Part107 Sora

Part 107 and SORA UAS Risk Assessment (flight-test-operations/uas/part107-sora)

Use when a small UAS (drone) operation must be screened for FAA 14 CFR Part 107 applicability and categorized for risk under the EASA SORA (Specific Operations Risk Assessment) methodology, ending in an operational safety case summary. The logic module scripts/part107_sora_logic.py implements the checks; the contract test scripts/test_part107_sora.py pins the correct answers. See references/part107-sora-refs.md for the regulatory background and the simplifications made.

Domain quick reference

Part 107 applicability (FAA 14 CFR Part 107, small UAS rule)

All checks must pass for the operation to be flown under Part 107. Any failed check lists the waiver or approval needed in waivers_required. Operations over 55 lb are outside Part 107 entirely (different certification path).

SORA operational categories from kinetic energy and population density

Kinetic energy: KE = 0.5 * mass_kg * speed_mps^2 (characteristic cruise speed, default 20 m/s). Ground risk class (GRC) comes from the intrinsic GRC table below. Category mapping (simplified, per sora_operational_category):

Intrinsic GRC table (JARUS SORA 2.0 style, simplified)

Rows: kinetic energy in joules. Columns: population density in people per square km. Value: intrinsic GRC (1-9).

Air risk class (ARC) from airspace type

Operating above 400 ft AGL escalates the ARC one level (manned traffic density grows with altitude).

SORA robustness levels and containment

Robustness of mitigations: none, low, medium, high. GRC reduction credit is 0, 1, 2, 3 respectively; final GRC is floored at 1. Claiming any mitigation credit requires operational containment (geofencing plus contingency procedures); that is what makes the reduction credible. High robustness means containment with automatic activation and fail-safe behavior.

BVLOS waiver considerations

BVLOS (beyond visual line of sight) is not permitted under vanilla Part 107. The operator needs a 14 CFR 107.31 waiver or FAA BVLOS rule approval (verify current FAA guidance), plus: observer or approved detect-and-avoid capability, remote ID compliance (14 CFR 89), airspace authorization for the whole BVLOS volume, lost link and contingency procedures, route weather and visibility minima, airframe reliability evidence, and crew training.

Workflow

1. Screen with part107_applicable(weight_lb, vlos, daylight, altitude_agl_ft, airspace_class, remote_pilot_cert, airspace_authorization). All checks must pass for Part 107 flight.
2. Estimate mass in kg (55 lb = 25 kg) and characteristic speed; call kinetic_energy(mass_kg, speed_mps) for KE.
3. Call ground_risk_class(ke_j, population_density) for the intrinsic GRC from the table.
4. Call sora_operational_category(mass_kg, population_density, speed_mps) to get the EASA category (open, specific, certified).
5. Call arc_from_airspace(airspace_type, altitude_agl_ft) for the ARC.
6. Choose the robustness of planned mitigations and call robustness_level(grc, mitigation) for the final GRC and the containment requirement.
7. If BVLOS is planned, call bvlos_waiver_considerations(vlos=False) and carry the considerations into the safety case.
8. Call ops_summary(...) to assemble the operational safety case summary block.

Worked example

2 kg (4.4 lb) multirotor, 20 m/s, over sparsely populated farmland (density 0.5 people/km2), Class G, 200 ft AGL, VLOS, daylight, remote pilot certificate held.

• part107_applicable(4.4) -> applicable True, no waivers.
• KE = 0.5 * 2 * 20^2 = 400 J.
• ground_risk_class(400, 0.5) -> GRC 3 (row 108-700 J, column < 1).
• sora_operational_category(2.0, 0.5) -> category open, GRC 3.
• arc_from_airspace("g", 200) -> ARC-a.
• robustness_level(3, "none") -> final GRC 3, no containment required.
• ops_summary -> summary shows APPLICABLE, OPEN, GRC 3, ARC-a.

25 kg UAS, 20 m/s, over a dense city (500 people/km2), Class C.

• KE = 0.5 * 25 * 20^2 = 5000 J.
• ground_risk_class(5000, 500) -> GRC 9 (row > 2400 J, column > 250).
• sora_operational_category(25.0, 500.0) -> category certified, GRC 9 (the 25 kg mass sits exactly on the open ceiling and the GRC forces the specific/certified boundary upward).
• arc_from_airspace("c") -> ARC-c.
• robustness_level(9, "high") -> final GRC 6, containment required.
• The operation needs Part 107.41 authorization (LAANC or waiver) and, realistically, a certified aircraft path.

Pitfalls

• Screening an over-55-lb aircraft with the Part 107 applicability check: those operations are outside Part 107 entirely and take a different certification path; within the rule, any failed check lists the waiver or approval needed in waivers_required.
• Computing kinetic energy on the wrong basis: KE = 0.5 * mass_kg * speed_mps^2 uses the characteristic cruise speed (default 20 m/s), and the 25 kg ceiling equals 55 lb.
• Reading the GRC from the kinetic energy alone: the intrinsic GRC table is kinetic energy by population density, so 5000 J over a dense city reads GRC 9 while the same energy over < 1 person/km2 reads GRC 5.
• Assuming mitigation credit is free: robustness credit (0/1/2/3 for none/low/medium/high) requires operational containment (geofencing plus contingency procedures), high robustness means automatic activation with fail-safe behavior, and the final GRC floors at 1.
• Flying BVLOS under vanilla Part 107: it is not permitted; BVLOS needs a 14 CFR 107.31 waiver or FAA BVLOS rule approval plus the observer/DAA, remote ID, airspace authorization, lost-link, and crew-training considerations.
• Treating 25 kg as safely inside the open category: the mass sits exactly on the open ceiling, so the GRC decides - 5000 J over a city lands certified with GRC 9, not open.

Behavior contract (gate 3)

The behavior contract is scripts/test_part107_sora.py against scripts/part107_sora_logic.py (stdlib unittest, offline, deterministic). Run:

python3 scripts/test_part107_sora.py

It asserts: 2 kg over sparse population -> open category with low GRC 3; 25 kg over a city -> specific/certified boundary with high GRC 9; weight over 55 lb fails Part 107 applicability; GRC table spot values; ARC mapping and altitude escalation; robustness reductions and the containment requirement; BVLOS waiver flag; and every invalid input raises ValueError.

References

• references/part107-sora-refs.md: 14 CFR Part 107 section map, EASA Regulation 2019/947 and SORA 2.0 background, simplification notes.
• scripts/part107_sora_logic.py: the logic module (pure Python, stdlib only).
• scripts/test_part107_sora.py: the behavior contract test.

Related skills

• flight-test-operations/planning/flight-test-safety: flight test safety planning for manned aircraft; pairs with the UAS risk screen when a UAS supports flight test instrumentation.
• flight-test-operations/planning/flight-test-planning: overall test planning context into which the UAS safety case feeds.

Compliance

• 14 CFR Part 107 is US government work (public domain); summarized with citations only, per standards-map.yaml policy.
• EASA SORA and Regulation 2019/947 referenced as guidance; paraphrased summary only in references/part107-sora-refs.md.
• compliance: STANDARDS-REF, gated: false.