Status: Accepted
Date: 2026-06-03
The airspeed failure behavior lane uses a new purpose-built mission,
assets/missions/airspeed_failure_behavior_mission.waypoints, not the legacy
airspeed_validation_mission.waypoints (which was for airspeed integration
testing and whose provenance must stay clean).
Locked geometry:
- Cruise altitude 100 m AGL (vertical margin so altitude loss / TECS fighting a bad airspeed is observable before terrain).
- 800 m reciprocal East/West measurement legs (~80 s East headwind, ~40 s West tailwind at the commanded 15 m/s with the -5 m/s reference wind).
- Fault injected on entering seq 4 (start of the East headwind measurement leg).
- Mission ends in RTL (seq 9); no landing sequence.
Completion semantics: completion = front-half progress + both measurement legs +
the planned seq-9 RTL reached and stabilized. A fault-triggered early
RTL/failsafe (AUTO->RTL before the measurement legs finish) is
autopilot_contained, not completion. The discriminator is the maximum mission
seq reached at the AUTO->RTL transition.
Full design rationale, alternatives, and open validation items:
("ADR (Proposed): Airspeed Failure Mission Design") and design_research.md.
Open validation (Phase 2 smoke): confirm seq numbering survives upload, the realized East-leg duration (~80 s), and clean RTL-completion detection.