Lionair 610 crash

[The man with no name]

Yes, that is a question with no good answer. But as you imply, whilst the 737 does have ancestry back to the 1960s, this was a new model, it should have modern systems and engineering controls. If this ends up being a single faulty AoA reading leading to this crash, Boeing shouldn't get out of it lightly.

It's easy to forget that modern airliners are incredibly complex machines and like any machine, complex or not, sometimes they malfunction. If the pilots are there for anything at all it is to resolve these problems before they hit the ground. Pilots wouldn't be needed at all if these problems never occurred.

 

[Quickstatus]

Yes zero position to achieve zero back pressure.

Rotation of the trim wheel is due to moving cables connected to a motor that turns a screw changing the angle of the elevator?

There must be a huge gear ratio to allow manual turning of the trim wheel in flight

 

[AviatorInsight]

(do commercial aircraft have terrain avoidance systems?). The pilots are then expected to deal with this by "pushing on a switch", which as soon as they stop pushing, returns the plane to a dive. All of this can apparently be stopped by hitting the "cutout switches" but according to jb747, hitting these at the wrong time could be very bad. So the pilot is trying to deal with an existing problem (of unknown complexity), fly the plane manually, pull out of a computer induced dive, continuously push switches (RSI anyone) and then decide when and how to cancel the dive response. Pilots are human and can possibly become confused by multiple conflicting problems and alarms and it seems to me Boeing have contributed to this possible confusion.

Terrain avoidance? No. Ground Proximity Warning Systems are in place that warn of your proximity to terrain. Would be good to have terrain avoidance systems and fly the RNP approach into ZQN without any fear that you definitely won't impact a hill.

Pilots will definitely become confused with multiple conflicting problems and alarms. The trick is knowing what is actually working and then try to ignore everything else. Easier said than done. Is the plane still flying? Good. What systems are not still affected? Take for example Aeroperu 603 which had a static port covered. After take off, while the aircraft was climbing the crew got multiple erroneous failures such as overspeed and underspeed at the same time. Their altimeter was also failing. The only instrument they had left was the radio altimeter (which actually was working because the system uses signals being bounced from the ground itself). Unfortunately because of all the other failures they didn't believe this instrument either.

I find it somewhat alarming that Boeing know of a problem that can happen with an A/P going off line (and you yourself confirm this happens due to any number of issues), yet Boeing's response is that the pilot(s) can fix it. If it turns out after the fullness of the investigation that it was indeed a contributing factor in this incident, then their "pilot can fix" solution is clearly flawed and may have cost 180+ people their lives.

There are 12 conditions in which the A/P will actually disengage. In all 12 situations it's because there's a fault in a system somewhere which is feeding the data to the A/P and it can no longer maintain control.

In one situation (and I for one have no idea why this happens) but in a go around (a normal procedure mind you) the A/P will disconnect! In another situation if the aircraft is not properly trimmed out (ie, no pressure applied on the control column at all) then you can't actually engage the autopilot.

 

[AviatorInsight]

Yes zero position to achieve zero back pressure.

Rotation of the trim wheel is due to moving cables connected to a motor that turns a screw changing the angle of the elevator?

There must be a huge gear ratio to allow manual turning of the trim wheel in flight

Correct. Manual trimming definitely gives your arm a workout but not impossible to use. In a go around with manual trim it becomes a crew exercise because you cannot hold the pressure of the aircraft in one hand and trim with the other hand quick enough to relieve the pressure...unless you're Arnie.

 

[AviatorInsight]

I dunno, but this gives me the creeps: It actually makes me surprised that there are so little accidents and, as an overall trend (I know, this year is turning out to be a rather sad outlier...), air traffic gets safer and safer. And surely, JB doesn't strike me as someone who'd be prone to sensationalise the issue.

There are so little accidents because the use of simulators and proper training with crew management have been a focus for years! But of course an airline is only as safe as its safety culture and training. There was talk of our cadets going straight onto the 737. However it was decided soon after that our training program in place wan't capable of adequately training low hour pilots on a complex machine. So it was canned.

 

[AviatorInsight]

The 737 is a complex machine no doubt about it. Trying to introduce more automation into a coughpit still with 60s technology, I believe could perhaps cause problems in the future. This would be an even stronger case for the FAA to put a stop to Boeing adding more components into an already dated flight deck. As I said in an earlier post, there's no reason why a newer version of the 737 could be made with 777 technology. Have the ADIR redundancies and multiple generator back ups. Have an autopilot that doesn't disconnect on go arounds.

As an example today I flew up to 15,000ft with no autopilot, no autothrottle, and no flight director guidance, it was all completely back to basics (was in day VMC), and was actually fun! Like any aircraft, pilots need to know their limitations and memory items cold. People make reference to checklists, in this thread, the runaway stabiliser checklist has memory items that need to be performed before the checklist is run because there is no time and action needs to be taken immediately.

I eagerly await to see the final report.

 

[jb747]

Have an autopilot that doesn't disconnect on go arounds.

The only time I've seen that in the last 34 years was when I accidentally pressed the disconnect!

 

[juddles]

At the end (and assuming the FR data is correct), he's doing 30,000 feet per minute vertically. That's the sort of thing you'd expect if the tail fell off (which, by the way, I'm not suggesting). I don't understand any of this, given the information we have so far.

JB, Aviatorinsight, and everyone else far more qualified in these areas, can you punch holes in my current theory - and I do realise I will probably use incorrect terminology, etc - I have no claim to aviation skills - but please let me explain:

My theory is that there was catastrophic failure of the elevators, or associated structure. Quite possibly the elevators actually becoming detached.

It has come to light that the 787 MAX has an issue where in certain circumstances the airplane computer tries to make significant adjustments to the pitch, due to erroneous speed/angle of attack data. I suspect in such control decision making, the computer is making adjustments based on what it believes is a much slower speed of the aircraft than the real airflow around it. This causes actions which put strain on the airframe, specifically the elevators. Very likely to be outside any permitted actions.

This aircraft had suffered a succession of similar erratic flights, where each time the computer, and probably the pilots, were performing repetitive harsh actions. Although the software/sensor/whatever faults were reported and that specific problem addressed each time, the airframe itself was suffering fatigue.

On the last flight, the pilots informed that they wished to return to the airfield, but they did not do so. It seems clear to me that they spent the rest of the flight fighting the computer. They knew of this sort of error, but were perhaps not exactly 100% with how to deal with it correctly. There were no mayday calls or such - as I said I suspect they were just trying to keep the aircraft in the air and rectify the problem.

The flightdata stuff shows and continual sequence of changes in altitude and speed, and I suspect that each time this occurred the airframe suffered more and more. Each time the computer making severe changes believing a lower speed, and each time the pilot reacting forcefully on the elevator to recover.

Due to loads that exceeded any design or usual flying operations parameters, eventually something broke. And hence the dive at the end that was not rescued from.

 

[jb747]

Juddles, I think you're reading too much into it. Nothing in previous flights would be anywhere near being able to cause structural damage.

It's all very interesting, but we don't know the 'why' yet.

 

[oz_mark]

I eagerly await to see the final report.

A thorough report will be quite telling:

1) Boeing seem to be in early with a butt covering exercise
2) The various goes at fixing problems, that don't seem to have got to the bottom of what was wrong
3) While they had sort of gained control, seems something additional was thrown into the mix of what they were dealing with.

I think this is much bigger than a LionAir issue...

 

[juddles]

....
I think this is much bigger than a LionAir issue...

yes.

 

[Quickstatus]

An incorrectly installed AoA sensor?

 

[jb747]

1) Boeing seem to be in early with a butt covering exercise

Really? A bulletin that says RTFM is a bit pointed, I thought.

2) The various goes at fixing problems, that don't seem to have got to the bottom of what was wrong

That's Lion, not Boeing.

3) While they had sort of gained control, seems something additional was thrown into the mix of what they were dealing with.

I don't see the need for that at all....

 

[Berlin]

yes.

Really? Given the (still very limited) evidence we have so far, that seems to me like a very bold statement. From all we know, especially about the safety record of Lion and the Indonesian airline industry in general, I'd put my money on shoddy maintenance combined with unskilled pilots. I'm known for being an Airbus fanboy but still- my guess would be that the one who's not to blame is Boeing. But that's pure speculation at this point, as so many guesses here are.

 

[juddles]

Really? Given the (still very limited) evidence we have so far, that seems to me like a very bold statement. From all we know, especially about the safety record of Lion and the Indonesian airline industry in general, I'd put my money on shoddy maintenance combined with unskilled pilots. I'm known for being an Airbus fanboy but still- my guess would be that the one who's not to blame is Boeing. But that's pure speculation at this point, as so many guesses here are.

Berlin, everything here is speculation. And guesses. If we refrained from that we would have nothing to talk about until the "final report" comes out in a year or three. "Putting your money" on "shoddy maintenance" by Lion, and saying the pilot was unskilled, is very aggressive speculation. In my humble opinion

 

[juddles]

As for how bold a statement is about boeing - they have produced and sold an aircraft with a known fault, that is sufficiently severe and frequent that they have developed for pilots an sop on how to regain control of the aircraft when the computer is doing it's best to crash it..........

 

[Berlin]

"Putting your money" on "shoddy maintenance" by Lion, and saying the pilot was unskilled, is very aggressive speculation. In my humble opinion

As aggressive as implying that Boeing has sold a faulty aircraft. In my humble opinion But I totally agree with you that everything here is speculation and we'd have to "otherwise we can wait until the final report". Which, agreed, would run against the purpose of this forum- after all, it's way too much FUN to speculate

 

[Quickstatus]

The human machine interdependency still has a way to before it is optimal.

 

[jb747]

As for how bold a statement is about boeing - they have produced and sold an aircraft with a known fault, that is sufficiently severe and frequent that they have developed for pilots an sop on how to regain control of the aircraft when the computer is doing it's best to crash it..........

I think you'd be mortified to see our checklists then. All checklists are full of interesting comments and procedures. That's why they exist.

 

[juddles]

I get that in something as complex as an aircraft there will always be bugs, and I am very appreciative that there is such a huge safety-focus that such checklists get prepared, so very professionally. Somewhere here something went ultimately, fatally wrong. I am not casting mud on boeing, but if they reached a point where an aircraft's glitches could not be managed by users, there is a problem somewhere in the line. I do not mean this in the verbatim, strict sense, but if there are known glitches that require perfect pilots to overcome, then there is a problem with the basic aircraft/systems. There are a gazillion 737's out there. Obviously many will be being used by possibly "second-rate" airlines/pilots.