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Boeing shares fell 4.3 percent in trading Tuesday after the company canceled conference call with airlines to discuss systems on the 737 MAX model which crashed in Indonesia in October Questions will be asked of their general management. You can't announce a key conference call about an issue of such worldwide concern and then cancel it moments before starting on flimsy grounds. "Time didn't suit some around the world". Huh. I bet all the key people at the operators would have been up and listening keenly at 3am for this. |
so, say all you want about corporate safety culture and cultural norms for cockpit behavior. I'm sure something of it played a role. Probably mx too. But the aircraft should never have put the crew in a position for this to matter, and especially not due to some feature withheld from the manuals. That's the point Boeing is going to have to eat. Maybe a bit more. Shares were $372 two weeks ago on 7 November when the technical questions started appearing in the media. Right now they're $317. Cancelling the 'conference' call may well be trying to put a floor on growing open short interest and of course admitting anything that may potentially incriminate executives/managers. |
According to The Seattle Times:
Boeing scratched a planned Tuesday conference call with airlines to reassure them about the safety of the 737 MAX, and will replace it with a series of regional meetings and conference calls with airlines “early next week in close proximity to our customers.” The switch is “to allow for more attendance, more time for Q&A and to accommodate different time zones,” Boeing said. “These meetings will be hosted by Boeing Field Service Representatives who are located regionally with our customers." The planned meetings are intended to allow Boeing engineering and maintenance staff to answer technical questions from their airline counterparts. The original teleconference call was arranged in response to queries from airlines after the disclosure of a new automated flight-control system introduced on the MAX that may be implicated in the fatal Oct. 29 crash of Lion Air flight JT610. A Boeing spokesman said it proved difficult to find a time that worked for all participants around the world. |
Originally Posted by b1lanc
(Post 10315976)
Is MCAS just new code (there was mention by Boeing a potential SW patch)?
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Suggest that software types plus others caarefully read and understand I Asimov
A robot may not injure a human being or, through inaction, allow a human being to come to harm. A robot must obey orders given it by human beings except where such orders would conflict with the First Law. A robot must protect its own existence as long as such protection does not conflict with the First or Second Law. RE a certain genie . . . And following an aviation accident, investigators “…must never, regardless of their discoveries, write off a crash as simply a case of bad luck. They must never, for fear of official ridicule, admit other than to themselves, which they all do, that some totally unrecognizable genie has once again unbuttoned his pants and urinated on the pillar of science.” |
Originally Posted by notapilot15
(Post 10316045)
If an IT(information technology) guy has to hazard a guess, it appears MCAS software doesn't cross check/validate sensor data or has no failsafe mechanism before trimming indefinitely. Completely a wild guess.
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Originally Posted by BuzzBox
(Post 10316076)
I'd be surprised if that were the case. The airworthiness regulations require that an aircraft must be capable of 'continued safe flight and landing...after any single failure of the stability augmentation system or any other automatic or power-operated system'. Perhaps there was a 'failsafe mechanism' that didn't work as intended. A latent software problem perhaps?
But everything to date ***seems** to indicate a single sensor error was adequate to override pilot input. |
“Override” pilot input? Had aircrew been aware of the procedure, no, the very existence of the stability system was not known. Sole source is unfortunate, but merely a poorly designed system that can be overridden, if recognized. It did not “override”, it was in competition with, but did not “cancel” pilot input. It was “unnoticed”. hence “unchallenged”. A less than robust system might have escaped causing the company its black eye; surely the Trim would have been selected out, and we wouldn’t be having this discussion? These are two distinct issues. Poor design made its way onto a self regulated flight deck. Keeping it from aircrews is inexcusable. If not, then blatantly stupid. imo |
Boeing: "However, though the manual omits mention of MCAS, it does describe exactly how a pilot should deal with uncommanded and unwanted movements of the horizontal tail, whatever the cause may be"
At 5000 feet doing 300 knots, roughly how much time does Boeing think the crew had to read the manual to troubleshoot a problem they didn't understand caused by a system they didn't know existed in order to save the aircraft? :sad: |
Originally Posted by Octane
(Post 10316092)
Boeing: "However, though the manual omits mention of MCAS, it does describe exactly how a pilot should deal with uncommanded and unwanted movements of the horizontal tail, whatever the cause may be"
At 5000 feet doing 300 knots, roughly how much time does Boeing think the crew had to read the manual to troubleshoot a problem they didn't understand caused by a system they didn't know existed in order to save the aircraft? :sad: It reeks. The old Boeing is only the 'same company' in name. The modern corporate is infested with slick suited, slick mouthed apologists. precisely nobody will be accountable and any semblance of 'empathy' diluted by yet another team of slick suited beaks, who carefully ensure that nothing is actually said nor construed that could be implied to mean responsibility. |
Originally Posted by Octane https://www.pprune.org/images/buttons/viewpost.gif Boeing: "However, though the manual omits mention of MCAS, it does describe exactly how a pilot should deal with uncommanded and unwanted movements of the horizontal tail, whatever the cause may be" At 5000 feet doing 300 knots, roughly how much time does Boeing think the crew had to read the manual to troubleshoot a problem they didn't understand caused by a system they didn't know existed in order to save the aircraft? https://www.pprune.org/images/smilie...y_dog_eyes.gif Did someone tried the following in a 737 sim , and what were the results ? a) 5000ft @300 Kts, full trim forward : do you keep pitch control ? b) if not how long does it take to re-trim back manually to regain pitch control? c) and is this time enough to stop the descent and level off within 5000 ft ? |
Originally Posted by Octane
(Post 10316092)
Boeing: "However, though the manual omits mention of MCAS, it does describe exactly how a pilot should deal with uncommanded and unwanted movements of the horizontal tail, whatever the cause may be"
At 5000 feet doing 300 knots, roughly how much time does Boeing think the crew had to read the manual to troubleshoot a problem they didn't understand caused by a system they didn't know existed in order to save the aircraft? :sad: |
.Unreliable Airspeed procedures (whether triggered by bad pitots, statics or AoA...). |
Originally Posted by AlexGG
(Post 10315448)
May well be muddy bottom or some other feature. Diving and underwater recovery is complicated, even in 30 ft of water.
Definitely complicate the searching process. |
Originally Posted by AGBagb
(Post 10316168)
...the Runaway Stabilizer issue has memory items - up to and including the cut-out switches and taking a firm grasp on the trim wheel - as well as the physical QRF. How many separate memory items a crew can handle at once, or in close sequence, is another issue of course: but memory items and the QRF are not one and the same thing. And it maybe that the runaway stabilizer (if that happened) was somewhat masked by (maybe...) not being flagged directly in the Unreliable Airspeed procedures (whether triggered by bad pitots, statics or AoA...).
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Originally Posted by FullWings
(Post 10316300)
But the big question is: how do you distinguish between normal and abnormal trim operation, given that STS/MCAS can move the stab during normal operation? What is the trigger for the Runaway Stabiliser memory items: continuous uncommanded trim movement. Was that the case here? Maybe not...
If you can't pull up because the yoke is too heavy you have to use the trim switches. Or maybe you would not use the trim switches because you are not running a checklist? Seriously? If the trim switches don't work it's obvious you need to do the Runaway Stabiliser checklist and use manual trim. You don't even need a checklist for that it's more like switching the autopilot off and flying by hand. |
Not already flying by hand? Isn’t the action of this Trim system (run/not run) suggestive of manual trim to the PNF? (“What are you doing?”). ? |
Originally Posted by wiedehopf
(Post 10316360)
So you won't notice that you can't maintain level flight?
If you can't pull up because the yoke is too heavy you have to use the trim switches. Or maybe you would not use the trim switches because you are not running a checklist? Seriously? If the trim switches don't work it's obvious you need to do the Runaway Stabiliser checklist and use manual trim. You don't even need a checklist for that it's more like switching the autopilot off and flying by hand. Also, the trim switches were probably working but the system would likely trim back the other way a bit later. Very insidious and difficult to deal with shortly after takeoff, especially as the operation of MCAS was unknown to the pilots... |
Originally Posted by FullWings
(Post 10316371)
That would apply if you were in the cruise and experienced a trim malfunction. In this case it was an aircraft getting airborne and having the symptoms of UAS. Would you expect the aircraft to be in trim when you’re unsure what speed you’re doing or whether you are speeding up or slowing down? No.
Also, the trim switches were probably working but the system would likely trim back the other way a bit later. Very insidious and difficult to deal with shortly after takeoff, especially as the operation of MCAS was unknown to the pilots... |
I agree with wiedehopf, AGBagb, and others above that it really shouldn't matter WHY the system is behaving or even exactly HOW, the crew's job is to react to what is happening and regain control. It's not exactly rocket science, pull and trim until you get the attitude you want. By concentrating on the precise nature of the failure we risk missing the fact that there are many ways in which the behaviour in question could arise. The THY accident at Schipol is a case in point - much was made of the single Rad Alt failure which ensured the thrust levers remained closed, and I believe the system was modified later, but there are many ways the AT might have failed, and if the crew had been monitoring their energy state properly they should have coped with all of them. Boeing will have to answer for their questionable judgment writing the FCOM, but they weren't on flight deck, the crew were.
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