Lion Air 737 Missing

[G-CPTN]

From the accounts that I have read, it seems like the situation was an accelerated track to a disaster that might have been 'unavoidable' within the time available.
It would be interesting set up the exact parameters in the sim and then see how the instructor managed, and then to introduce experienced (but unaware) pilots to the same scenario and finally some young inexperience FOs (without prior briefing) followed by each of the candidates being briefed as per the list and seeing if they could cope within the time available.

IMO, much would be learned from this exercise as to whether recovery was possible as some seem to believe.

AF447 was a relatively easy problem compared to the current event.

[Boac]

From what (little) I know, CPTN, and based on the 'warnings' issued by Boeing and the FAA, I disagree - it seems to me that in the benign weather conditions existing the problem should have been sorted out. They made it to 5000ft on course, and I cannot see how any of what I understand happened would have prevented a safe return.

Confusing indications/warnings - yes. A 'malignant' trim intent on harm - yes. A system that had not been thought through and fully tested - probably. BUT, looking out of the window, and with the working instruments in front of them, a flyable aircraft. My guess is that they allowed distraction and excessive focus on the airspeed issue/checklist to distract them from the more dangerous event of the trim. There would, in all probability, have been two of the three airspeed indicators showing the correct speed, and likewise altitude, and possibly three depending on the failures.

The crew on the previous flight appear to have passed control to the 'working' pilot side and sorted it out. Remember the ?Everglades? crash where sorting out a broken light bulb distracted all 3 crew from noticing the aircraft was descending into the ground?

It could well be I am doing a huge injustice to the crew - we will know when the FDR and CVR are analysed.

"AF447 was a relatively easy problem compared to the current event." - I am 180 out from you on that one. A clear indication of a full stall in front of two pilots and they did not notice. Whether el Capitano on return from his love nest noticed I do not know, but neither of the 2 handling pilots did. Yes, the stupid Airbus was causing confusion with an inhibited stall warning, but - basic flying? Full power, nose way up in the sky and descending like a brick. What would a PPL instructor say to a student pilot? "Symptoms of a stall, Sir?"

[Capetonian]

It is tempting to say that this airline is seriously accident-prone, but it might just be that the press is now going to highlight any incident, however minor.

A Lion Air passenger jet has been involved in another accident -- just a week after a plane from the Indonesian airline crashed with the loss of all 189 people on board.

In the latest incident, the jet clipped a pole as it taxied to the runway at Bengkulu airport on Sumatra island ahead of its flight to Jakarta.

The plane's left wing was visibly damaged, forcing all passengers to disembark. They were flown to the capital later Wednesday evening aboard a different aircraft.

Lion Air spokesman Danang Prihantoro said all 143 passengers and seven crew were safe.

"Lion Air apologises to all passengers for any inconvenience... it has sent a team to inspect the aircraft," the spokesman said.

The transport ministry said it would launch an immediate investigation.

"The plane and the pilot have been grounded for investigation," said Pramintohadi Sukarno, a senior ministry official.

[Slasher]

From what I know Lyin' Scare needs a bloody good dose of Western expat infiltration into its Training Dept. I'm not suggesting kids but experienced blokes 45 years old and over.

I'm fuctifino how this so-called 'airline' stays in business. At its present standard I wouldn't go anywhere near it with a 10 foot barge pole. I assume it's the 'allah's will' religious fatalism which pervades that area.

[Sisemen]

Better late than never Caco.

[flynverted]

Flown heaps of times with lionair and garuda...cgk-bpn- cgk Not my favorite airline, but never a worry flying with them...
Only prollem is trolley dollies not letting me put electronics under seat in front of me...

I know the problems of flying an indo airline

********************************

Would fly ind o again

*********************************

Never a problem here

****************************

[Boac]

It seems now that there was a lapse in the procedures at Boeing for introducing a new system on the MAX. This system, MCAS (Maneuvering Characteristics Augmentation System), is supposed to provide a nose down input at high angles of attack (AoA) ie near the stall. It appears this may have been driven by the input of a minimum of 1 of the two AoA gauges fitted.

This system, it seems, was not fully 'notified' to crews or operating airlines.

If it is as it seems, and it 'accepts' a single 'rogue' AoA input as a trigger, that is wrong. To my mind, it should either compare and reject an 'illogical' value OR average the two and produce a warning in both situations.

I still, however, reserve judgement on the way the crew of the LionAir handled the events.

There are lots of calls for 'raw' AoA information to be available to crews. It is great and if properly trained, an excellent tool. We flew it extensively on the Harrier in the low-speed regime BUT were properly trained in its use. However, just sticking an indication somewhere in the cockpit WITHOUT a whole new training programme will not work. It would not have saved the AF447 crew, I'm sure, as they were totally lost in what was happening to their aircraft and would have been most unlikely to have noticed an AoA value.

[Alisoncc]

I still, however, reserve judgement on the way the crew of the LionAir handled the events.

When I was flying puddle-jumpers for a living manually setting the trim was part of everyday life. I can well imagine in modern heavies it's all taken care of. Even the thought of some automated system driving the trim to it's extreme limits, probably with no indication of doing so, would be as scary as hell. Massive stuff up by Boeing, even criminal negligence.

Alison

[Boac]

"probably with no indication of doing so," - unless the 737 MAX cockpit is vastly different to previous, there will be a firkin great wheel clanking round by the inboard knees. Difficult to miss.

I feel any 'negligence' will lie in the software that gives such authority (apparently) to a single input.

[Alisoncc]

"probably with no indication of doing so," - unless the 737 MAX cockpit is vastly different to previous, there will be a firkin great wheel clanking round by the inboard knees. Difficult to miss.

Even if gradually creeping around a few fractions of a degree per minute?

Knew of a light Cessna that had had the control runs incorrectly tensioned. Luckily found on a test flight after a major. If you watched the trim wheel closely you could see it slowly turning. IIRC the Kingair that crashed recently in Melbourne was a trim issue. Apparently the riggers had turned it to an extreme limit, and in the preflight checks the sole pilot had missed it on his list. Did not fly well at all. Crunch.

[Slasher]

I agree with Boac's last two posts.

In the 727 the trim wheels were known affectionately as 'the meat cutter' - derived from the fast and furious action of the butcher's machine. The 737-200 had similar but not as fast. In the 737-400 it was not as noisy and furious but damn obvious when it moved.

A bit on the 320 in this regard. When manually flying a steep turn the automatic stab trim will cutout when passing 40* AoB. This of course is entirely logical since trimming in a steepie is never to be done. Auto trim is restored when returning through the same bank angle. For a false AoA vane input (as against a stall warning), a death dive will occur in Normal Law (i.e. AoA protection) by using the elevators only. By switching off two ADRs the flight controls will revert to Alternate Law in which all protections are lost (save Load Factor limit). Manual stick input response is then restored and a smooth pullout can then be initiated. In all cases auto stab trim is NEVER used by the system.

Note that the para above is nutshell only.

[ian16th]

Aviation Week's latest.

What is probably a silly question from a former fairy.

Does the B-737 still hang onto 'Grandfather Rights' for the number of doors for escape purposes?
If so, are there any other 'sneak through the loop holes' items that Boeing use by keeping the a/c type as a B-737.

[Boac]

"a few fractions of a degree per minute" - don't know where you got that from? I am unaware of any published trim rate from MCAS but I think it would have been continuous with a faulty AoA input.

[OFSO]

I don't understand a system with two inputs being compared. On the Ariane launch vehicle three computers are used to check inputs from sensors, with any two always able to override a third.

[ian16th]

I don't understand a system with two inputs being compared. On the Ariane launch vehicle three computers are used to check inputs from sensors, with any two always able to override a third.

There are several approaches to fault tolerance in computers, the 'voting' of odd number as you describe is one, but Tandem and Stratus managed with 2 or 2 times 2 of things.

I had a nice presentation of the Stratus system, on a diskette; no way of reading it these days.

[Alisoncc]

"a few fractions of a degree per minute" - don't know where you got that from? I am unaware of any published trim rate from MCAS but I think it would have been continuous with a faulty AoA input.

Boac, the inference being that if it wasn't being watched constantly it could move slowly without being noticed. This is the effect of incorrectly tensioned control lines on non-flyby-wire aircraft. IIRC used to be referred to as "trim creep".

[Boac]

You will see from https://theaircurrent.com/aviation-safe ... cas-jt610/ that MCAS apparently runs for about 10 seconds moving the tail 2.5 degrees when it receives an AoA input. 10 seconds of the 'knee cracker' would worry anyone, BUT I have a feeling that with an AoA vane 'stuck' at max it would just keep running. We need the FDR and CVR to be sure what was going on.

[Alisoncc]

Thanks for the explanation Boac.

In the topic "Plane crash at Essenden" recently discussed on this forum the accident investigation board determined:-

the accident was a result of one of the flight control trim tabs being set incorrectly. Failure of the pilot to realise the rudder trim was set fully to the left caused a longer than normal takeoff, and caused the aircraft to slip and yaw to the left once airborne. Ultimately the uncorrected configuration caused a loss of control of the aircraft.

This is a reference to my thoughts.

Alison

[Slasher]

From boac's link above:

There is another explanation, according to a Tuesday report in The Wall Street Journal: “One high-ranking Boeing official said the company had decided against disclosing more details to cockpit crews due to concerns about inundating average pilots with too much information — and significantly more technical data — than they needed or could digest.”

Well that's just plain stupid and dangerous. A pilot had to know the systems of his aircraft intimately - including any PFM boxes whether 'too much information' or not.

If the above quote is true then Bill's mob really fuct up badly.

[Mrs Ex-Ascot]

It seems that the vultures have started to come out

https://www.bbc.com/news/world-asia-46230496