, compute the volumetric energy density from those four build parameters, size the witness coupon sample plan for material property verification, and check the additive manufacturing qualification record for first article completeness. Trigger: additive manufacturing, volumetric energy density, laser power, scan speed, hatch spacing, layer height, witness coupon, powder bed fusion, AM build parameter.

0
installs
▌
Fault Tree Uncertainty Analysis · ashfordeou bundle
Use when you must quantify the epistemic uncertainty band around a quantified fault-tree probability: convert each basic-event lognormal error factor to a lognormal sigma with the 90 percent normal quantile, combine the per-event sigmas into the lognormal sigma of the tree probability weighted by the Fussell-Vesely fractions, form the two-sided 90 percent lognormal-confidence-band around the top probability, compute the exceedance-probability of the true value above a target probability, and decompose the variance of the spread into per-event uncertainty-variance-shares. Produces the per-event sigmas, the combined sigma, the band bounds, the exceedance probability and the variance shares that gate confidence in a top-event number. Trigger: fault-tree uncertainty analysis, lognormal error factor, lognormal confidence band, uncertainty variance share.

0
installs
▌
Equivalent Level Of Safety · ashfordeou bundle
Use when you must develop an Equivalent Level of Safety (ELOS) finding for a civil aircraft or system certification item that cannot show literal compliance with an applicable airworthiness regulation paragraph: state the regulation intent and its safety objective, quantify or qualify the achieved safety level of the design, list the compensating measures that close the gap, compute the safety margin against the numeric probability target (25.1309 catastrophic 1e-9 per flight hour) when the rule is quantitative, and return the finding recommendation (finding recommended, conditional, or not supportable) with the reasons list. Produces the per-item ELOS assessment with margin, compensation coverage and the verdict that gates the certification finding package. Trigger: equivalent level of safety, ELOS finding, deviation finding, regulation intent, compensating measure, non-literal compliance, safety margin, 21.21.

0
installs
▌
Engine Failure Takeoff Flight Test · ashfordeou bundle
Use when you must reduce the engine-out takeoff flight test: locate the engine failure point in the measured ground run at the failure speed VEF, add the V1 recognition time segment, integrate the continued takeoff to the 35 ft obstacle at the measured engine out climb rate, and set the decision speed V1 at the balanced field intersection where the stop distance curve equals the continued engine out takeoff distance curve. Produces the engine failure distance, the recognition distance, the continued engine out distance, the balanced field V1 and distance, and the runway fit verdict. Trigger: balanced field, engine out takeoff, decision speed V1, VEF, engine failure flight test, 35 ft obstacle, takeoff field length, field length verdict.

0
installs
▌
Rotorcraft Performance Flight Test · ashfordeou bundle
Use when you must reduce a rotorcraft performance flight test from measured data: convert measured main rotor torque and rotor speed into shaft power, compute the measured figure of merit from the ideal induced power and the measured power, correct measured hover power to a reference weight and density altitude with the induced and profile fraction split, correct a measured vertical rate of climb for the test weight, reduce hover power-required points measured across density altitudes to a hover ceiling against the available power, and check the test day against the flight manual limits. Produces the measured power, measured figure of merit, corrected power, corrected vertical rate of climb, the OGE and IGE hover ceiling altitudes, and the test verdict that gate the flight test report. Trigger: rotorcraft-performance-flight-test, rotorcraft-hover-flight-test, measured-figure-of-merit, torque-to-power, hover-ceiling-determination, weight-density-correction.

0
installs
▌
Special Process Qualification · ashfordeou bundle
Use when a special process must be qualified rather than inspected, when a process change triggers requalification, or when preparing for NADCAP accreditation or AS9100 production control. Assess special process qualification in aerospace manufacturing: determine whether a welding, heat treatment, NDT, surface finishing, or composites process stays qualified under a proposed change by classifying the change type (parameter, equipment, personnel, time interval) against the qualified envelope and the process qualification record, and build or validate the record checklist of parameters with ranges, variables, qualification date, and validity. Trigger: special process, qualification, requalification, process qualification record, NADCAP, heat treat, welding, process control.

0
installs
▌
Operating Support Hazard Analysis · ashfordeou bundle
Use when you must run or review the operating and support hazard analysis (O&SHA) for an aircraft or system per ARP4761A: identify hazards from operational scenarios and maintenance tasks, score each hazard on the severity by likelihood risk matrix, assign the risk index and acceptability band, and flag safety critical maintenance tasks for the hazard log. Produces the scored hazard register, the acceptability verdict per hazard, and the critical task list that feed the system safety assessment. Trigger: operating and support hazard analysis, O&SHA, maintenance hazard, ground operations hazard, risk matrix, hazard log, critical task.

0
installs
▌
Rotorcraft Autorotation Flight Test · ashfordeou bundle
Use when you must reduce a rotorcraft power-off autorotation demonstration flight test: least-squares fit the telemetered pressure-altitude samples against time over the steady autorotative descent, read the measured sink rate from the fitted slope, run the rotor-RPM checks across the entry decay, steady descent and flare recovery against the declared floor, band and recovery target, compute the altitude lost to the recovery from the flare-initiation and re-established level-flight altitudes, and give the PASS or FAIL verdict per check plus the overall demonstration verdict. Produces the fitted slope, intercept and R-squared, the measured sink rate in the realistic 8 to 15 m/s autorotative band, the three rotor-RPM check verdicts, the altitude loss with its limit verdict and margin, and the overall verdict gating the demonstration. Trigger: rotorcraft-autorotation-flight-test, measured-sink-rate, rotor-rpm-band-check, autorotation-demonstration-reduction, flare-altitude-loss.

0
installs
▌
Rotorcraft Blade Element Hover Performance · ashfordeou bundle
Use when you must determine the blade-element hover performance of a helicopter main rotor: the thrust coefficient from the collective pitch schedule, rotor solidity, lift-curve slope and Betz tip loss factor, the inflow ratio from the uniform-inflow hover closure, the collective pitch required to hover at a target thrust coefficient, the torque coefficient with its induced and profile split, and the rotor shaft torque, shaft power and hover figure of merit from the coefficients. Produces a hover blade-element summary and a collective pitch polar across the pitch range of the same rotor. Trigger: blade element theory, thrust coefficient, torque coefficient, collective pitch, tip loss factor, hover figure of merit.

0
installs
▌
Rotorcraft Forward Flight Climb Test · ashfordeou bundle
Use when you must reduce a rotorcraft forward-flight climb flight test from measured data: reduce the measured rate of climb from the least-squares pressure-altitude windows of the steady climb runs across the airspeed sweep, convert the calibrated airspeeds to true airspeed at the test density, correct the measured rate of climb to the reference weight and the standard day with the rho/weight ratio law, identify the best-rate-of-climb speed Vy at the peak of the corrected rate-of-climb curve, and reduce the Vy-schedule climb runs across density altitudes to the service ceiling at the 0.5 m/s rotorcraft convention. Produces the corrected rates of climb, Vy, the maximum rate of climb and the climb ceilings that gate the rotorcraft climb flight test assessment. Trigger: rotorcraft-forward-flight-climb-test, rotorcraft climb flight test, best-rate-of-climb speed, measured rate of climb, climb ceiling determination.

0
installs
▌
Preliminary System Safety Assessment · ashfordeou bundle
Use when conducting the preliminary system safety assessment (PSSA) per ARP4761A: derive safety requirements from FHA outcomes, allocate function and item development assurance levels (FDAL/IDAL) to the proposed system architecture, and apportion the quantitative safety target for each failure condition across the contributing channels and functions. The PSSA uses fault tree, failure mode, and common cause analysis style arguments to show that the architecture can meet the quantitative safety targets before implementation, then hands the allocated safety requirements and derived requirements to the system safety assessment (SSA) for verification against the implemented system. Trigger: preliminary system safety assessment, PSSA, ARP4761A, safety target allocation, FDAL, IDAL, development assurance level, quantitative safety requirement, redundant channel allocation.

0
installs
▌
Rotorcraft Height Velocity Diagram Test · ashfordeou bundle
Use when you must reduce a rotorcraft height-velocity (dead-man-curve) demonstration flight test from the hover and low-speed engine-failure runs: measure the recognition delay, the height loss and time to establish autorotation and complete the flare or landing from the baro/radar altitude traces, apply the reaction time allowance, interpolate the dead-man-curve boundary height where height loss plus recovery altitude equals the starting height at each speed, build the avoid-region map over the height and speed grid, and compare it against the predicted height-velocity diagram for the clearance verdict. Produces the recognition delay, the establishment and recovery times, the height-loss split with the flare and recovery altitudes, the boundary heights with and without the reaction allowance, and the per-speed clearance margins and verdicts that gate the demonstration. Trigger: rotorcraft-height-velocity-diagram-test, dead-man-curve boundary, hover engine-failure height-loss.

0
installs
▌
Lateral Directional Stability Flight Test · ashfordeou bundle
Use when you must plan and reduce the static lateral-directional stability flight test from steady-heading sideslip data: build the rudder-fixed and rudder-free sideslip sweep matrix at constant airspeed, fit the rudder and aileron deflection gradients versus sideslip angle, estimate the directional stability from the fitted rudder gradient with a declared rudder control power and the lateral dihedral stability from the fitted aileron gradient with a declared aileron control power, record the pedal-force gradient, and issue the weathercock and dihedral stability verdicts for the stability demonstration. Produces the sweep matrix, the fitted gradients, the signed directional and lateral stability estimates, the pedal-force gradient and the verdicts that gate the demonstration. Trigger: steady-heading sideslip, sideslip sweep, rudder gradient, aileron gradient, rudder-fixed stability, rudder-free stability, weathercock stability, dihedral effect, pedal-force gradient.

0
installs
▌
Msg3 Maintenance Analysis · ashfordeou bundle
Use when you must run the MSG-3 maintenance steering group decision logic to develop a scheduled maintenance program for an aircraft system or component: categorize each failure mode by effect visibility (evident to the flight crew or hidden) and consequence (safety-significant or economic-only), select the applicable scheduled maintenance task categories (lubrication, servicing, operational check, visual check, inspection, functional check, restoration, discard), and assign the interval verdict including the hidden failure exposure rule at half the single-failure interval. Produces the failure category, the recommended task set with rationale, and the interval verdict that gate the maintenance program development handoff. Trigger: MSG-3, maintenance steering group, scheduled maintenance, hidden failure, evident failure, task category selection, exposure rule, interval determination, maintenance program development.

0
installs
▌
Rotorcraft Forward Flight Performance Test · ashfordeou bundle
Use when you must reduce a rotorcraft level-flight performance flight test from measured data: convert measured main rotor torque and rotor speed samples into shaft power across a forward-flight speed sweep, correct the measured power-required polar to a reference weight and standard day with the induced and profile power split, fit the corrected polar, and read off the best-endurance speed at the minimum-power point, the best-range speed at the tangent from the origin, and the maximum level-flight speed Vh against the maximum continuous available power. Produces the measured torque-to-shaft-power values, the corrected polar, the fitted curve coefficients, the best-endurance speed, the best-range speed and the Vh verdict that gate a rotorcraft level-flight performance assessment. Trigger: rotorcraft-forward-flight-performance-test, rotorcraft-forward-flight, level-flight-speed-sweep, torque-to-shaft-power, power-required-polar, vh-determination, max-continuous-power.

0
installs
▌
Ica Cmr Ali Classification · ashfordeou bundle
Use when you must classify certification maintenance items: sort each candidate from certification into airworthiness limitation items (life-limited parts, damage-tolerance inspections, fuel-tank flammability checks), certification maintenance requirements, or routine scheduled maintenance using a fixed certification-driver rule table, then compute the ALS coverage of a maintenance program as matched required items over the total required and check per-item interval compliance against the type-certificate ALS maximum intervals. Produces a per-item verdict with rationale, class counts, the ALS coverage fraction, and the non-compliant and missing ALS item lists. Trigger: airworthiness limitations section, ALS coverage, certification maintenance requirement, life-limited part, damage-tolerance inspection, fuel-tank flammability, instructions for continued airworthiness.

0
installs
▌
Type Certificate Data Sheet · ashfordeou bundle
Use when you must compile and validate a type certificate data sheet: check that every required section is present (models, type design, approved engines and propellers, weights, certification basis, operating limitations, noise standards), validate the weight block consistency (max ramp at or above max takeoff, max landing at or below max takeoff, all positive), validate the category airspeed limitations (transport requires VMO or MMO; normal, utility and acrobatic categories require VNE), check the approved configuration consistency, and diff two revisions of the record into a per-section change summary for type certificate amendment or STC integration review. Produces the missing-section list, the validation error list, the summary counts, and the revision change report. Trigger: type certificate data sheet, TCDS record, type design record, approved engine models, weight block, category airspeed limits, VMO, MMO, VNE, TCDS revision diff.

0
installs
▌
In Service Safety Assessment · ashfordeou bundle
Use when you must assess in-service safety data for a civil aircraft fleet against the type-design safety assessment predictions: collect field events from service difficulty reports and airline reliability reports grouped by failure condition, compute the observed event rate over the fleet exposure, compare it with the predicted rate from the safety objective, apply the single-event rule for hazardous or catastrophic events, and decide whether the experience is safety-significant. Produces the observed rate, the Poisson exceedance statistic, the significance verdict, and the corrective action route (no action, continued monitoring, service bulletin, or airworthiness directive request) with an urgency band. Trigger: in-service safety assessment, continued airworthiness, service difficulty report, field event rate, fleet exposure, observed versus predicted rate, single-event rule, ARP5150, safety significance, airworthiness directive request.

0
installs
▌
Airworthiness Directive Compliance · ashfordeou bundle
Use when you must evaluate airworthiness directive compliance: test each aircraft in an operator fleet against the directive effectivity by affected model and serial range, compute the remaining compliance margin in the directive's own basis (flight cycles, flight hours, or calendar months from the effective date), classify each aircraft as open, due, or overdue against the directive grace band, and roll up the per-directive fleet compliance report with applicable, open, due and overdue counts and the strict compliance rate. Produces per-aircraft statuses and the fleet report. Trigger: airworthiness directive, AD applicability, directive effectivity, compliance margin, compliance time remaining, grace band, due aircraft, overdue aircraft, fleet compliance report, mandatory airworthiness action.

0
installs
▌
Notch Sensitivity · ashfordeou bundle
Use when a hole, fillet, or other stress raiser must be accounted for in a fatigue assessment of a structure. Compute the stress concentration factor and fatigue notch factor for a notched aerospace part: determine Kt for an elliptical or circular hole from the geometry, estimate the Peterson material constant from the ultimate tensile strength, convert Kt into the fatigue notch factor Kf with the Peterson and Neuber corrections using the notch root radius, evaluate the notch sensitivity q, and apply the effective stress amplitude to the fatigue strength check. Trigger: stress concentration factor, fatigue notch factor, notch sensitivity, Neuber, Peterson, notch root radius, effective stress amplitude.

0
installs
▌
Stress Life Curve · ashfordeou bundle
Use when S-N test data must be reduced to a Basquin curve, an endurance limit must be determined from runout tests, or a fatigue life must be predicted from a stress amplitude for a structure. Determine the stress-life (S-N) fatigue curve from test data and use it for fatigue life prediction: fit the Basquin equation S = A * N^b to the S-N test points by log-log regression, read the endurance limit from the runout stress level, and predict the cycles to failure at a given stress amplitude or the allowable amplitude for a required life. Trigger: stress-life-curve, sn-curve, basquin-equation, endurance-limit, fatigue-life-prediction, sn-data.

0
installs
▌
Shear Center Analysis · ashfordeou bundle
Use when you must locate the shear center of a thin-walled open section under transverse shear: walk the contour from the free edge accumulating the first moment Q, build the V*Q/I shear-flow distribution, integrate the wall-shear resultant and its moment, and report the shear-center offset from the web, centroid or corner in millimeters for channel, Z, angle, hat and slit single-cell box sections, with the bending shear-stress check tau = V*Q/(I*t) at the critical wall station. Doubly symmetric I-beam and closed box sections carry the shear center at the centroid by symmetry, so the leaf reports their web shear-flow maximum instead. Produces the shear-center coordinates, the offset from the stated reference, the per-wall shear flow q(s) and the vertical-resultant equilibrium check that gate open-section spar, stiffener and frame design. Trigger: shear center, shear flow, channel section, Z-section, angle section, thin-walled spar, stiffener, I-beam web shear, transverse shear.

0
installs
▌
Gust Maneuver Loads · ashfordeou bundle
Use when you must compute aircraft structural loads from gust and maneuver conditions per FAR 25.341 and FAR 25.337: discrete 1-cosine gust load factor n = 1 + (rho0*V_e*a*K_g*U_de)/(2*W/S), gust alleviation factor K_g = 0.88*mu_g/(5.3+mu_g) with mass ratio mu_g = 2*(W/S)/(rho*cbar*a*g), limit maneuvering load factor 2.5 (normal) or 3.8 (commuter/transport) at VA with linear variation to 0 at VD, V-n diagram construction with the corner point at VA and gust lines at VB/VC/VD, envelope verdicts and margin checks. Produces the V-n diagram, gust and maneuver load factors, and pass/fail envelope margins. Trigger: gust loads, maneuver loads, gust load factor, V-n diagram, flight envelope, FAR 25.341, FAR 25.337, discrete gust, 1-cosine gust, gust alleviation factor, mass ratio, load factor, corner point, maneuvering speed, VA VB VC VD, margin check.

0
installs
▌
Battery Sizing · ashfordeou bundle
Use when you must size the traction battery pack of an electric aircraft or eVTOL from the mission energy and power requirements: convert the mission draw into the required pack energy with the depth of discharge limit and discharge efficiency, add the reserve, lay out the series and parallel cell counts for the target pack voltage, check the discharge C-rate against the cell limit, verify the minimum cell voltage under peak load against the cutoff with the cell internal resistance, and estimate pack mass and volume from typical cell and pack energy densities. Produces series and parallel cell counts, pack energy, the C-rate and voltage drop verdicts, and mass and volume estimates that gate vehicle energy storage sizing. Trigger: battery pack sizing, electric aircraft battery, eVTOL energy storage, traction battery, C-rate check, depth of discharge, series parallel cell count, pack voltage, discharge voltage drop.

0
installs
▌
Nacelle Sizing · ashfordeou bundle
Use when the task is nacelle geometric sizing, inlet capture and highlight sizing, cowl thickness, wetted area, or nacelle drag bookkeeping for a high bypass turbofan. Size the engine nacelle geometry for a turbofan: derive the fan face area and diameter from the fan mass flow, density, Mach number and temperature; enlarge the fan face to the inlet highlight area with the lip area ratio; compute the free stream capture area and the A0/A1 capture area ratio at the flight Mach number; scale the nacelle length from the fan diameter with a length to diameter ratio; set the cowl maximum thickness from a thickness to chord ratio; estimate the cowl wetted area with a shape factor; and bookkeep the nacelle drag into friction, form and interference components. Trigger: nacelle sizing, inlet highlight, fan face area, capture area ratio, cowl thickness, wetted area, nacelle drag.

0
installs
▌
Spoiler Sizing · ashfordeou bundle
Use when you must size the flight and ground spoiler panels of a transport aircraft: split roll authority between the primary roll channel and the roll spoilers from the roll rate and damping derivative, size flight spoiler panel area and deflection for the roll assist share, size the ground spoiler lift dumper area from the touchdown lift dump, estimate the speed brake and lift dump drag increments, compute the spoiler hinge moment for the actuator, and check the limits. Produces spoiler areas, deflections, drag increments, hinge moments, and a sized verdict. Trigger: spoiler sizing, flight spoiler, ground spoiler, lift dump, speed brake, roll spoiler, roll assist share, spoiler panel area, lift dumper, spoiler deflection.

0
installs
▌
Airfoil Geometry · ashfordeou bundle
Use when you must work with classic NACA airfoil geometry: decode NACA 4-digit, 5-digit, and 6-series designations into camber, camber position, and thickness; compute the 4-digit thickness distribution, mean camber line ordinates and slope; and derive leading-edge radius and section area from the public-domain NACA formulas. Produces the geometry parameters that feed section selection, structural depth checks, and coordinate generation for panel or CFD analysis. Trigger: naca airfoil, camber, thickness distribution, mean line, leading edge radius, section area, airfoil coordinates.

0
installs
▌
Oblique Shock · ashfordeou bundle
Use when you must analyze an oblique shock in supersonic compressible flow: compute the wave angle beta from the upstream Mach number M1 and the flow deflection angle theta with the theta-beta-M relation, find the weak and strong solutions, the maximum deflection angle for an attached shock, and the downstream Mach number, static pressure, density, temperature, and stagnation pressure ratios across the shock. Covers shock polar basics: the weak branch keeps the flow supersonic with little stagnation pressure loss, the strong branch goes subsonic, and a deflection above the limit detaches the shock. Produces the wave angle, downstream state, and deflection limit for wedge, compression-corner, and inlet analyses. Trigger: oblique shock, shock wave, wave angle, deflection angle, theta-beta, wedge, compression corner, detached shock, shock polar, weak solution, strong solution, supersonic flow.

0
installs
▌
Prandtl Meyer · ashfordeou bundle
Use when you must compute Prandtl-Meyer expansion relations for supersonic compressible flow: derive the expansion angle from the Mach number, find the downstream Mach number after the flow turns away from itself by a given angle, compute the total turning angle across the expansion fan, and the static pressure ratio across it. Produces the Prandtl-Meyer angle, the downstream Mach number, the turning angle, and the pressure ratio that gate supersonic airfoil, inlet, and nozzle analysis. Trigger: prandtl-meyer, expansion fan, mach number, supersonic flow, turning angle, compressible flow.

0
installs
▌
Rayleigh Flow · ashfordeou bundle
Use when you must compute the rayleigh-flow state change of a perfect gas heated or cooled in a constant-area frictionless duct: convert the inlet Mach number into the Rayleigh-line ratios against the sonic state T/T*, p/p*, rho/rho*, T0/T0*, p0/p0*; find the maximum heat addition that thermally chokes the duct from a subsonic or supersonic inlet Mach number, q_max = cp*T1*(1 - M^2)^2/(2*(gamma+1)*M^2); recover the exit Mach number after a given heat addition per unit mass on the inlet branch; and report the entropy rise from the second law. Produces the station ratio set, the choking heat addition, the exit Mach and stagnation pressure ratio, and the entropy rise, in SI units, that gate the heat-addition duct assessment. Trigger: heat addition duct, thermal choking, rayleigh flow, rayleigh line, constant area frictionless duct.

0
installs
▌
Airworthiness Liaison · ashfordeou bundle
Use when you must manage DO-178C airworthiness and certification liaison for an airborne software item: confirm the certification basis items with evidence, score stage-of-involvement audit readiness against the software level threshold, and track open liaison items to closure before authority audits. Produces the certification-basis coverage account, the SOI readiness verdict, and the open-item action flags that keep the certification plan on schedule. Trigger: airworthiness liaison, certification liaison, soi audit, certification basis, authority communication, audit readiness.

0
installs
▌
Power Analysis · ashfordeou bundle
Use when you must determine the sample size or the statistical power of a planned comparison: compute the minimum sample size per group for a two-sample pooled z-based comparison at a significance level, target power and effect size, with the one-sample and one-sample-proportion variants, round up to whole groups, and evaluate the achieved power at the rounded sample size. Produces the per-group sample size, the total sample size and the achieved power that gate qualification-test planning and experiment sizing. Trigger: power analysis, minimum sample size, sample size per group, statistical power, achieved power, type II error, effect size, half sigma shift, eighty percent power, two-sample comparison, qualification-test planning.

0
installs
▌
Skill Authoring · ashfordeou bundle
Use when you must author a NEW conformant SKILL.md for the agentskills.io format under SEP-2640-style delivery: build the frontmatter template from the required fields (name kebab-case matching the folder, description with action and use-when and trigger clauses, Apache-2.0 license, compliance flag, standards references, gated boolean, metadata version and author), then run the deterministic pre-publish conformance check that reports missing or invalid required fields before a leaf is published. SEP-2640 stays an emerging spec, so the authoring discipline targets the stable agentskills.io content surface. Trigger: skill authoring, SKILL.md template, frontmatter, kebab-case name, pre-publish conformance check, SEP-2640, agentskills.io.

0
installs
▌
Adaptive Control · ashfordeou bundle
Use when you must design and simulate a model-reference adaptive controller (MRAC) for a first-order plant with an unknown plant coefficient: run the reference model from the command, form the control as the sum of a state-feedback term and a feedforward term with adaptive gains, update the gains online with the gradient (Lyapunov-motivated) adaptation law scaled by the tracking error, and assess convergence of the tracking error and of the gains toward the ideal-cancellation values. Produces the error history, the gain histories and the convergence verdict that gate an adaptive control assessment. Trigger: adaptive-control, mrac, model-reference-adaptive, adaptation-law, tracking-error, unknown-plant.

0
installs
▌
Deadbeat Control · ashfordeou bundle
Use when you must design a deadbeat-control law for a discrete-time plant given by its pulse transfer function: verify admissibility for direct deadbeat synthesis (every plant pole and zero strictly inside the unit circle), solve the deadbeat design equation that places every closed loop pole at the origin of the z plane, form the finite-settling-time controller difference equation from the plant polynomials, and simulate the closed loop to confirm the output reaches and holds the reference in the minimum number of sample periods with the minimum-settling-time control sequence. Produces the admissibility verdict, the controller coefficients, the settling sample and settling time, the step response and control effort histories, the steady-state tracking check and the control effort summary that gate a deadbeat digital control assessment. Trigger: deadbeat-control, finite-settling-time, pole-placement-at-origin, minimum-settling-time, z-domain-deadbeat.

0
installs
▌
Gnss Raim Fde · ashfordeou bundle
Use when you must run receiver autonomous integrity monitoring (RAIM) fault detection and exclusion on an overdetermined GNSS pseudorange measurement set: build the geometry matrix H from satellite line-of-sight unit vectors, solve the overdetermined least-squares navigation solution, form the residual test statistic and compare it against a chi-square threshold at 1e-5 false-alarm probability, compute the horizontal protection level from the worst-case satellite slope, and identify the faulty satellite by the largest normalized residual for exclusion. Produces the detection verdict, the horizontal protection level, and the excluded-satellite recommendation that gate a GNSS integrity and availability assessment. Trigger: RAIM, receiver autonomous integrity monitoring, fault detection and exclusion, horizontal protection level, chi-square threshold, normalized residual, GNSS integrity.

0
installs
▌
Ilqr Ddp · ashfordeou bundle
Use when you must run iterative LQR / differential dynamic programming (ilqr-ddp) on a nonlinear discrete-time system: roll the nominal control forward through the two-state soft-landing dynamics under gravity and quadratic drag, run the backward Riccati pass that forms the value-function quadratics Qx, Qu, Qxx, Qux, Quu and the local affine control law u = ubar + K(x - xbar) + k at each step, and execute the forward pass with backtracking line search and regularization until the total cost converges. Produces the converged control sequence, the touchdown state of the constant-descent-rate landing, the feedforward and feedback gain sequences, the per-iteration cost, alpha and mu traces, and the model-versus-actual improvement comparison gating the optimal soft-landing trajectory. Trigger: ilqr-ddp, differential dynamic programming, iterative LQR, backward Riccati pass, local affine control law, forward rollout, nonlinear soft-landing flare.

0
installs
▌
Rendezvous Phasing · ashfordeou bundle
Use when you must plan an orbital rendezvous phasing maneuver: compute the drift rate needed to cover a phase angle in a transfer time, size the phasing delta-v around a circular orbit, and check the closing rate against the allowed value. Produces the drift rate, the delta-v estimate, and the closing rate verdict that gate the maneuver plan. Trigger: rendezvous, phasing orbit, closing rate, orbital maneuver, delta-v, chase.

0
installs
▌
Diesel Cycle · ashfordeou bundle
Use when you must compute the operating point of a reciprocating compression-ignition aircraft powerplant: the air-standard Diesel cycle thermal efficiency from the compression ratio, the specific-heat ratio and the cutoff ratio of the constant-pressure heat-addition model, the isentropic compression temperature ratio and state temperatures, the four-stroke indicated power from the indicated mean effective pressure, displacement and crankshaft speed, the brake power at the mechanical efficiency, and the brake specific fuel consumption from the fuel flow and the brake power on Jet-A. Produces the single-point summary dict with the ideal Diesel cycle efficiency, the state temperatures, indicated and brake power, BSFC in both units, thermal efficiencies, volumetric fuel flow and the reference-only compression-ignition band verdict, the bands reported and never enforced. Trigger: diesel-cycle, air-standard-diesel-cycle, compression-ignition, cutoff ratio, jet-a-fuel-cycle.

0
installs
▌
Hybrid Rocket Motor · ashfordeou bundle
Use when you must size and analyze a hybrid rocket motor burning a solid fuel grain with a fluid oxidizer: compute the fuel regression rate from the oxidizer mass flux, solve the oxidizer to fuel ratio, find the chamber pressure equilibrium with the choked nozzle discharge, derive the mass flow, thrust and total impulse, and judge the O/F shift as the port opens. Reference-only typical HTPB grain constants cover the nitrous oxide and liquid oxygen oxidizers. Produces the ballistics summary with the O/F ratio, chamber pressure, burn time, thrust, impulse and the O/F shift trend. Trigger: hybrid rocket motor, regression rate, solid fuel grain, oxidizer to fuel ratio, O/F shift, HTPB, hybrid grain.

0
installs
▌
Rocket Engine Cycle · ashfordeou bundle
Use when you must assess liquid rocket engine feed cycles at a fixed thrust, chamber pressure, and propellant pair: compare pressure-fed against the pump-fed gas-generator, staged-combustion, and expander cycles, compute the pump discharge pressure, the oxidizer and fuel pump powers, the turbine drive power and the cycle power balance, and size the pressure-fed feed-tank mass penalty. Produces the feasible cycle set, pump and turbine power balance, drive mass fraction, tank mass penalty, and a cycle selection verdict. Trigger: rocket-engine-cycle, feed-cycle, gas-generator cycle, staged-combustion, expander-cycle, pressure-fed, pump-fed, pump-power, turbine-power.

0
installs
▌
Rocket Gravity Loss · ashfordeou bundle
Use when you must account for gravity loss in a launch-vehicle powered ascent: compute the burn time from the propellant load and its flow rate, the launch thrust-to-weight ratio from the sea-level thrust and the initial mass, the gravity loss as g0 times the burn time for a vertical ascent or as g0 times the burn time times the sine of a constant mean flight-path angle for a pitched ascent, and the effective ascent delta-v as the ideal delta-v minus the gravity and drag losses. Produces the burn time, launch thrust-to-weight ratio, gravity loss and effective ascent delta-v that turn an ideal delta-v budget into an ascent-feasible requirement. Trigger: gravity loss, powered ascent, launch vehicle ascent, burn time, thrust-to-weight ratio, vertical ascent, pitched ascent, effective delta-v.

0
installs

671 published skills · page 2 of 7