BB solves JT 610 crash
Why aren’t all 737 Max 8/9’s sitting on the ground until this is resolved?
The airlines flying this junk are listed entities and there is commercial impact.
The regulator is captured to ensure there is no commercial impact.
The regulator is captured to ensure there is no commercial impact.
Tell me Krusty or Rated De, in what exact ways does the Speed Trim System differ on the Max vs the NG?
Why is one safe and the other not?
Or a more simple question, could the pilots at any time use the main electric trim to trim nose up, overriding the STS inputs?
Would the Runaway Stabilizer checklist memory items have alleviated the problem?
I don’t know the answer to all these questions but one ought to before calling for the grounding of a fleet.
What the hell is going on here?
I know all the facts aren’t in, but I just can’t get my head around what appears to be an “initiative” driven by what seems to be a complete loss of faith in pilots.
A system that can induce a nose down trim, that’s right trim, if the angle of attack exceeds (or the system believes it has exceeded) certain limits. Who the F#ck came up with that idea?
A lot has been said and written about the Colgan crash. Sure the Captain allowed himself to be distracted at a critical phase of fight. Certainly he reacted incorrectly to the onset of the stall warning, and we pretty well know the rest. I know this falls into the realms of speculation, but what if the Captain of Colgan 3407 noticed the decreasing airspeed before the normal stall warning activated. This would have occurred at a much lower airspeed if the ice speed system had been disabled, or not fitted at all? I flew for a company who had fitted the ice speed system to our regional turboprops. The initial results were less than encouraging. False warnings, failure to activate correctly and an enormous spike in inadvertent stall warnings. As a result, this new system that was supposed to save pilots from themselves, was deactivated for more than a year so it could be sorted out.
The role of the ice speed system in the Colgan crash, although touched upon, didn’t get the type of attention that I believe it deserved. I have a feeling however that this latest “Safety initiative” might be a little more difficult to justify.
A system that can induce a nose down trim, that’s right trim, if the angle of attack exceeds (or the system believes it has exceeded) certain limits. Who the F#ck came up with that idea?
A lot has been said and written about the Colgan crash. Sure the Captain allowed himself to be distracted at a critical phase of fight. Certainly he reacted incorrectly to the onset of the stall warning, and we pretty well know the rest. I know this falls into the realms of speculation, but what if the Captain of Colgan 3407 noticed the decreasing airspeed before the normal stall warning activated. This would have occurred at a much lower airspeed if the ice speed system had been disabled, or not fitted at all? I flew for a company who had fitted the ice speed system to our regional turboprops. The initial results were less than encouraging. False warnings, failure to activate correctly and an enormous spike in inadvertent stall warnings. As a result, this new system that was supposed to save pilots from themselves, was deactivated for more than a year so it could be sorted out.
The role of the ice speed system in the Colgan crash, although touched upon, didn’t get the type of attention that I believe it deserved. I have a feeling however that this latest “Safety initiative” might be a little more difficult to justify.
This “initiative” is nothing new, albeit has been refined in the Max.
This is an excerpt from the 737 NG flight manual:
It’s fair to say the 737 NG is pretty prolific and there have not been a string of accidents attributed to this system so let’s hold off on suggesting the system is innately dangerous and should not be flying.
This is an excerpt from the 737 NG flight manual:
As airspeed decreases towards stall speed, the speed trim system trims the stabilizer nose down and enables trim above stickshaker AOA. With this trim schedule the pilot must pull more aft column to stall the airplane.
Beer, that isn't exactly how the FAA describes what could happen in it's EAD:
and
It appears that this is not the STS, but a new system called the MACS.
Unsafe Condition
This 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. We are issuing
this AD to address this potential resulting nose-down trim, which 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.
This 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. We are issuing
this AD to address this potential resulting nose-down trim, which 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.
The 737-8/-9 uses a Flight Control Computer command of pitch trim to improve longitudinal handling characteristics. In the event of erroneous Angle of Attack (AOA) input, the pitch trim system can trim the stabilizer nose down in increments lasting up to 10 seconds.
You are quite right and I said from the outset that the STS on the Max is different to the NG but the basic premise is similar. The aircraft will attempt to trim itself during manual flight to correct a speed variation or stall. I’ve not flown the max and I don’t profess to know the intricacies of its system.
However, I believe on both types, you can still use main electric trim to reverse and correct an undesired STS input. (It will wait 5 or 10 seconds and then have another crack at it). And the Runaway Stabilizer checklist will rectify the fault (even if you are left holding the trim wheel).
However, I believe on both types, you can still use main electric trim to reverse and correct an undesired STS input. (It will wait 5 or 10 seconds and then have another crack at it). And the Runaway Stabilizer checklist will rectify the fault (even if you are left holding the trim wheel).
I must admit, after reading Blogg’s post, I rest my case.
Quote:
“The more they overtake the plumbing, the easier it is to stop up the drains.”
Commander Montgomery (Scotty) Scott.
Quote:
“The more they overtake the plumbing, the easier it is to stop up the drains.”
Commander Montgomery (Scotty) Scott.
Last edited by KRUSTY 34; 15th Nov 2018 at 10:02.
It's worth noting - especially in the sea of speculation above! - that, so far as I am aware, there's no specific news on the FDR data either. Nothing that Boeing or the FAA have said so far is explicitly linked to the FDR for this airframe. The FAA directive could be part-based on the FDR data; but it could equally - imho - be based on what is known about the flight from ATC data and communications, plus paperwork and witness statements about the prior difficulties that this particular a/c had recently encountered. So, previous flight crews could all have said that, having gone to manual flight following sensor disagree alerts, they then encountered strong and unexpected nose-down stab trim, uncommanded by them.
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Interesting observation. If true, does that mean everything written on the accident is nothing more than pure speculation or informed discussion which in turn becomes perceived fact ?
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Interesting observation. If true, does that mean everything written on the accident is nothing more than pure speculation or informed discussion which in turn becomes perceived fact ?
Originally Posted by Centaurus
If true, does that mean everything written on the accident is nothing more than pure speculation or informed discussion which in turn becomes perceived fact ?
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He’s changed his ‘assessment’ quite a bit but still no retraction or apology.
https://www.theaustralian.com.au/bus...8798adc77e0f16
https://www.theaustralian.com.au/bus...8798adc77e0f16
The Lion Air B737 Max crash of October 29 had warning bells and red flags all over it because of ongoing technical problems with the aircraft.
During the flight on October 26, the captain had no speed or altitude information on his PFD (primary flight display). The same occurred on the flight of October 27. On the flight of October 28 after takeoff from Bali, the captain’s stall warning stick shaker activated on rotation. The captain handed control to the co-pilot while troubleshooting the problem.
On flap retraction, they had three automatic nose-down trim occurrences. He declared an emergency and over the next several minutes ran three non-normal checklists in the order of “airspeed unreliable”; “altitude disagree” and “runaway stabiliser” which has the final item, “stab (stabiliser) trim” switches to “cut off”. This solved the automatic nose-down trim events. The captain then told ATC the problem was solved and the co-pilot flew the rest of the flight to Jakarta using manual trim (no autopilot) with the captain’s stick shaker activated.
The technical log entries post flight apparently did not give a clear picture to the incoming October 29 captain of the full extent of what he was to endure. The position of the horizontal stabiliser (STAB) is always set at a negative angle in relation to the wing so as to supply a downforce to keep the aircraft in trim –_balanced so that the pilot has little or no pitch control column pressure from the elevator, which is hinged at the back of the STAB.
I have examined at length the DFDR (digital flight data recorder) traces of the Lion Air fatal flight of October 29, and they paint a damning and tragic picture of what unfolded.
On rotation for takeoff the captain’s stall warning stick shaker activated and remained active for the whole 12-minute flight. Call this takeoff time “0”.
At 0 plus 2 minutes at an altitude of 2150 feet, the flap was retracted and followed by 10 seconds of automatic MCAS nose-down trim (AND). This was followed by manually activated nose-up trim (ANU) while holding the control column back to give up elevator.
At 0 plus 3 minutes, the flaps were extended to 5 degrees and the AND stopped.
At 0 plus 5 minutes the flaps were retracted and the AND ran for 10 seconds and was countered by pilot ANU.
For the next 6 minutes there were over 20 automatic AND, each time followed by a pilot ANU. At 0 plus 11 minutes there were 4 AND, each followed by a very small manual ANU correction until the horizontal stabiliser had full nose-down trim and entered a dive which full nose-up elevator could not prevent.
0 plus 12 minutes end DFDR traces as the aircraft crashed.
It is obvious the captain was totally befuddled by the events occurring. He failed to identify what was happening to the extent that he fought against the automatic nose-down trim instead of disabling it with the stab-trim cut-off switches near the throttle quadrant.
Stabiliser trim motors are designed to reduce load with brief activation. To be running almost continuously, down and up, for over 6 minutes may have brought the electric motors close to seizure.
The cockpit voice recorder is needed to paint a fuller picture of this tragic event and the search is continuing at the moment. It is obvious that this flight should never have been allowed to happen.
During the flight on October 26, the captain had no speed or altitude information on his PFD (primary flight display). The same occurred on the flight of October 27. On the flight of October 28 after takeoff from Bali, the captain’s stall warning stick shaker activated on rotation. The captain handed control to the co-pilot while troubleshooting the problem.
On flap retraction, they had three automatic nose-down trim occurrences. He declared an emergency and over the next several minutes ran three non-normal checklists in the order of “airspeed unreliable”; “altitude disagree” and “runaway stabiliser” which has the final item, “stab (stabiliser) trim” switches to “cut off”. This solved the automatic nose-down trim events. The captain then told ATC the problem was solved and the co-pilot flew the rest of the flight to Jakarta using manual trim (no autopilot) with the captain’s stick shaker activated.
The technical log entries post flight apparently did not give a clear picture to the incoming October 29 captain of the full extent of what he was to endure. The position of the horizontal stabiliser (STAB) is always set at a negative angle in relation to the wing so as to supply a downforce to keep the aircraft in trim –_balanced so that the pilot has little or no pitch control column pressure from the elevator, which is hinged at the back of the STAB.
I have examined at length the DFDR (digital flight data recorder) traces of the Lion Air fatal flight of October 29, and they paint a damning and tragic picture of what unfolded.
On rotation for takeoff the captain’s stall warning stick shaker activated and remained active for the whole 12-minute flight. Call this takeoff time “0”.
At 0 plus 2 minutes at an altitude of 2150 feet, the flap was retracted and followed by 10 seconds of automatic MCAS nose-down trim (AND). This was followed by manually activated nose-up trim (ANU) while holding the control column back to give up elevator.
At 0 plus 3 minutes, the flaps were extended to 5 degrees and the AND stopped.
At 0 plus 5 minutes the flaps were retracted and the AND ran for 10 seconds and was countered by pilot ANU.
For the next 6 minutes there were over 20 automatic AND, each time followed by a pilot ANU. At 0 plus 11 minutes there were 4 AND, each followed by a very small manual ANU correction until the horizontal stabiliser had full nose-down trim and entered a dive which full nose-up elevator could not prevent.
0 plus 12 minutes end DFDR traces as the aircraft crashed.
It is obvious the captain was totally befuddled by the events occurring. He failed to identify what was happening to the extent that he fought against the automatic nose-down trim instead of disabling it with the stab-trim cut-off switches near the throttle quadrant.
Stabiliser trim motors are designed to reduce load with brief activation. To be running almost continuously, down and up, for over 6 minutes may have brought the electric motors close to seizure.
The cockpit voice recorder is needed to paint a fuller picture of this tragic event and the search is continuing at the moment. It is obvious that this flight should never have been allowed to happen.
Not only is there no apology for his earlier libel, he seeks to stick the knife into the Captain further.
Statements like : "It is obvious that the Captain was totally befuddled...." and: "He failed to identify....."
So BB was a fly on the cockpit wall and saw all this befuddlement and failure, did he?
A writer with his technical knowledge but less focused on laying blame before the investigation has been completed would be decent enough to say no more about the crew's performance in this tragedy than: "it appears from information so far retrieved that the crew were overwhelmed by a failure that had not been foreseen and they had never seen in the simulator".
His last statement about the flight should have never been allowed is, however, spot on.
Statements like : "It is obvious that the Captain was totally befuddled...." and: "He failed to identify....."
So BB was a fly on the cockpit wall and saw all this befuddlement and failure, did he?
A writer with his technical knowledge but less focused on laying blame before the investigation has been completed would be decent enough to say no more about the crew's performance in this tragedy than: "it appears from information so far retrieved that the crew were overwhelmed by a failure that had not been foreseen and they had never seen in the simulator".
His last statement about the flight should have never been allowed is, however, spot on.
Last edited by Mach E Avelli; 13th Dec 2018 at 23:58.
I enjoy reading the yarns of an old 70's Mirage pilot in Friday's Australian. Shoots from the hip and believes his own bull$hit. Very entertaining and I wish the articles longer. Actually, I wish he'd sink a few beers and then write, so the yarns could match the "epicness" of a Friday night, or any night for that matter, at an air force mess where there was a fighter squadron.
I do cringe at his comments on civil aviation matters and his fallback as an EK captain. He writes like a mercenary contract pilot with little regard to the holistic complexities of civil airline flying or empathy or understanding of wider piloting issues. Having flown in the Middle East myself, this is not untypical, where anyone from any background, could flourish amongst pretty modest standards, just so long as you don't make a stand on professional agendas commonly accepted in the first world .
I do cringe at his comments on civil aviation matters and his fallback as an EK captain. He writes like a mercenary contract pilot with little regard to the holistic complexities of civil airline flying or empathy or understanding of wider piloting issues. Having flown in the Middle East myself, this is not untypical, where anyone from any background, could flourish amongst pretty modest standards, just so long as you don't make a stand on professional agendas commonly accepted in the first world .
Well, I’m sorry.
The assertion that the Captain should have done this, or should not have done that, along with the emerging evidence that this poor crew were not properly informed or trained in this so called new safety feature, shows an ignorance of human limitations that frankly I find breathtaking.
At at the end of the day that aeroplane was out to kill them. And it succeeded!
The assertion that the Captain should have done this, or should not have done that, along with the emerging evidence that this poor crew were not properly informed or trained in this so called new safety feature, shows an ignorance of human limitations that frankly I find breathtaking.
At at the end of the day that aeroplane was out to kill them. And it succeeded!
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I enjoy reading the yarns of an old 70's Mirage pilot in Friday's Australian. Shoots from the hip and believes his own bull$hit. Very entertaining and I wish the articles longer. Actually, I wish he'd sink a few beers and then write, so the yarns could match the "epicness" of a Friday night, or any night for that matter, at an air force mess where there was a fighter squadron.
I do cringe at his comments on civil aviation matters and his fallback as an EK captain. He writes like a mercenary contract pilot with little regard to the holistic complexities of civil airline flying or empathy or understanding of wider piloting issues. Having flown in the Middle East myself, this is not untypical, where anyone from any background, could flourish amongst pretty modest standards, just so long as you don't make a stand on professional agendas commonly accepted in the first world .
I do cringe at his comments on civil aviation matters and his fallback as an EK captain. He writes like a mercenary contract pilot with little regard to the holistic complexities of civil airline flying or empathy or understanding of wider piloting issues. Having flown in the Middle East myself, this is not untypical, where anyone from any background, could flourish amongst pretty modest standards, just so long as you don't make a stand on professional agendas commonly accepted in the first world .
Emotionally intelligent professional people do not wear spurs.
I smell a rat.
A brand new airliner takes on a mind of it's own after being fed erroneous information from a faulty sensor/unit. Despite the efforts of the crew it crashes violently, killing nearly 200 people. All the while in day VMC, and after less than 15 minutes of flight time. How is this anything but a total disaster, yet it's gone strangely quiet on mainstream media. Now the investigators say they are lacking the resources to locate the CVR!
If this tragic event had occurred over the suburbs of LA or Sydney, it would have been the scandal of the Decade.
My conspiracy meter is running at around 90% at the moment.
A brand new airliner takes on a mind of it's own after being fed erroneous information from a faulty sensor/unit. Despite the efforts of the crew it crashes violently, killing nearly 200 people. All the while in day VMC, and after less than 15 minutes of flight time. How is this anything but a total disaster, yet it's gone strangely quiet on mainstream media. Now the investigators say they are lacking the resources to locate the CVR!
If this tragic event had occurred over the suburbs of LA or Sydney, it would have been the scandal of the Decade.
My conspiracy meter is running at around 90% at the moment.
Last edited by KRUSTY 34; 17th Dec 2018 at 10:35.
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My conspiracy meter is running at around 90% at the moment.
In that particular instance, I have the personal feeling that MH 370 will never be found simply because there are certain people in positions of power/responsibility/whatever who do not want it to be found!
![Hmmm](https://www.pprune.org/images/smilies/yeees.gif)
May I suggest that the same applies to the inability to locate this CVR?
Thread Starter
Bingo, Pinky!