PPRuNe Forums - View Single Post - Boeing 737 Max Software Fixes Due to Lion Air Crash Delayed
Old 18th Apr 2019, 17:51
  #696 (permalink)  
Join Date: Dec 2002
Location: UK
Posts: 2,487
Likes: 0
Received 25 Likes on 12 Posts
The FAAs position on simulator training could be justified if based on the re-run Flight Ops review (was this the same team which overlooked MCAS first time round?).

However, if alternative views on training requirements for the 737 Max reconsider what is known, what has been learnt from these accidents, then simulation must be considered, even mandated. In particular for the recognition and timely action for trim runaway (trim moves, is this normal STS, or normal MCAS, or failed trim - 5 sec observation to differentiate). MCAS adds a further dimension to the evaluation process; a longer time period for recognition could generate more out of trim before its inhibited. Also the relevance of speed management - trim forces, requires hands on training.

Probably the most important aspect is to appreciate the feel of a mis-trimmed aircraft, switch selection, and the difficulty with manual (wheel) trim operation, particularly if starting with larger out of trim conditions. Also practicing the procedure required to regain control (Boeing advice on "aerodynamically relieving airloads" using manual stabilizer trim); is this really the same as in previous aircraft? Is it acceptable now?

MCAS is required to meet certification requirements, but the need for that reflects a difference between NG and Max, which is not necessarily adjusted through out the flight envelope (where MCAS is not programmed to operate). Is the Max the same, or just good enough to be called the same; what pilot compensation is assumed in this.
A further thought is if the Max pitch characteristics change the nose-up trim runaway case. Does the engine/ nacelle nose-up pitching moment aid nose up failures? Also, there has been little said about the engine/nacelle affecting downwash.

If the Canadian position reflects these aspects, then perhaps other certification authorities will ask similar questions relating to the overall safety case, not just that relevant to MCAS mods.
What were the Flight Ops review terms or reference?
Who will review the overall safety scene for the Max based on the findings of the accident investigations, and when.
What was the initiating factor in these accidents; vane, vane output, software conversation / corruption; a random effect, Murphy, Sod, or calculable probability?

safetypee is offline