Indonesian aircraft missing off Jakarta
Right, Concours77: blame the same doctor for my hernia scar as for my wife's scar from her C section.(no, I've never been treated by her OB).
Your statement is so general as to be useless, as I see it.
You can write all of the rules that you want to write; following up on that to see that the rules are carried out, or that the rules themselves cause problems, costs money. Is that your point? Just how much transparency do you expect from the Indonesian regulator?
Culture has an impact on operations. (SFO, 777, et al)
Your statement is so general as to be useless, as I see it.
You can write all of the rules that you want to write; following up on that to see that the rules are carried out, or that the rules themselves cause problems, costs money. Is that your point? Just how much transparency do you expect from the Indonesian regulator?
Culture has an impact on operations. (SFO, 777, et al)
So I choose not to fly on the 787. Neither will I fly on the A330. My call. It is an “informed decision”. If my life depended on flying somewhere, I might fly the Dreamliner, but, again, it is MY informed decision....
LoCo and 3rd world has nothing to do with this, the discussion revolves around a blatant lapse in judgment, perhaps law, by Boeing, and feigned ignorance by FAA.
Elitist? Bet your ass. Boeing relied on a “loophole”, the FAA deserves worse condemnation. Nothing worse than a crooked cop.
The decisions to keep flying paying passengers with a consistent flight control problem was a local problem. Nobody in the FAA made them do that. (For all that the FAA have some holes in their block of cheese ...) I have addressed my concerns about trouble shooting/maintenance documentation in the Tech Log thread. Back to lurk, the signal to noise ratio in this thread is unfavorable.
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Had the 737 been designed with fan engines from the very start, it may have aquired a different control architecture - like having a stick pusher, and a larger elevator. But when we come to designing the Max, adding a stick-pusher and new elevator to a 1967 certification might be considered a major modification, requiring complex certification issues. But just tweaking the STS system to add a nose down trim at the stall - well that is just a minor mod. Who would even notice? I mean, it is such a minor tweak that we don’t even need to put it in the F-COM or QRH.....
You see the problem....?
I don't quite follow that, seeing as the 727 didn't have wing-mounted engines..
Silver
Last edited by silverstrata; 25th Nov 2018 at 20:55. Reason: add quote
Lonewolf #1672, as yet we do not know what trouble shooting was performed or rectification completed, save a report of a new AoA sensor.
My post #1650 raised questions about AoA malfunction indications, where some aspects could direct maintenance toward AoA and Airspeed vice trim and control. These aspect or similar would support previous pilot reports of airspeed problems and maintenance logs relating to AoA, vice an (unidentified) trim problem.
It might even be possible for an intermittent AoA fault to remain isolated from MCAS, no trim movement etc; or alternatively with trim problems, no knowledge of which AoA sensor was at fault, save detailed information linking vane side with stickshake side. Plenty of room for ambiguity, engineer-pilot liaison, weak/non existent technical-flight manual information … …
It would be interesting to know what Boeing records show of fleet wide maintenance, fault finding, or component change, in these areas. Similarly to hear of any operator problem in these areas, and how the problem was identified and rectified, presumably without grounding the aircraft.
New AoA vane manufacturer, new part number on the 737 Max ?? Just a thought.
My post #1650 raised questions about AoA malfunction indications, where some aspects could direct maintenance toward AoA and Airspeed vice trim and control. These aspect or similar would support previous pilot reports of airspeed problems and maintenance logs relating to AoA, vice an (unidentified) trim problem.
It might even be possible for an intermittent AoA fault to remain isolated from MCAS, no trim movement etc; or alternatively with trim problems, no knowledge of which AoA sensor was at fault, save detailed information linking vane side with stickshake side. Plenty of room for ambiguity, engineer-pilot liaison, weak/non existent technical-flight manual information … …
It would be interesting to know what Boeing records show of fleet wide maintenance, fault finding, or component change, in these areas. Similarly to hear of any operator problem in these areas, and how the problem was identified and rectified, presumably without grounding the aircraft.
New AoA vane manufacturer, new part number on the 737 Max ?? Just a thought.
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Wx = VMC
Primary Controls = Free & Correct
Engines = 2x Good
Pilots/CRM = ?
Mx = ?
Trim Controls = ?
Owner Factors = ?
So you want to put all the blame on the manufacturer and/or regulators?
Stabilizer Trim is a fraction of the above equation and even the previous crew (and perhaps the two crews before?) dispatched that problem posthaste.
What makes you think this crew would have run the "MCAS Runaway Checklist" had one existed?
THIS IS textbook Runaway Stabilizer (for which there IS a checklist) by any definition and it was NOT addressed AFAIK at this time.
I hope I'm wrong but it's not looking that way ATM.
Fly the plane. That's what professional pilots do IMHO.
Last edited by climber314; 25th Nov 2018 at 21:57.
@ Climber
This doesn't look like classic "runaway trim".
It looks like erratic unwanted trim that I can reverse when I use the switch on the yoke, And then 5 seconds later the damned thing trims down again.
So if the trim would have continued down the instant I released that switch I would have claimed "runaway trim" and gone thru the procedure. That 5 second delay would puzzle me. Not sure about the previous flight cockpit conversation, but looks like they had a few minutes to decide on "runway trim" procedure, take action and fly to the destination.
It is a good bet that any crew following the "runaway trim" procedure right away would have made it back to the airport, just like the previous crew. But the symptoms do not seem clear, and the new MCAS may not have been briefed or flown in a sim.
Gums...
This doesn't look like classic "runaway trim".
It looks like erratic unwanted trim that I can reverse when I use the switch on the yoke, And then 5 seconds later the damned thing trims down again.
So if the trim would have continued down the instant I released that switch I would have claimed "runaway trim" and gone thru the procedure. That 5 second delay would puzzle me. Not sure about the previous flight cockpit conversation, but looks like they had a few minutes to decide on "runway trim" procedure, take action and fly to the destination.
It is a good bet that any crew following the "runaway trim" procedure right away would have made it back to the airport, just like the previous crew. But the symptoms do not seem clear, and the new MCAS may not have been briefed or flown in a sim.
Gums...
Indeed, the MCAS tweek is just like a stick pusher, except that instead of an instantaneous 'push' that can be easily identified and corrected by the pilot through a 'pull' on the control column, we have a stab trim that must first be identified as the problem and then cannot be countered by a manual pull - the obvious and intuitive correction.
Is this not a case of putting a digital 'band-aid' on a hydro-mechanical flight control system without much thought being given to the difference?
Sounds like a full FBW system should be mandated in this circumstance.
Is this not a case of putting a digital 'band-aid' on a hydro-mechanical flight control system without much thought being given to the difference?
Sounds like a full FBW system should be mandated in this circumstance.
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There is no "Erratic Behaviour Trim" checklist in any 737. Max or otherwise.
Checklists are a troubleshooting aid/guide and are not an answer to every conceivable issue that may arise.
Some people are inherently better at troubleshooting logic than others.
For a good example of this see the recent Southwest diversion to PHL where the PF used a checklist AND her brain when she flew her own flaps and airspeed.
You can't train for that.
Checklists are a troubleshooting aid/guide and are not an answer to every conceivable issue that may arise.
Some people are inherently better at troubleshooting logic than others.
For a good example of this see the recent Southwest diversion to PHL where the PF used a checklist AND her brain when she flew her own flaps and airspeed.
You can't train for that.
I beg to differ, you can; it's called military aviation. Air Forces around the world select for and train to very high standards of competency for the very simple reason that they need to. It is however highly selective and comparatively very, very expensive.
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Point conceded with an * on highly selective.
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That said, the previous crew had dealt with it successfully despite (probably) having no idea about MCAS. They identified the issue as a runaway stabiliser and dealt with it accordingly. Even though they wrote it up as STS running reverse, it did give the airline / accident crew advanced warning of stabiliser issues on the aircraft and how to resolve them. We are of course still speculating on what briefing the accident crew received concerning the flight control issues from the previous sector and what had been done to rectify them in the interim.
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A lot of engineers use circuit breakers like switches. Using them to reset systems all the time. Eg I brought an A320 in with a popped fuel pump breaker. These are a no no reset until the circuit has been checked. Engineer came up whilst I was writing it up pushed the breaker back in switched on the pump for about 10 sec & then asked for the log to sign it off.
Carrying engineers for observation is great but do not let them touch anything. Air & ground are not the same in terms of consequences.
Carrying engineers for observation is great but do not let them touch anything. Air & ground are not the same in terms of consequences.
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The 'dedicated' identification process for Lion Air 610 victims has ended on the 23rd of November. The end status is as mentioned earlier - 125 persons identified and 64 either unidentified or missing. Remains found thereafter will go through the 'general' process. The families of the unidentified and missing persons will be provided with a death certificate, and they will have the same rights as the families of those that were identified.
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My red highlight - This is true the pic shows that the MCAS ND trim was being recovered by NU trim which also inhibited MCAS until it ran again. This continues until just before the dive when for some reason the NU trim input is just brief inputs and insufficient to recover to normal 'level flight' trim position. MCAS runs as it has been and ND trim becomes unrecoverable. What changed for the last 5 or 6 trim switch inputs as they became blips rather than recover to level trim? Had the previous inputs been continued with we would not be having this discussion.
But there was also the AMP on board, maybe on the flight deck, maybe not, maybe to find out the root cause of the stick pusher and trim down after the AOA exchange before the flight before did not help. In that case though, what happened right after flaps up would have been expected by the crew, and not using trim cut out would have been by intention. Test flight with a full pax load, hard to believe, but ...
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If the CVR is not found we will probably never know.
But there was also the AMP on board, maybe on the flight deck, maybe not, maybe to find out the root cause of the stick pusher and trim down after the AOA exchange before the flight before did not help. In that case though, what happened right after flaps up would have been expected by the crew, and not using trim cut out would have been by intention. Test flight with a full pax load, hard to believe, but ...
But there was also the AMP on board, maybe on the flight deck, maybe not, maybe to find out the root cause of the stick pusher and trim down after the AOA exchange before the flight before did not help. In that case though, what happened right after flaps up would have been expected by the crew, and not using trim cut out would have been by intention. Test flight with a full pax load, hard to believe, but ...
The CVR will be found - it is a matter of search organization, the will of all parties and patience. The search area is relatively small so it is a matter of when not if.
The CVR's importance to the investigation and to consequences for all parties cannot be overstated. So funding such a search will not be an issue.
AF447's wreckage & both recorders were found after two years of searching under ~3000m of water and after some repair work both yielded their data. The higher forward speed here presents different 'trajectories" of the parts than AF447 but we assume that these are search experts and that there is lots of oversight.
They're not even at the 30-day mark yet.
Since it hasn't been mentioned yet with regarding to sensors, computer voting-systems trying to mimic "decidability", redundancies in mission-critical / single-point-of-failure systems and the impossibility of getting it right 100% of the time with only 3 sensors, (Perpignan), two documents from Leslie Lamport and one from Kevin Driscoll are worth the time and effort:
Reaching Agreement in the Presence of Faults - Leslie Lamport
The Byzantine Generals Problem - Leslie Lamport
Byzantine Fault Tolerance, from Theory to Reality - Kevin Driscoll
From Driscoll:
The CVR's importance to the investigation and to consequences for all parties cannot be overstated. So funding such a search will not be an issue.
AF447's wreckage & both recorders were found after two years of searching under ~3000m of water and after some repair work both yielded their data. The higher forward speed here presents different 'trajectories" of the parts than AF447 but we assume that these are search experts and that there is lots of oversight.
They're not even at the 30-day mark yet.
Since it hasn't been mentioned yet with regarding to sensors, computer voting-systems trying to mimic "decidability", redundancies in mission-critical / single-point-of-failure systems and the impossibility of getting it right 100% of the time with only 3 sensors, (Perpignan), two documents from Leslie Lamport and one from Kevin Driscoll are worth the time and effort:
Reaching Agreement in the Presence of Faults - Leslie Lamport
The Byzantine Generals Problem - Leslie Lamport
Byzantine Fault Tolerance, from Theory to Reality - Kevin Driscoll
From Driscoll:
What You Thought Could Never Happen
In English, the phrase “one in a million” is popularly used to describe the highly improbable. The ratio itself is difficult to comprehend. The easiest way to give it reason is to equate it to real-world expectations. For example, the probability of winning the U.K. National Lottery is around one in fourteen million; the probability of getting struck by lightning in the U.S. is around one in six hundred thousand [1]. It is not safe to rely on intuition for reasoning about unfathomably small probabilities (for example, the 1-in-1,000,000,000 maximum failure probability for critical aerospace systems, (usually expressed as 10-9 hrs).
It is problematic in two ways: (1) real-world parallels are beyond typical human experience and comprehension; (2) faults that are not recognized, such as Byzantine faults, are incorrectly assumed to occur with zero or very low probability. The lack of recognition causes additional issues in that it allows the manifestation of such faults to pass unnoticed or be otherwise misclassified, reinforcing the misconception of low probability of occurrence.
The lack of recognition leads to repeating the “Legionnaire’s Disease” phenomenon. After its “discovery” in 1976, a search of medical records found that the disease had seldom occurred for many decades. The lack of shared knowledge and the disease’s rarity made each occurrence appear to be unique. Only after 1976 was it realized that all these “unique” occurrences had a common cause. Similarly, an observation of a Byzantine failure will not be recognized as being an instance of a known class of failure by those who are not intimately familiar with Byzantine failures. The intent of this paper is to redress this situation. Drawing from the authors’ experiences with Byzantine failures in real-world systems, this paper shows that Byzantine problems are real, have nasty properties, and are likely to increase in frequency with emerging technology trends. Some of the myths with respect to the containment of Byzantine faults are dispelled and suitable mitigation strategies and architectures are discussed.
In English, the phrase “one in a million” is popularly used to describe the highly improbable. The ratio itself is difficult to comprehend. The easiest way to give it reason is to equate it to real-world expectations. For example, the probability of winning the U.K. National Lottery is around one in fourteen million; the probability of getting struck by lightning in the U.S. is around one in six hundred thousand [1]. It is not safe to rely on intuition for reasoning about unfathomably small probabilities (for example, the 1-in-1,000,000,000 maximum failure probability for critical aerospace systems, (usually expressed as 10-9 hrs).
It is problematic in two ways: (1) real-world parallels are beyond typical human experience and comprehension; (2) faults that are not recognized, such as Byzantine faults, are incorrectly assumed to occur with zero or very low probability. The lack of recognition causes additional issues in that it allows the manifestation of such faults to pass unnoticed or be otherwise misclassified, reinforcing the misconception of low probability of occurrence.
The lack of recognition leads to repeating the “Legionnaire’s Disease” phenomenon. After its “discovery” in 1976, a search of medical records found that the disease had seldom occurred for many decades. The lack of shared knowledge and the disease’s rarity made each occurrence appear to be unique. Only after 1976 was it realized that all these “unique” occurrences had a common cause. Similarly, an observation of a Byzantine failure will not be recognized as being an instance of a known class of failure by those who are not intimately familiar with Byzantine failures. The intent of this paper is to redress this situation. Drawing from the authors’ experiences with Byzantine failures in real-world systems, this paper shows that Byzantine problems are real, have nasty properties, and are likely to increase in frequency with emerging technology trends. Some of the myths with respect to the containment of Byzantine faults are dispelled and suitable mitigation strategies and architectures are discussed.
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Some interesting commentary and quotes in this article with highlights as follows:
“There are so many questions it’s sort of hard to put in one short statement,” said Roger Cox, a retired investigator with the U.S. National Transportation Safety Board and a former airline pilot.
“I would be very interested in knowing why one crew was able to cope with this stick shaker and trim anomaly, and why the next crew could not,” Cox said. “And I’d want to know why Lion Air could not or would not repair the problem.”
Cox cautioned that the flight data doesn’t tell the complete story. A cockpit recorder, which would help indicate what pilots were thinking about the malfunctions, hasn’t been recovered yet. And while the situation of conflicting instruments and alarms could have been confusing, he said he’d seen “a lot worse” in other investigations.
It’s reasonable to ask why the pilots didn’t shut off the trim system during the roughly 10 minutes they were assessing the plane’s behavior, he said. A decades-old emergency procedure teaches pilots to flip two switches to cut power to the motor that was pushing the nose down.
Even more vexing is why the plane exhibited the same malfunctions it had on the previous flight after it was supposedly repaired overnight. On a flight from Bali to Jakarta on Oct. 28, the plane’s stick shaker on the captain’s side of the plane was active for almost all of the roughly 90-minute flight and the angle of attack readings had the same errors, the data shows.
“Number one, why did the previous crew continue that flight?” Cox said. “Number two, did they or did they not make an appropriate write-up? The third question is how come you signed this thing off” to fly the next day.
https://www.bloombergquint.com/busin...ing#gs.WE5NkUQ
“There are so many questions it’s sort of hard to put in one short statement,” said Roger Cox, a retired investigator with the U.S. National Transportation Safety Board and a former airline pilot.
“I would be very interested in knowing why one crew was able to cope with this stick shaker and trim anomaly, and why the next crew could not,” Cox said. “And I’d want to know why Lion Air could not or would not repair the problem.”
Cox cautioned that the flight data doesn’t tell the complete story. A cockpit recorder, which would help indicate what pilots were thinking about the malfunctions, hasn’t been recovered yet. And while the situation of conflicting instruments and alarms could have been confusing, he said he’d seen “a lot worse” in other investigations.
It’s reasonable to ask why the pilots didn’t shut off the trim system during the roughly 10 minutes they were assessing the plane’s behavior, he said. A decades-old emergency procedure teaches pilots to flip two switches to cut power to the motor that was pushing the nose down.
Even more vexing is why the plane exhibited the same malfunctions it had on the previous flight after it was supposedly repaired overnight. On a flight from Bali to Jakarta on Oct. 28, the plane’s stick shaker on the captain’s side of the plane was active for almost all of the roughly 90-minute flight and the angle of attack readings had the same errors, the data shows.
“Number one, why did the previous crew continue that flight?” Cox said. “Number two, did they or did they not make an appropriate write-up? The third question is how come you signed this thing off” to fly the next day.
https://www.bloombergquint.com/busin...ing#gs.WE5NkUQ
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“Number one, why did the previous crew continue that flight?” Cox said. “Number two, did they or did they not make an appropriate write-up? The third question is how come you signed this thing off” to fly the next day.
https://www.bloombergquint.com/busin...ing#gs.WE5NkUQ
https://www.bloombergquint.com/busin...ing#gs.WE5NkUQ
The slowed but continued march towards a financial reason (hence cost) for everything eventually brings with it consequences..
Captain Sullenberger, recites a story he read in an aviation magazine which sums it up.
The retiring airline Captain reflecting on his career stated "We used to be selected and assessed on our judgement. Now we are selected and assessed on our (corporate) compliance."
'Commercial pressures' and all that....
A question about manual trimming.
Years ago, I had a jumpseat ride in a 732 and more recently, I had some time in an NG Level D simulator, so I’m aware how quickly (and noisily) the trim wheels rotate, when trimming is done via the control column switch.
If the stabilizer is at the maximum nose-down position, how many turns and how much time does it take to manually restore the stabilizer to a typical position for trimmed cruise flight?
Years ago, I had a jumpseat ride in a 732 and more recently, I had some time in an NG Level D simulator, so I’m aware how quickly (and noisily) the trim wheels rotate, when trimming is done via the control column switch.
If the stabilizer is at the maximum nose-down position, how many turns and how much time does it take to manually restore the stabilizer to a typical position for trimmed cruise flight?
Last edited by India Four Two; 26th Nov 2018 at 23:14. Reason: Spelling
The NG FCOM notes:
The effort required to manually rotate the stabilizer trim wheels may be higher under certain flight conditions.
Excessive air loads on the stabilizer may require effort by both pilots to correct mis-trim. In extreme cases it may be necessary to aerodynamically relieve the airloads to allow manual trimming.