Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive' • Hacker News Board

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#281

Post by CaptainZapp » Fri, Apr 05, 2019, 10:14 AM UTC

7952 wrote: post #275

simion314 wrote: post #250

Earlier quoted context omitted.

So you blame the pilot that he is not training itself in the new hidden changes of the airplane? Isn't Boeing duty to create the checklists/procedures for the possible issue ? or we let this work for the pilots internet forums? Though from the article it appears that pilots followed all the official procedures,

Of course it is Boeing and airlines responsibility. But if for some reason that training was absent I would expect pilot to seek the information themselves. To suggest otherwise is an insult to their intelligence and professionalism. Of course pilots are going to take an interest in crashes on the aeroplane they fly! Particularly when it is the biggest aviation story in years. Porbably something that they discuss reg…

But if for some reason that training was absent I would expect pilot to seek the information themselves.

Here[1]'s a rather sobering read for you what happened to a pilot who tried exactly that.

Spoiler alert: It was not a smart carreer move at that time.

[1] https://qz.com/1584233/boeing-737-max-what-happened-when-one...

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#282

Post by piva00 » Fri, Apr 05, 2019, 2:02 PM UTC

treis wrote: post #225

mhandley wrote: post #7

Will be interesting to see the details when the report is actually public. It does sound like the scenario that Mentourpilot explored in the simulator is close to what happened, namely: Bad AoA probe causes MCAS to trim down, and also to indicate IAS disagree. Pilots increase throttle as per non-normal checklist to reduce the risk of stalling due to unreliable airspeed. Pilots disable electric stabilizer trim, as per…

>Pilots increase throttle as per non-normal checklist to reduce the risk of stalling due to unreliable airspeed. Pilots disable electric stabilizer trim, as per Boeing's advice, without trimming back to neutral trim. Pilots likely started to trim up with the manual trim wheels, but that's very slow, and gets harder as airspeed increases. I can see that at extreme trim and high speed that it could be difficult to manu…

IIRC the problem with MCAS is that it will "reset" the maximum of 2.5 deg every time it kicks in, so it goes: MCAS kicks in -> apply max 2.5 deg -> pilot correction -> MCAS kick in -> ANOTHER +2.5 deg max, and it goes cycling every 10-20 seconds.

At least I recall reading this from some comment here in HN from someone well versed with the 737 MAX.

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#283

Post by jki275 » Fri, Apr 05, 2019, 3:16 PM UTC

dis-sys wrote: post #274

jki275 wrote: post #152

Earlier quoted context omitted.

The last minute when they grounded them? I don't recall them "defending" anything, anyway, they simply held off grounding them until they got a little bit of data to back it up.

> they simply held off grounding them until they got a little bit of data to back it up In my dictionary I have the following term which FAA and Boeing both actively ignored/violated. pre·cau·tion /prəˈkôSH(ə)n/ noun a measure taken in advance to prevent something dangerous, unpleasant, or inconvenient from happening.

You have to balance "precaution" with "knee-jerk".

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#284

Post by TheSpiceIsLife » Fri, Apr 05, 2019, 11:03 PM UTC

VBprogrammer wrote: post #107

mhandley wrote: post #89

Earlier quoted context omitted.

There's no trim tab on a 737 - the whole horizontal stabilizer is moved to trim the aircraft in pitch. Normally this is done electrically, but the stabilizer jackscrew can also be moved using manual trimwheels that move the jackscrew using physical cables. Whether this is possible at high airspeed while the stabilizer is trimmed nose down, and the elevator is being pulled up as hard as you can to avoid diving - that'…

Something else I've started to wonder about is what the manouvering speed is on a 737. I can't find a good reference but 280 knots is suggested as a turbulent air penetration speed which should be in the same ballpark Applying full back elevator above this speed can bend the airplane (cyclic movements even more so).

The rudder / vertical stabiliser snapped off this one https://en.wikipedia.org/wiki/American_Airlines_Flight_587

Re: Ethiopian Airlines Boeing 737 pilots 'could not stop nosedive'

#285

Post by _5uxp » Sat, Apr 06, 2019, 10:54 AM UTC

matt4077 wrote: post #12

I’d love to see those people who accused the airline and crew of being incompetent to apologize in the light of these reports. It was shameful to see Boeing actively encouraging that narrative behind the scenes. Especially considering it plays on racist stereotypes equating „Africa“ with bad training/bad safety record/…. The idea of „dingy third world airline“ was ridiculous on its face, considering how bad a fit fly…

Ryanair doesn't have a single crash with fatalities in their history and they're worse? They fly more frequently yet they're safer. That safety rating seems not that reliable.