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Malcolm

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38 minutes ago, Maverick said:

Mr Edward Sirait, Lion Air Group's president director, denied that the company cut corners or dissembled in logbooks. In an interview in his sparsely furnished office, he said the company had twin priorities: growth and safety.

Hey Dumbass. you put the wrong one first.

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VP, I think that the "corporate-leadership world" is neither new, nor brave.

We don't know whether this is an organizational failure, a training issue, or a technical, (software drives the MCAS which uses the STS system, (which is FCC-driven), or design & certification issue. There just isn't sufficient information so all pleadings have to be taken as such, and not as data.

Below is a detail of one of the recorder traces now available. Based on the assumption that this is real data from a reliable source, one can see that the crew's manual trim inputs appeared to be working to counter the MCAS/STS system inputs, with a degrading trend towards ND stabilizer trim. The actual behaviours of the crew in terms of cut-out switches or holding the actual trim wheel remain unknown. An interim report is to be published next week on the 28th.

 

2018-11-22_110021_DFDR-1-mod-XL.jpg

 

2018-11-23_083924_ManTrim%20vs%20MCAS%20

Edited by Don Hudson

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Hi Don

It's premature of course, but in my view the available information seems to suggest control was lost only because of 'same type differences confusion'.

Even worse than dealing with known variances, this crew apparently did not have any useful information to begin with regarding the operation of the new system, which almost certainly would have led to the bewilderment that seems to have confounded the situation?

Imagine the fast moving three dimensional mystery that may have began when the uninformed crew responded NG style to an apparent trim runaway that was occurring concurrent with an instrument mismatch.

During the crew's initial response the ten second ND 'on' limit may have been reached a nano-second after the pilot reversed the column against the perceived runaway, which caused him to believe he had overcome the problem conventionally, but when the system began trimming ND again a few seconds later, the uniformed pilots entered into a losing fight to control the aircraft?

Also, although it may have been VFR, we don't know that a horizon was discernible on that day.

 

 

 

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9 hours ago, Maverick said:

'Spend the minimum': How Lion Air hid equipment failures and beat regulators

 

Would have quicker and easier to write that article if the journalist had listed everything that Lion Air was doing right in their operation - Nothing!

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Hi DEFCON;

The CVR is crucial to the investigation. It needs to be determined if, and how quickly the crew reached their overload point, and whether the cut-off switches were actually mentioned.

Discussion with the previous crews who flew the aircraft are equally crucial. If the only thing stopping the STS/MCAS from trimming was the use of the cut-off switches, it appears as though the crew on the previous day's flight in which the problem re-occurred, may have used them. If they did, and the accident crew did not, that places different emphasis and focus on what happened, at least until it is determined what the accident crew did.

There is the more serious question in my opinion, of what appears to be a very subtle single-point-of-failure regarding the loss of AoA data. One failure should not render a system incapable of working normally. 

A discussion about "decideability" in computer systems is appropriate. Why should two sensors out-vote one in every case? There is no "Occam's Razor" algorithm!

The industry has not really dealt with the question and usually accepts that two out of three sensors/inputs will satisfy most failures because of the humans in the cockpit for one thing, (a separate argument against autonomous flight), but in truth, it is at least 7. (There is a reason for this but it's borrrring). Seven is of course impractical and with 98.6F still warming the seats perhaps a long way off. But QF72, AF447 and this accident is evidence that that three may not be.

The report on the Lion Air land-short incident a while back indicates some training-and-standards issues. The captain received an "SB" for not going around on an approach that demanded the GA, and he pressed on after taking control from the F/O at low altitude when the F/O lost visual contact with the runway in a squall, (if I recall all this correctly... 😉 )

Edited by Don Hudson

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Don

An answer to your question regarding the THS.

 

"1) Uncommanded nose down stabilizer trim is associated with an AOA failure condition that occurs during manual flight only;

 2) In an AOA failure condition the pitch trim system can trim the stabilizer nose down in increments lasting up to 10 seconds;

3) The nose down stabilizer movement can be stopped and reversed using electric stabilizer trim switches, but may restart 5 seconds after the electric stabilizer trim switches are released;

4) Only the STAB TRIM CUTOUT switches can deactivate the pitch trim system;

5) Without proper pilot intervention, it is possible for the stabilizer to reach the nose down limit;

6) After the STAB TRIM CUTOUT switches are OFF, manual stabilizer trim must be used for the remainder of the flight."

 

The answer to Rudder's earlier question in respect of  'Point #5' is still a bit of a mystery.

 

 

Edited by DEFCON

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Hi DEFCON;

Thanks, much appreciated. They are in reference only to the MCAS I believe, as there is no AoA input to the STS. The cut-off switch(es) are required by the QRH if the stabilizer continues to move after resisting movement with the control column, (there is a cut-off switch on the control columns beneath the cockpit floor that senses physical force/resistance and stops electrical power to the larger electric trim motor). #6 makes sense as one would not re-engage, (use the electrics) for a system that has proven faulty. The QRH also uses the word "continuously" regarding movement of the stabilizer. As you say, the movement here wasn't continuous or at manual rates which is what one normally sees in the sim when practising the abnormal. The trim-wheel would be moving with the MCAS as we would know.

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Don

"There is the more serious question in my opinion, of what appears to be a very subtle single-point-of-failure regarding the loss of AoA data. One failure should not render a system incapable of working normally."

That is a very important question considering the magnitude of the upset and departure from stable flight that's going to occur every time one of this type has a failure of some part of its AoA indication system.

 

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https://www.nytimes.com/2018/11/27/world/asia/indonesia-lion-air-crash-.html?action=click&module=Top Stories&pgtype=Homepage

 

Black Box Data Reveals Pilots’ Struggle to Regain Control of Doomed Jet

Nov. 27, 2018

Wheels from Lion Air flight 610 were recovered from the sea this month.Ulet Ifansasti/Getty Images

merlin_146253483_56aae730-fb2a-4f1a-b631
Wheels from Lion Air flight 610 were recovered from the sea this month.Ulet Ifansasti/Getty Images

Data from the jetliner that crashed into the Java Sea last month shows the pilots fought to save the plane almost from the moment it took off, as the Boeing 737’s nose was repeatedly forced down, apparently by an automatic system receiving incorrect sensor readings.

The information from the flight data recorder, contained in a preliminary report prepared by Indonesian crash investigators and scheduled to be released Wednesday, documents a fatal tug-of-war between man and machine, with the plane’s nose forced dangerously downward more than two dozen times during the 11-minute flight. The pilots managed to pull the nose back up over and over until finally losing control, leaving the plane, Lion Air Flight 610, to plummet into the ocean at 450 miles per hour, killing all 189 people on board.

The data from the so-called black box is consistent with the theory that investigators have been most focused on: that a computerized system Boeing installed on its latest generation of 737 to prevent the plane’s nose from getting too high and causing a stall instead forced the nose down because of incorrect information it was receiving from sensors on the fuselage.

In the aftermath of the crash, pilots have expressed concern that they had not been fully informed about the new Boeing system — known as the maneuvering characteristics augmentation system, or M.C.A.S. — and how it would require them to respond differently in case of the type of emergency encountered by the Lion Air crew.

“It’s all consistent with the hypothesis of this problem with the M.C.A.S. system,” said R. John Hansman Jr., a professor of aeronautics and astronautics and director of the international center for air transportation at the Massachusetts Institute of Technology.

Boeing has said that the proper steps for pulling out of an incorrect activation of the system were already in flight manuals, so there was no need to detail this specific system in the new 737 jet. In a statement on Tuesday, Boeing said it could not discuss the crash while it is under investigation but reiterated that “the appropriate flight crew response to uncommanded trim, regardless of cause, is contained in existing procedures.”

A fuller account of problems with the sensors on the fuselage, called angle-of-attack sensors, is expected to be part of a full report on the crash by Indonesian investigators. But one of those sensors was replaced before the plane’s next-to-last flight after having transmitted some angle and speed data incorrectly, investigators say.

“The pilots fought continuously until the end of the flight,” said Capt. Nurcahyo Utomo, the head of the air accident subcommittee of the Indonesian National Transportation Safety Committee, which is leading the crash investigation.

Family members grieving after police handed over the remains of their relatives who had been aboard Lion Air Flight 610.Ed Wray/Getty Images

merlin_146305071_8394a1b0-b16f-46e9-9081
Family members grieving after police handed over the remains of their relatives who had been aboard Lion Air Flight 610.Ed Wray/Getty Images

Captain Nurcahyo said that the M.C.A.S. system had been activated and is a central focus of the investigation.

Details of the black box data were contained in a briefing for the Indonesian Parliament and were first disclosed publicly in the Indonesian media. The data was subsequently posted and analyzed in a blog post by Peter Lemme, a satellite communications expert and former Boeing engineer.

Much remains unknown about the doomed flight, including why a plane that had encountered problems with the sensors was permitted to fly in the first place. Investigators have yet to recover the cockpit voice recorder, which could provide further insight into the steps taken by the pilots and whether they followed the correct procedures. The pilot had handed control of the plane to the co-pilot just before the plane went into its final dive.

Despite Boeing’s insistence that the proper procedures were in the handbook, also called the emergency checklist, pilots have said since the accident that Boeing had not been clear about one potentially vital difference between the system on the new 737s and the older models. In the older versions, pilots could help address the problem of the nose being forced down improperly — a situation known as “runaway stabilizer trim” — by pulling back on the control column in front of them, the pilots say.

In the latest 737 generation, called the Max, that measure does not work, they said, citing information they have received since the crash. The pilots on Lion Air Flight 610 appear to have forcefully pulled back on their control columns to no avail, before the final dive, according to the information from the flight data recorder.

Capt. Dennis Tajer, spokesman for the American Airlines pilot union and a 737 pilot, said he could not comment on any aspect of the investigation. But, he said, “in the previous model of the 737, pulling back on the control column, Boeing says will stop a stabilizer runaway.”

Information provided to American Airlines from Boeing since the crash, Captain Tajer said, “specifically says that pulling back on the control column in the Max will not stop the runaway if M.C.A.S. is triggered. That is an important difference to know.”

Boeing said in its statement on Tuesday that the existing procedures covered the latest 737 model.

Bulletins from Boeing and the Federal Aviation Administration of the United States since the crash indicate that pilots could overcome an incorrectly activated M.C.A.S. with a series of steps. First, they would have had to activate switches on the outside of the control columns in front of both the pilot and co-pilot. Those switches are for electrically controlling the trim — the angle of the stabilizers on the plane’s tail. The pilot of Flight 610 appears to have done that repeatedly to bring the nose up, but the M.C.A.S. reactivated each time, as it was designed to do, forcing the nose back down, and the pilot had to repeat the process again and again.

The stabilizer is the larger of the two surfaces on the tail wing, and is ordinarily controlled by an electrical motor. Behind the stabilizer is the elevator, activated by the control columns in front of both the pilot and co-pilot. Both can move the nose up and down.

Body bags containing the remains of the Lion Air Flight 610 victims at Tanjung Priok port in Jakarta. There were no survivors among the 189 people on board.Beawiharta/Reuters

Body bags containing the remains of the Lion Air Flight 610 victims at Tanjung Priok port in Jakarta. There were no survivors among the 189 people on board.Beawiharta/Reuters

From there, the pilots should have hit two electrical cutout switches to shut down the M.C.A.S. and turn the stabilizer movement over to manually controlled wheels at the ankles of the pilot and co-pilot — wheels connected to cables that would move the stabilizer. It is not clear whether the pilots of Flight 610 tried that procedure.

The futile struggle by the pilots to regain control can be seen in colorful jagged lines in graphs contained in the report to the Indonesian Parliament, documenting the seesaw motion of the nose as the system pushed it down at least two dozen times before the plane’s fatal nose-dive.

From the moment Flight 610 took off just after dawn from the airport in Jakarta, the Indonesian capital, the Max 8 jet was recording errant data from one of the two angle-of-attack sensors on the nose of the plane that records the pitch at which a plane is climbing or descending.

Angle-of-attack sensors are crucial in determining if a plane is stalling.

It is not clear whether the false data, which was on the pilot’s side of the plane, was attributable to a problem with the sensor itself or with the computer that processes the sensor’s information. But hours before the plane took off on its final flight, it had also recorded problems with an angle of attack sensor as it traveled from the resort island of Bali to Jakarta.

On that next-to-last flight, the angle discrepancy between the two sensors was 20 degrees, according to officials from Indonesia’s National Transportation Safety Committee, which has been leading the investigation into the crash.

On the final flight, the discrepancy was also 20 degrees, said Captain Nurcahyo.

Plane crashes rarely can be blamed on a single, catastrophic malfunction. More often, a problem spirals out of control as maintenance crews fail to spot or address an underlying issue and then the flight crew takes a series of steps that lead to a fatal outcome.

Lion Air, Indonesia’s largest airline, has a notoriously flawed safety record. Government investigators have accused the carrier of ignoring their commands to ground planes with proven problems.

The plane that crashed on Oct. 29 had experienced days of incorrect data readings, according to Indonesian officials. In fact, before the penultimate flight, engineers had replaced one of the angle-of-attack sensors.

Why the plane recorded incorrect angle-of-attack data after the sensor had been changed is not clear. Soerjanto Tjahjono, the head of Indonesia’s National Transportation Safety Committee, said that the replacement part was not new but was “serviceable” and had certification from the F.A.A. of the United States.

Edited by dagger

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s & safety

  • JT610 pilots struggled against Max 8's nose down commands

JT610 pilots struggled against Max 8's nose down commands

  • 28 November, 2018
  • SOURCE: Flight Dashboard
  • BY: Mavis Toh
  • Singapore

Data retrieved from the flight data recorder of the Lion Air Boeing 737 Max 8 that crashed on 29 October shows that the jet’s nose was repeatedly forced down before the pilots lost control of the aircraft.

The chart detailing parameters of the accident flight was released by Indonesia’s National Transport Safety Committee (NTSC) in a presentation to the Indonesian parliament on 22 November. The data will likely form the backbone of a preliminary report that the committee is scheduled to be released on 28 November.

Asset Image

Indonesia's National Transport Safety Committee

The data shows that the aircraft pitched nose-down more than two dozen times during the 11-minute flight, with the pilots pulling the nose up each time, before eventually losing control of the aircraft.

The aircraft's cockpit voice recorder has not been recovered.

The NTSC says the aircraft’s Maneuvering Characteristics Augmentation System (MCAS) kicked in during the flight, and is a central focus of the investigation, Indonesian media reports. At issue is also how erroneous angle-of-attack sensor information could have forced the aircraft's nose down.

MCAS is a new feature added to the 737 Max to enhance pitch characteristics while the aircraft is being manually flown at a high angle of attack with the flaps up. The system commands stabiliser movement, without pilot input, to pitch the aircraft nose down.

The presentation also shows a chart from the previous day's flight between Denpasar and Jakarta, where the aircraft’s nose was also pushed down repeatedly early in the journey. The crew of that flight too made over a dozen nose up commands. The difference from the doomed JT610 was that the MCAS appeared to have been turned off thereafter, and the aircraft continued to its destination without further incident.

Early this month, Boeing issued a bulletin to 737 Max operators, directing them to “existing flight crew procedures” to address circumstances involving erroneous angle-of-attack information.

The Lion Air Max 8 was operating from Jakarta to Pangkal Pinang when it crashed into the sea, killing all 189 passengers and crew on board.

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Hi DEFCON;

Re,

Quote

"That is a very important question considering the magnitude of the upset and departure from stable flight that's going to occur every time one of this type has a failure of some part of its AoA indication system. "

It is indeed a big question, for the FAA, for Boeing, for Lion Air management & maintenance personnel.

The MCAS was introduced on the Max for aerodynamic reasons and affects primary flight controls. So robust testing including behaviour during all potential failure modes as part of the engineering process of various failure modes would be expected. Anticipating single-points-of-failure which carry with them the potential for "loss of the mission" is part of such a process.

A swapping of AoA sensors following a flight on which the stall warning system was activated for the entire flight, both systems which involve primary flight controls, would require a test flight.

I see that the validity of the CofA is now under examination.

 

 

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Good Summary from the BBC

Quote

Lion Air crash: Investigators say plane was 'not airworthy'

 

Indonesian investigators have said the Lion Air plane that crashed last month killing 189 people was not airworthy and should have been grounded.

The Boeing 737 Max plane crashed into the Java Sea shortly after departing from Jakarta on 29 October.

A preliminary report has found technical problems had been reported on previous flights.

The 737 Max is a new version of Boeing's original 737 and has become its fastest selling plane.

The preliminary report details what is known by authorities about the short time the plane was in the air, but investigators said it did not give a definitive cause for the accident.

What's in the report?

The findings by the National Transport Safety Committee (KNKT) suggest that Lion Air put the plane back into service despite it having had problems on earlier flights.

The pilots appeared to struggle with an automated system designed to keep the plane from stalling - a new feature in the 737 Max family.

Anti-stall systems prevent a plane from pointing upwards at too high an angle, where it could lose its lift.

However, during the 29 October flight, the plane's automatic anti-stalling system repeatedly forced the plane's nose down, even when the plane was not stalling - possibly due to a faulty sensor, the report said.

Pilots tried to correct this by pointing the nose higher, until the system pushed it down again. This happened more than 20 times.

It is unclear why the pilots did not employ procedures to disable the automated system.

Nurcahyo Utomo, aviation head at the National Transport Safety Committee, said it was "too early to conclude" whether the anti-stall system had contributed to the crash.

He added that the plane experienced similar problems during its previous flight from Denpasar in Bali to Jakarta.

"In our opinion, the plane was no longer airworthy and it should not have continued," he said. The committee's report itself, though, does not spell out that conclusion.

The report said that Lion Air's safety culture should be improved and the airline should ensure the operations manual is followed "in order to improve the safety culture".

It also says the carrier must ensure "all operations documents are properly filled and documented".

Chart showing flight data for Lion Air JT610 Presentational white space

What does Boeing say?

In a statement, plane manufacturer Boeing said that it was "deeply saddened" by the loss of the Lion Air flight.

"As our customers and their passengers continue to fly the 737 Max to hundreds of destinations around the world every day, they have our assurance that the 737 Max is as safe as any airplane that has ever flown in the skies."

Boeing said that "the appropriate procedure to address unintended horizontal stabiliser movement" was contained in the relevant flight manuals.

It said that the preliminary report showed that the correct procedures to counter the plane's nose being pushed down were carried out during the Denpasar flight the day before the crash.

However, it was not clear if they procedures were followed during the 29 October flight that crashed, Boeing added.

In an interview with the BBC, KNKT aviation head Nurcahyo Utomo appeared to dispute Boeing's account about the flight manuals.

"We haven't found the information in the manual relevant to the new feature to the 737- MAX, related to the feature for the stall prevention system," he said.

Some pilots have also complained that they were not given all the relevant information about the differences between the latest anti-stall system, and older models, US media report.

How did the 29 October crash unfold?

The plane was making a one-hour journey to the western city of Pangkal Pinang when it went down.

The jet crashed following a request from the pilot for permission to turn back to the airport minutes after taking off from Jakarta.

Map of crash Presentational white space

Investigators had previously revealed that the plane, on previous flights, had experienced technical problems related to airspeed and altitude readings.

Therefore the "angle-of-attack" sensor, which contributes to those readings, had been changed the day before the crash.

The plane's flight data recorder has been retrieved but authorities are yet to locate the cockpit voice recorder which could provide more information about how the pilots reacted.

Victims' families are suing Boeing over alleged faults with the jet's design, focusing on the automated safety feature.

Presentational grey line

'We want to understand who is responsible'

Rebecca Henschke, BBC Indonesia editor, Jakarta

Rini Soegiyono's sister and brother-in-law were on the flight. After hearing the preliminary findings, she said she had mixed emotions.

"Sad, grieving, mourning, angry and disappointed - these are all the words that describe how I am feeling. But I am trying to be objective and strong."

She, like many grieving families, is mostly frustrated that the search for the remaining passengers has officially ended.

"There are still 64 families who haven't had their loved ones' remains identified and we have had to really push to get Lion Air and the authorities to search again for them. It's not good enough."

They want the airline to fund a search to find the remaining passengers as well as the cockpit voice recorder that hasn't been retrieved. It will be key, she says, to understanding what went wrong.

"We are watching and waiting to understand who is responsible. I know the world is also watching. It's important to know so it will not happen again. We don't want any family to have to go through what we are going through."

Presentational grey line

Indonesia's air safety record

Budget airline Lion Air has in recent years risen to become a major player in South East Asia's low cost aviation sector.

The airline, which also operates Batik Air and Wings Air, has a dubious safety record, though, and has had more accidents than other airlines in the country.

Overall, Indonesia's aviation safety record has improved a lot since the days when even its national carrier Garuda was blacklisted from European and US airports over safety concerns.

Graphic showing Indonesian airline accidents  

 

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Thanks for the link Don.

I believe you're spot on, an analysis of the root causes would seem to be in order.

Something that stands out to me:

The total time of the Captain and FO were fairly close as was their experience on type.

Both started with Lion Air during the same year, presumably at the bottom of a growing list that now must have over 1100 pilots on it.

The majority of the 41 year old FO's 5000 hours were acquired on type at a carrier that's been undergoing rapid expansion since he began employment yet he never got beyond the CPL?

 

 

 

 

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Things may be unraveling at Boeing as a result of this accident. Inside rumours are suggesting the merged former McDonnell-Douglas managers who have now risen to the top of their Boeing departments have carried along a a different standard of doing business. I suppose it’s only natural to start pointing fingers but they say the 787 intro disaster and now the Max are examples of the other airplane makers poor management. This story could get very interesting. 

Edited by blues deville

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42 minutes ago, blues deville said:

Things may be unraveling at Boeing as a result of this accident. Inside rumours are suggesting the merged former McDonnell-Douglas managers who have now risen to the top of their Boeing departments have carried along a a different standard of doing business. I suppose it’s only natural to start pointing fingers but they say the 787 intro disaster and now the Max are examples of the other airplane makers poor management. This story could get very interesting. 

Do senior managers at Boeing make the decisions on what is - and isn’t - published in the FCOM, or what is covered in the training footprint? I would assume that stuff would come from their Operations group. 

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The merger was over 20 years ago.  How can anyone say there is any remnant of a previous culture at play?  I don’t buy it...  there is only one Boeing company.

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