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-   -   Ethiopian airliner down in Africa (https://www.pprune.org/rumours-news/619272-ethiopian-airliner-down-africa.html)

guadaMB 10th Mar 2019 17:19

After all of my career in SAR, It's absolutely "regular" to find non-authorized people on wreck sites...

EternalNY1 10th Mar 2019 17:22


Originally Posted by J J Carter (Post 10412363)
It's absurd that flight telemetry and data is not transmitted in real time to satellites and sent back to the aircraft manufacturer.rather than being recorded on FDRs that are lost at sea or destroyed

It's being worked on.

https://aireon.com/


Super VC-10 10th Mar 2019 17:22

Meanwhile, over at Wikipedia...

https://en.wikipedia.org/wiki/Ethiop...nes_Flight_302

NWA SLF 10th Mar 2019 17:30

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.

DaveReidUK 10th Mar 2019 17:34

Flight profile from runway to last captured ADS-B point:

https://cimg8.ibsrv.net/gimg/pprune....c701b07701.jpg

Altitudes AGL are shown to scale, corrected for QNH, although I can't vouch for the accuracy of GE's terrain elevations.

763 jock 10th Mar 2019 17:39

Yep. The CEO should be there. But tinkering with the wreckage? Nobody should be touching anything apart from the investigators.


b1lanc 10th Mar 2019 17:40


Originally Posted by Lonewolf_50 (Post 10412617)
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?

That was kind of where I was headed. But, the Max is now in Comet territory I'm afraid. Waiting another 6 months until another augers in should not be an option - again making no assumptions as to cause.


physicus 10th Mar 2019 17:41

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.



derjodel 10th Mar 2019 17:46


Originally Posted by wingview (Post 10412595)
Three Boeing nose down crashes in a few month's...?!

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.

Lonewolf_50 10th Mar 2019 17:48


Originally Posted by physicus (Post 10412667)
Read the AD. Loss/malfunction of a SINGLE AOA sensor can result in nose down trim input being automatically applied.

would rather we not get into an A versus B thing, those just add noise to no good end.
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.
Yes, we agree on that. What I was thinking was that with the recency of LionAir accident, MAX crews would tend to be aware of the procedure in the AD, so perhaps looking at that failure mode first is a red herring? No idea. Not enough info. One hopes the FDR/CVR data remain intact.

Nieuport28 10th Mar 2019 17:55


Originally Posted by JamesT73J (Post 10412509)
From that article:
https://i.imgur.com/Rq95L56.png

This is highly unusual, right? Aviators have been expected and encouraged to learn such things.

IMO, the industry needs to look at this especially with the Max and the upcoming 797. I’m totally opposed to designing any inherent aerodynamic instability into a commercial airframe corrected by software. The statement from Boeing scares the hell out of me. It also scares the hell out of me that we are heading in the direction of ATP’s requiring F-35 levels of training.

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.

excrab 10th Mar 2019 17:58


Originally Posted by derjodel (Post 10412673)


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.

I didn’t realise that the Flydubai crash happened “in the last few months”,
and it was totally different circumstances (night / IMC / poor weather). And an 800,
not a MAX.

TylerMonkey 10th Mar 2019 18:00

Copilot had 200 hours on type ?

or 200 hrs total career . . . ?

CONSO 10th Mar 2019 18:01

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. ??

jimjim1 10th Mar 2019 18:01


Originally Posted by DaveReidUK (Post 10412661)
I can't vouch for the accuracy of GE's terrain elevations.

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)

Chronus 10th Mar 2019 18:05

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.

Flyingmac 10th Mar 2019 18:08

"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.

eppy 10th Mar 2019 18:10

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

L337 10th Mar 2019 18:13


Originally Posted by NAROBS (Post 10412554)
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

It happens all the time. The software and hardware is constantly adjusting in the background. As speed increases and decreases trim and control sensitivity is being modified, all the time. All without the pilot being told, and totally unaware. It is called a well designed aeroplane.

Gilles Hudicourt 10th Mar 2019 18:19

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).....







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