Lionair 610 crash

[ric_melb]

ABC News are reporting that Indonesian officials say that this Lion Air plane had trouble with the air speed indicator on its last four flights. This information is apparently confirmed by the flight data recorder.

 

[Quickstatus]

Media reporting crash investigators saying FDR showing airspeed indicator problems over several flights.

AF447 was an airspeed indicator problem but in the dark.

This one in daylight and clear weather.

 

[jb747]

Media reporting crash investigators saying FDR showing airspeed indicator problems over several flights.

AF447 was an airspeed indicator problem but in the dark.

This one in daylight and clear weather.

AF447 was a minor issue, which was turned into an accident by a totally unwarranted response. If the pilot flying had simply flown the current attitude (which would have been about 2.5º nose up), and left the power exactly where it was (about 85%), nothing would have happened. It would have reverted to alternate law, and after a few minutes the airspeed would have started working again.

 

[moa999]

this Lion Air plane had trouble with the air speed indicator on its last four flights. This information is apparently confirmed by the flight data recorder.

Will be interesting to see if it was reported by the other two pilots and whether any maintenance was conducted after those flights.

Presumably at some point if an issue keeps reoccurring despite maintenance some greater investigation would be needed

 

[juddles]

AF447 was a minor issue, which was turned into an accident by a totally unwarranted response. If the pilot flying had simply flown the current attitude (which would have been about 2.5º nose up), and left the power exactly where it was (about 85%), nothing would have happened. It would have reverted to alternate law, and after a few minutes the airspeed would have started working again.

I am feeling a huge difference between real pilots, to whom something like a simple airspeed indicator fault is something that is naturally overcome, and human drones that do not have a capacity any bigger than automatic systems and responses. Do you agree?

 

[jb747]

I am feeling a huge difference between real pilots, to whom something like a simple airspeed indicator fault is something that is naturally overcome, and human drones that do not have a capacity any bigger than automatic systems and responses. Do you agree?

Whilst I agree with the basic premise, I think we should be careful not to assign that sort of blame here. It may prove to be the case, but unlike some of the media commentators I don't think there is anywhere near enough information to say what happened.

If we hark back to Rostov, that was certainly a major case of pilot error, but it was in turn brought on by an airline that made no attempt to manage fatigue....they probably didn't even believe in the concept. The blame there lies totally with management, though I doubt that they would ever accept it.

 

[davidj]

Media reporting crash investigators saying FDR showing airspeed indicator problems over several flights.

It confirms what we already know. There was issues with ASI and elevator feel unit.

If you have a look at the flight data over the days before it mirrors the incident flight data well. What ever happened on the day before wasn't exactly fixed.

 

[ermen]

Sounds serious?!


via Bloomberg

WASHINGTON (Nov 7): Boeing Co is preparing to send a bulletin to operators of its new 737 Max models warning that erroneous readings from a flight-monitoring system can cause the planes to aggressively dive, said a person familiar with the matter.

The warning is based on preliminary findings from last week’s crash of one of the planes off the coast of Indonesia, said the person, who asked not to be named discussing details that are still confidential. The bulletin, which will be released as early as Wednesday morning Jakarta time, will alert pilots to follow an existing procedure to handle the problem, the person said.

Under some circumstances, the Max jets will automatically try to push down the nose if they detect that an aerodynamic stall is possible. One of the critical ways a plane determines if a stall is imminent is a measurement known as angle of attack, which senses the angle at which the wind is passing over the wings.

A Lion Air 737 Max 8 carrying 189 people dove into the Java Sea at high speed on Oct 29 minutes after takeoff. The pilots, who were dealing with an erroneous airspeed indication, had radioed a request to return to Jakarta to land, but never turned back toward the airport, according to Indonesia’s National Transportation Safety Committee and flight-track data.

It wasn’t immediately clear if the airspeed issue had any connection with the angle-of-attack matter. A spokesman for Chicago-based Boeing couldn’t immediately be reached for comment.


Can be read here:-
Boeing is said close to issuing warning on 737 Max after crash

 

[jb747]

Interesting. I presume they're talking about a stick pusher. As far as I know, you can override them, unless you happen to be in an Airbus.

 

[moa999]

And from the seemingly well informed mandela499 on airliners net

I managed to get bits of the previous post flight maintenance reports from various sources. It looks like the unreliable airspeed indications from the last 4 flights may not have been caused by a single generated warning/fault on the sensor detection (ie: not purely a pitot issue).Am now getting info (which needs confirmation) that over the past week, whenever a problem occur, it would appear, get rectified according to the FIM and TSM, then fly again, get the same warning, fix it again, then the aircraft would generate a different problem. If this is true then the guys on the ground had little chance to pick up on them as a "repetitive problem" (which would require a different kind of troubleshooting). When taking a step back, it does appear that this may be an ADR issue (not a sensor input to the ADR, but the ADR itself). The major problem with this, is the STS (Speed Trim System)... which if taking erroneous ADR feeds, could lead to...

 

[samh004]

You need to dissociate G loading and attitude. The two are not the same thing. Whilst -1G from straight and level will quickly give you a steep dive, it would also allow you to fly straight and level...if you happened to roll inverted first.

Offtopic I know, but reminds me of Flight (2012 movie), loosely based on Alaska Airlines Flight 261.

AF447 was a minor issue, which was turned into an accident by a totally unwarranted response. If the pilot flying had simply flown the current attitude (which would have been about 2.5º nose up), and left the power exactly where it was (about 85%), nothing would have happened. It would have reverted to alternate law, and after a few minutes the airspeed would have started working again.

IIRC, wasn't it a pitot issue and the first officer didn't relinquish control from his joystick, whether absent mindedly or not, resulting in the captain not able to control the plane from a stall? Been a while since I watched one of the air crash investigation shows on it.

 

[jb747]

STS sounds like an odd system...

Speed trim is applied to the stabilizer automatically at low speed, low weight, aft C of G and high thrust - i.e. on most take-offs. Speed trim is a dual channel system. Sometimes you may notice that the speed trim is trimming in the opposite direction to you, this is because the speed trim is trying to trim the stabilizer in the direction calculated to provide the pilot with positive speed stability characteristics. The speed trim system adjusts stick force so the pilot must provide significant amount of pull force to reduce airspeed or a significant amount of push force to increase airspeed. Whereas pilots are typically trying to trim the stick force to zero. Occasionally these may be in opposition.

 

[jb747]

IIRC, wasn't it a pitot issue and the first officer didn't relinquish control from his joystick, whether absent mindedly or not, resulting in the captain not able to control the plane from a stall? Been a while since I watched one of the air crash investigation shows on it.

The whole thing started with pitot icing, which gave unreliable airspeed.

The actions for this are prefaced by the statement..."if safe conduct of flight impacted". And then it goes into a procedure, with starts with an attitude and power setting. The first part of the problem was that the safety of the flight was not immediately impacted. It was stable, and basically doing nothing...a long way from the ground. In that case, there is no reason to follow on with this procedure, and some others (i.e. the ECAM) become more appropriate. But, the FO flying has gone with the procedure and select 5º nose up, and climb thrust, all automatics off. At altitude 5º nose up is a very big change. Step climbs normally involve an attitude change of about half a degree, but he's added about 2.5º. Whilst all this is happening, the aircraft has reverted to alternate law, which means that the angle of attack (i.e. stall) protection is no longer available. You'll get a warning, but the aircraft will no longer automatically limit the angle of attack. The flying FO ultimately uses FULL aft stick to hold the nose up, reaching up to around 15º (makes no sense). The aircraft stalls. He still holds full aft stick. Stall gets very deep. NB, it takes substantial force to hold aft stick.

The stall warning ultimately stops, because the angle of attack is now so great that the aircraft doesn't believe it could be real.

The other FO (much more experienced FO) takes over, and applies the correct recovery procedures. The aircraft starts to respond, and as the AoA reduces, the stall warning starts again, because it's now back in the believable range. Sadly, the original FO presses the override button and takes control back from the other FO....and goes back to applying full aft stick.

By the time the Captain got back to the flight deck it was all way too late.

 

[RooFlyer]

From the Oz today ( can't l link, sorry)

Responding to the Lion Air jetliner crash that killed 189 people in Indonesia last week, manufacturer Boeing and US aviation regulators intend to issue twin safety warnings about potentially suspect flight-control software that can confuse pilots and lead to a steep descent of the affected aircraft type, according to people familiar with the matter.

The moves are the first public indication that investigators suspect a possible software glitch or misinterpretation by pilots – related to an essential system that measures how high or low a plane’s nose is pointed – may have played an important part in the sequence of events that caused the Boeing 737 Max 8 to plunge into the Java Sea.

The anticipated actions by Boeing and the US Federal Aviation Administration are preliminary, these people said, and are expected to stop short of urging or mandating replacement or inspection of any specific onboard system. Rather, they amount to an official red flag for pilots, highlighting potential hazards stemming from the interaction of certain software with various other coughpit alerts, and reiterating the importance of following standard procedures under such circumstances.

 

[Quickstatus]

The moves are the first public indication that investigators suspect a possible software glitch or misinterpretation by pilots – related to an essential system that measures how high or low a plane’s nose is pointed – may have played an important part in the sequence of events that caused the Boeing 737 Max 8 to plunge into the Java Sea.

Not necessarily the aircraft nose, though the nose would have a fixed relationship to the AoA reference line which is either the chord of the wing (though some wings have a twist) or commonly the fore-aft fuselage centreline. Doesn't matter which so long as the reference line is defined.
The angle between the fuselage centreline which ordinarily can pass through the nose, and the horizon is not the AoA but the pitch angle

AoA can be defined as the difference between the pitch angle and the flight path angle (also known as the climb or descent angle relative to the horizon)

 

[RooFlyer]

Have now put the Oz's report in quotes

And here's the link:
Boeing, FAA to issue safety alerts following Lion Air crash

 

[jb747]

It's not a fly by wire aircraft, so the amount of control any software can have is limited.

I’ll be interested to see the actual Boeing bulletins, as opposed to a media interpretation.

 

[Quickstatus]

It's not a fly by wire aircraft, so the amount of control any software can have is limited.

I’ll be interested to see the actual Boeing bulletins, as opposed to a media interpretation.

Can the 737 systems in any scenario input a pitch down independent of pilot command?

 

[jb747]

Can the 737 systems in any scenario input a pitch down independent of pilot command?

AV flies the 737, so he’ll have a much better answers than me.

I assume that there is a stick pusher but that should be something you can override. Runaway trim, in any of these aircraft, is far more powerful than the elevator, but on the Boeings I’ve flown it will cut out if you push or pull against it, and there are cutout switches with easy reach.

 

[Quickstatus]

Runaway trim,

What are the first indicators of a runaway trim?

Have you done SIMS with runaway trim or improperly set trim scenarios?

The "cutout switches" refer to the switches to disable the trim motors?