Canada, Europe Add MAX Fixes

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The FAA has signed off on significant changes to the Boeing 737 MAX’s flight control systems mandated by Canada and the European Union. The changes won’t delay the return to service but will cost Boeing money in the long term. According to the Seattle Times, the European Aviation Safety Administration (EASA) has demanded three changes beyond the rewrite of the software behind the Maneuvering Characteristics Augmentation System (MCAS). The MCAS rewrite is fundamental to the aircraft’s recertification. Canada is insistent on one of those changes. The FAA has told Boeing that it will require the potentially costly fixes but not until after the plane is cleared to fly. The MAX has been grounded for more than a year after two fatal crashes in Indonesia and Ethiopia that started with bad data from a single angle of attack indicator. 

EASA wants pilots to be able to shut off the stick shaker when it’s obviously been triggered erroneously. The stick shaker operated for almost the full length of the six-minute flight that ended in a nearly supersonic dive in Ethiopia. It also wants the fix that makes MCAS require agreement from two AOAs to apply to other systems. EASA also wants the MAX to have the equivalent level of redundancy provided by the third AOA that is on all Airbus aircraft. It doesn’t have to be a third AOA but it does have to provide the same redundancy. EASA says the pilots on both aircraft were inundated by cacophonous and contradictory alarms about the state of flight from a single bad sensor and wants an unspecified fix for that. Canada is adamant only about the stick shaker shut-off, saying it added unnecessarily and unhelpfully to the stress in the cockpit of the crash airplanes. As an interim fix it’s proposing a flight manual amendment to show pilots the location of the circuit breaker for the stick shaker (on one of the overhead panels) and to add “collars” to identify it.

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10 COMMENTS

  1. “…As an interim fix [Canadian authorities are] proposing a flight manual amendment to show pilots the location of the circuit breaker for the stick shaker (on one of the overhead panels) and to add ‘collars’ to identify it.”

    Another Boeing “secret,” revealed. A shocking coverup.

  2. You can’t make any airplane crash proof if their is mass confusion on the flight deck, but as training standards lag around the globe it seems we are trying to do just that. Years ago a B52 crashed in the pacific because the pilots though they were in a high speed dive( air speed indicator failure). They were actually in a stall. They had full nose up trim and the wheel in their lap and the Nav told them their Doppler speed was about 100 knots. The Aircraft commander had never noticed in all his hours that at cruise speed the trim was always 1 1/2 to 2 units nose down and that it was a lot quieter on the flight deck than a high speed dive ought to be. The Air Force taught me to drive a T37 and T38 but I had learned to fly, thankfully, in the civilian world by flying about 25 different airplanes and hangar flying around the FBO with lots of WW2 guys and Ag guys, Exec guys. I was a very fortunate kid. The military rams folks through training in one year in a sterile environment that allows few mistakes, which isn’t much time to absorb a ton of “air sense”.

  3. Have these two agencies thought through the consequences of someone erroneously disabling the stick shaker? In fact, though I don’t recall the specific accident, I thought there was one crash that was a result of the stick shaker being disabled in the accident aircraft.

  4. Other than in a sim, can any airline pilot recall a situation where a stick shaker
    would be activated?
    I say this as a comment was made that disabling this is detrimental to the safety of the rest of the flight.
    Please tell me the situation you would get in to to activate this device.
    (Of course we know what causes a stall, but how would YOU allow it?)

    • A stick shaker could, as has, activated due to pitot tube failures or damage (f.e. a bird strike). In these occasions it could be beneficial to stop the noise/haptic feedback. But, one must know what he/she is doing and what state the aircraft is in before pulling that C/B !

  5. Mauro H is correct. The Hawker 800xp that I fly has some checklist scenarios that call for deactivating by pulling stick shaker circuit breaker. The end of those checklists have cautions about doing so. I don’t see a problem with this change asked for by Canada. The training of pilots for flying this plane is another matter.