Originally Posted by
Loose rivets
Well the motor is of course adjacent to the jackscrew, but my suggested boost would need to be like powered steering, sensing the applied effort on the cables and boosting that long run. It would also have to be at the rear.
My concerns were for a situation where the European agency - and others - continue to refuse recertification due to control loads. A worst case scenario.
If EASA is interpreting the rules hard, then this trim assist may need to fulfill DAL-A if the new system can result in a runaway.
Either you have a mechanical solution to handle put of trim situations, or your have a system with electronics software etc.
If the current system had fulfilled DAL A, then we would not have had the two accidents.
MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
25.671: Control systems: General
The aeroplane must be shown by analysis, tests, or both, to be capable of continued safe flight within the normal flight envelope, without requiring exceptional piloting skill or strength after the following failures:
-A runaway of a flight control to an adverse position and jam must be accounted for if such runaway and subsequent jamming is not extremely improbable (Probability of 1 x 10-9 or less per flying hour )