4 ms·

I'm very surprised this article remains published. It directly contradicts the actual narrative of events (including the EAD that, if followed as by the first f

I'm very surprised this article remains published. It directly contradicts the actual narrative of events (including the EAD that, if followed as by the first flights with recorded MCAS issues, offered a prevention for the subsequent crashes) and unfortunately perpetuates incorrect definitions and understandings of runaway trim and unstable airframes.

sofixa 5y ago
> including the EAD that, if followed as by the first flights with recorded MCAS issues, offered a prevention for the subsequent crashes The one that was followed by the Ethiopian pilots and the plane still crashed, resulting in the grounding of the 737 Max by all aviation authorities bar the FAA?
- WalterBright 5y ago
  It wasn't followed by the Ethiopian pilots. For reference: Boeing Emergency Airworthiness Directive "Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTOUT switches to CUTOUT. Manual stabilizer trim can be used before and after the STAB TRIM CUTOUT switches are moved to CUTOUT." https://theaircurrent.com/wp-content/uploads/2018/11/B737-MAX-AD-1107.pdf https://theaircurrent.com/wp-content/uploads/2018/11/B737-MA... I highlighted the omitted action.
  - ummonk 5y ago
    You keep saying this every time the 737 Max comes up on HN. I don't know why you still can't understand that "can be" has a very different meaning from "must be", and the Ethiopian Airlines pilots followed the procedures as written. The Boeing airworthiness directive was incredibly poorly written, and Boeing is to blame for this, not the pilots who attempted to follow the directive as written.
    - WalterBright 5y ago
      I bring it up because nobody else ever does. If they did not understand the EAD, all of it, it was their job to get clarification. P.S. At least you read it. That's nice to see, and rare.
      - sofixa 5y ago
        Like all the pilots, including from Lion Air, that requested extra training from Boeing and were laughed at?
        WalterBright 5y ago
        Asking for clarification is not like asking for more training.
        sofixa 5y ago
        But after Boeing laughed at their "incompetence" for asking for training, how could they confidently ask for clarification?
        WalterBright 5y ago
        Someone that unconfident shouldn't be a pilot. Besides, consider that overhead is a matrix of circuit breakers. Their purpose is so the pilot can individually shut down each system. They work just like the breakers in your house. The stab trim, however, is so important the switch is right there on the console within quick & easy reach. It's still a breaker, though. It works by cutting off all power to the trim motors. It's really not rocket science. It's a freakin' switch.
    - salawat 5y ago
      It also didn't mention that you had 5 seconds after the release of the electronic trim switch to flip the CUTOUT before MCAS poured back on the trim, but as I recall that took more digging to find out afterward. This was also not pointed out in any type of pilot accessible documentation either; nor did it apparently make it's way to the FAA; as I recall them mentioning it was supposed to at max apply .6 degrees trim at once, but was later changed to ramp up to 2.5 degrees trim repeatedly, without an updated safety analysis. Paperwork update failure: https://www.avweb.com/recent-updates/business-military/mcas-certification-flawed-report/ https://www.avweb.com/recent-updates/business-military/mcas-... Electric stab trim switch reset of MCAS activation timer was mentioned in the final report. https://www.faa.gov/foia/electronic_reading_room/boeing_reading_room/media/737_RTS_Summary.pdf https://www.faa.gov/foia/electronic_reading_room/boeing_read...

sofixa 5y ago

> including the EAD that, if followed as by the first flights with recorded MCAS issues, offered a prevention for the subsequent crashes The one that was followed by the Ethiopian pilots and the plane still crashed, resulting in the grounding of the 737 Max by all aviation authorities bar the FAA?

WalterBright 5y ago
It wasn't followed by the Ethiopian pilots. For reference: Boeing Emergency Airworthiness Directive "Initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied. Electric stabilizer trim can be used to neutralize control column pitch forces before moving the STAB TRIM CUTOUT switches to CUTOUT. Manual stabilizer trim can be used before and after the STAB TRIM CUTOUT switches are moved to CUTOUT." https://theaircurrent.com/wp-content/uploads/2018/11/B737-MAX-AD-1107.pdf https://theaircurrent.com/wp-content/uploads/2018/11/B737-MA... I highlighted the omitted action.
- ummonk 5y ago
  You keep saying this every time the 737 Max comes up on HN. I don't know why you still can't understand that "can be" has a very different meaning from "must be", and the Ethiopian Airlines pilots followed the procedures as written. The Boeing airworthiness directive was incredibly poorly written, and Boeing is to blame for this, not the pilots who attempted to follow the directive as written.
  - WalterBright 5y ago
    I bring it up because nobody else ever does. If they did not understand the EAD, all of it, it was their job to get clarification. P.S. At least you read it. That's nice to see, and rare.
    - sofixa 5y ago
      Like all the pilots, including from Lion Air, that requested extra training from Boeing and were laughed at?
      - WalterBright 5y ago
        Asking for clarification is not like asking for more training.
        sofixa 5y ago
        But after Boeing laughed at their "incompetence" for asking for training, how could they confidently ask for clarification?
        WalterBright 5y ago
        Someone that unconfident shouldn't be a pilot. Besides, consider that overhead is a matrix of circuit breakers. Their purpose is so the pilot can individually shut down each system. They work just like the breakers in your house. The stab trim, however, is so important the switch is right there on the console within quick & easy reach. It's still a breaker, though. It works by cutting off all power to the trim motors. It's really not rocket science. It's a freakin' switch.
  - salawat 5y ago
    It also didn't mention that you had 5 seconds after the release of the electronic trim switch to flip the CUTOUT before MCAS poured back on the trim, but as I recall that took more digging to find out afterward. This was also not pointed out in any type of pilot accessible documentation either; nor did it apparently make it's way to the FAA; as I recall them mentioning it was supposed to at max apply .6 degrees trim at once, but was later changed to ramp up to 2.5 degrees trim repeatedly, without an updated safety analysis. Paperwork update failure: https://www.avweb.com/recent-updates/business-military/mcas-certification-flawed-report/ https://www.avweb.com/recent-updates/business-military/mcas-... Electric stab trim switch reset of MCAS activation timer was mentioned in the final report. https://www.faa.gov/foia/electronic_reading_room/boeing_reading_room/media/737_RTS_Summary.pdf https://www.faa.gov/foia/electronic_reading_room/boeing_read...