Boeing 737 Max8 Aircraft Crashes and Investigations [Part 7] 16

[Sparweb]

This post is the continuation from this series of previous threads:

thread815-445840
thread815-450258
thread815-452000
thread815-454283
thread815-457125
thread815-461989

This topic is broken into multiple threads due to the length to be scrolled, and images to load, creating long load times for some users and devices.
If you are NEW to this discussion, please read the above threads prior to posting, to avoid rehashing old discussions.

Thank you everyone for your interest! I have learned a lot from the discussion, too.

Some key references:
Ethiopian CAA preliminary report (Link is now broken. See PDF download below, 3 MB)

Indonesian National Transportation Safety Committee preliminary report

A Boeing 737 Technical Site

Washington Post: When Will Boeing 737 Max Fly Again and More Questions

BBC: Boeing to temporarily halt 737 Max production in January

www.sparweb.ca

 

[Alistair_Heaton]

BTW the trim doesn't work properly because they can't fix it....... And now your into arguing about should an aircraft be aloud to fly without it being fixed.

My view is it should be fixed, and me and my family won't go in one until it is.

Its personal choice.

Enjoy flying untied and Airsouthwest....Because i suspect they will be the only ones operating them for quite a few years. And its not because they want to.

 

[waross]

I am conflicted.
I won't say that i will never fly Boeing.
Those are words that I don't want to eat.
How much will I pay to avoid flying Boeing?
I will easily pay 10% more to avoid flying Boeing.
How much more will I be willing to pay?
15%?
20%?
That is my conflict. How much more than 10% will I pay to avoid Boeing?



Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[3DDave]

Alistair - your puddle jumper doesn't do Mach .85 so the trim range can be limited to what you can handle. In any case, the trim situation has been repaired. The main thing exposed is carelessness in training; PIA 8303 emblazons that for all to see. For certain after I read the Lion Air report I could have been dumped into the Ethiopian cockpit out of a burlap sack and handled the situation without problem. But that's from reading the AD, the FCOM update, and the Lion Air preliminary report. It's sad when professional pilots refuse to act in a professional manner and do their homework and worse when the CAA of their country is part of covering up that lack of training. Feel free to comment about the FAA and Boeing, but the Ethiopian CAA were given clear notice of a potentially fatal circumstance avoidable by training and did nothing; neither Boeing nor the FAA had any information the design decision could result in the loss of an aircraft.

By the way - the electric trimmer was never necessarily disabled from working. The pilots chose not to use them. The action was no different than an intermittent short circuit.

Airbus software -

https://www.flightglobal.com/progra...ic-after-touch-and-go-accident/135182.article

Seems like they rushed it out the door to make money.

 

[Alistair_Heaton]

Max speed of Mach 0.82 but its more limited by transonic flow than anything else. We never go near that to be honest.

Range over 3300 Nautica miles.

They haven't repaired the small manual trimming window of airspeed. And electric trim still has a single failure mode redundancy.

BTW I wouldn't avoid Boeing. Just wouldn't fly on a MAX for a very long time until its been proved safe.

And I actually completely agree with the comments about the regulation and training world wide. How to tackle that one I really don't know.

I also think that they need to completely go through the Grandfather rights about what is actually allowed and what is required to be completely revisited with every new flavour of aircraft in a series.

 

[3DDave]

It's not the trimming window of airspeed - it's the amount of mis-trim that sets the load. Letting 90 pounds of trim force build on the wheel before you try to trim manually is a problem. That's your redline speed, not normal operating speed where you normally trim, or have you moved from the Dash?

Ground all the Airbusses until all that defective software has been repaired. Obviously if a flight instructor can crash one just touching the trim wheel they are a death trap in the waiting.

 

[Alistair_Heaton]

Moved from the dash to A220, spent the last 3 months learning the new aircraft.

100 hours on the ground school for the aircraft plus another 50 hours company course on SOP's and emergency equipment and other stuff.

75 hours in the simulator.

There are various events that the aircraft goes way out of trim in seconds and you need to get it back ASAP, Upset recovery happens every 6 months for the last 10 years brought on after the airbus crash after 9/11. A variety of events can trigger it from post TCAS event and wake vortex through to thunderstorm, ayssemetric slat-flap failure can also be a bit of a bitch and trigger it. The main reason why you get hit by it though is wake vortex off other aircraft which in real life happens every couple of months. Never had it in real life as bad as the sim, but you can get easily 100 knts of airspeed change in 1-2 seconds either way with above 30 degs bank and +- 30 deg pitch changes in sim and attitudes requiring full control inputs before they develop in real life. Its one of the exercises we get every 6 months. Its one of the exercises the sims are not really able to do because they can't do G forces and most of them the motion system can't react fast enough so the visuals/instruments get out of sync with the motion until you get things back near normality. You can't do it in the aircraft because its nearly impossible to set up and you would end up bending alot of airframes. There is some specialists sims out there but they are not type specific that can simulate G force but they involve huge rooms with centrifuges and are mostly used for mil fighter pilots and research.

Sometimes you have no choice in the matter what energy condition your given the aircraft in . You just have to get it back to something sensible.

Even though the dash is turbo fans in some ways its closer to a swept wing jet than other turboprops only the saab 2000 is in the same class. Its limited to FL250 by regulation due to most of them not having drop down masks in the back. But its more than capable of getting up to over FL320. Its max speed is 280 knts compared to about 330 knts on a swept wing jet. The main difference is the amount of drag we can configure which is due to the props that can act as colossal air brakes so we can get away with murder with energy management. They tend not to make a fuss with experienced Dash pilots with transition to sweptwing jets compared to transitioning from say an ATR turboprop.

The main issue with the 737 NG trim is the redundancy level. The older classics had two trim motors and the pilot electric trim was a completely different circuit to the other automatic trims, Different power source and wiring. With the NG they did away with the second motor. So your left with 1 which everything goes through. Kill the power to it for what ever reason and the only backup it the pilot who has a limited window they can operate it in. Which is actually a downgrade from the 737-500 which had an extra level of redundancy. Plus they also increased the size of the stab and decreased the size of the wheel. So in effect made the window much smaller

I am pretty certain that the 737 product range is now dead and this situation of having a single redundancy level linked with a window of pilot ability to trim will never be allowed to happen again.

I still don't have a clue about proper FBW airbus. The Bombardier FBW logic and philosophy is different. But you can tell that they committed significant resources in the human factors side of things and the whole human interaction with it in various states. The people that have flown both say that the Global and A220 is about 20 years ahead of Airbus FBW. Its about time Airbus got together 30 odd human interaction specialists plus users plus engineers like Bombardier did and sorted out all the issues instead of sticky plaster fixes when ever a snag surfaces.

As with all these things the safe stats tell no lies.

 

[3DDave]

It's actually a large enough window. It's just not normal to let the trim exceed such a huge amount. For certain the Lion Air pilots had no trouble making their 90 minute flight on manual trim.

I expect the original motors were brushed motors replaced with a far more reliable brushless motor. No incidents seem to have happened to an NG over the change. Ever.

Did Bombardier handle the spilled coffee problem? I mean, it was in a 1950s movie and even now Airbus aircraft can crash if a misdirected cup is spilled.

Weird that Airbus would not be some latest and greatest since their main selling point is cross-cockpit compatibility. How do they make that update without handing market to Boeing or Bombardier products? Well, now they can do the same far-too-expensive training to make the transition; ooops. The large airlines are shedding pilots like crazy so I expect it will be a while before they sell many.

I'm just fascinated that if another Airbus crashes the same as the one I mentioned - will every CAA ground them for a complete software review and dig though the relationship with EASA and have the press call Airbus callous money grubbing killers or are we stuck with a situation like the initial Lion Air crash where a minor maintenance problem is turned into a disaster by a combination of software and pilot error? It's at the same point that Boeing was working on a fix, but Ethiopian wasn't interested in either waiting for the fix or seeing their pilots got trained and caused the second crash. Small wonder Airbus has not said anything. I wonder what else they are hiding.

 

[Alistair_Heaton]

It's the a350 which has the coffee issue I think.

To be honest since I started doing multi crew with a centre pedestal it's pretty heinous crime to put any fluids near it. Most have procedures which fluids and food are handed rounds the back of the seat so they stay away to the side away from the pedestal. I believe now this is written in the FOM of all types now. Because if they don't have it and everyone else does then it must be ok. Bit like the cycling of controls in flight upset when the tail fell off the Airbus after 9/11. No aircraft will like 350ml of coffee spilled on it and it will create issues. It shouldn't though shut engines down. No doubt that a mod will come out with a water proof engine run switch and wire to the computer.

You have your view it's sufficient window with one level of redundancy instead of the two on the 737 classic. Seen so many aircraft Sims way out of trim due to various various factors. And we have had enough elevator authority due to it being a trim tab on the elevator or we have to go 6-7 items into the failure tree before we can't use the thumb trim.

This only the FAA flight tests everyone else is going to have a shot and the Canadians have already said they want a shaker silencers. And then we have the training requirements and cross type currency.

I think they will be lucky to make 2500 of them. I hope they have already started thinking about the next 737 replacement.

We are actually very much in agreement about training and the state of the current regulators and the current min standard. Where we differ is if this redundancy state is acceptable on a 2015 designed aircraft. And what the likely hood is a getting the world wide pilot population up to standard that the could deal with it and not kill everyone rather regularly. you can shout and scream as much as you like they should be able to. But it is extremely doubtful it will ever happen. You could of course limit your sales to countries that do maintain sufficient standards. But the your product would be dead as a dodo because you could never get the sales volume.

 

[waross]

Aside from the attitude that software is cheaper, what effect would changing the fulcrum of the stabilizer have on the forces generated by an out of trim condition?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[LionelHutz]

I'm still not believing the original 737 had dual stabilizer motors. Was any proof ever posted? The redundancy was the manual wheel.

 

[davefitz]

Spilled coffee- sounds like the "pepsi syndrome" skit from saturday night live in 1979, where a spilled pepsi on the control room's operator console causes a nuclear power plant meltdown .Probably not so funny in real life.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[3DDave]

The point is that, with the AoA response sorted, the MAX is as safe as the NG has been, including 3rd world underfunded training. And that Ethiopia had clear notice and did not need to train their pilots at all - just ground the planes and wait for the fix. As soon as they decided to fly, the risk was 100% in their hands. You just said they have full upset training all the time for rudder use in vortex shedding. Why are they depending on training to handle a software problem? OTOH, why didn't Ethiopian aggressively train the MCAS FCOM before returning to service? Just like PIA 8303 they did every single step wrong.

Still, in 2020, no aircraft control system should depend on a pilot never spilling a drop. Does Airbus not understand how water works?

 

[Alistair_Heaton]

It's 1 collosal Jack screw and the autopilot trim system electric motor and then the manual electric trim motor on a gear box then under that the gear and wires from the manual trim wheel. On the classic.

The Ng is smaller electric motor doing everything with the manual under it.

I posted pictures of them. On the classic it's a forklift and three techs to shift one. On the Ng is a two man lift.

The change did away with 3 dual core 20 amp cable runs from front to back And replaced it with a single core 5 amp signal run. So it was a pretty major weight saving.

It's pretty obvious why they did it. Max went one stage further than the Ng and took away the automatic kill switch in the front. You got all or nothing. Ng if the automatics took a hairy fit you could kill them but keep the electric trim. Which meant all the automatics went down to single layer before manual trimming required. But it was all through a single motor in the back you just killed one of the inputs to it selectively.

 

[Alistair_Heaton]

Btw there is over 5 pages of issues with the max. Nearly two of them should have prevented initial certification but we're undeclared to the regulator's.

It's not just MCAS which stopped it flying. It was the cause but things quickly escalate.

They put a huge number of crews through the SIM including the director the FAA. The majority of them were western legacy crew that had been flying 737 for years all flavours. That's actually what killed it and made Boeing give up arguing. The results will never be public but it really wasn't pretty. Over 50% of them ran the wrong checklist.

Once it's flying again it's not finished with. They will have to fit smart pitot tubes to it to increase the number of AOA sources. And there is a load of other stuff that will have to be changed within a couple of years.

From what I can tell the main wiring looms are going to have to be split. And control runs need moved. So every single aircraft will have to be taken back to metal internally.

You might have a few token airframes in the air by Christmas if the training side of things is sorted quickly. You will get new builds up relatively quickly but the old fleet is going take years to process. Then there is the storage snags which will be hell to sort out and cause many brown pants moment's with flaps and gear issues.

I agree you on fluids can get a fair amount of drips in the cockpit anyway with cold soaked airframes and condensation. The old Jetstream used have a river coming down the roof sometimes down the back of the overhead panel. Never seemed to kill anything but wasn't pleasant especially when it froze after a short turn round. Good for keeping ice cream frozen though on the grab handles which could get down to -20 Deg in flight. The q400 they were much warmer with no risk of sticking to them.

 

[waross]

Spilled coffee, spilled Pepsi.
There was an incident about 30 or 40 years ago in a British Columbia pulp mill.
An operator spilled his coffee on his keyboard.
This caused some unintended control actions.
The ultimate result was an unexpected release of chlorine gas which poisoned some workers in a normally safe location in the plant.
As I remember they were rendered unconscious. I don't remember if there were any fatalities.
The potential for lethal consequences is very real with large amounts of chlorine.
Chlorine was one of the gases used in WW1.

The first killing agent was chlorine, used by the German military.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[3DDave]

On the Max it turned out the disable switch did not matter. The pilots did not use the trim switches to maintain the plane in trim even though powered trim was still effective, even after allowing 90 pounds of mistrim to accumulate. I know going off on tangents about things that might also have happened and have, in fact, not happened is an entertainment and adding straw to the strawman. The fact remains that the electric trim system did not fail; the accident pilots chose not to use it. The successful flight did use it correctly.

Any pilot failing to identify the correct checklist after two crashes should have been kicked from ever flying again, assuming they did not do the right thing and resign. I think that was clear on Atlas Air 3591. Two major crashes and anyone failing after that? It's not the airplane that causes that.

I would like to see the test evaluations myself, rather than second or third hand rumor. Was it a failure to follow in robotic fashion but still operate the aircraft safely or was it let go of the wheel and let the plane crash? Oh, of course, the main human factors and training failure event of this century will be withheld; no one would want that to get out to avoid the same thing happening again. (That's sarcasm)

 

[Alistair_Heaton]

I don't blame you for wanting to know. i would quiet like to see them as well. There is nothing out there just a few rumours which are 5th hand plus.

I very much doubt it will ever be made public due confidentiality clauses mainly from Boeing and FAA.

As I said apparently it wasn't pretty even from instructors on type from top of the line Airlines which you would expect to have the best pilots on the market.

I think it was more failure to identify correctly the situation and failure to follow the required checklist to the end. No fatal crashes occurred and that was the public statement and there is no evidence to prove otherwise. The MCAS simulations as per the accidents with pre warned crews were also rather aerobatic for comfort.

The QRH for the MAX is truly horrendous to navigate. Its thick as hell and there are multiple combinations and choice points which way you go.

My current ECAS runs a red white and yellow system with a pointer next to the most important checklist to complete. Things are deferred to descent and approach and landing checklists as required. There is no memory involved. So we do all the red checklists, then we do the white. Then the yellow cautions. When we hit the decent and approaches it changes things for the none standard setup same as landing. If things are sensed they are setup correctly they are missed out.

The max could have had the same system, which is in the 777 and 787. But it didn't due grandfathering and the ipad training requirement.

Like it or not and arguments one way or the other, there was multiple failings of the certification process. The aircraft should never have been in the air. 30 mins on an ipad also was not valid as far as training went. It was a combination of large customer airlines and Boeing prioritising money over safety.

The current series of electro powered sims have been found to be under powered on certain controls compared to real life. Pilots have the strength to over power the actuators which then register a displacement which then give a control deviation. In real life you get wire stretch and then its rock solid with no movement. Quite what they are going to do about that I have no clue.

Waross its been a on going issue since I was in nappies fluids and control panels. History never seems to be learned from. I must admit most control rooms over the last 30 years there has been a ban on fluids. For me that goes from Biscuit factories through to Nukes. And if they had to be brought in then it was under a work card system even cleaning fluids for the floor. I will say I haven't seen a spill on a central console in some 13 years flying, and that one when it occurred was on a old analogy machine and required a complete strip down. And the amount of electrical gubbins in it has stayed with me ever since. Lord only knows what the current central pedestal has in it. I have described the machine as 200 computers flying in close formation. Even the Canadians just laughed at that comment In general most drink bottled water and coffee comes in cups with a lid in cockpits and goes no where near it.

But even with personal practises to try and prevent accidents things happen. We had a accident with a UK mil Airbus where someone put a camera into the area around the control stick and aerobatics occurred. Millions of pounds worth of training, military discipline for 20 plus years and still such a basic don't do that root cause occurred. There are a sizable group of people sticking up for that pilot as well who was court martialled over the event.

To be honest what the pilots did or didn't do in the two accidents hasn't been the focus for some time now. There has been that many findings since that apart from a few voices saying it should never have been grounded in the first place pretty much everyone has given up pushing that line. Even the Boeing PR machine has realised its not working. USA market is not big enough to carry the product by itself so either keep the international customers and regulators happy or don't fly it. Home politics on the subject are pretty much meaningless.

 

[Alistair_Heaton]

Don't want to start another thread about pilot incompetence.

Just reading about a aircraft atr managing to come into contact with the sea after the crew turned off the protection on approach.

How the hell they escaped that one I have zero clue.

I actually have alot of feeling and agreement with 3D on the subject of crew standards and training. Unfortunately I have zero ideas how to change the current situation.

 

[3DDave]

If it wasn't pretty there must have been a rash of resignations. A misplaced wire could reproduce the same situation. I wonder why no one said anything about their failure.

 

[Alistair_Heaton]

If there is a rash of resignations then the planes don't fly.
If the planes are limiting due to compete crew then the price goes up.
If the OEM's are willing to limit supply to compete airlines then the price goes up.

Or do you want bucket price tickets and zero crew competent. Most punters want bucket prices.

So either the OEM designs for zero flight crew competence or they die due market forces your choice.