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Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

reuters.com

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Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

#251

Post by oldgradstudent »

24gttghh wrote: post #125
oldgradstudent wrote: post #76

Earlier quoted context omitted.

The first officer in Ethiopian Airlines Flight 302 was confirmed to have 350 flight hours, which is much lower then the US standard for the large carriers. Southwest Airlines, for example requires: > Flight Experience: 2,500 hours total or 1,500 hours Turbine total. Additionally, a minimum of 1,000 hours in Turbine aircraft as the Pilot in Command* is preferred. Southwest considers only Pilot time in fixed-wing aircr…

These are all pilot qualifications. The first officer was new and had ~200 flight hours. The pilot/captain had over 8000 flight hours. [0] Look at Ethiopian Airlines own job postings![1] >Qualifications: Must hold a current and valid JAA/FAA or ICAO ATPL/CPL A current 777 type rating Minimum Flight time *3500 hours* jet time *2500 hours* Pilot in command on jet aircraft Command time in excess of 500 hours on 777 [0]…

Is this clear enough?

https://www.faa.gov/news/press_releases/news_story.cfm?newsI...

These are the minimum FAA requirements. Major airlines have higher requirements, while regionals have lower requirements.

The US is unique because flying is far more affordable and common, especially when compared to the alternative of going to a university, even a reasonable state school.

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

#252

Post by Atheros »

jandrese wrote: post #249
itronitron wrote: post #247

Earlier quoted context omitted.

Seems like it would have been sufficient to cause the crash, or are you saying that if the pilots let MCAS do its thing that the plane would not have crashed?

Crash causes: 1. Faulty MCAS 2. Insufficient pilot training 3. Boeing design changes (MCAS used to be disabled automatically if the pilot applied sufficient counter-input, this feature was removed in the -MAX series, requiring the pilot to explicitly disable the system using a separate button) Take away any 1 of those causes and the plane doesn't crash. They all had to happen at the same time for these two tragedies…

The Swiss cheese model of accident causation.

https://en.wikipedia.org/wiki/Swiss_cheese_model

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

#253

Post by foldr »

jandrese wrote: post #246
foldr wrote: post #230

Earlier quoted context omitted.

The captain wasn't at the controls. I'm not sure what you mean by "throttle up". They were at full TOGA thrust.

The copilot actually suggested to use the airbrakes at one point. Neither Bonin nor Robert, nor the third crew member (Marc Dubois, the captain) who entered the cockpit 90 seconds into the episode, recognized that the aircraft had stalled despite multiple cues. In the confusion, Bonin misinterpreted the situation as meaning that the plane was flying too fast and actually reduced the thrust and moved to apply the spee…

I know what the Popular Mechanics article says, but I cannot find any confirmation of the key points in the official accident report, which I take to be much more reliable.

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

#254

Post by asynchronous13 »

jandrese wrote: post #249
itronitron wrote: post #247

Earlier quoted context omitted.

Seems like it would have been sufficient to cause the crash, or are you saying that if the pilots let MCAS do its thing that the plane would not have crashed?

Crash causes: 1. Faulty MCAS 2. Insufficient pilot training 3. Boeing design changes (MCAS used to be disabled automatically if the pilot applied sufficient counter-input, this feature was removed in the -MAX series, requiring the pilot to explicitly disable the system using a separate button) Take away any 1 of those causes and the plane doesn't crash. They all had to happen at the same time for these two tragedies…

additionally

4. Insufficient regulatory over site

5. Failed safety analysis

FAA pushed much of the safety analysis to Boeing engineers due to lack of funding and external pressures to help Boeing speed through certification.

The safety analysis was performed on incorrect data. The initial safety report said the MCAS system could lower the nose by 0.6 degrees. After flight testing, that value was increased to 2.5 degrees but the safety analysis was never updated to reflect the new parameters. Additionally, the MCAS system could reset each time the pilot attempted to override, and it could change 2.5 degrees for each reset. So effectively it was unbounded. The numbers on the safety report did not reflect the actual system. If the real numbers had been updated, the problem likely would have been caught sooner.

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

#255

Post by 24gttghh »

oldgradstudent wrote: post #251
24gttghh wrote: post #125

Earlier quoted context omitted.

These are all pilot qualifications. The first officer was new and had ~200 flight hours. The pilot/captain had over 8000 flight hours. [0] Look at Ethiopian Airlines own job postings![1] >Qualifications: Must hold a current and valid JAA/FAA or ICAO ATPL/CPL A current 777 type rating Minimum Flight time *3500 hours* jet time *2500 hours* Pilot in command on jet aircraft Command time in excess of 500 hours on 777 [0]…

Is this clear enough? https://www.faa.gov/news/press_releases/news_story.cfm?newsI... These are the minimum FAA requirements. Major airlines have higher requirements, while regionals have lower requirements. The US is unique because flying is far more affordable and common, especially when compared to the alternative of going to a university, even a reasonable state school.

They only introduced that rule in 2013 as your link states, and it doesn't seem like most other places bother with such high requirements.[0]

"On Ethiopian flight 302, the first officer may have had just 200 hours, but the captain, a 29-year old career Ethiopian Airlines pilot, had a very respectable 8,000 hours under his belt. There’s no indication, at this point in the investigation, that crew experience may have been a factor in the accident."

I still don't see why you are harping on the experience angle when there seems to be much more evidence that the weird Boeing "secret" anti-stall system(MCAS) seems to be in play, since Boeing is trying to come up with an update for it...Also the general maintenance issues that seems to have occurred before at least one of the flights where the same issue was noted and/or the faulty sensors were ignored by groundcrew.

[0]https://thepointsguy.com/news/how-much-experience-do-pilots-...

And FTA this thread is about:

"French air accident investigation agency BEA said on Tuesday the flight data recorder in the Ethiopian crash that killed 157 people showed “clear similarities” to the Lion Air disaster. Since the Lion Air crash, Boeing has been pursuing a software upgrade to change how much authority is given to the Manoeuvring Characteristics Augmentation System, or MCAS, a new anti-stall system developed for the 737 MAX.

Some U.S. pilots have complained they were unaware of the new system, which is mentioned in the index of the aircraft’s full manual but not the text, according to a version seen by Reuters. Airlines have some discretion to customize the manuals.

The cause of the Lion Air crash has not been determined, but the preliminary report mentioned the Boeing system, a faulty, recently replaced sensor and the airline’s maintenance and training."

So yeah, blame the flight crew... /s

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

#256

Post by wereHamster »

rational_indian wrote: post #45
wereHamster wrote: post #41

Earlier quoted context omitted.

Note that AoA and the angle of the airframe body (relative to the horizon) may not be the same. Even if the airframe is pointing downwards (below the horizon) or really high up doesn't mean the wings have a sufficient AoA to generate lift.

Can't the IMU sense if you are generating lift (or not)?

I'm doubtful. Consider this: the aircraft can experience a downward acceleration (eg. due to turbulences) without being in a stall. Measuring the AoA is still the most reliable way (assuming the sensor itself is reliable) to detect impeding stall.

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

#257

Post by ddalex »

mjevans wrote: post #239
js2 wrote: post #199

Earlier quoted context omitted.

I agree it is a training problem, but it also seems the case that some pilots understand the fundamentals of flight and how a plane operates than others. So when a plane misbehaves, some pilots may have an intuitive sense of what to do, while others are stuck pattern matching and running through checklists. To make a terrible analogy that trivializes the complexity of flying a jet (because I can't think of a better o…

I agree with this and want to expand: Following a recipe == auto pilot; reacting to deviations from the expected / working with new realities == chef (not cook). The whole point of still having humans in the cockpit, aside from being slightly cheaper than automation right now, is the ability to react to and correct for the unexpected. I agree that this is a terrible engineering design, but that it's only one of the c…

One of the issues I'm perceiving with the Strings Of Things that Go Wrong / Swiss Cheese model is that as we fix more and more of the ~more likely~ faults to appear, the faults that will continue to appear will be of the less likely variety, so to say more obscure corner cases.

The problem is that training cannot efficiently prepare somebody to identify and fix obscure corner cases while under pressure.

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

#258

Post by oldgradstudent »

24gttghh wrote: post #255
oldgradstudent wrote: post #251

Earlier quoted context omitted.

Is this clear enough? https://www.faa.gov/news/press_releases/news_story.cfm?newsI... These are the minimum FAA requirements. Major airlines have higher requirements, while regionals have lower requirements. The US is unique because flying is far more affordable and common, especially when compared to the alternative of going to a university, even a reasonable state school.

They only introduced that rule in 2013 as your link states, and it doesn't seem like most other places bother with such high requirements.[0] "On Ethiopian flight 302, the first officer may have had just 200 hours, but the captain, a 29-year old career Ethiopian Airlines pilot, had a very respectable 8,000 hours under his belt. There’s no indication, at this point in the investigation, that crew experience may have b…

> They only introduced that rule in 2013 as your link states

The major carriers were always stricter. The 2013 rule changed to address a problem at the regional carriers.

> and it doesn't seem like most other places bother with such high requirements.[0]

Which I explicitly stated in my original post:

>>> The European carriers, on the other hand, do not have such strict requirements.

> I still don't see why you are harping on the experience angle

I weren't. I pointed out a specific misunderstanding in the comment I've responded to.

>>>> How would it even be possible for US pilots to sustainably have „much higher levels of experience“? Do non-US pilots fly only two days a week? Do they all die before age 40?

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

#259

Post by js2 »

ddalex wrote: post #257
mjevans wrote: post #239

Earlier quoted context omitted.

I agree with this and want to expand: Following a recipe == auto pilot; reacting to deviations from the expected / working with new realities == chef (not cook). The whole point of still having humans in the cockpit, aside from being slightly cheaper than automation right now, is the ability to react to and correct for the unexpected. I agree that this is a terrible engineering design, but that it's only one of the c…

One of the issues I'm perceiving with the Strings Of Things that Go Wrong / Swiss Cheese model is that as we fix more and more of the ~more likely~ faults to appear, the faults that will continue to appear will be of the less likely variety, so to say more obscure corner cases. The problem is that training cannot efficiently prepare somebody to identify and fix obscure corner cases while under pressure.

Maybe not plausible, but why not give the pilot a single switch to disable all automation so they can fly the plane without interference.

Re: Cockpit voice recorder of Lion Air jet depicts pilots' frantic search for fix

#260

Post by fencepost »

VBprogrammer wrote: post #226
js2 wrote: post #221

Earlier quoted context omitted.

This must have been mighty confusing without knowing about MCAS. It’s like trying to fly a black box instead of flying a plane.

Yeah, I can imagine. I mentioned elsewhere, the previous flight managed to develop a reasonable mental model (they thought that the Mach Trim System was responding to a wrong airspeed input). Saying that, failing to guess what's going wrong shouldn't result in a big hole in the ground. This is pretty interesting if you haven't seen it before: https://vimeo.com/159496346

For the curious, it's a presentation on "Automation Dependency" in flying, done by someone from American Airlines.
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