It appears that a new flight control system aboard the Boeing 737 MAX that pilots were not told about may have contributed to the crash of a Lion Air flight that killed all 189 aboard.
Boeing's new plane has new anti stall software that does not turn off even if flight controls are placed in manual mode and may have led to the crash that occurred in clear weather shortly after take off.
According to the Wall Street Journal:



How on earth can you add such a system to a modern passenger carrying airliner and not tell any of the carriers about it?!
I'm really flabbergasted about this. Did Boeing send 189 people to their deaths by with holding critical flight control information?




Boeing Withheld Safety Information on the 737 Model, According to Safety Experts and Others

Not cool if true.

I know Boeing had to modify the flight control software (what there is) on the MAX due to the changed CG and thrust line of the LEAP engines, because they are heavier and mounted more up and forward than the regular CFMs on the NG. HOWEVER, in my experience, shortly 4000 hours on the 737NG, once you position the stab trim cutoff switches to cutoff, there is nothing preventing the pilots to retain full control, as the controls are still conventional cable-connected directly to the control surfaces. Small grain of salt since I haven’t flown the MAX, but the type rating is the same as the NG, and this is what limits Boeing quite strictly in what they could change for the MAX and still retain the same type certificate.. which by now is 51 years old, interestingly enough. Would be fun to try my hand at one of the old JT8D-powered -100s or -200s.

4000 hours?



Wow, you've kept yourself busy...

No, SAS has kept me busy! Flying 900 hours a year at work. Actually I looked at the wrong column in my logbook It’s over 4000 total, 3000 on the 737.

The captain and the first officer had approximately 6000 hrs and 4000hrs respectively, but don't know if that is total time or time on type.

Unlikely that the full story is being told.

I would like to know what the connection was between the defective air sensor equipment and this crash was.

I'd also like to know whether this system caused a sort of runaway trim incident or otherwise how the controls themselves responded to whatever software commands were being applied.

Not enough information yet.

IF, and this is a big if, since as you say we don’t know enough details yet, the «hidden» Boeing system trims the plane nose down uncommanded, the pilots really should be able to recognize and correct the issue, by applying the «Runaway stabilizer» non-normal memory items and checklist. This switches off any automatic trim, as well as the electric trim switches on the stick, giving pilots full control of everything, but maybe leaving the plane quite nose-heavy until trimmed back towards neutral. Indonesian aviation in general, and Lion Air in particular, is not exactly known for the quality of pilot training. A colleague of mine worked for them for a couple of years, and he said a lot of pilots didn’t even attend the yearly rating renewal in the sim, but still were allowed to fly.

Lion Air has suffered several fatal accidents, some of which were perfectly preventable. They have also written off several 737s through what cannot be described as anything but gross incompetence and mismanagement.

I for one will never fly on an Indonesian aircraft, with the possible exception of Garuda, the flag carrier.

from what I know of the 737, the trim can be stopped by force by simply grabbing the trim wheel and stopping it from moving. painful but less so than crashing into the ocean.

if the new boeing system trims the aircraft down without moving the trim wheel (electronic decoupling?), that is one thing, but if these pilots ignored the spinning trim wheel and let it trim the aircraft down so far to the point that they could no longer hold the nose up, well.. another preventable accident.

agree that flying indonesian carriers (in fact nearly all southeast asian carriers) is gambling with your life. laziness is rampant. taking off with no preflight inspection, taking off with gust locks still in place, etc. the crews and organizations don't seem to value their own lives.

i have a feeling that as with most accidents this was a series of small problems with the airplane, airline and pilots that resulted in the worst case outcome. i strongly doubt that this new boeing system itself was solely responsible for the crash.

i do believe that every pilot who values his life should take a look at some of the training put out by american airlines in the mid 90's. i'm sure it's been updated but one of the specific scenarios talked about in the training was runaway trim and how to maneuver an aircraft that has run out yoke control in any direction. some people dislike it because it's rumored that a pilot broke his airbus apart because of stuff he learned in the training, but i think that is still has a lot of merit. could save your life some day.
https://www.youtube.com/watch?v=WfNBmZy1Yuc

(Warning, there are a few disturbing crash CVR transcripts in the video, don't watch unprepared)

Any system that locks pilot out of control should not exist. wasnt this the cause for that pitot thing that cause a plane to france to crash ?

Yep, grabbe g th3 trim wheel is indeed the last memory item on the checklist if none of the other remedies don’t work. Can be painful, but yeah, less so than crashing.

The trim wheel will always move with the electric trim since everything is cable-connected. Actually a great clue for pilots. If the trim wheels move for any length of time without the pilots having done anything, you’re better turn your brain on and see what’s going on.

I feel like this conversation, or a very similar one, was had here years back about some sort of auto system after an airliner crash. Anyone remember?

https://en.m.wikipedia.org/wiki/Air_France_Flight_447

There are other ones besides the Air France incident.

The Asiana KSFO crash was caused by misconfigured autopilot on approach and failure of a crew of 4 in the cockpit (!!!) to keep their hands on the throttle and failure to monitor approach speed as it dwindled away trying to keep the nose following the flight director without the power to do so. So the problem? The crew did not bother using their eyes to verify the autopilot was in the approach config, and they did not use their eyes to verify they were maintaining ref speed, they did not use their hands to verify the throttles were at the correct position to maintain ref.

Asia is rife with $hite flying practices. I have tried do to my part to correct this through training better CRM and cockpit familiarization techniques in Asia but there's only so much one person can do, and not all airlines agree with or have the motivation to do this kind of training.

There was an incident where an F/O in Japan rolled the aircraft nearly inverted after putting in significant rudder trim while trying to unlock the flight deck door to let the captain back in from a toilet break. He thought the rudder trim knob was the FD Door lock switch. What was the problem? He didn't bother using his eyes to verify what switch he was handling.

Too much automation, not enough manual flight and real airplane familiarity. Automation only works well when the pilots are trained well and aren't idiots. If the automation fails for whatever reason, it's critical that pilots actually still remember how to fly. In east and especially southeast Asia, these skills are long gone.

Distraction from flying the airplane continues to be a leading factor in crashes around the world. Most of the aircraft that have crashed in the past 20 years that involve equipment failure also involve a significant component of the crew forgetting to fly the aircraft using basic tools like their eyeballs to look outside, still serviceable backup equipment (Installed on EVERY airliner), and basic flight skills. Most of these crashes involve aircraft that were still perfectly able to fly.

There was a crash of a private jet in Turkey or Iran a few months ago. On climb, nearing cruise alt, the pilot and copilot airspeed indicators disagreed and the captain's side ASI indicated the aircraft was in an overspeed condition and the overspeed warning sounded. What did she do? Pull back the throttles, slow down. Was that a smart thing to do when you have a L/R airspeed disagree situation at high weight and near cruise altitude? NO WAY! You're going to die! There is a reason that zone is called coffin corner.

The F/O was a little smarter about things and tried to bust out the non normal checklist dealing with this situation, but was interrupted by the captain several times. They never did get to go through the checklist.

What the captain actually accomplished by pulling back the throttle was put the aircraft into a stall at cruise altitude. I don't know the CG details of that particular plane, but if you stall your jet at high flight levels in a normal climb / cruise attitude, your CG is going to be so far aft, and your AoA so high, you'll never get out of it. Many (Most?) planes will just fall out of the sky and unless you magically move your entire load to the front of the airplane, you're going to waffle or spin into the ground without having a real chance of recovery - MAYBE a shot at it at very low altitude where the air is thick and if the engines are powerful enough to push you over the AoA "hump". This crash killed the entire jet, all women coming home from a bachelorette party. There is a recovery procedure for this but it requires serious practice in a simulator. Those who have ever messed around with Falcon BMS have probably done something like this (Rocking chair). The airflow disruption to the engines caused flameout and then they never had a chance.

Other options she had: Go through the non normal checklist like her F/O wanted to. This would probably have resulted in them using a backup airspeed indicator. She could have also used data and sensations available to her - did the jet suddenly encounter wind or turbulence that pushed the aircraft into overspeed? Did the autothrottle do anything strange just now? What does the other ASI say? What does the backup ASI say? Do they indicate you're out of envelope? Still don't know what is going on? Checklist. Is the autopilot doing something strange? Can you see outside? Are you at a normal flight attitude? Checklist time. If the plane is still misbehaving and taking you out of the flight envelope, Click click, click click, AP off, AT off. Fly the plane bro.
https://www.pprune.org/rumours-news/606416-turkish-private-jet-down-iran-5.html

FWIW just about every airplane ever built in history can structurally withstand 1G flight SIGNIFICANTLY above VMO / VNE. And if you actually do get to the real max speed you'll probably know it because the damned thing will be shaking itself to pieces before you get there. Mach tuck is an issue at higher altitudes. Still going to take a while to reach that speed while in normal cruise config. You certainly have enough time to take a look at a checklist especially if some of your data sources are suspected to be faulty.

Yep, real stick and rudder skills are deteriorating, unfortunately. Lots of 200~hour wonders behind the controls these days. In addition to AF447 and Asiana at SFO, there have been several preventable accidents the last few years. Turkish at Amsterdam was also a 737 that crashed due to a faulty radio altimeter, again the trim wheels went clickclickclickclick for about ten seconds with no reaction from the flight crew. Then there was the West Air CRJ900 in Sweden that lawn darted due to a failure of the captain’s inertial reference system. Air Asia off Indonesia with a rudder centering failure that caused the aircraft to roll 8 degrees per second. No reaction from the flight crew before the bank was past 60 degrees. They flew it into the water. All of these should have been preventable.

Longbow, are you a pilot too?

yep, but not much experience with the 737. until recently i was doing a lot of work in japan and korea with 777 and 747 crews. now in canada aiming at a seat flying whatever, with some proper stripes on my shoulders.

Capt. Vanderburg's training videos specifically mention the airliner survivability track record once bank gets around 60-90 degrees. Nearly every aircraft bites the dust once that happens without the proper technique being applied to immediately rectify it. He goes through those recovery techniques in his videos and none of them involve rolling out at 1G for passenger comfort.

my practice-religiously-in-free-time scenario list continues to grow every year, but includes such lovelies as uncommanded asymmetric thrust reverser in flight, uncommanded full rudder, unfixable flap asymmetry, runaway trim both up and down, and fire in cabin/hold stuff.

those seem to be the most common preventable but unforgiving accidents that can happen. response time to fix them or die seems to be less than 10 seconds in most fatal accidents. give yourself a 3-5 second human factors delay and it sure makes you feel like you're earning that paycheck.

New update from Juan Brown about the Lion flight



https://www.youtube.com/watch?v=s3LrsvaCUoo

Preliminary report on the crash: http://www.jacdec.de/2018/10/29/lion-air-boeing-737-max-8-crashed-into-java-sea-off-jakarta/

So on the previous two flights the crew had the same problem but managed to disable the auto pilot and manually trim the aircraft, and on the flight before the fatal crash the crew felt it was serious enough to broadcast a PAN PAN PAN message.

Were the crew on the fatal flight not informed of the problems being had by the aircraft?

Sounds pretty cut and dried to me.

If one of the crew had grabbed the trim wheel handle and held it in place, it would've continued flying. Stab trim cutout switches are there by the throttle, they didn't go for them, information overload, OK, but still, had they just grabbed the wheel and stopped it, they wouldn't have crashed.

I don't know the 737 that well but I would bet that simply holding the wheel in place manually would move the sensors enough to reset any MCAS logic timer trying to re-trim the aircraft down.

How could they not notice the trim indicator hitting the stops.

Bad maintenance by a bad airline with bad management flown by pilots who unfortunately can't handle things. Runaway stab trim's one of the more common practice scenarios at any serious airline. They should have known how to handle this. The MCAS may have contributed to the problem but the airplane was still flyable. They let the thing configure itself into a crash.

If the MCAS is some kind of godly system that can set trim regardless of physically holding the trim wheel I'll eat my words, but Boeing doesn't usually design planes that way.

It isn’t. The MCAS starting to trim at random is covered by the same old Runaway stabilizer QRH checklist. Any decent airline crew should be able to handle it.