Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

Indonesian aircraft missing off Jakarta

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

Indonesian aircraft missing off Jakarta

Old 20th Nov 2018, 22:25
  #1441 (permalink)  
 
Join Date: Mar 2015
Location: North by Northwest
Posts: 394
Originally Posted by DingerX View Post
Look, there's a lot we don't know. Here's what I have good probabilities for:
1. The CVR will be recovered in due time. Yes, there's a lot of noise at the moment, but it'll happen. They may even "call off the search", but they'll get it.
2. They flew into an undocumented state. Odds are it was the same undocumented state as the previous flight or three. And odds are that this flight crew, for whatever reason, was less well equipped to deal with it. A potentially lethal situation just needs to keep reappearing before someone takes up the offer. Fate is the hunter.

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.
​​​​
​​​​​
That's why I would be really curious if the maintenance manuals even mention MCAS. If true that Southwest replaced two sensors to try and resolve an issue where autothrust wouldn't engage, is maintenance also unaware? Is MCAS just new code (there was mention by Boeing a potential SW patch)? If they completely disabled MCAS, then the stall characteristics of the Max would not be the same as previous generations potentially providing an avenue for another lethal situation to occur. I'm not sure there is an easy way out of this for Boeing.
b1lanc is offline  
Old 20th Nov 2018, 22:56
  #1442 (permalink)  
 
Join Date: Oct 2002
Location: London UK
Posts: 6,255
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
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.

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.
WHBM is offline  
Old 21st Nov 2018, 01:25
  #1443 (permalink)  
 
Join Date: Sep 2017
Location: Europe
Posts: 1,548
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.
One can almost bet that senior management and their beaks are more concerned with the NYSE and the spot price than they are of the integrity of the investigation.
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.
Rated De is offline  
Old 21st Nov 2018, 01:30
  #1444 (permalink)  
 
Join Date: Mar 2002
Location: Here & there
Posts: 743
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.
Boeing to hold regional meetings with airlines on 737 MAX, while execs try to reassure employees
BuzzBox is offline  
Old 21st Nov 2018, 01:46
  #1445 (permalink)  
 
Join Date: Oct 2015
Location: USA
Posts: 415
Originally Posted by b1lanc View Post
Is MCAS just new code (there was mention by Boeing a potential SW patch)?
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.
notapilot15 is offline  
Old 21st Nov 2018, 03:23
  #1446 (permalink)  
 
Join Date: Mar 2014
Location: WA STATE
Age: 74
Posts: 1
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.
And add a dash of Ernie Gann

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.
CONSO is offline  
Old 21st Nov 2018, 04:03
  #1447 (permalink)  
 
Join Date: Mar 2002
Location: Here & there
Posts: 743
Originally Posted by notapilot15 View Post
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.
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?
BuzzBox is offline  
Old 21st Nov 2018, 04:26
  #1448 (permalink)  
 
Join Date: Mar 2014
Location: WA STATE
Age: 74
Posts: 1
Originally Posted by BuzzBox View Post
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?
Many many posts ago in this thread- this SLF asked about ' wha happen to the concept for critical sensors of three-sensors- 2 votes needed to forward data .'

But everything to date ***seems** to indicate a single sensor error was adequate to override pilot input.
CONSO is offline  
Old 21st Nov 2018, 04:37
  #1449 (permalink)  
 
Join Date: Nov 2016
Location: Lakeside
Posts: 428
“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


Concours77 is offline  
Old 21st Nov 2018, 05:07
  #1450 (permalink)  
 
Join Date: Oct 2001
Location: Lost, but often Indonesia
Posts: 595
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?
Octane is offline  
Old 21st Nov 2018, 05:16
  #1451 (permalink)  
 
Join Date: Sep 2017
Location: Europe
Posts: 1,548
Originally Posted by Octane View Post
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?
Precisely.
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.
Rated De is offline  
Old 21st Nov 2018, 07:06
  #1452 (permalink)  
Pegase Driver
 
Join Date: May 1997
Location: Europe
Age: 69
Posts: 2,642
Originally Posted by Octane
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?
A couple of simple questions , maybe asked already, I could have missed them in the thread ;
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 ?
ATC Watcher is offline  
Old 21st Nov 2018, 08:13
  #1453 (permalink)  
 
Join Date: Aug 2008
Location: New York / Southern France
Age: 65
Posts: 95
Originally Posted by Octane View Post
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?
Fair enough. But 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...).
AGBagb is offline  
Old 21st Nov 2018, 08:37
  #1454 (permalink)  
 
Join Date: Apr 2006
Location: where I lay my hat
Posts: 87
.Unreliable Airspeed procedures (whether triggered by bad pitots, statics or AoA...).
As was mentioned in the excellent video, a single AOA failure on its own, would also create cautions for unreliable airspeed, which I found surprising, given that AOA and airspeed are different things (albeit interrelated)?..
midnight cruiser is offline  
Old 21st Nov 2018, 10:37
  #1455 (permalink)  
 
Join Date: Oct 2018
Location: SG
Posts: 2
Originally Posted by AlexGG View Post
May well be muddy bottom or some other feature. Diving and underwater recovery is complicated, even in 30 ft of water.
In addition to mud and debris, there are gas pipings on the sea bed.
Definitely complicate the searching process.
​​​​​​
Vivo1718 is offline  
Old 21st Nov 2018, 11:46
  #1456 (permalink)  
 
Join Date: Dec 2003
Location: Tring, UK
Posts: 1,404
Originally Posted by AGBagb View Post
...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...).
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...
FullWings is offline  
Old 21st Nov 2018, 12:55
  #1457 (permalink)  
 
Join Date: Jul 2014
Location: Germany
Posts: 339
Originally Posted by FullWings View Post
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...
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.
wiedehopf is offline  
Old 21st Nov 2018, 13:05
  #1458 (permalink)  
 
Join Date: Nov 2016
Location: Lakeside
Posts: 428
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?”). ?

Last edited by Concours77; 21st Nov 2018 at 13:22.
Concours77 is offline  
Old 21st Nov 2018, 13:14
  #1459 (permalink)  
 
Join Date: Dec 2003
Location: Tring, UK
Posts: 1,404
Originally Posted by wiedehopf View Post
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.
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...
FullWings is offline  
Old 21st Nov 2018, 13:29
  #1460 (permalink)  
gmx
 
Join Date: Nov 2018
Location: Brisbane
Posts: 25
Originally Posted by FullWings View Post
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...
​​​​​ Your description doesn't make sense. The crew radio'd a return to base early in the flight. Assumption is they disengaged autopilot at that point, or it abdicated. They then had the aircraft under some sort of control (basically level at 5000 feet) for six minutes. That's a long time. If they were counteracting insidious MCAS trim for those six minutes then they knew they had a stabiliser runaway. Did they complete the checklist ? If so, was it ineffective ? Or did some other failure overwhelm the aircraft ? All unanswered...
gmx is offline  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.