Ethiopian airliner down in Africa
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From: Hadlow
Joined: Jul 2009
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From: USA
All this trashing of Boeing's incorporation of software using AOT sensor input to prevent a stall being a bad design - does it take into account the A320 Roussillan crash in which improper maintenance of the AOT sensors provided bad data to the software from which the crew was unable to resolve the problem and crashed. Although the Lion Air investigation is not yet complete people are now ready to ground the MAX and change a solution that involved AOT sensor input through software to avert an accident. I assume their grounding will involve Airbus as they also use AOT sensor input to prevent stalls. Have we reverted to the DC-10 times of grounding a plane destroying a company only to find that a maintenance base used an unauthorized procedure that resulted in carnage. Maybe there is an inherent problem but I've never seen a such a crowd of "shoot first and ask questions later" people. And yes, I do own Boeing stock but I also am invested in Airbus.
Joined: Mar 2015
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From: North by Northwest
T
A data point from a bit further up: the captain of this flight was recently qualified in this model (November). His previous experience was in other aircraft. (perhaps previous 737 models, that info will doubtless become available in due course).
Would his conversion training have had the benefit of what came to light after the LionAir accident, or, would that training course have been before the LionAir accident?
A data point from a bit further up: the captain of this flight was recently qualified in this model (November). His previous experience was in other aircraft. (perhaps previous 737 models, that info will doubtless become available in due course).
Would his conversion training have had the benefit of what came to light after the LionAir accident, or, would that training course have been before the LionAir accident?
Joined: May 2010
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From: Usually on top
NWA SLF Read the AD. Loss/malfunction of a SINGLE AOA sensor can result in nose down trim input being automatically applied. The fact that there’s an automated system producing flight control input is in contravention to the fundamental operating philosophy of Boeing aircraft, and it has consequentially and not surprisingly caught out the crews. It is also now evident that the MCAS system (implemented due to a certification requirement for pitch stability during high power applications like G/As) appears to have been written in a bit of a hurry, without taking the usual redundancy philosophy into account.
We don’t know whether that was a factor in this accident until FDR/CVR are located and analysed.
Airbus operating philosophy is very different, and has been proven in the past to not do anything stupid to the aircraft unless a) multiple sensor inputs have been disabled/crippled, and b) pilots do stupid stuff like resetting flight stability essential computers in-flight by getting out of their seat and pulling CBs on maintenance panels meant for ground and engineering use only.
We don’t know whether that was a factor in this accident until FDR/CVR are located and analysed.
Airbus operating philosophy is very different, and has been proven in the past to not do anything stupid to the aircraft unless a) multiple sensor inputs have been disabled/crippled, and b) pilots do stupid stuff like resetting flight stability essential computers in-flight by getting out of their seat and pulling CBs on maintenance panels meant for ground and engineering use only.
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From: Vienna
Four. Fly Dubai also crashed nose down. Also, all last major airliners crashed were Boeings...
What if modern planes are so stretched when it comes to performance attributes that FBW is safer at this point? E.g., MCAS is a non-FBW hack to make max certifiable.
What if modern planes are so stretched when it comes to performance attributes that FBW is safer at this point? E.g., MCAS is a non-FBW hack to make max certifiable.
Joined: Aug 2009
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From: Texas
The point you mention there was raised in the LionAir thread about two versus three on the AoA gages: if only two, one's vote wins, the good one or the bad one?
If the "bad one's" vote wins, what then? The AD was issued with the understanding of the system (as you note) folded in.
We don’t know whether that was a factor in this accident until FDR/CVR are located and analysed.
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From: New York
MCAS was implemented due to the forward placement of the engines on the Max. Any commercial FBW aircraft should be an aerodynamically stable design. FBW should only be for control surfaces, not to allow the airframe to actually “fly.” This “improved efficiency at all cost” factor may be at a critical point.
CRM is challenging enough today.
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From: The middle
and it was totally different circumstances (night / IMC / poor weather). And an 800,
not a MAX.
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From: WA STATE
SLF here- I'm amazed at the stampede to MCAS blame absent any other info. The last I heard re MCAS was that it was disabled until flaps UP. It ***seems *** that from the altitude figures above terrain and time after takeoff- that flaps were**** probably **** not up. Beyond that admitted speculation, including rants about chicken.... airlines, why not wait till more facts and data as from tower, fdr and cockpit voice data/facts. ??
Joined: Oct 2007
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From: Here
GE seems to use a radar satellite survey with 30m vertical resolution on a 90m grid. Some areas are much better with a laser survey. I guess this case is likely to be a radar area.
https://www.quora.com/How-accurate-a...n-Google-Earth
https://productforums.google.com/for...th/3Th8MuHzKtE
https://dds.cr.usgs.gov/srtm/version...PDF-89020B.pdf
PERFORMANCE SPECIFICATION DIGITAL TERRAIN ELEVATION DATA (DTED)
(their caps)
https://www.quora.com/How-accurate-a...n-Google-Earth
https://productforums.google.com/for...th/3Th8MuHzKtE
https://dds.cr.usgs.gov/srtm/version...PDF-89020B.pdf
PERFORMANCE SPECIFICATION DIGITAL TERRAIN ELEVATION DATA (DTED)
(their caps)
Joined: Jan 2008
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From: Hotel Sheets, Downtown Plunketville
Judging by the picture of the CEO inspecting what appears to be the largest piece of wreckage around, with the crater in the background, it must have involved considerable kinetic energy to dig that size of a crater and displace the apparent volume of surface soil banked around it, particularly given it is hard African terra firma. The extensive scorched earth around the area of impact is evidence of instant atomisation and simultanious explosion of the on board fuel. It is somewhat reminiscent of the early B737`s un-commanded rudder deployment accidents. Wing over and almost a vertical dive, 80t +, at over 400kts. Considering the height reached before the event, somehow I cannot quite envisage stab/elevator to have achieved what must have been a very aggressive control input.
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Aviation Qualifications: PPL
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From: N.YORKSHIRE
"This emergency AD was prompted by analysis performed by the manufacturer showing that if an erroneously high single angle of attack (AOA) sensor input is received by the flight control system, there is a potential for repeated nose-down trim commands of the horizontal stabilizer. This condition, if not addressed, could cause the flight crew to have difficulty controlling the airplane, and lead to excessive nose-down attitude, significant altitude loss, and possible impact with terrain."
That's enough to keep me off them.
That's enough to keep me off them.
Joined: May 2010
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From: London
Very quick response from the NY Times - especially for a Sunday.
Are There Problems With the Boeing 737 Max? A Second Deadly Crash Raises New Questions
https://www.nytimes.com/2019/03/10/w...x-8-crash.html
the lunatic fringe
Joined: May 2001
Posts: 621
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From: Everywhere
Boeing's statement sounds to me like the current corporate vogue of down playing everything that's a non-smiley event, "Move along, nothing to see here".
Trouble is once you've been exposed to 600C temperature there's not much left to put "Some cream on it".
A software device that alters the trim during flight transition from one stage to another, possibly without notifying the aircrew - unbelievable. Why haven't aircrew, en masse, especially seniors, raised objections to this ?
N
Trouble is once you've been exposed to 600C temperature there's not much left to put "Some cream on it".
A software device that alters the trim during flight transition from one stage to another, possibly without notifying the aircrew - unbelievable. Why haven't aircrew, en masse, especially seniors, raised objections to this ?
N
Joined: Dec 2013
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From: Montréal
MCAS Question
Correct me if I’m wrong, but in the case of the Lion Air accident, from what I understood, an AOA probe fault caused the MCAS to put a forward trim on the horizontal stabiliser, causing a fault that essentially looked like a runaway trim, a situation that a pilot could have recovered from by treating it like a runwaway trim.
If the above statement is correct, my question is this : did the MCAS also activate the stick shaker or any other kind of stall warning?
Because recovering from a down trimming runaway trim (pulling back on a very heavy control wheel) while at the same time having a stick shaker and some other indication telling you you are about to stall (which normally would require lowering the nose).....
If the above statement is correct, my question is this : did the MCAS also activate the stick shaker or any other kind of stall warning?
Because recovering from a down trimming runaway trim (pulling back on a very heavy control wheel) while at the same time having a stick shaker and some other indication telling you you are about to stall (which normally would require lowering the nose).....
Last edited by Gilles Hudicourt; 10th March 2019 at 18:49.
Joined: Oct 2017
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From: Vienna
That said, Fly Dubai and the Amazon 767 nosedived under similar circumstances. And as fsr as I remember some people disputed the official Fly dubai story that the pilot keptnholding the trim button.
in any case, with 3 boeing nosedives officially unexplained yet, the situation is interesting to say the least, mcas or not (and since ET probably happened before flaps up, we might have 3 boings nosediving without mcas, whic is actually even worse, isn‘t it?)
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From: Netherlands
Aireon's satellite constellation (Iridium Next) has actually been completed as of January of this year, and they state their systems would be operational Q1 2019. It is quite possible part or all of their hardware was collecting data today.They advertise an 'Alert' service that is free but still needs to be enrolled in by operators. I am curious if such data would be made available, either publicly or to the airline or investigators.
Their data would overlap with the ADS-B data collected by FR24, but was collected on superior receivers that are much less sensitive to terrain from their orbit, so more datapoints may well be available.
Their data would overlap with the ADS-B data collected by FR24, but was collected on superior receivers that are much less sensitive to terrain from their orbit, so more datapoints may well be available.