[Jeroen]

Originally Posted by norhog

The reason of lion air crash was..
1. Faulty sensor giving wrong reading about the AOA.
2. There was no mention of automation system interfering with manual inputs by pilots and ways to switch it off.
Had the point 2 been known the computer could have been switched off and the plane could have landed by the pilots normally.

Technically we do not know, until the final report is published. Even the preliminary report is skimpy on details.

The system you are referring to is known a MCAS.

https://theaircurrent.com/aviation-s...em-mcas-jt610/

We do know that this particular plane had a Runaway Stabiliser NNC (Non Normal Checklist). (it disables the MCAS).

The crew who flew the plane the day before encountered, from what it seems, (near) identical and ran through three non normal checklist, which included the non normal checklist for a runaway stabiliser. We don’t know whether the crew of this ill fated flight ran this check list as well. And if so, why were they not successful?

So although the mention of the MCAS system in pilot documentation is scarce, there is NCC that need to be followed if a pilot finds himself in an apparent runaway stabiliser scenario.

Pilots do not have deep insights into how systems work. They do not need to. During the design phase the manufacturer figures out to what extend pilots need to know how system works, the characteristics etc. How to documental, how to train for it etc. So pilots system knowledge tends to be more on a functional level, at best.

There are lots of systems and system components that do stuff, without the pilot knowing about it. Which is fine as long as pilots know how to recognise faults/problems and take appropiate system (in this case the NCC details how the automation system needs to disabled.

The Boeing bulletin that was published a while ago, refers back to existing procedures and stresses the need for operator to familiarise themselves with the content.

I lack the expertise to make any calls on whether that was done appropriately in this particular case. Lots of debate regarding this raging on the pilots forums.

Jeroen

[norhog]

https://youtu.be/zfQW0upkVus

This is a bit old. Can the Boeing directive or FAA directive be shared here.

[Jeroen]

Originally Posted by norhog

[ Can the Boeing directive or FAA directive be shared here.

Has already been shared. If you would read through the thread you will find it.

Jeroen

[vharihar]

Have they found the QAR and all the DFDRs?

I thought they had till a few weeks ago found just the CVR and one or some of the DFDRs.

[Rahul Bhalgat]

Originally Posted by vharihar

Have they found the QAR and all the DFDRs?

I thought they had till a few weeks ago found just the CVR and one or some of the DFDRs.

When I read last, only the FDR was found. The CVR is thought to be burried inside the mud at the bottom of the ocean. It may not be found in near future.

[vharihar]

Originally Posted by Rahul Bhalgat

When I read last, only the FDR was found. The CVR is thought to be burried inside the mud at the bottom of the ocean. It may not be found in near future.

There are several FDRs in an aircraft (at different locations). This is my understanding (after reading the superb novel titled Airframe by Michael Crichton).

They've found just one?

[Rahul Bhalgat]

Originally Posted by vharihar

There are several FDRs in an aircraft (at different locations). This is my understanding (after reading the superb novel titled Airframe by Michael Crichton).

They've found just one?

I think there was only one FDR on this aircraft. With this FDR, all the flight data has been recovered and it has revealed how the aircraft behaved on it's last flight.

If the CVR is recovered, it will throw some more light. But FDR's recovery is more important. If the luck offers us only one out of the two (and offers us a choice), it is better that we ask for FDR.

[V.Narayan]

https://www.nytimes.com/interactive/...ction=Trending

From the New York Times. Very interesting and well put sequence of events in those 14 minutes.

[libranof1987]

They have finally found the CVR. Hopefully all the data is retrieved successfully and along with the FDR, investigators can understand why the plane went down, or rather, couldn't be kept flying.

Indonesian Navy divers have recovered the cockpit voice recorder from Lion Air Flight 610, a discovery that could help solve the mystery of why the brand-new Boeing 737 MAX 8 plunged into the Java Sea, killing all 189 people on board.

Divers and crew cheered when the device was lifted onto the deck of a ship Monday morning local time.

The cockpit voice recorder (CVR), which is one of two so-called "black boxes," was buried under eight meters (26 feet) of mud on the seabed and was found inside the current search area of 500 to 1,000 meters (546 to 1,093 yards) from the crash site, Navy spokesman Lt. Col. Agung Nugroho told CNN.

https://edition.cnn.com/2019/01/14/a...ntl/index.html

[balenoed_]

Originally Posted by libranof1987

They have finally found the CVR. Hopefully all the data is retrieved successfully

Yeah, but have to wait until the final report.

JAKARTA (Reuters) - Indonesian authorities do not plan to provide a public update on the contents of a cockpit voice recorder from a Lion Air jet that crashed, killing 189 people, until a final report is released in August or September, an official said on Tuesday.

The recording needs to be filtered first due to “background sounds” hindering the transcription, said Soerjanto Tjahjono, the chief of the transportation safety committee (KNKT).

“It might take one or two weeks because it was noisy inside (the cockpit),” he told Reuters. The transcription would not be made public until KNKT’s final report is released “between August to September”, he said.

[DWind]

Shouldn't the background sounds (various warnings + sound associated with application of a control on cockpit) and the sequence of those alerts also be part of investigation? Why is it being filtered?
I understand CRM allows for audible affirmation / challenge of one pilot's action and decisions by other pilot but it might only capture key decisions/actions. The rest of the story would be filled in by the "background noise". So I am not sure why authorities are interested only voice transcript or am I understanding it wrong?

[Jeroen]

Originally Posted by DWind

Shouldn't the background sounds (various warnings + sound associated with application of a control on cockpit) and the sequence of those alerts also be part of investigation? Why is it being filtered?
I understand CRM allows for audible affirmation / challenge of one pilot's action and decisions by other pilot but it might only capture key decisions/actions. The rest of the story would be filled in by the "background noise". So I am not sure why authorities are interested only voice transcript or am I understanding it wrong?

They are filtering out background noises. Typically that is for instance wind noise. Yes they do want to hear the alarms, switches been thrown, levers pulled, everything and obviously the voice. But a cockpit can be a noisy place, so they want to get rid of everything that is not relevant to what happened.

Jeroen

[vharihar]

Any update on this? Its been more than a month since they found the CVR, I believe. How long does it take to filter out background noise and analyse the conversation/data?

[vharihar]

Originally Posted by Jeroen

Technically we do not know, until the final report is published. Even the preliminary report is skimpy on details.

The system you are referring to is known a MCAS.

https://theaircurrent.com/aviation-s...em-mcas-jt610/

We do know that this particular plane had a Runaway Stabiliser NNC (Non Normal Checklist). (it disables the MCAS).

The crew who flew the plane the day before encountered, from what it seems, (near) identical and ran through three non normal checklist, which included the non normal checklist for a runaway stabiliser. We don’t know whether the crew of this ill fated flight ran this check list as well. And if so, why were they not successful?

So although the mention of the MCAS system in pilot documentation is scarce, there is NCC that need to be followed if a pilot finds himself in an apparent runaway stabiliser scenario.

...

Jeroen

Shouldn't there be more AOA sensors like say 5 (3 is still too close), and the MCAS system should act based on an "overwhelming majority" voting, say something like: Normally all 5 sensors should be in agreement. But if 4 or more sensors indicate a stall, then MCAS should automatically start doing its stuff and give visual feedback to pilot with *non-obvious* hints to disable MCAS. If 3 or fewer sensors indicate stall, then MCAS should do nothing but just give an easy visual indication to pilot with *obvious* hints to disable MCAS? Any reason why this isn't done?

Maybe make it 7 sensors.

[mpksuhas]

As per below news link, Boeing is coming up with a fix for the issue.

Link


Also, as of yesterday night DGCA has grounded 737 Max.