Boeing 737 Max8 Aircraft Crashes and Investigations [Part 5] 19

[Sparweb]

This is the continuation from:

thread815-445840
thread815-450258
thread815-452000
thread815-454283

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

Indonesian National Transportation Safety Committee preliminary report

A Boeing 737 Technical Site

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

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF

 

[Sparweb]

Last week I spent some time in the Seattle area, touring the Boeing factory, aviation museum etc. It put me in the area to take this picture. It may LOOK like a picture of some 40 airplanes, but it's actually a picture of FOUR BILLION DOLLARS:

Somewhat larger version of the photo at this link.

This is not to minimize the tragic effect that the accidents have had on the victims and their families. If anything, this photo reinforces to me the principle that our western society upholds the safety of people from around the world, and that there is a light on the things we do and the ways we do them. If we were allowed to do our work in secret, we would never learn from our mistakes. If we offered nothing but arbitrary punishment for such fatal mistakes, there would never be risks taken such as the design and development of technological marvels such as intercontinental aircraft. That would leave the regions of the world more isolated from each other.

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF

 

[Alistair_Heaton]

Would love to do that tour.

I have managed to avoid visiting Toulose so far for an ATR rating, but spent quiet a bit of time flying the corporate bus service out of Filton on the J41. The wing production and transport of them was most impressive. The Beluga is a sight to be seen in real life, its way stranger than the pictures.


There is still nothing new from the EASA side of things apart from alot of personal sceptisism about the projected time line by Boeing. Alot think that it might get recerified for USA only airspace. A mention of China airspace just produces laughs.


And nobody can see Boeing being able to recruit enough short term contract A&P technicians with the current recruitment to be able to sort things out quickly. I presume alot of the aircraft won't have their final paper work completed so the won't have to use licensed technicians whichh will help.
And it also seems for FAA pilots the 1 million per airframe hit has won the day over safety.

 

[davefitz]

Seattle area is a great place to tour aviation technology related to Boeing, and other mfr's technology as well. I recall a presentation at the monthly ASME meeting in 2001 of the Boeing efforts to maintain a small fleet of ME 262 german jets,which were recovered at the end of WW2 and kept in working order at the Everett airfield. That meeting was packed to standing room only , as the presenter described the recovery efforts and the ways such older fighter jets are modified to permit modern use.

The first few years of their use in the USA retained the original machine guns, as a required weight balance issue, but when the FAA finally inspected them in '49, the inspector said that civilian jets may not fly with mahcine guns, so off went the guns and on went some other form of ballast. The oringinal jet engines were replaced with the same type of jet engines used by cruise missiles in the 80's ( these same engines are also used by small helicopters). Apparently some millionaires have contracted to have Boeing engioneers ( in their spare time) build replicas of the ME 262 , coming to an airfield near you.

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

 

[SwinnyGG]

I've done the Everett tour and aviation museum, and it is excellent.

It's one of the few tours I've done where you're in close proximity to and have an excellent view of what's actually being made (unlike, for example, the Miller-Coors tour in Golden, CO where you're behind glass listening to prerecorded stuff the whole time).

The museum also has an excellent collection of cool aircraft. Highlights for me were the A-12 and one of the first 747s.

 

[Lou Scannon]

How Miller and Coors is brewed... must have been riveting

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[zeusfaber]

I doubt it - to be honest, riveting's more likely to have been how the 747 was made. oblig

A.

 

[Lou Scannon]

Nice one!

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[Sparweb]

Well since we're talking factory tours...

https://www.eng-tips.com/viewthread.cfm?qid=457298

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF

 

[davefitz]

I heard that part of the proposed fixes to the 737 Max is to operate both FC computers simultaneously , and if they disagree with each other , immediately disable both of them and engage manual flight control. It would seem that this strategy would generate additional risks if the FCC disengaged during a landing.

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

 

[Alistair_Heaton]

Most landings are manually flown anyway.

If they are doing a reduced minima approach cat 2 or cat 3 there are already procedures to deal with automation failures during the approach.

What the worry is if they then have to go-around and they have no protection against the dodgy stability that MCAS was put in for. And the approach and takeoff phases are the high risk area to get bird strikes which is what happened in one of the crashes and it took out one of the AoA sensors.

The risk will be quantified and if its deemed too high then the aircraft won't get re certified again without them mitigating the risk.

 

[Lou Scannon]

Apparently this isn't the first time the FAA has been seen to be deficient in their safety role. Link

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[Alistair_Heaton]

Apparently its the rest of the world regulators who have caused the latest delay.

A meeting last month was cut short by them and Boeing told that their documentation was insufficient on the dual FCC setup. So they have to re submit.

 

[Sparweb]

You can point fingers if you like, but it's hard to give Boeing much credit. The standard they failed to meet was the required standard decades ago, and Boeing has supposedly been applying the standard all this time. If trust is lost, then it has to be gained back with more rigorous proof.
And it makes the FAA look bad, too. No surprise they want to check every box, cross every tee, dot every i.


No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF

 

[Alistair_Heaton]

I don't think it was even more rigorous proof than normal. There was apparently pretty much zero technical details on what they had done to pair up the FCC's and when verbally asked about the setup they failed to give a coherent reply. And they claim it doesn't have to meet FBW certification standards.

Apparently the FAA was quiet happy to sign it off, EASA started asking questions, management waffle commenced. Once it was finished the meeeting was cut short by the other regulators.

Patrick Ky (EASA) has stated that EASA will be certifying parts of the flight control system independantly to the FAA to the EU transport committee.

"The agency has come up with four conditions that have to be met before the MAX can fly again in Europe. Primarily, all modifications must be approved by EASA itself. Additionally, EASA demanded a “broader review of the design of safety critical systems” of the MAX which had previously been performed by the FAA. “That was not very popular with our American colleagues,” Ky hinted. EASA also wants a “complete understanding” of the Lion Air and Ethiopian Airlines accidents both from a technical and operational point-of-view. Finally, the agency wants to ensure that flight crews are adequately trained."

 

[Alistair_Heaton]

I suspect the big problem the FAA has with EASA doing a review is they know fine that there will be a multitude of other issues appear outside certification.

More than a few will show that they haven't been doing their job properly for decades.

I am sticking with my prediction that it won't be flying outside the USA by next summer season.

Although quiet how the US pax will feel about flying on an aircraft that the rest of the world won't fly on I really don't know, if the FAA decides to certify while the others don't. Then we will be into the situation which was a complete pain in the backside when I started out that you had different models and certification per area of operation.

And the 777x certification timeline is pretty much a work of fiction now.

 

[waross]

I can't help thinking that with the billions lost so far, Boeing could have solved the problem of low ground clearance and found a way to extend the landing gear and relocate the engines under the wings, ten times over.
Rather than address the problem they are apparently still trying to mitigate the symptoms of the problem.
After many years of experience trouble shooting I can't count the number of times that I have seen that approach fail.


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

 

[LittleInch]

waross,

We've looked at that many times - they would need quite a lot more undercarriage clearance hence total re design of the wing root

Also the other big issue is simply the size of the stabilisers compared to the elevators and also that there is now only one jack screw instead of other systems wholly manually controlled / driven to control their angle.

These issues also exist with the 737NG, but they didn't have a potential mad system moving them Nose down.

But yes, it seems they have no choice other than to address the symptoms or scrap all the existing 737 max aircraft.

We all know the FAA is going to under pressure to get the 737 max flying again and their dual role puts them in conflict.

I don't doubt for one second that there are differences in opinion between the different regulators and that the FAA has lost the respect of the other parties and there may be a power play going on here.

I went trawling yesterday and this dual FCC comparison story surfaced in early August which implies it is a bit of a last minute design to try and resolve the structural design issues. It doesn't sound like the best plan to me, but I can see the point - if either FCC goes haywire, shut both down and hand the controls to the pilot. Not sure it will stand the scrutiny of the regulators though.....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[charliealphabravo]

Boeing could have solved the problem of low ground clearance and found a way to extend the landing gear and relocate the engines under the wings,

I don't see how the landing gear and engine relocation under the wing is related or helpful. This would increase the problem created by the larger Leap engines. Lowering the center of thrust with respect to the center of mass, either by increasing the engine diameter or lowering position of the engine, will increase the nose up tendency and increase the need for MCAS input and the amount of hard built-in trim (decreasing efficiency).

 

[LittleInch]

The issue with the Max is mainly due to the fact that the engine nacelles themselves start to generate lift at high angles of attack.

When you look at the two engines between say a 737 and a A320 the actual centerline isn't that far away.

The 737 engine looks like even now it had some help from the manufacturer to move some components to the top to minimize the height.

The AA320 with a similar engine is much rounder.

737 max

A320 neo

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.