[Peetwo]

Flight JT610: Update 15 Nov 2018.

Via the Oz (not necessarily in chronological order):

Lion Air fault ‘not in 737 training manual’

ROBYN IRONSIDE
Pilots have piled pressure on Boeing over a potential issue unique to the 737 Max aircraft not outlined in training manuals
https://www.theaustralian.com.au/busines...df6c26699f

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Pilots berate Boeing over potential issue with 737 Max aircraft following Lion Air crash

Pilots have turned up the heat on Boeing over a potential issue unique to the 737 Max aircraft that is not outlined in the flight training manual.

The issue came to light last week, when Boeing and the Federal Aviation Administration warned airlines operating 737 Max of the potential for the automated stall-prevention system to push down the nose of the plane hard, making the aircraft difficult to control.

The system known as MCAS, receives information on the angle of the aircraft and is unique to the Max.

If that information is flawed, as is thought to be the case with the Lion Air crash off Indonesia last month, the MCAS issues repeated nose down commands to the flight computer potentially leading to a steep dive or crash.

The American Airlines’ pilots association issued an alert to their members about the anomaly with the MCAS this week.

“This is the first description you, as 737 pilots, have seen,” said an email from the Allied Pilots Association (APA) this week.

“It is not in the American Airlines 737 Flight Manual Part 2, nor is there a description in the Boeing manual. It will be soon.”

APA safety committee chairman Mike Michaelis said it was “pretty asinine for (Boeing) to put a system on an aeroplane and not tell the pilots operating that aeroplane, especially when it deals with flight controls”.

“Why weren’t they trained on it?” Captain Michaelis said.

The gravity of the problem and the lack of transparency by Boeing, is thought to be behind the Federal Aviation Administration’s decision to release an emergency airworthiness directive last week, rather than a routine bulletin.

“It suggests there is a problem they hadn’t previously seen,” said Australian Federation of Air Pilots technical and safety director Marcus Diamond.

“This is the aeroplane pitching nose up and down with air data, so to me it is a new failure.”

A statement from Boeing did not address why the potential issue was not included in the flight training manual.

“We are taking every measure to fully understand all aspects of this incident, working closely with the investigating team and all regulatory authorities involved,” said the statement.

“We are confident in the safety of the 737 Max.”

The APA email said at the present time there had been no anomalies found with American Airlines’ 737 Max 8 aircraft.

“That is positive news but it is no assurance that the system will not fail,” said the email.

“It is mechanical and software-driven. That is why pilots are at the controls.”

It went on to say that “awareness was the key with all safety issues, and no pilots were aware that this anomaly may occur”.

“There is a mitigation procedure. No different than should you experience an engine failure.”

No Australian carriers operate 737 Max 8 aircraft as yet but Silk Air flies the aircraft into Cairns and Darwin from Singapore.

The investigation into the crash of Lion Air flight JT610 is continuing following the completion of the body retrieval process.

All 189 people on board the flight died when it crashed into the Java Sea on the morning of October 29, just 13 minutes after takeoff.

The aircraft had experienced problems with airspeed indication on previous flights and technicians had replaced an angle of attack sensor.

Days after the crash the Lion Air technical director was suspended, along with several technicians.

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FAA launches Boeing probe
ANDY PASZTOR, ANDREW TANGEL
US aviation regulators have launched a probe into the safety analyses of Boeing in the wake of the Lion Air disaster.
https://www.theaustralian.com.au/busines...292799e440

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US aviation regulators launch probe into Boeing’s safety analyses in wake of Lion Air crash

US aviation regulators, responding to last month’s Lion Air jet crash, launched a high-priority probe of the safety analyses Boeing has performed over the years. Regulators are interested in what information Boeing distributed to airlines regarding potential hazards associated with a new automated flight-control system introduced on the latest versions of workhorse 737 aircraft.

The Federal Aviation Administration on Tuesday said it was reviewing details surrounding the safety data and conclusions the Chicago plane maker previously provided the agency as part of certifying 737 MAX 8 and MAX 9 models. The agency’s statement, which came after roughly two weeks of declining to comment on any facet of the accident that killed all 189 people on board, also indicated that officials are looking into training requirements for pilots.

Signalling that future regulatory action and generally stepped-up oversight of Boeing’s risk-assessment procedures are coming, the statement said, “the FAA and Boeing continue to evaluate the need for software and/or other design changes,” including “operating procedures and training as we learn from the ongoing crash probe headed by Indonesian authorities.”

The statement is the clearest sign yet of internal FAA concerns stemming from preliminary clues about why the twin-engine aircraft plunged in the Java Sea at a steep angle and high speed.

A Boeing spokesman didn’t immediately respond to questions on Tuesday. On Monday, the Chicago-based plane maker said: “We are taking every measure to fully understand all aspects of this incident, working closely with the investigating team and all regulatory authorities involved.” When Boeing opted to install the new flight-control feature, according to government officials, the company concluded it was virtually impossible for a combination of sensor failure, pilot actions and automated nose-down commands by the new system to result in a serious safety hazard.

But now, with preliminary crash data indicating the plane experienced just such a sequence of events before crashing, the company’s risk analyses and decision making are under heightened public scrutiny. So, too, is the oversight of the FAA, which agreed to allow two US airlines to start flying the new models without Boeing providing cockpit crews or senior pilots details about how the new flight-control system operates and what risks it may pose under unusual circumstances, by automatically and strongly pushing down an aircraft’s nose.

Investigators haven’t determined the cause of the Lion Air crash, and safety experts cautioned it was too early to tell precisely how large a role the new flight-control system played in the tragedy. But as more clues emerge and crash investigators delve deeper into design issues and the interplay of various computerised systems and cockpit displays, more of the focus is shifting to the assumptions of those initial Boeing safety assessments.

More than 200 737 MAX planes have been delivered to airlines worldwide, including US carriers Southwest Airlines, American Airlines and United Airlines. That represents a fraction of the thousands of 737s in use.

Indonesian investigators are still searching for the plane’s cockpit-voice recorder, which could contain vital information about what the pilots saw and did as they wrestled with a suspected flurry of sometimes conflicting electronic warnings, unreliable airspeed displays and a seemingly uncontrollable aircraft gaining speed as it hurtled toward the water. Investigators and safety experts have said that after a certain point, the crew may have had only seconds to react appropriately.

A November 10 memo from Southwest management to its pilots, which was reviewed by The Wall Street Journal, indicated Boeing omitted information from flight manuals about the stall-prevention system because pilots weren’t likely to find themselves in situations involving its features.

Shortcomings in Boeing’s risk-analysis procedures previously prompted major regulatory, financial and public relations headaches for the company. It initially failed to recognise or counteract potentially fire-prone rechargeable lithium batteries installed on Boeing’s flagship 787 aircraft. All of the jets were temporarily grounded until Boeing and the FAA agreed on a foolproof fix.

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Boeing left pilots flying blind
ROBYN IRONSIDE
Pilots were not told about an automatic nose-down feature in the 737 Max that may have contributed to the fatal Lion Air crash.
https://www.theaustralian.com.au/busines...c596b5ebdd

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Boeing’s silence on 737 system left pilots flying blind

The US aviation regulator will examine information Boeing provided airlines about its 737 Max following revelations the manufacturer did not tell pilots about a new system on the aeroplane.

Pilot unions in the US this week raised concerns about the MCAS, or manoeuvring characteristics augmentation system, which in certain unusual conditions issues nose-down commands to the aircraft, potentially causing it to dive or even crash.

The anomaly came to light as a possible cause of last month’s Lion Air crash involving a near- new 737 Max 8.

Information issued by Boeing and the US Federal Aviation ­Administration in the wake of the crash raised awareness of the system and its potential to render an aircraft difficult to control.

That prompted two pilots’ ­associations in the US to speak out, and question why they were not made aware of the feature before the 737 Max went into service. There are 219 737 Max 8s in service globally, operated by dozens of carriers, including American and Southwest Airlines.

The FAA is believed to be reviewing information provided by Boeing to airlines about the aircraft as part of the agency’s involvement in the Lion Air crash investigation.

A preliminary report is due to be released by Indonesia’s National Transportation Safety Committee at the end of the month. A statement from the FAA yesterday said it “continued to evaluate the need for software and/or other design changes to the aircraft including operating procedures and training”.

Australian Transport Safety Bureau chief commissioner Greg Hood said it was good that no Australian carriers were operating the 737 Max as yet.

“It was certainly a sternly worded emergency airworthiness directive (from the FAA),” Mr Hood said.

“But we have a great deal of confidence with the two main investigation agencies, in Indonesia and the US.”

Virgin Australia group executive Rob Sharp said by the time the airline took delivery of their first 737 Max 8, in a year’s time, any “fixes” would have been sorted.

“I’d rather the actual equipment work on the day, and I fully expect to get full visibility on that from Boeing because that’s what they’ve done in the past,” Mr Sharp said.

“Ours haven’t even started (being manufactured) yet. We are just locking in our specifications.”

He said he held no concerns about the aircraft’s safety, with 40 on order from Boeing.

But Australian Federation of Air Pilots technical and safety director Marcus Diamond said Boeing had some questions to answer.

“You can’t predict what conditions humans are going to put them into, and if you put in an overriding system, you can’t predict all the situations that might trigger that system.”

Mr Diamond pointed to an Airbus A320 demonstration flight at the Habsheim Air Show in France in 1988, in which the pilots did a low pass over an airfield.

“Because they passed so low, the aircraft’s automated system thought it was landing and overruled the pilot’s attempts to climb. It landed in trees and several passengers died,’’ he said.

And from leehamnews.com: https://leehamnews.com/2018/11/14/boeing...he-pilots/

Boeing’s automatic trim for the 737 MAX was not disclosed to the Pilots
leehamnews.com/2018/11/14/boeings-automatic-trim-for-the-737-max-was-not-disclosed-to-the-pilots/

November 14, 2018

By Bjorn Fehrm
November 14, 2018, © Leeham News.: The automatic trim Boeing introduced on the 737 MAX, called MCAS, was news to us last week. Graver, it was news to the Pilots flying the MAX since 18 months as well.

Boeing and its oversight, the FAA, decided the Airlines and their Pilots had no need to know. The Lion Air accident can prove otherwise. 



The background to Boeing’s 737 MAX automatic trim

The automatic trim we described last week has a name, MCAS, or Maneuvering Characteristics Automation System.

It’s unique to the MAX because the 737 MAX no longer has the docile pitch characteristics of the 737NG at high Angles Of Attack (AOA). This is caused by the larger engine nacelles covering the higher bypass LEAP-1B engines.

The nacelles for the MAX are larger and placed higher and further forward of the wing, Figure 1.

Figure 1. Boeing 737NG (left) and MAX (right) nacelles compared. Source: Boeing 737 MAX brochure.

By placing the nacelle further forward of the wing, it could be placed higher. Combined with a higher nose landing gear, which raises the nacelle further, the same ground clearance could be achieved for the nacelle as for the 737NG.
The drawback of a larger nacelle, placed further forward, is it destabilizes the aircraft in pitch. All objects on an aircraft placed ahead of the Center of Gravity (the line in Figure 2, around which the aircraft moves in pitch) will contribute to destabilize the aircraft in pitch.

Figure 2. The 737-800 (yellow) overlaid on the 737 MAX 8 (purple), with the line denoting the CG in pitch. Source: Leeham Co. and 737 ACAP.

The 737 is a classical flight control aircraft. It relies on a naturally stable base aircraft for its flight control design, augmented in selected areas. Once such area is the artificial yaw damping, present on virtually all larger aircraft (to stop passengers getting sick from the aircraft’s natural tendency to Dutch Roll = Wagging its tail).

Until the MAX, there was no need for artificial aids in pitch. Once the aircraft entered a stall, there were several actions described last week which assisted the pilot to exit the stall. But not in normal flight.

The larger nacelles, called for by the higher bypass LEAP-1B engines, changed this. When flying at normal angles of attack (3° at cruise and say 5-8° in a turn) the destabilizing effect of the larger engines are not felt.

The nacelles are designed to not generate lift in normal flight. It would generate unnecessary drag as the aspect ratio of an engine nacelle is lousy.

The aircraft designer focuses the lift to the high aspect ratio wings.

But if the pilot for whatever reason manoeuvres the aircraft hard, generating an angle of attack close to the stall angle of around 14°, the previously neutral engine nacelle generates lift. A lift which is felt by the aircraft as a pitch up moment (as its ahead of the CG line), now stronger than on the 737NG. This destabilizes the MAX in pitch at higher Angles Of Attack (AOA). The most difficult situation is when the manoeuvre has a high pitch ratio. The aircraft’s inertia can then provoke an over-swing into stall AOA.

To counter the MAX’s lower stability margins at high AOA, Boeing introduced MCAS. Dependent on AOA value and rate, altitude (air density) and Mach (changed flow conditions) the MCAS, which is a software loop in the Flight Control computer, initiates a nose down trim above a threshold AOA.

It can be stopped by the Pilot counter-trimming on the Yoke or by him hitting the CUTOUT switches on the center pedestal. It’s not stopped by the Pilot pulling the Yoke, which for normal trim from the autopilot or runaway manual trim triggers trim hold sensors. This would negate why MCAS was implemented, the Pilot pulling so hard on the Yoke that the aircraft is flying close to stall.

It’s probably this counterintuitive characteristic, which goes against what has been trained many times in the simulator for unwanted autopilot trim or manual trim runaway, which has confused the pilots of JT610. They learned that holding against the trim stopped the nose down, and then they could take action, like counter-trimming or outright CUTOUT the trim servo. But it didn’t. After a 10 second trim to a 2.5° nose down stabilizer position, the trimming started again despite the Pilots pulling against it. The faulty high AOA signal was still present.

How should they know that pulling on the Yoke didn’t stop the trim? It was described nowhere; neither in the aircraft’s manual, the AFM, nor in the Pilot’s manual, the FCOM. This has created strong reactions from airlines with the 737 MAX on the flight line and their Pilots. They have learned the NG and the MAX flies the same. They fly them interchangeably during the week.

They do fly the same as long as no fault appears. Then there are differences, and the Pilots should have been informed about the differences.

MTF...P2