ashfordeOU

@ashfordeou source repo

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Load Spectrum Counting · ashfordeou bundle
Use when you must build a fatigue load spectrum from a mission load history: count cycles with the rainflow method, derive level-crossing and exceedance spectra, aggregate per-phase loads into a mission spectrum, apply spectrum truncation, and evaluate cumulative damage with Miner's rule on a Basquin S-N curve. Produces the rainflow cycle counts, the exceedance spectrum table, the truncated spectrum, and the cumulative damage fraction that gate the fatigue life assessment. Trigger: rainflow, cycle counting, exceedance spectrum, level crossing, load spectrum, mission profile, spectrum truncation, fatigue life.

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Cylindrical Shell Buckling · ashfordeou bundle
Use when you must compute the buckling of a curved unstiffened circular cylindrical shell with the NASA SP-8007 knockdown method: the axial-compression knockdown factor from the shell radius and thickness, the axial critical buckling stress 0.605*gamma*E*t/r, the bending knockdown factor, the bending critical moment, the cross-section ovalization collapse moment, and the plasticity correction factor. Produces the knockdown factors, the critical stress and moments, and the governing verdict between bifurcation and ovalization collapse for a curved-shell stability check. Trigger: cylindrical shell buckling, SP-8007 knockdown, shell axial compression, cylinder bending, ovalization collapse, curved panel stability, fuselage barrel buckling.

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Brake Energy Sizing · ashfordeou bundle
Use when you must size the aircraft wheel brake system from the kinetic energy it must absorb: compute the rejected-takeoff (RTO) brake energy at the decision speed and the landing-stop brake energy at the touchdown speed, divide the total energy over the braked wheels, estimate the required carbon heat sink mass per brake from the allowable temperature rise and the specific heat, check the temperature rise of the selected heat sink, and estimate the braking distance at the design deceleration. Produces the RTO and landing energies, the per-brake energy, the governing case, the required heat sink mass, the temperature rise and margin, the braking distance, and the pass or fail verdict that gates the wheel brake sizing. Trigger: brake energy sizing, rejected takeoff energy, wheel brake heat sink, carbon brake mass, brake temperature rise, braking distance at V1, rto brake energy, landing stop brake energy.

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Landing Gear Layout · ashfordeou bundle
Use when you must lay out the landing gear arrangement of an aircraft against its center-of-gravity envelope: compute the tipback angle at the aft CG limit about the main gear contact, the tail strike clearance angle at rotation, the lateral turnover angle from the wheel track at the forward CG limit, and the nose gear load fraction band across the CG travel. Produces the three layout angles in degrees, the nose gear load fraction at the forward and aft CG limits with band verdicts, and the main gear position check that gate the landing gear configuration. Trigger: landing gear layout, tipback angle, tail strike clearance, lateral turnover, nose gear load fraction, main gear position, wheel track, CG travel limits.

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Landing Gear Sizing · ashfordeou bundle
Use when you must size the landing gear for an aircraft at the sizing level: split the maximum landing weight over the struts, compute the nose and main gear loads from the CG position and the wheelbase, size the shock absorber stroke from the sink speed and the landing load factor, and check the tire rating margin. Produces the static loads, the required stroke, and a gear sized or tire overloaded verdict that gate the landing gear configuration. Trigger: landing gear, strut load, wheelbase, nose gear, main gear, shock absorber stroke, sink speed, tire rating, landing load factor.

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Bow Shock Standoff · ashfordeou bundle
Use when you must estimate the detached bow-shock standoff distance ahead of a blunt nose: compute the standoff ratio Delta over R with the classical Billig-form correlations for a sphere nose and a circular cylinder leading edge at gamma 1.4, convert the ratio to a physical standoff distance for a given nose radius, and report the trend checks that the standoff decreases with Mach and that the cylinder standoff exceeds the sphere standoff at the same Mach. Produces the standoff ratio, the standoff distance and the sanity flags that gate blunt-body nose-radius trades and shock-layer thickness estimates. Trigger: bow shock standoff, billig correlation, stagnation streamline, shock layer thickness, detached shock distance, blunt body nose radius.

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Mil Std 1553 Bus Loading · ashfordeou bundle
Use when you must compute the MIL-STD-1553 bus loading: convert a minor-frame message schedule into wire-word counts per message type (command and status overhead plus data words), apply the fixed 24 microsecond word slot at the 1 Mbps data rate, sum the schedule time, and return the bus utilization against the minor-frame length with an 80 percent loading guideline verdict. Produces per-message wire words and time, the schedule total, the percent utilization, the headroom to the 80 percent budget, and a FITS or OVER verdict. Trigger: mil std 1553 bus loading, minor frame schedule, wire word count, bus utilization, data bus load, bc to rt, rt to bc, rt to rt, message overhead, loading headroom.

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Environmental Qualification · ashfordeou bundle
Use when planning or reviewing DO-160 environmental qualification of airborne equipment: map equipment categories to applicable test-condition sections (temperature, altitude, humidity, vibration, EMC, lightning, and others), verify that the planned test matrix covers every required section, and check operating-temperature ranges per equipment category. Section names and typical category temperature ranges are provided as reference data, with category-specific exclusions to be confirmed against the current revision; all logic is deterministic, offline stdlib. Trigger: DO-160, environmental qualification, test conditions, temperature, altitude, vibration, EMC, lightning, humidity, equipment category.

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Flight Planning · ashfordeou bundle
Use when you must build and check a flight management system flight plan: compute great-circle leg distances between waypoints, verify the vertical profile against crossing constraints, and total the track distance for fuel and time planning. Produces the leg distance check, the vertical constraint verdict, and the flight plan validity flag that gates dispatch planning. Trigger: flight planning, flight management system, waypoints, vertical profile, track distance, fms.

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Deadline Monotonic Scheduling · ashfordeou bundle
Use when you must decide the fixed-priority schedulability of an avionics flight software task set whose per-task relative deadlines are not the implicit period: order the tasks by deadline-monotonic priority assignment so the shorter deadline ranks higher, run the exact jitter-aware fixed-point response-time iteration against each task's own deadline, and cover constrained deadlines (D no greater than T) and arbitrary deadlines (D beyond T) with the busy-period job scan when a queued job can be the worst. Produces the deadline-monotonic priority order, the per-task worst-case response times against the per-task deadlines, the release-jitter recomputation when a higher-priority task carries release jitter, the feasible verdict for the whole set, and the divergence verdict when an iterate or a queued job's response crosses its deadline. Trigger: deadline monotonic scheduling, constrained deadline, arbitrary deadline, release jitter, relative deadline, shorter deadline priority.

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Exact Binomial Test · ashfordeou bundle
Use when you must test an observed count against a hypothesized proportion: compute the exact binomial tail probability of k or fewer successes in n trials under a null proportion p zero, form the two-sided p-value by doubling the one-sided tail mass capped at one with an optional mid-p variant and a continuity-corrected normal cross-check, and decide the verdict against a significance level. Produces the exact p-value, the lower and upper tail masses, the observed direction, and the small-count recommendation that gate attribute-data significance claims. Trigger: exact binomial test, binomial tail probability, k of n successes, single proportion significance, mid p correction, attribute data significance.

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Grubbs Outlier Test · ashfordeou bundle
Use when you must test a normal sample for a single outlier: compute the sample mean and standard deviation, form the Grubbs G statistic as the largest absolute deviation from the mean divided by the sample standard deviation, compare it against the two-sided 0.05 critical value for the sample size from an embedded reference table with linear interpolation between listed sizes, and report the outlier verdict with the flagged value. Produces the G statistic, the critical value, the reject or no-outlier verdict, the rejected value and index, and the mean and standard deviation, screening a measured data set for one spurious reading before further statistical work. Sibling leaves cover screening without a probability model, parametric significance tests, rank-based procedures, and ordering-randomness tests. Trigger: grubbs-outlier-test, grubbs g statistic, single-outlier-test, grubbs critical value, outlier screening of measured data, normal sample spurious reading check.

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Information Entropy · ashfordeou bundle
Use when you must compute the information content of a symbol distribution: the Shannon entropy in bits per symbol of a measured count distribution or probability mass function, the binary entropy function of a two-symbol source, the uniform-distribution entropy bound log2 of the symbol count, and the minimum source-coding bit rate as entropy times symbol rate. Produces the entropy, the uniform bound, the redundancy verdict against it, and the minimum bit rate that gates data-channel and quantization assessments. Pure Python stdlib, deterministic. Trigger: information-entropy, shannon-entropy, binary-entropy-function, source-coding-bound, information-content, telemetry symbol distribution, source coding bit rate, symbol distribution entropy.

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Kruskal Wallis Test · ashfordeou bundle
Use when you must compare three or more independent groups without the normality assumption: run the Kruskal-Wallis test by merging all observations, assigning average ranks for ties, computing the H statistic, applying the ties correction denominator, evaluating the p-value from the chi-square survival function with k minus 1 degrees of freedom, and returning the verdict at the chosen significance level. Produces H, the ties-corrected H, degrees of freedom, p-value, per-group rank sums and the gate verdict for non-normal group data. Trigger: kruskal wallis test, h-statistic, distribution-free k sample significance, rank-based multi-group comparison, chi-square survival p-value, coating batch roughness, process temperature settings.

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Density Altitude · ashfordeou bundle
Use when you must compute the density altitude from the pressure altitude and the outside temperature: the ISA deviation, the density ratio sigma from the ISA pressure ratio and the temperature ratio, and the density altitude via the troposphere closed-form inverse with the stratosphere branch. Produces the density altitude in meters and feet for hot-day and cold-day takeoff and performance checks. Trigger: density altitude, pressure altitude, outside air temperature, non-standard day, ISA deviation, density ratio, hot day, cold day, takeoff performance, performance reduction.

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Breguet Range · ashfordeou bundle
Use when you must estimate the cruise range of a transport aircraft with the Breguet range equation: combine speed, thrust specific fuel consumption, and lift to drag ratio with the initial and final masses to produce the cruise range in meters, the cruise time from range and speed, and the final mass from the fuel fraction. Produces the range, cruise time, and final mass that gate the mission performance assessment. Trigger: cruise range, TSFC, lift to drag, fuel fraction, cruise time.

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Energy Height · ashfordeou bundle
Use when you must compute the energy state of an aircraft for performance and maneuverability analysis: derive the specific excess power Ps from thrust, drag, speed, and weight, express the total energy as the energy height combining the geometric altitude with the kinetic height from the airspeed, convert between kinetic and potential energy in climb and cruise trades with the zoom climb gain and the speed bleed for an altitude gain, and recover the speed from a target energy height. Produces the excess power in watts, the specific excess power in m/s, the energy height in meters, the zoom climb gain, and the speed after the energy trade that gate the energy maneuverability assessment. Trigger: energy height, specific excess power, zoom climb, energy maneuverability, kinetic energy.

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Lead Lag Compensation · ashfordeou bundle
Use when the task is lead lag compensation, phase margin improvement, steady state error reduction, or compensator design for a flight control loop. Design phase lead and phase lag compensators for aerospace flight control and GNC loops: compute the plant phase margin at gain crossover from the open loop transfer function, size the phase boost the lead network must add to meet the phase margin specification, derive the lead ratio alpha from the boost, place the lead zero and pole at the new crossover frequency, and size the lag network pole zero pair below crossover to lift the steady state error constant. Produces the compensator transfer function, its zero and pole, the crossover frequency, and the compensated loop phase margin that gate the control law design. Trigger: phase lead compensator, phase lag compensator, lead lag network, phase margin, gain crossover, steady state error, error constant.

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Python Control Design · ashfordeou bundle
Use when designing and validating feedback control laws with Python control-systems tooling: evaluate gain and phase margins against acceptance limits (6 dB and 45 degrees), classify closed-loop stability from the margins, and apply Ziegler-Nichols tuning to get initial PID gains. Supports controller sanity checks (positive proportional, non-negative integral and derivative gains) before simulation or root-locus and Bode iteration. Pairs with the ARP4754A development-assurance context for control law development. Trigger: control law, pid, transfer function, state space, gain margin, phase margin, root locus, bode, stability, controller tuning.

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Dubins Path Planning · ashfordeou bundle
Use when you must plan the shortest fixed wing path between two heading constrained poses with Dubins curves: compute the left and right arc centers for the minimum turn radius, find the outer or inner tangent points between the turn circles, form the six CSC and CCC path families (RSR, LSL, RSL, LSR, RLR, LRL), and select the minimum length path. Produces the Dubins path type, total length, segment lengths, arc centers, and waypoints that gate UAS path planning and waypoint guidance. Trigger: dubins path planning, minimum turn radius path, shortest path with heading constraints, CSC and CCC path families, arc tangent path, fixed wing turn radius, path length between poses.

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Gage Rr Anova · ashfordeou bundle
Use when you must run the ANOVA estimator for a gage repeatability and reproducibility study: decompose total variation of replicated balanced readings into part, operator, part-by-operator interaction and equipment sums of squares, estimate variance components with the non-negative interaction floor, compute equipment, appraiser, interaction, combined GRR, part and total variation, the percent GRR verdict on the 10/30 acceptance bands, part and interaction F statistics, and the number of distinct categories. Produces the ANOVA table, variance components, verdict and ndc that gate measurement system approval. Trigger: gage rr anova, variance component decomposition, operator part interaction F test, distinct categories count.

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Compressor Map · ashfordeou bundle
Use when you must analyze an axial compressor operating map: identify map points, correct mass flow and rotor speed to standard-day conditions, compute surge margin and operating-line clearance, and judge whether an operating point sits on-map, approaching the surge line, or on the surge line. Produces surge margin percent, corrected flow in kg/s, corrected speed in rpm, and a surge-risk verdict in SI units that gate the engine acceleration and operability review in the FAR-33 engine design context. Trigger: compressor map, surge line, surge margin, operating line, corrected flow, corrected speed, choke line, map point, engine acceleration.

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Rocket Turbopump · ashfordeou bundle
Use when you must size the centrifugal pump inside a liquid rocket engine turbopump: convert the discharge pressure rise and propellant flow into the pump head, compute the dimensionless specific speed from the shaft speed, flow, and head, estimate the impeller tip speed and diameter from the design head coefficient, compute the pump power at the pump efficiency, assess the suction performance with the available net positive suction head and the suction specific speed, and judge the cavitation margin against the suction specific speed limit. Produces the head, specific speed, tip speed, impeller diameter, pump power, NPSH, and cavitation verdict that gate the turbopump design review. Trigger: rocket turbopump, pump specific speed, suction specific speed, net positive suction head, impeller tip speed, LOX pump sizing, cavitation margin.

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Attitude Control Sizing · ashfordeou bundle
Use when you must size the attitude control subsystem actuators for a spacecraft: compute the momentum wheel capacity for a commanded slew, check the detumble rate against the allowed rate, and verify the wheel momentum margin before the ADCS design review. Produces the slew momentum requirement, the detumble verdict, and the margin check that gates actuator selection. Trigger: attitude control, momentum wheel, adcs sizing, slew rate, detumble, spacecraft pointing.

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Eclipse Time · ashfordeou bundle
Use when you must compute the time a spacecraft spends inside the earth shadow during each orbit: derive the beta angle of the orbit plane relative to the sun vector from the inclination, the right ascension of the ascending node, and the sun position, then evaluate the shadow fraction from the beta angle and the orbit radius and multiply by the orbital period to produce the eclipse time and the daylight fraction. Produces the beta angle in degrees, the shadow fraction, and the eclipse time in seconds that gate eclipse duration inputs for spacecraft power and thermal sizing. Trigger: eclipse time, earth shadow, beta angle, shadow fraction, orbit plane, sun vector, eclipse duration.

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Diagonal Tension Field Webs · ashfordeou bundle
Use when you must analyze a plane shear web above its shear-buckling stress with the diagonal tension field idealization: compute the tension field ratio of the applied shear above the buckling stress, take the classical 45 degree tension field angle or accept the angle for a non-45 web, and compute the diagonal web tension stress, the flange and end post axial loads from the diagonal tension, the rivet shear flows on the flange and end post attachments, and the margin against buckling. Produces the post-buckled web state and the attachment loads that gate the shear web reserve check. Trigger: diagonal tension field, tension field angle, web tension stress, post-buckled shear web, tension field attachment loads, shear web reserve.

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Random Vibration Analysis · ashfordeou bundle
Use when you must compute the random vibration response of a structure or equipment item to a base-input acceleration power spectral density: single-degree-of-freedom transmissibility |H(f)|^2 = 1/((1-r^2)^2 + (2*zeta*r)^2), response PSD G_out(f) = |H(f)|^2 * G_in(f), RMS response in g from the Miles equation sigma = sqrt((pi/2)*f_n*Q*G_in(f_n)) with Q = 1/(2*zeta), numerical integration of the response PSD over a supplied spectrum, 3-sigma peak level, and the equivalent static load factor n_eq = 3*sigma for equipment qualification screening. Produces response PSD points, g-rms and 3-sigma response levels, and screening load factors. Trigger: random vibration, PSD response, Miles equation, transmissibility, base excitation, g-rms, power spectral density, vibration qualification.

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N2 Diagram · ashfordeou bundle
Use when you must build or review an N2 interface diagram for an aerospace systems engineering model: derive the NxN interface matrix from the function or component list and the interface pair list, count the interfaces per element from the row and column sums, flag the missing data links against the required interface list, and identify isolated elements with no interfaces. Produces the interface matrix, the per-element interface counts, and the missing link and isolation report that gate the interface requirements review. Trigger: N2 diagram, N2 interface matrix, interface pair, data link, interface count, missing interface.

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Openvsp Geometry · ashfordeou bundle
Use when you must build the parametric aircraft geometry in the OpenVSP style for conceptual design: define the wing planform from the span, the root and tip chords, the sweep, the dihedral and the twist, define the fuselage from its length and stationwise radii, and add the tail surfaces and nacelles, then compute the derived geometry quantities: the wing area, the aspect ratio, the mean aerodynamic chord, the wetted areas, the component volumes and the component centroids that feed the mass properties model. Produces the geometry parameter table and the derived quantities that gate sizing and mass estimation. Trigger: parametric geometry, wing planform, mean aerodynamic chord, wetted area, component volume.

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Cg Envelope · ashfordeou bundle
Use when you must analyze the center-of-gravity envelope of a vehicle: derive the cg station from component weights and arms, check the operating cg against the forward and aft limits, test an operating point against the envelope polygon in the cg versus weight plane, compute the static margin from the neutral point normalized by the mean aerodynamic chord, and track the cg excursion as the fuel burns between loading states. Produces the cg station, the limit verdict, the polygon membership with the violated limit, the static margin verdict, and the fuel-burn cg shift that gate the loading analysis. Trigger: cg envelope, static margin, neutral point, forward limit, aft limit, envelope polygon, cg excursion, fuel burn.

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Mass Budget · ashfordeou bundle
Use when you must build the vehicle mass budget for the conceptual design: allocate the subsystem masses, apply the growth allowance and the contingency margin policy, roll up the total estimated mass, and check the margin-backed total against the MTOW target. Produces the mass breakdown, the total mass with margin, and the within-target or over-target verdict that gate the weight control plan. Trigger: mass budget, growth allowance, contingency margin, MTOW target, mass breakdown.

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Apu Fuel Burn Sizing · ashfordeou bundle
Use when you must compute the APU fuel burn: take the generator electrical output and the bleed mass flow at a fixed load point for a conceptual aircraft or rotorcraft auxiliary power unit, convert the electrical output into generator shaft power through the generator efficiency, convert the bleed mass flow into its load-compressor pumping-power equivalent with the adiabatic compressor work relation at the stated pressure ratio, sum both into the total equivalent shaft load, and convert that load into fuel flow through the APU thermal efficiency and the fuel lower heating value. Produces the generator shaft power, the bleed pumping-power equivalent, the total equivalent shaft load, and the fuel flow in kg/s and kg/h. Trigger: apu fuel burn, auxiliary power unit fuel flow, apu load compressor, bleed pumping power, apu generator shaft power, apu fuel flow rate.

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Fuel Jettison Sizing · ashfordeou bundle
Use when you must size the fuel jettison system: from the maximum takeoff weight and the maximum landing weight, compute the fuel mass that must be dumpable and the required average jettison rate to reach the landing weight within the 15-minute limit of FAR 25.1001, apply the design margin to the required rate, split the design flow over the dump mast count, and verify the resulting time to landing weight against the 900 s limit. Produces the dumpable fuel mass, the required and design jettison rates, the per-mast flow, and the time-to-landing-weight PASS or FAIL verdict that gate the jettison system sizing. Trigger: fuel jettison sizing, fuel dump rate, jettison time to landing weight, dump mast flow split, FAR 25.1001, 15-minute landing weight rule.

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Wing Planform Sizing · ashfordeou bundle
Use when you must size the wing planform geometry at the design point: compute the wing area from the takeoff gross weight and the chosen wing loading, convert the aspect ratio into the span, set the taper ratio and derive the root chord, tip chord, and mean aerodynamic chord with its spanwise station, and select the sweep angle from the cruise Mach so the section normal Mach stays at or below the section critical Mach. Produces the planform dimensions that feed weight estimation, fuel tank volume, control surface sizing, and the aerodynamic analysis leaves. Trigger: wing planform, wing area, aspect ratio, taper ratio, mean aerodynamic chord, sweep angle, cruise Mach.

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Aerodynamic Heating · ashfordeou bundle
Use when you must estimate the aerodynamic heating at the stagnation point of a hypersonic body: stagnation-point convective heat flux from the Sutton-Graves correlation using freestream density, flight velocity and nose radius, radiation-equilibrium wall temperature from the Stefan-Boltzmann balance at a chosen surface emissivity, and the nose-radius bluntness trade that scales the flux for blunt versus sharp geometries. Produces the stagnation heat flux, the radiation-equilibrium temperature and the bluntness comparison that gate a thermal protection material choice. Trigger: aerodynamic heating, stagnation-point-heating, sutton-graves, radiation-equilibrium-temperature, nose-radius-bluntness, reentry heating, thermal protection.

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Wave Drag Area Rule · ashfordeou bundle
Use when the task is wave drag estimation, area ruling, Sears-Haack bodies, drag divergence, or cross-sectional area distribution in transonic design. Compute transonic wave drag with the Whitcomb area rule: build the streamwise cross-sectional area distribution of a wing-body combination, size the Sears-Haack minimum-drag body for a given length and volume, evaluate its zero-lift wave drag, and estimate the drag-divergence Mach number and the parabolic wave drag rise above it. Produces the Sears-Haack radius and area distributions, the equivalent drag area, the wave drag coefficient and force, and the area-rule fuselage pinch that smooths the total area distribution. Trigger: wave drag, area rule, Sears-Haack, drag divergence, cross-sectional area.

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Rta Time Control · ashfordeou bundle
Use when you must compute the required time of arrival (RTA) function of a flight management system: estimate the arrival time at a downstream waypoint from the remaining distance and ground speed, derive the speed adjustment needed to satisfy the RTA time constraint, check the constraint against the achievable arrival window set by the minimum and maximum cruise Mach bounds, and return the Mach command, the predicted time error and the feasibility verdict for the FMS time control. Produces the ETA, time error, required ground speed and Mach command, achievable window and remaining time error. Trigger: required time of arrival, RTA time constraint, speed adjustment, arrival window, time error, 4D trajectory, FMS time control, Mach command.

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Shared Resource Access Control · ashfordeou bundle
Use when you must account for shared-resource blocking in a fixed-priority avionics task set: assign each protected resource its priority ceiling from the tasks that lock it, compute the worst-case blocking time each task can suffer from lower-priority tasks under the priority ceiling protocol, and run the response-time analysis with the blocking term to decide schedulability. Produces the per-resource ceiling map, the per-task worst-case blocking times, the response times with blocking, and the schedulability verdict that gate an avionics task set design. Trigger: shared resource access control, priority ceiling protocol, priority inheritance, stack resource policy, worst case blocking, blocking time bound, schedulability with blocking.

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Monte Carlo Sampling · ashfordeou bundle
Use when you must estimate the distribution of an output quantity by Monte Carlo sampling: draw seeded pseudo-random samples from a uniform input range, compute the sample mean and the sample standard deviation, extract percentile confidence intervals, and bin the draws into a histogram. Produces the sample statistics, the confidence interval, and the histogram counts that gate the sampling study. Trigger: monte carlo sampling, random seed, sample size, percentile, confidence interval, histogram, pseudo-random draws, output distribution.

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Tolerance Stackup · ashfordeou bundle
Use when you must compute the assembly tolerance stack-up from the part tolerances with the worst case and root sum square methods: sum the absolute tolerances for the worst case total, take the root sum square for the statistical total, sum the signed nominals into the assembly nominal dimension, and produce the assembly limits and the dominant variance share. Produces the worst case total, the RSS total, the assembly limits, and the dominant contributor that gate the fit assessment. Trigger: tolerance stack-up, worst case, root sum square, RSS, assembly limits, dominant contributor, nominal dimension.

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Specific Range · ashfordeou bundle
Use when you must compute the specific air range of an aircraft in cruise: divide the true airspeed by the fuel flow to produce the specific air range in meters per kilogram, derive the fuel flow from the thrust specific fuel consumption and the required thrust, estimate the instantaneous range from speed, thrust specific fuel consumption, weight, and lift to drag ratio, and convert a block distance into the fuel burn for the sector. Produces the specific air range, fuel flow, and fuel burn that gate the cruise fuel economy assessment. Trigger: specific air range, fuel flow, instantaneous range, meters per kilogram, sector fuel burn.

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Digital Control Design · ashfordeou bundle
Use when you must design a sampled-data digital control loop in the z-domain: discretize a continuous plant with a zero-order hold, emulate a continuous compensator with the Tustin bilinear transform with frequency prewarping, compute discrete PID coefficients in the position and velocity forms, check the sampled poles against the unit circle for stability, and select the sample rate from the closed-loop bandwidth. Produces the discretized plant coefficients, the emulated compensator, the discrete PID gains, the stability verdict and the sample-rate verdict that gate a digital control design. Trigger: z transform, zero order hold, zoh, tustin bilinear emulation, frequency prewarping, discrete pid, unit circle stability, sample rate selection.

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Feedback Linearization · ashfordeou bundle
Use when you must apply feedback linearization to a nonlinear plant with a known exact model: compute the Lie derivatives of the output along the drift and control vector fields to establish the relative degree, invert the decoupling scalar at the operating state, form the linearizing control that cancels the nonlinear terms so the output channel obeys the linear relation y^(r) = v, apply the outer linear tracking loop with the assigned closed-loop pole placement, and check the internal dynamics via their zero dynamics before accepting the design. Produces the relative-degree verdict, the linearizing control with the decoupling scalar, the exactly linearized closed-loop response against the assigned closed form, and the zero-dynamics stability verdict that gates the design. Trigger: feedback linearization, input output linearization, lie derivative, relative degree, decoupling matrix, linearizing control, zero dynamics, internal dynamics stability.

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Inertial Navigation · ashfordeou bundle
Use when you must assess an inertial navigation system (INS): estimate position error growth from accelerometer bias and gyro drift, check the Schuler period and the leveling response, compare strapdown and gimbaled mechanization, and scope alignment and INS/GPS integration. Produces the double-integration position error from an accelerometer bias, the cubic position error from gyro drift, the bounded Schuler steady-state offset, and the Schuler period and frequency. Trigger: inertial navigation, ins, strapdown, gimbaled, gyro drift, accelerometer bias, schuler period, gyrocompass alignment, ins/gps integration, inertial measurement unit.

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Layup Cure · ashfordeou bundle
Use when you must engineer a composite laminate layup and cure process: build the ply book with orientation, material, and thickness per ply, verify the laminate is symmetric and balanced, design the cure cycle (vacuum application, heat ramp, cure dwell, cool-down, autoclave vs out-of-autoclave vs press pressure), predict degree of cure with an Arrhenius kinetics model integrated over the temperature profile, relate glass transition temperature to degree of cure, and disposition C-scan porosity against the acceptance limit. Produces the ply book, symmetry and balance verdicts, the cure cycle timeline with pressures, the predicted degree of cure, Tg, and the C-scan acceptance verdict. Trigger: composite layup, ply book, laminate, symmetric, balanced, cure cycle, autoclave, out-of-autoclave, OOA, degree of cure, epoxy, 350F, glass transition, Tg, C-scan, porosity.

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Visual Inspection · ashfordeou bundle
Use when you must plan and execute a visual inspection (VT) of an aerospace part and turn viewing geometry and lighting into inspection decisions: compute the borescope aperture ratio that sets light gathering and image brightness, size the magnification needed to resolve a target surface indication size at a given working distance, apply the inverse-square law to convert lamp intensity to illuminance and meet the lighting requirements in lux or foot-candles, size the field of view and the number of scan positions for full surface coverage, and compare measured surface indications with the acceptance criteria for a pass-fail disposition. Produces the aperture ratio, magnification, illuminance, and acceptance verdict that gate visual inspection decisions. Trigger: visual inspection, VT, borescope, aperture ratio, magnification, working distance, illuminance, lux, foot-candles, lighting requirements, surface indication, field of view, resolution limit.

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Cea Rocket Combustion · ashfordeou bundle
Use when you must predict the thermochemistry and performance of a rocket propellant combination in the spirit of NASA CEA: compute the adiabatic flame temperature and the chamber conditions from the propellant choice, the mixture ratio, and the chamber pressure with a simplified frozen-flow equilibrium over representative species, derive the characteristic velocity (c-star) and the ideal vacuum and sea-level specific impulse, run a mixture ratio trade, and estimate gamma, the molecular weight of the combustion products, the c-star efficiency, and the sensitivity of Isp to the mixture ratio. Produces the chamber temperature, the equilibrium composition, the c-star, the ideal Isp values, and the trade table, in SI units. Trigger: adiabatic flame temperature, characteristic velocity, c-star, vacuum specific impulse, mixture ratio trade, frozen flow, combustion thermochemistry.

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Electrothermal Thruster · ashfordeou bundle
Use when you must compute the electrothermal thruster operating point for electric propulsion: useful heating power from input power and heating efficiency, propellant mass flow from chamber temperature rise, ideal vacuum exhaust velocity, thrust, specific impulse, thrust efficiency and thrust-to-power ratio for a resistojet or arcjet family point. Produces a single-point performance summary with the power budget decomposition and a typical-band verdict. Trigger: electrothermal thruster, resistojet, arcjet, heated propellant, power to thrust, ammonia, nitrogen, hydrogen, helium propellant, specific impulse.

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Turbojet Cycle · ashfordeou bundle
Use when you must analyze an ideal single-stream turbojet core cycle at flight conditions: compute the freestream stagnation temperature from the flight Mach number, the compressor exit temperature from the pressure ratio, the fuel-to-air ratio from the turbine inlet temperature and the combustor efficiency, the turbine exit temperature from the compressor-turbine work balance, the nozzle exit temperature and exit velocity, the net specific thrust as the exit velocity minus the flight velocity, the turbojet TSFC and the propulsive efficiency. Produces the station temperatures, the specific thrust and the TSFC that gate core-engine matching and cycle-trade studies. Trigger: turbojet core cycle, ideal turbojet, compressor-turbine matching, turbine inlet temperature, net specific thrust, turbojet TSFC, core-engine matching, cycle trade study.

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Combustion Chamber Design · ashfordeou bundle
Use when you must size and assess the combustion chamber of a rocket engine: compute the characteristic velocity (c-star) from the chamber pressure, the throat area, and the propellant mass flow, estimate the theoretical c-star from the chamber temperature, the molecular weight, and the specific heat ratio, size the throat area from the propellant flow and the chamber pressure, compute the thrust coefficient and the thrust from the chamber pressure and the throat area, and derive the chamber volume from L-star, the contraction ratio from the chamber area and the throat, and the vacuum specific impulse from the thrust and the mass flow. Produces the chamber sizing dict that feeds the nozzle-design and the engine balance. Trigger: rocket combustion chamber, characteristic velocity, c-star, thrust coefficient, contraction ratio, chamber pressure, chamber volume, L-star, throat area.

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Magnetometer Calibration · ashfordeou bundle
Use when you must estimate the in-flight magnetometer bias vector with scalar-checking batch least squares: expand |m_k - b|^2 = B_k^2 over the measured body-frame samples m_k and the known field magnitudes B_k, build the 4-unknown rows [-2 m_k, 1] with right sides B_k^2 - |m_k|^2, solve the normal equations A^T A x = A^T y by partial-pivot Gaussian elimination, and recover the bias from the first three unknowns with the fourth unknown |b|^2 as the consistency check. Produces the bias vector, the consistency gap against the recovered bias norm, the max fit residual, and the calibrated samples that gate attitude determination. Trigger: magnetometer calibration, scalar checking, in-flight bias estimation, hard-iron offset, field magnitude consistency.

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Reaction Jet Limit Cycle · ashfordeou bundle
Use when you must estimate the RCS attitude-hold propellant demand of a reaction-jet limit cycle: the control angular acceleration from the control torque and axis inertia, the angular rate at the deadband crossing, the firing duration of each braking pulse, the delta-V and propellant mass per pulse and per cycle, the aggregate cycle period, the cycle count over the mission life, and the three-axis lifetime propellant total with an activity duty factor. Produces the per-axis limit-cycle state and the three-axis propellant total that gate whether reaction-jet attitude hold is propellant-feasible. Trigger: rcs attitude hold, reaction jet limit cycle, deadband crossing rate, braking pulse firing, limit cycle period, thruster pulse, attitude hold propellant.

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Orbital Decay · ashfordeou bundle
Use when you must estimate orbital decay and deorbit lifetime of a low Earth orbit spacecraft from atmospheric drag: compute the ballistic coefficient from mass, drag area, and drag coefficient, the altitude decay rate and decay per orbit, the decay per day, and the deorbit lifetime down to a target altitude with the closed-form exponential lifetime, then assess compliance with the 25-year disposal rule and size drag augmentation for end-of-life deorbit. Trigger: orbital decay, atmospheric drag, ballistic coefficient, deorbit lifetime, decay rate, drag area, 25-year disposal rule, LEO disposal, decay per orbit, drag augmentation.

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Solar Array Sizing · ashfordeou bundle
Use when sizing a spacecraft EPS solar array or photovoltaic panel: array area, power demand, eclipse fraction, cell efficiency, packing factor, degradation, end of life, solar irradiance. Compute spacecraft solar-array sizing: determine the required photovoltaic array area in square meters from the orbit-average power demand, the eclipse fraction, the solar cell efficiency, the packing factor, and the end-of-life degradation over the mission life, then verify the array margin at end of life. Trigger: solar array sizing, array area, cell efficiency, degradation, power demand, eclipse fraction, photovoltaic.

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Random Vibration Fatigue · ashfordeou bundle
Use when you must estimate fatigue damage directly from a random-vibration response PSD: compute the psd-spectral-moments of a one-sided stress power spectral density by trapezoid integration, derive the expected-peak-rate, and apply the narrow-band Rayleigh model and the Dirlik amplitude mixture (dirlik-method) for the expected damage rate under a Basquin S-N curve with gamma closed forms; convert each damage rate to a fatigue life in hours. Produces the spectral moments, the expected peak rate, the narrow-band-damage and Dirlik damage rates, and the fatigue life verdict that gates random-vibration fatigue screening. Trigger: random vibration fatigue, spectral fatigue, Dirlik method, PSD moments, narrow band fatigue life, response stress PSD, peak rate.

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Ice Protection Sizing · ashfordeou bundle
Use when you must size the thermal ice protection system for an aircraft surface in FAR/CS 25 Appendix C continuous maximum icing: choose evaporative anti-icing, running-wet anti-icing or cyclic de-icing, compute the protected area from the icing-critical geometry, estimate the droplet catch efficiency from MVD and airspeed, compute the evaporative heat flux and running-wet surface temperature with the freezing fraction, size the electrothermal power or bleed air mass flow, and return the protect verdict with the protection mode, required power or bleed flow and surface temperature. Trigger: ice protection, anti-ice, de-ice, evaporative anti-icing, running wet, catch efficiency, protected area, heat flux, bleed air mass flow, MVD.

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Divergence Speed · ashfordeou bundle
Use when you must compute the static aeroelastic divergence condition of a lifting surface: calculate the divergence dynamic pressure from the torsional stiffness, the reference area, the chord, the lift curve slope, and the aerodynamic-center-to-shear-center offset ratio, convert it to the divergence speed at sea level, and assess the divergence margin against the design dive speed, flagging risk when the margin falls below the required 1.15 threshold. Produces the divergence dynamic pressure, the divergence speed, and a margin verdict that feed torsional stiffness sizing for divergence clearance. Trigger: divergence speed, divergence dynamic pressure, torsional stiffness, aerodynamic center, shear center, divergence margin, static aeroelastic divergence.

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Laminar Far Wake · ashfordeou bundle
Use when you must compute the two-dimensional laminar far-wake velocity-defect profile and drag downstream of a thin flat plate or slender body at zero incidence, the Goldstein 1933 similarity wake: evaluate the Gaussian cross-stream velocity-defect profile with the spread parameter U/(4*nu*x), the centerline-defect decay as x^-1/2 and the wake half-width growth as x^1/2 downstream of the trailing edge, integrate the momentum deficit across the wake with the wake-momentum-integral drag identity D = rho*U*integral u1 dy to recover the plate drag, and link the far-wake traverse to the laminar Blasius trailing-edge momentum state with the 0.664 constant. Produces the wake velocity-defect and recovered-velocity profiles, the decay and spreading laws and the wake-survey drag in SI units that anchor laminar wake diagnostics and drag checks. Trigger: laminar-far-wake, far-wake-velocity-defect, wake-momentum-integral, velocity-defect-profile, wake-survey-drag.

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Transonic Similarity · ashfordeou bundle
Use when you must apply compressibility corrections to subsonic aerodynamic coefficients: compute the Prandtl-Glauert factor and the refined Karman-Tsien correction for the pressure coefficient at a given Mach number, evaluate the transonic similarity parameter linking thickness and sweep effects, and estimate the critical Mach number at which local flow first reaches sonic speed. Produces corrected pressure coefficients and corrected lift slope, the critical Mach estimate, and drag-divergence Mach guidance for airfoil selection and high-subsonic wing design. Trigger: compressibility correction, Prandtl-Glauert, Karman-Tsien, transonic similarity, critical Mach number, pressure coefficient.

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Radius To Fix Leg · ashfordeou bundle
Use when you must construct the lateral path of a radius-to-fix leg: compute the turning center of the constant-radius RF leg for an RNP AR procedure from the entry fix, the inbound track, the published radius and the turn direction, validate that the exit fix lies on the radius circle, and derive the swept central angle, the along-arc length, the exit track and the chord. Produces the RF-leg geometry dict that gates a flyable-arc check for procedure design. Trigger: radius to fix, RF leg, turn center, arc length, path terminator, rnp ar procedure, constant radius arc, flyable arc check.

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Airborne Weather Radar · ashfordeou bundle
Use when you must compute airborne weather radar operating-point quantities for convective weather avoidance: convert radar reflectivity factor Z to rainfall rate and back with the Marshall-Palmer Z-R relation, estimate the antenna elevation tilt that scans a storm cell top from own altitude and slant range, derive the flat-earth ground range to the cell, check a tilt setting against ground clutter return geometry, and rate echo intensity into standard levels from the reflectivity. Produces the rainfall rate, the required tilt angle, the ground range, the clutter check verdict and the echo level that gate weather radar tilt management in the cockpit. Trigger: airborne weather radar, convective weather avoidance, storm cell top, antenna tilt, reflectivity factor, rainfall rate, marshall palmer, echo level, ground clutter.

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Digital Filter Design · ashfordeou bundle
Use when you must compute the coefficients of a digital Butterworth IIR lowpass or highpass frequency-selective filter from a cutoff frequency, sample rate, and order: prewarp the analog cutoff, map the normalized Butterworth poles through the bilinear transform, build the b and a coefficients with unity DC or Nyquist gain, evaluate the magnitude response in dB at any frequency, and apply the filter to a sampled signal with the direct-form difference equation. Produces the coefficient vectors, the 3 dB point check at the cutoff, passband and attenuation band gains, the filtered signal, and a design verdict from the Schur-Jury stability table. Trigger: digital filter design, Butterworth, bilinear transform, IIR lowpass, highpass filter, cutoff frequency, prewarping, filter coefficients, 3 dB point.

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Numerical Integration · ashfordeou bundle
Use when you must integrate a function numerically: select the composite trapezoid rule, the composite Simpson rule, or Gauss-Legendre quadrature for the integrand, compute the integral estimate, and estimate the error with Richardson extrapolation of the trapezoid rule. Produces the integral estimate, the chosen method with its justification, and the error estimate that gate quantitative analysis of smooth, endpoint-singular, and high-degree integrands. Trigger: numerical integration, trapezoid rule, simpson rule, gauss legendre, quadrature, error estimate, definite integral.

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Propeller Range · ashfordeou bundle
Use when you must compute the cruise range of a propeller or turboprop aircraft: form the range with the propeller Breguet equation from power specific fuel consumption and propeller efficiency at a given lift to drag ratio, convert a pounds per horsepower hour PSFC into SI kilograms per watt second when needed, and derive the final mass from the fuel fraction. Produces the cruise range in meters and kilometers for fuel planning between the initial and final mass. Covers the propeller branch of the Breguet range family that the jet-only range relation leaves open. Trigger: propeller range, turboprop cruise range, PSFC, power specific fuel consumption, propeller efficiency, fuel fraction, lift to drag ratio, mass ratio.

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Speed Stability · ashfordeou bundle
Use when you must assess the static speed stability of a fixed-wing transport from its trim drag balance: build the thrust required curve versus true airspeed from the drag polar, its zero lift drag and induced drag factor, derive the curve slope dT/dV, classify each level flight trim speed as speed stable or speed unstable on the back side of the curve, locate the minimum drag speed boundary where the slope crosses zero, and compute the slow flight stability margin between a proposed minimum speed and the unstable region of reversed command. Produces the thrust required curve points, the slope classification table, the minimum drag speed, the stability verdict at every trim speed, and the speed stability margin that gate the minimum speed selection. Trigger: speed stability, back side of curve, region of reversed command, minimum drag speed boundary, trim speed classification, slow flight stability margin, thrust curve slope.

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Thrust Required · ashfordeou bundle
Use when you must compute the thrust required and power required curves for level unaccelerated flight from the drag polar: derive the total drag coefficient from the zero lift drag coefficient and the induced drag factor, compute the thrust required and the power required at a given equivalent airspeed, weight, wing area, and air density (for example the sea level density 1.225 kg/m^3), and locate the characteristic points: the minimum drag speed where the parasite drag equals the induced drag, the minimum power speed, and the minimum thrust at the maximum lift to drag ratio. Produces the thrust required curve, the power required curve, the minimum drag speed, the minimum power speed, and the minimum thrust that gate the level flight performance assessment. Trigger: thrust required, power required, minimum drag speed, minimum power speed, drag polar, level flight.

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Spin Testing · ashfordeou bundle
Use when the task is spin flight testing, spin recovery, spin resistance, or recovery parachute planning. Plan and execute the spin flight test: build the spin test point matrix across configurations, center of gravity positions, weights, and altitudes, flag the points outside the approved CG envelope, classify the entry, incipient, and developed spin phases from the rotation, apply the recovery control procedure and check the recovery against the turn count and altitude loss limits, decide when the recovery parachute is required, and judge the FAR 25.201 spin resistance verdict with pro-spin controls held at the stall. Produces the test point matrix, the phase classification, the recovery verdict, the parachute decision, and the spin resistance assessment. Trigger: spin testing, spin entry, incipient spin, developed spin, spin recovery, recovery parachute, spin resistance, FAR 25.201, spin test point matrix.

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Coverage Path Planning · ashfordeou bundle
Use when you must plan a boustrophedon area-coverage search path for a fixed-wing UAS or rotorcraft over a rectangular survey region: compute the ground swath width from the sensor cross-track field of view and altitude, derive the track spacing from the required side overlap, lay out the alternating lawnmower passes, add the 180 degree half-circle turns at the vehicle turn radius, and sum the total path length and survey time at cruise speed. Produces the swath width, track spacing, pass count, pass headings, total path length and survey time that gate an aerial survey or search mission plan. Trigger: coverage path planning, boustrophedon, lawnmower pattern, aerial survey flight lines, swath width, side overlap, track spacing, area search pattern.

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Gnss Rtk Positioning · ashfordeou bundle
Use when you must compute the position of a GNSS rover relative to a fixed base station from double-difference carrier-phase observables: form the per-satellite single differences across the receivers at each epoch of a common-view observation arc, then the double differences across satellite pairs and epochs, and solve the stacked least-squares normal equations for the float baseline and the per-pair float ambiguities. Resolve the integer ambiguities by rounding candidate sets around the float solution with a ratio test on the float covariance, impose the winning integer set, and re-solve for the fixed baseline with per-axis 1-sigma precision. Produces the float baseline and the fixed rover baseline in ECEF, the resolved integer ambiguity set with its ratio, and the fixed ENU offset at the base. Trigger: carrier phase differential, RTK positioning, integer ambiguity resolution, double difference baseline, fixed baseline ENU offset.

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Kalman Filter Design · ashfordeou bundle
Use when you must design or run a discrete-time Kalman filter for single-axis state estimation in SI units: predict the state and its error covariance through the dynamics model, compute the innovation and innovation variance, calculate the Kalman gain, and correct the state and covariance from a noisy measurement. Produces the predicted and corrected states, the error covariance, the Kalman gain, and the innovation sequence that gate a navigation or estimation assessment. Trigger: kalman filter, state estimation, kalman gain, innovation variance, error covariance, process noise, measurement noise, estimator design, sensor fusion, recursive least squares.

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Risk Management · ashfordeou bundle
Use when the task is risk assessment, mitigation planning, or operational risk review rather than dispositioning an actual nonconformance or closing a CAPA. Assess and plan mitigation for aerospace quality risks per AS9100D operational risk management: compute FMEA risk priority numbers from severity, likelihood, and detection ratings, classify RPN bands, score the post-mitigation residual RPN from reduction credits, derive occurrence probability from production history, apply the 5x5 severity-likelihood risk matrix, and rank risks for mitigation priority with residual-risk acceptance checks. Produces the risk register entries, mitigation plan, and residual-risk verdicts that AS9100D 8.1.1 requires before production changes proceed. Trigger: risk management, risk assessment, mitigation planning, operational risk, RPN, FMEA, risk matrix, residual risk.

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Piston Engine Cycle · ashfordeou bundle
Use when you must compute the operating point of a reciprocating four-stroke aircraft powerplant for general-aviation propulsion: the air-standard Otto cycle thermal efficiency from the compression ratio and the specific-heat ratio, the four-stroke indicated power from the indicated mean effective pressure, the displacement and the crankshaft speed, the brake power at the mechanical efficiency, and the brake specific fuel consumption from the fuel flow and the brake power. Produces the single-point summary dict with the ideal cycle efficiency, indicated and brake power, BSFC in both reporting units, thermal efficiencies, volumetric fuel flow and the reference-only general-aviation band verdict in one call, the published bands reported and never enforced. Trigger: piston-engine-cycle, air-standard-otto-cycle, compression ratio Otto efficiency, four-stroke engine, mean effective pressure, indicated power, brake power, mechanical efficiency, brake specific fuel consumption, BSFC.

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Adhesive Bonded Joints · ashfordeou bundle
Use when you must analyze a single-lap adhesive bonded joint between two identical adherends: compute the Volkersen shear-lag parameter from the adherend modulus and thickness and the adhesive shear modulus and thickness, the average adhesive shear stress from the load, bond width and overlap length, the peak shear stress at the bondline ends with the shear-lag correction, and the joint margin against the adhesive allowable shear stress. Produces the average and peak stresses, the peak to average concentration, the margin ratio with MS margin, and the pass or fail verdict. Trigger: adhesive bonded joint, single lap joint, shear lag parameter, adhesive shear stress, overlap length, Volkersen shear distribution, bondline peak stress, adhesive allowable.

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Creep Stress Relaxation · ashfordeou bundle
Use when you must compute the stress relaxation of a preloaded metallic part held at fixed total strain at elevated temperature: evaluate the closed-form integral of the fixed-strain relaxation ODE for a Norton power-law creeping material, the relaxed stress sigma(t) = [sigma_0^(1-n) + (n-1)*A*E*t*exp(-Q/(R*T))]^(1/(1-n)) from the initial preload stress, the hold time, the temperature and the Norton constants A, n, Q and elastic modulus E, the retained-preload fraction after the hold, the time for the preload to relax to a target fraction, and the preload-retention margin against a required retained fraction with the PASS or FAIL verdict for bolted joints, spring preloads and interference-fit fasteners. Produces the relaxed stress, the retained-preload fraction and the retention margin verdict at the operating point. Trigger: creep-stress-relaxation, norton-relaxation-closed-form, preload-retention, fixed-strain-creep-relaxation, relaxed-stress-fraction, elevated-temperature-preload.

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Fta Fmea · ashfordeou bundle
Use when scoping or executing FTA (fault tree analysis) and FMEA (failure modes and effects analysis) per ARP4761A: compute minimal cut sets from AND/OR gate structures, check cut-set probability sanity against the top event probability, select the analysis set for an assurance level (FTA/FMEA always, CCA at levels A and B), and map FMEA failure-condition severity to development assurance levels. Pairs with ARP4754A development assurance; all logic is deterministic, offline stdlib. Trigger: fault tree, FTA, FMEA, FMECA, cut set, minimal cut set, failure modes, common cause, severity, probability.

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Control Surface Sizing · ashfordeou bundle
Use when the task is control surface sizing, aileron sizing, elevator area, rudder area, roll rate requirement, pitch moment authority, yaw authority, hinge moment, or deflection limits. Size the aileron, elevator, and rudder control surfaces of a fixed-wing aircraft from control power: the aileron area from the roll rate requirement with the roll damping derivative, the elevator area from the pitch moment requirement with the elevator effectiveness, the rudder area from the yaw moment requirement for the engine-out case, the hinge moment for the actuator, and the deflection limits against the typical travel ranges. Trigger: control surface sizing, aileron sizing, elevator area, rudder area, hinge moment, deflection limits.

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Electrical Wire Sizing · ashfordeou bundle
Use when you must size an aircraft electrical wire run: select the smallest conductor gauge whose bundled ampacity at the ambient temperature meets the continuous load with the bundle and temperature derating applied, check the round-trip voltage drop over the run length at the load current against the bus tolerance, compute the percentage drop, and report the selected gauge, its ampacity margin, the voltage drop and the percent-drop verdict. Produces the conductor gauge selection and the drop verdict that close the load-to-distribution chain. Trigger: power feeder gauge selection, conductor ampacity, ampacity derating, wire voltage drop, percent drop, bus tolerance.

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Avionics · ashfordeou
Use when a task concerns avionics and flight software assurance for civil aircraft: guide the router to the avionics pack, whose DO-178C software lifecycle sub-skills cover planning, development, verification, and configuration management, whose DO-254 sub-skills cover airborne electronic hardware planning and verification, whose DO-330 tool-qualification sub-skill covers software tool credit, whose DO-160 environmental-qualification sub-skill covers equipment test conditions, and whose far-cs25 airworthiness sub-skill covers the transport-category certification basis. This pack is the airborne software and hardware certification spine. Trigger: avionics, airborne software, flight software, DO-178C, DO-254, DO-330, DO-160, airborne electronic hardware, airworthiness certification, software levels, tool qualification, environmental qualification.

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Propulsion · ashfordeou
Use when a task concerns aircraft or rocket propulsion: guide the router to the propulsion pack: gas-turbine-cycle Brayton, regenerative-cycle regenerator efficiency, real-cycle-effects component losses, turbofan-cycle turbofan parameters, bypass-ratio-trade bypass design, turbofan-off-design part-power behavior, free-turbine power turbine matching, turbine-stage stage velocity triangles, axial-compressor-stage compressor stage, compressor-map operating maps, multi-stage-compressor stacked stages, rocket-sizing rocket sizing, nozzle-design nozzles, propellant-selection propellant trade, ramjet-cycle ideal ramjet performance, ramjet-inlet supersonic inlet starting. Trigger: propulsion, gas turbine, Brayton cycle, regenerator, turbofan, bypass ratio, rocket equation, delta-v, rocket nozzle, area ratio, propellant, axial compressor, compressor map, multi-stage compressor, off-design turbofan, real cycle, free turbine, power turbine, turboshaft, ramjet, ramjet inlet, Kantrowitz, specific thrust, specific impulse.

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Structures · ashfordeou
Use when a task concerns aerospace structures and materials: guide the router to the structures pack: calculix-linear linear FEA, calculix-nonlinear Newton-Raphson and load stepping, modal-analysis natural frequencies, residual-strength fracture, crack-growth crack propagation, widespread-fatigue-damage MSD/MED, miner-damage cumulative damage, goodman-diagram mean-stress corrections, load-spectrum-counting rainflow, laminate-stiffness CLT/ABD, composite-bolted-joints bearing and bypass, sandwich-panels core shear and wrinkling, failure-criteria Tsai-Wu, mmpsd-allowables A-/B-basis, material-selection property indices, ramberg-osgood elastic-plastic stress-strain. Trigger: structures, FEM, stress analysis, margin of safety, CalculiX, nonlinear, modal, fatigue, crack growth, widespread fatigue damage, MSD, MED, Miner, Goodman, rainflow, laminate, Tsai-Wu, bolted joint, sandwich panel, allowables, MMPDS, material selection, Ramberg-Osgood, plastic strain, plate buckling, panel buckling, shear buckling.

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Aerodynamics · ashfordeou
Use when a task concerns aerodynamics: guide the router to the aerodynamics pack: airfoil-selection family choice, xfoil-analysis polars, airfoil-geometry NACA geometry, airfoil-optimization shape trade, cfd-convergence residuals, cfd-turbulence-modeling model selection, cfd-mesh-generation grids and y-plus, vortex-lattice-method VLM, panel-method potential flow, normal-shock shock relations, oblique-shock theta-beta-M, prandtl-meyer expansions, swept-wing-aerodynamics sweep, transonic-similarity Karman-Tsien, supercritical-airfoil aft loading, wave-drag-area-rule area rule, drag-polar polar, parasite-drag zero-lift drag, lift-curve-slope lift slope, boundary-layer-theory flat-plate layers, ground-effect in-ground lift, high-lift-systems flap and slat clmax. Trigger: aerodynamics, airfoil, polar, drag polar, sweep, Mach, boundary layer, ground effect, high lift, vortex lattice, panel method, transonic.

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Gnc Autonomy · ashfordeou
Use when a task concerns guidance, navigation, and control for aerospace vehicles: guide the router to the gnc-autonomy pack: orbit-dynamics Hohmann and J2 drift, rendezvous-phasing phasing maneuvers, attitude-dynamics quaternion kinematics, navigation-frames ECEF/NED/WGS-84, inertial-navigation INS drift and Schuler, dilution-of-precision GDOP/PDOP, python-control-design PID margins, root-locus-design closed-loop poles, state-space-analysis controllability, pid-control-design Ziegler-Nichols, lqr-design Riccati gains, dymos-trajectory pseudospectral optimization, proportional-navigation the PN law, command-to-line-of-sight CLOS guidance, pursuit-guidance capture conditions, kalman-filter-design state estimation. Trigger: GNC, navigation, control, orbit dynamics, Hohmann, rendezvous, attitude dynamics, quaternion, ECEF/NED/WGS-84, INS, Schuler, dilution of precision, GDOP, PID, root locus, controllability, proportional navigation, command to line of sight, pursuit guidance, kalman filter, state estimation.

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Cross Cutting · ashfordeou
Use when a task concerns the skill delivery layer, the standard atmosphere, engineering documentation, or numerical analysis: guide the router to the cross-cutting pack. SEP-2640 skill-delivery, skill-evaluation, skill-authoring cover SKILL.md conformance, quality, authoring; isa-atmosphere, unit-conversion, and temperature-conversion cover atmosphere and units; engineering-margins and engineering-report cover margins and reports; tolerance-stackup assembly tolerancing and position-tolerance-calc GD&T position tolerance; convergence-verification Richardson, least-squares-regression OLS, uncertainty-propagation GUM, numerical-integration quadrature, finite-difference-derivatives finite differences, monte-carlo-sampling sampling. Trigger: skill delivery, SEP-2640, skill evaluation, skill authoring, SKILL.md, ISA, unit conversion, temperature conversion, margin of safety, tolerance stack-up, worst case, RSS, GD&T, position tolerance, engineering report, least squares, uncertainty, numerical integration.

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Space Systems · ashfordeou
Use when a task concerns space systems engineering for European space projects: guide the router to the space-systems pack. ECSS software-engineering criticality, software-verification verification depth, systems-engineering lifecycle gates, power-thermal-budget EPS and battery sizing, communication-link-budget link margin, thermal-design radiator sizing, command-data-handling telemetry, sun-pointing sun vector geometry, star-tracker star identification, attitude-control-sizing reaction wheels, attitude-determination-triad TRIAD, magnetorquer-control B-dot detumbling, sun-synchronous-inclination J2 nodal regression, keplerian-elements orbital elements, ground-track-repeat repeat ground track, eclipse-time duration and shadow fraction. Trigger: space systems, ECSS, power budget, battery, link budget, thermal, telemetry, sun pointing, star tracker, attitude control, TRIAD, attitude determination, magnetorquer, sun synchronous, inclination, orbital elements, ground track, eclipse time, beta angle.

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Vehicle Design · ashfordeou
Use when a task concerns aircraft or vehicle conceptual design and sizing: guide the router to the vehicle-design pack: tow-estimation takeoff gross weight, weight-estimation class-I weights, payload-range-diagram payload-range trade, fuselage-sizing cabin layout, tail-sizing tail volume coefficients, landing-gear-sizing strut loads, ws-tw-trade wing loading and thrust-to-weight, fuel-tank-sizing fuel volume and ullage, inertia-estimation moments of inertia, cg-envelope static margin, mass-budget mass rollup and growth allowance, wing-box-sizing spar sizing, fuselage-skin-stringer panel sizing, parametric-cost CERs, operating-cost DOC, life-cycle-cost LCC and learning curves. Trigger: vehicle design, sizing, weight estimation, takeoff gross weight, payload range, fuselage, tail volume, landing gear, strut loads, wing loading, thrust to weight, fuel tank, cg envelope, static margin, mass budget, growth allowance, wing box, spar, skin stringer, parametric cost, direct operating cost, life cycle cost, LCC.

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Flight Mechanics · ashfordeou
Use when a task concerns aircraft flight mechanics: guide the router to the flight-mechanics pack. breguet-range cruise range, breguet-endurance loiter endurance, specific-range cruise fuel economy, takeoff-performance takeoff distance, climb-performance rate of climb, oei-climb-gradient OEI climb gradient, energy-height specific excess power, descent-performance descent, turn-performance turn rate and load factor, glide-performance glide ratio and sink rate, wind-effects wind triangle and groundspeed, longitudinal-stability neutral point and static margin, lateral-directional-stability dihedral and Dutch roll, dynamic-stability short period and phugoid, trim-analysis stick trim, aileron-reversal control reversal speed. Trigger: flight mechanics, breguet range, loiter endurance, fuel flow, takeoff, rate of climb, OEI, engine out, energy height, specific excess power, descent, turn rate, glide ratio, sink rate, static margin, Dutch roll, phugoid, trim, aileron reversal.

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Do297 · ashfordeou bundle
Use when scoping an IMA platform, planning module acceptance, or laying out development assurance steps for an integrated modular avionics system. Plan the integrated modular avionics (IMA) platform architecture in the spirit of DO-297: identify the IMA modules, application partitions, and shared resources, allocate applications to partitions with CPU, memory, and I/O budgets, and check the allocation for resource contention against integrity and availability requirements. Produce the module and application allocation plan, the resource budget table, and the module acceptance criteria that support incremental certification of the platform. Trigger: integrated modular avionics, IMA architecture, module acceptance, incremental certification, partition allocation, resource budget.

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Manufacturing Quality · ashfordeou
Use when a task concerns aerospace manufacturing and quality management: guide the router to the manufacturing-quality pack. AS9100 quality, nonconformance-control, supplier-control, counterfeit-prevention, calibration-control, corrective-action, document-control, and statistical-process-control cover QMS scoping, disposition, supplier risk, counterfeit scoring, calibration, CAPA closure, controlled documents, and SPC; first-article-inspection, delta-fai, and fai-revalidation cover AS9102 FAI; ndt-method-selection, ultrasonic-inspection, eddy-current-inspection, and radiographic-inspection cover NDT. Trigger: manufacturing quality, AS9100, AS9102, first article inspection, QMS, corrective action, CAPA, 8D, five whys, document control, FAI, revalidation, counterfeit prevention, nonconformance, disposition, MRB, supplier control, calibration, test accuracy ratio, statistical process control, SPC, Cpk, NDT, radiography, ultrasonic, eddy current, depth of penetration.

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Flight Test Operations · ashfordeou
Use when a task concerns flight test operations: route to the flight-test-operations pack: envelope-expansion corner speed, load-factor-envelope load factor, v-speeds cert speeds, stall-speed-determination stall speed, stall-characteristics-testing stall behavior, accelerate-stop-distance rejected takeoff, takeoff-distance-determination takeoff distance, landing-distance-determination landing distance, glide-flight-test glide, flight-loads-survey strain calibration, flutter-testing flutter margin, ground-vibration-testing GVT, limit-cycle-oscillation LCO, dynamic-stability-flight-test mode damping, engine-flight-test performance, flight-test-planning planning, flight-test-instrumentation sensors, flight-test-data-reduction reduction, flight-test-safety risk and go no-go, telemetry-data-acquisition telemetry, test-point-matrix-design matrix. Trigger: flight test, envelope expansion, stall speed, V1, landing distance, flutter, GVT, instrumentation, test point, telemetry, dynamic stability, engine flight test.

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Planning · ashfordeou bundle
Use when planning DO-178C software certification for airborne systems or equipment: determine the software level or DAL (A-E) from failure-condition severity, draft the PSAC (Plan for Software Aspects of Certification), and scope planning-phase artifacts such as the PSAC, SDP, SVP, SCM, and SQA plans. Covers ARP4754A FDAL/IDAL allocation and ARP4761A severity-to-DAL propagation, including coverage-depth implications per level: A requires MC/DC, B requires decision coverage, C requires statement coverage, D and E require none. Trigger: DO-178C planning, PSAC, software level determination, DAL assignment, development assurance, certification planning, ARP4754A, ARP4761A, airborne software certification.

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Power Input · ashfordeou bundle
Use when reviewing a power-input test plan, analyzing captured input-power waveforms against the equipment category, or deciding whether a transient event stays within its category envelope. Assess DO-160 Section 16 power-input characteristics of airborne equipment: verify measured AC and DC steady-state voltages against normal and emergency limits, compute voltage-sag depth and voltage-surge height as percentages of nominal, check frequency-variation tolerance for 400 Hz AC buses, and verify transient-recovery time after a sag or surge event. Trigger: DO-160, power-input, voltage-sag, voltage-surge, frequency-variation, transient-recovery, emergency-power.

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Systems Engineering Safety · ashfordeou
Use when a task concerns aircraft or system-level engineering and safety assurance: guide the router to the systems-engineering-safety pack, covering ARP4754A systems-planning, requirements-traceability, requirements-allocation, verification-planning, and validation, ARP4761A safety-assessment, fta-fmea, common-cause-analysis, particular-risk-analysis, operating-support-hazard-analysis, and markov-analysis, and MBSE systems-engineering, sysml-modeling, state-machine, n2-diagram, and trade-study-analysis. This pack is the systems-level spine above item-level software and hardware assurance. Trigger: systems engineering, systems safety, ARP4754A, ARP4761A, safety assessment, fault tree, FMEA, common cause, particular risk, rotor burst, traceability, validation, allocation, verification planning, O&SHA, state machine, reachability, MBSE, SysML, N2 diagram, interface matrix, FDAL, IDAL, FHA, PSSA, SSA, trade study, Pugh matrix, Markov analysis, availability, MTTF.

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Development · ashfordeou bundle
Use when you must develop DO-178C airborne software lifecycle data for avionics items: capture high-level and low-level requirements, maintain bidirectional requirement-to-code trace links, identify derived requirements, and apply design/coding standards scaled to software level. Produce development-phase artifacts (requirements, design, code, trace matrix) for verification, with traceability closure and independent review at levels A and B. Ensure protection and safety assurance trace from top-level system protection needs down to low-level implementation and code, and maintain full coverage of verification results against each requirement and design element. Track verification coverage depth linking each test, analysis, or review outcome to originating requirements. Trigger: DO-178C development, requirements traceability, protection trace, protection assurance, safety assurance trace, verification coverage, derived requirements, low-level requirements, coding standards, software design, lifecycle data.

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Verification · ashfordeou bundle
Use when verifying DO-254 airborne electronic hardware: determine the verification methods that apply to a simple or complex AEH item, check whether independent verification is expected at the hardware design assurance level, validate requirements-based test coverage against the A/B and C/D ratios, review hardware/software integration evidence, and confirm the verification effort is complete against the required method set. Methods scale from reduced verification for simple AEH to test, analysis, and review for complex AEH. Trigger: do-254, verification, airborne electronic hardware, aehl, hardware design assurance, requirements-based test, hardware/software integration, review, analysis.

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Panel Method · ashfordeou bundle
Use when the task is panel method setup, source or doublet panels, Neumann or Dirichlet boundary conditions, Kutta condition enforcement, pressure distribution on an airfoil or fuselage, or potential flow over 3D bodies. Compute the surface pressure distribution and force coefficients for an airfoil or body in incompressible potential flow with a panel method: build panel geometry from a closed point list, assemble the source panel influence matrix for the Neumann boundary condition, assemble the doublet panel influence matrix for the Dirichlet boundary condition, solve the linear system, evaluate the surface velocity and pressure coefficient, integrate pressure for lift and drag, and apply the Kutta condition to fix trailing-edge circulation. Trigger: panel method, source panel, doublet panel, kutta condition, neumann boundary condition, dirichlet boundary condition, pressure coefficient, potential flow, 3d body.

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Cfs Architecture · ashfordeou bundle
Use when designing a cFS app, explaining cFS layering, or simulating software bus routing for flight software. Model and simulate NASA core Flight Software (cFS) architecture: explain the cFE/OSAL/PSP layering (Executive Services, Software Bus, Event Services, Table Services, Time Services, File Services), structure apps with the classic APP_Init, APP_Execute, APP_Data pattern, and route messages by 16-bit message ID over a software bus publish/subscribe model, with a pure-Python simulation that registers apps, subscribes to message IDs, publishes payloads, routes queued messages in publish order, stamps telemetry sequence counters, and logs events by severity. Trigger: cFS, core flight software, cFE, OSAL, PSP, software bus, publish subscribe, app skeleton, telemetry pipeline.

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Fprime Component · ashfordeou bundle
Use when designing or reviewing an F Prime topology, checking opcode and port-type consistency, or generating the component scaffold manifest. Model and validate a NASA JPL F Prime (F´) flight software component architecture: define components as active, queued or passive, attach typed input and output ports plus serial interfaces, register commands with unique opcodes, declare telemetry channels and severity-flagged events, connect producer outputs to consumer inputs across a topology, schedule component input ports in rate groups, and run a deterministic clocked dispatch simulation that records invocations, deliveries, command log entries and telemetry samples with per-channel sequence counters. Produces the validated component model, the connection and rate group report, and a scaffold manifest for code generation. Trigger: F Prime, F´, component framework, topology, rate group, command dispatch, telemetry channel, port connection, flight software modeling.

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Ima Partitioning · ashfordeou bundle
Use when sizing an ARINC 653 partition schedule, writing the partition configuration table, or reviewing inter-partition communication ports against frame, period, and latency budgets for certification. Compute and validate ARINC 653 integrated modular avionics (IMA) partition configurations: check partition schedule feasibility by summing the partition durations within the major frame and verifying that each partition receives its period slot, build the partition configuration table from frame and window data, bound sampling port and queuing port message latency for inter-partition communication, and scope the health monitoring responsibilities for fault detection and recovery. Trigger: ARINC 653, IMA, partition scheduling, major frame, MAF, sampling port, queuing port, inter-partition communication, health monitoring.

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Beam Vibration · ashfordeou bundle
Use when you must compute the natural frequencies of a continuous beam member: exact Euler-Bernoulli bending frequencies in hertz for pinned-pinned, cantilever, clamped-clamped and free-free end conditions from the characteristic-equation roots cos x cosh x = -1 and cos x cosh x = 1, the closed-form pinned-pinned law n^2 pi^2 sqrt(EI/(m L^4))/2pi, the shared rule f_n = (beta_n L)^2 sqrt(EI/(m L^4))/2pi, and a Rayleigh-quotient fundamental estimate omega^2 = 20 EI/(m L^4) for non-uniform cantilever shapes. Produces member natural frequencies for vibration clearance and excitation checks; complements the discrete 2-DOF modal-analysis leaf. Trigger: euler bernoulli beam, characteristic equation roots, cantilever beam, pinned-pinned beam, clamped beam frequency, free-free beam, rayleigh quotient, vibration clearance.

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Modal Analysis · ashfordeou bundle
Use when you must run a modal analysis of a two degree of freedom mass-spring structural model: compute the natural frequencies in rad/s and Hz, derive the mode shape ratios, and check an excitation frequency against the natural frequencies for resonance risk. Units are SI: masses in kg, stiffnesses in N/m, frequencies in rad/s and Hz. Trigger: modal analysis, natural frequency, mode shape, resonance, eigenvalue, vibration, two degree of freedom.

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671 published skills · page 4 of 7