14 CFR 25.1309: equipment, systems, and installations (transport aircraft certification)
Systems must be designed so that a failure condition that would prevent continued safe flight is extremely improbable, with warning information to let the crew take corrective action; the basis for redundancy and failure analysis in transport aircraft.
Draft mapping. Drafted by the Register's agents from the rule's text and not yet confirmed by a person. It is the Register's reading, not legal advice: whether and how the rule applies to you is a question for counsel.
Controls this rule maps to
Required by the text The rule's text requires a measure that is this control, or plainly includes it. Implied A binding rule whose purpose needs this control, but whose text does not name it. The Register's reading. Recommended A voluntary standard or guidance recommends it; nothing binds you to it. Proposed Appears in a proposed rule or proposed provision that is not yet in force.
| Control | Strength | Where in the rule, and why | Confidence | Missing or failed in |
|---|---|---|---|---|
| Input redundancy and disagreement check C-I2 | Implied | a single sensor driving a flight control function failed this standard's intent (MCAS) | high | 1 case |
| Warnings designed as alerts C-I4 | Required by the text | warning information adequate for the crew to act | high | 4 cases |
| Human takeover with a time window C-R3 | Implied | the crew must be able to take corrective action within the time available | medium | 2 cases |
Cases that cite this rule
| Case | How the case cites it | Outcome |
|---|---|---|
| Boeing 737 MAX MCAS | FAA certification rules (Part 25) | Ended in harm |