737 MAX grounded
03-17-2019, 07:46 AM
#72
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The situation they put themselves in was: a heavy jet at FL350, a pilot commanded pitch attitude that exceeded 15 degrees nose up while constantly remaining above 10 degrees, with a vertical speed that briefly exceeded +6500 fpm resulting in a rapid climb from FL350 to FL380. That is the error that led to the undesired state, not the frozen pitot tubes.
03-17-2019, 10:53 AM
#73
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Joined APC: Dec 2013
Posts: 501
The situation they put themselves in was: a heavy jet at FL350, a pilot commanded pitch attitude that exceeded 15 degrees nose up while constantly remaining above 10 degrees, with a vertical speed that briefly exceeded +6500 fpm resulting in a rapid climb from FL350 to FL380. That is the error that led to the undesired state, not the frozen pitot tubes.
At around 2 h 08, the PNF proposed “go to the left a bit [...]”. The HDG mode was activated and the selected heading decreased by about 12 degrees in relation to the route. The PNF changed the gain adjustment on his weather radar to maximum, after noticing that it was in calibrated mode. The crew decided to reduce the speed to about Mach 0.8 and engine de-icing was turned on.
At 2 h 10 min 05, likely following the obstruction of the Pitot probes by ice crystals, the speed indications were incorrect and some automatic systems disconnected. The aeroplane’s flight path was not controlled by the two copilots. They were rejoined 1 minute 30 later by the Captain, while the aeroplane was in a stall situation that lasted until the impact with the sea at 2 h 14 min 28.
At 2 h 10 min 05, the autopilot then the auto-thrust disconnected and the PF said “I have the controls”. The aeroplane began to roll to the right and the PF made a nose-up and left input. The stall warning triggered briefly twice in a row. The recorded parameters showed a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS). The flight control law reconfigured from normal to alternate. The Flight Directors (FD) were not disconnected by the crew, but the crossbars disappeared.
2 h 10 m 5 is when the wild flying started. Not before.
Only gets worse from there. My only point is this could have been any aircraft type if the crew isn't properly trained. And let's be realistic... This certainly wasn't the first Airbus, Boeing, Embraer, whatever to encounter conditions outside the certification limits of the airplane. This one didn't go down because the "scary computers" or lack of tactile feedback. But I digress..
Last edited by Barley; 03-17-2019 at 11:28 AM.
03-17-2019, 02:06 PM
#74
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Position: On the bus,seat 0A
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I thought the issue with the engines had more to do with increased thrust capability? Not saying aerodynamics, lift from the larger nacelle isn't an issue, but wouldn't more power combined with the forward and upward placement of the engines on the wing being the major factor?
03-17-2019, 02:51 PM
#75
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Joined APC: Apr 2010
Posts: 696
Forward (plus larger) sure does when the AOA is high. Think of yawing a bit for a similar example, now bolt on a big vertical stab ahead of the CG. Not exactly good for control.
03-17-2019, 02:55 PM
#76
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The error was flying into a powerful storm. That quickly obstructed the pitot tubes with ice crystals. The errors continued to cascade from that point. This is from the final accident report:
At around 2 h 08, the PNF proposed “go to the left a bit [...]”. The HDG mode was activated and the selected heading decreased by about 12 degrees in relation to the route. The PNF changed the gain adjustment on his weather radar to maximum, after noticing that it was in calibrated mode. The crew decided to reduce the speed to about Mach 0.8 and engine de-icing was turned on.
At 2 h 10 min 05, likely following the obstruction of the Pitot probes by ice crystals, the speed indications were incorrect and some automatic systems disconnected. The aeroplane’s flight path was not controlled by the two copilots. They were rejoined 1 minute 30 later by the Captain, while the aeroplane was in a stall situation that lasted until the impact with the sea at 2 h 14 min 28.
At 2 h 10 min 05, the autopilot then the auto-thrust disconnected and the PF said “I have the controls”. The aeroplane began to roll to the right and the PF made a nose-up and left input. The stall warning triggered briefly twice in a row. The recorded parameters showed a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS). The flight control law reconfigured from normal to alternate. The Flight Directors (FD) were not disconnected by the crew, but the crossbars disappeared.
2 h 10 m 5 is when the wild flying started. Not before.
Only gets worse from there. My only point is this could have been any aircraft type if the crew isn't properly trained. And let's be realistic... This certainly wasn't the first Airbus, Boeing, Embraer, whatever to encounter conditions outside the certification limits of the airplane. This one didn't go down because the "scary computers" or lack of tactile feedback. But I digress..
At around 2 h 08, the PNF proposed “go to the left a bit [...]”. The HDG mode was activated and the selected heading decreased by about 12 degrees in relation to the route. The PNF changed the gain adjustment on his weather radar to maximum, after noticing that it was in calibrated mode. The crew decided to reduce the speed to about Mach 0.8 and engine de-icing was turned on.
At 2 h 10 min 05, likely following the obstruction of the Pitot probes by ice crystals, the speed indications were incorrect and some automatic systems disconnected. The aeroplane’s flight path was not controlled by the two copilots. They were rejoined 1 minute 30 later by the Captain, while the aeroplane was in a stall situation that lasted until the impact with the sea at 2 h 14 min 28.
At 2 h 10 min 05, the autopilot then the auto-thrust disconnected and the PF said “I have the controls”. The aeroplane began to roll to the right and the PF made a nose-up and left input. The stall warning triggered briefly twice in a row. The recorded parameters showed a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS). The flight control law reconfigured from normal to alternate. The Flight Directors (FD) were not disconnected by the crew, but the crossbars disappeared.
2 h 10 m 5 is when the wild flying started. Not before.
Only gets worse from there. My only point is this could have been any aircraft type if the crew isn't properly trained. And let's be realistic... This certainly wasn't the first Airbus, Boeing, Embraer, whatever to encounter conditions outside the certification limits of the airplane. This one didn't go down because the "scary computers" or lack of tactile feedback. But I digress..
https://m.youtube.com/watch?v=n-hbWO0gL6g
03-17-2019, 10:35 PM
#77
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Joined APC: Nov 2013
Position: On the bus,seat 0A
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If you are talking thrust, it doesn't matter how far forward (or aft the engines are mounted, only how far below (or above) the thrust line is relative to the CG (presuming the engines aren't mounted at an angle).
03-18-2019, 04:47 AM
#78
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Joined APC: Mar 2018
Posts: 1,358
It went down because of a basic ignorance of pitch + power = performance. The modern day ab initio training academy airline pilot product. Same with the Air Asia A320. Slaved to automation from day one with little skill to fall back on.
https://m.youtube.com/watch?v=n-hbWO0gL6g
https://m.youtube.com/watch?v=n-hbWO0gL6g
03-18-2019, 05:23 AM
#79
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Joined APC: Feb 2018
Posts: 579
Only gets worse from there. My only point is this could have been any aircraft type if the crew isn't properly trained. And let's be realistic... This certainly wasn't the first Airbus, Boeing, Embraer, whatever to encounter conditions outside the certification limits of the airplane. This one didn't go down because the "scary computers" or lack of tactile feedback. But I digress..
03-18-2019, 05:29 AM
#80
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Joined APC: Aug 2005
Position: Retired 121 pilot
Posts: 1,033
The situation they put themselves in was: a heavy jet at FL350, a pilot commanded pitch attitude that exceeded 15 degrees nose up while constantly remaining above 10 degrees, with a vertical speed that briefly exceeded +6500 fpm resulting in a rapid climb from FL350 to FL380. That is the error that led to the undesired state, not the frozen pitot tubes.
Yes, the flight crew didn't properly handle the situation, but the root cause started with the frozen pitot tubes.
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