MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
I have not seen anything stating that the MCAS paid any attention to pilot input. The length of the MCAS trimming appears to be solely determined by Mach and altitude. Lower altitude, close to ten seconds. Nice try on blaming the pilots again, though.
The pilots of neither airplane got anywhere close to a stall...and in fact were pulling with all their might because the 'mountain' (rising terrain, ocean) wasn't budging.
Strike two.
The pilots of neither airplane got anywhere close to a stall...and in fact were pulling with all their might because the 'mountain' (rising terrain, ocean) wasn't budging.
Strike two.
The discussion was for what MCAS was designed to do when the AoA system was working correctly.
MCAS should also be dependent on AoA - which it was doing in the accident aircraft. The amount of trim is dynamic pressure dependent so there's that, but it should gradually apply trim AND as the AoA increases and stop if the AoA stops increasing rather than running continuously for no reason. Again, under the conditions it was designed for. Since the AoA was not decreasing, MCAS ran until the timer ran out.
OldnGrounded
It was not a secret by the time the ET302 flight crashed. I knew how it was working with the failed AoA data and how it responded to the pilots from the preliminary report that was issued in, what, December? Months before ET302. I think that knowing a little about it was what made things worse for ET302 as the pilots seemed to pick some details and actions out-of-order and in the worst possible way, as if they recalled reading something about it once but were foggy on the details.
A critical piece I've never seen is the force required to hold the nose up through the progress of the accident flights and at what point the forces should have been high enough to demand attention to pitch trim.
It was not a secret by the time the ET302 flight crashed. I knew how it was working with the failed AoA data and how it responded to the pilots from the preliminary report that was issued in, what, December? Months before ET302. I think that knowing a little about it was what made things worse for ET302 as the pilots seemed to pick some details and actions out-of-order and in the worst possible way, as if they recalled reading something about it once but were foggy on the details.
A critical piece I've never seen is the force required to hold the nose up through the progress of the accident flights and at what point the forces should have been high enough to demand attention to pitch trim.
pullling hard back on the yoke due to muscle memory while under negative g
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Many months ago it was highlighted that the 737 had a smaller elevator in relation to the stabiliser than other Boeing aircraft. The longer this goes on the more relevant it appears.
Also given MCAS was a turbo trim speed - more reason to pull back on the yoke than use the slow trim switch to gain height.
I honestly doubt the crews noticed much in the way of any G forces, but that is just a guess.
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Finally Another Test Flight
After no apparent test flights for almost three weeks, there was finally another flight yesterday,. Hopefully Friday the 13th will bring some luck to Boeing.
If you haven't looked at the flight tracking for these test flights as of yet, you are missing something fascinating. Go to flightaware.com and for the flight, type in BOE1. Then scroll down to see the flights by date.
If you haven't looked at the flight tracking for these test flights as of yet, you are missing something fascinating. Go to flightaware.com and for the flight, type in BOE1. Then scroll down to see the flights by date.
The ground was close- pushing forward would be not a thing to do, when you wish to climb G or no G every visual indicator was pull up.
Also given MCAS was a turbo trim speed - more reason to pull back on the yoke than use the slow trim switch to gain height.
I honestly doubt the crews noticed much in the way of any G forces, but that is just a guess.
Also given MCAS was a turbo trim speed - more reason to pull back on the yoke than use the slow trim switch to gain height.
I honestly doubt the crews noticed much in the way of any G forces, but that is just a guess.
I prefer not to be narrow minded, so happy to hear your relevance of the G.
FWI, my limited experience with G's and flying.
Is that the fun beat ups dog fighting over the beach to impress some campers in a Pitts and a Yak proved to have much higher G recorded on the meter than a aerobatic display. The dog fight seemed less G than the hard display on my body - but the G meter showed much different.
P.S I am not a pilot but have worked in the industry in several countries at many levels since 1985 also a aircraft owner
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After no apparent test flights for almost three weeks, there was finally another flight yesterday,. Hopefully Friday the 13th will bring some luck to Boeing.
If you haven't looked at the flight tracking for these test flights as of yet, you are missing something fascinating. Go to flightaware.com and for the flight, type in BOE1. Then scroll down to see the flights by date.
If you haven't looked at the flight tracking for these test flights as of yet, you are missing something fascinating. Go to flightaware.com and for the flight, type in BOE1. Then scroll down to see the flights by date.
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Quote:
Originally Posted by Grebe 
Well- simply by pullling hard back on the yoke due to muscle memory while under negative g
Well- simply by pullling hard back on the yoke due to muscle memory while under negative gLast edited by OldnGrounded; 14th Dec 2019 at 13:16.
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It is a known phenomenon that some people react to negative G with a large and sustained PUSH on the stick to a crazy attitude (+forward trim if applicable), even if there are massive visual cues that it is excessive. For example, it has resulted in fatal glider accidents after a winch cable break (first action, adopt a normal gliding attitude = brief period of negative G), where the pilot has pushed, and continued to push extreme nose down, right into the runway clearly visible outside the canopy.
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Quote:
Originally Posted by Grebe Well- simply by pullling hard back on the yoke due to muscle memory while under negative g
Well- simply by pullling hard back on the yoke due to muscle memory while under negative g1) As I recall, the flight recorder traces on one of the flights did show negative g due to flight path altitude change ??
2) My frame of reference was to the pilots body, positive g being what you get when you are normally pushed down towards your butt, and negative being when your motion is towards your brain or top of head while sitting.
3) If one assumes you start in level flight i/n smooth air- then 1 g positive. IF you or HAL pushes stick forward or moves elevator - stabilizer such that you rapidly start to dive, the flight path ** starts** to be circular in the vertical plane. And assuming you stayed in the ' outside' loop, pilot-passengers would be experiencing negative G- ( motion towards your head ) throughout. Just how much would depend mostly on velocity. And unless you are strapped in, you will float up !
4) Several examples come to mind - Vomit comet with a 707, etc in a parabolic flight path
A ' circular ' orbit around the earth since you- station- are ' falling' towards the center of earth, etc in a mostly circular flight path.
Nuff...
Sick, #4508 ‘It is a known phenomenon that some people react to negative G with a large and sustained PUSH on the stick to a crazy attitude (+forward trim if applicable), ’
See Flydubai accident - not so much negative ‘g’ as a reduction - less than 1.
Any technical references or formal definition for this phenomenon ?
See Flydubai accident - not so much negative ‘g’ as a reduction - less than 1.
Any technical references or formal definition for this phenomenon ?
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Groooannnn- suspect some missed my sarcasm for starters - but perhaps a bit more explanation by this SLF as to the negative g comment- For the real pilots here - please excuse me -its just attempt to clarify what I think someone missed is the frame of reference- being the pilots-crew- passenger frame .
*As experienced, of course. We're really talking about relative acceleration, but neg-G is the usual terminology.
Last edited by OldnGrounded; 14th Dec 2019 at 15:25. Reason: Clarification
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Sick, #4508 ‘It is a known phenomenon that some people react to negative G with a large and sustained PUSH on the stick to a crazy attitude (+forward trim if applicable), ’
See Flydubai accident - not so much negative ‘g’ as a reduction - less than 1.
Any technical references or formal definition for this phenomenon ?
See Flydubai accident - not so much negative ‘g’ as a reduction - less than 1.
Any technical references or formal definition for this phenomenon ?
https://uk.flightaware.com/live/flight/BOE1
Flightaware is nice since you can replay the flight by positioning and moving the slider on the speed/altitude chart and it shows the corresponding aircraft position on the track. The slider is shown below at 18 mins.
