Boeing 737 Max8 Aircraft Crashes and Investigations [Part 8] 24

[Sparweb]

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

thread815-445840
thread815-450258
thread815-452000
thread815-454283
thread815-457125
thread815-461989
thread815-466401

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 from Ethiopia is now broken. See link from NTSB Investigations below)

Indonesian National Transportation Safety Committee preliminary report

NTSB Investigations

NTSB Safety Recommendation Report: Assumptions Used in the Safety Assessment Process and the
Effects of Multiple Alerts and Indications on Pilot Performance

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

Pulitzer Prize, For groundbreaking stories that exposed design flaws in the Boeing 737 MAX that led to two deadly crashes and revealed failures in government oversight.

http://www.sparweb.ca

 

[Lou Scannon]

I vaguely recall from my first year economics class that monopolies are bad, and duopolies are only less bad. Here we have a de facto duopoly.
Maybe transport aircraft manufacturing needs to become a regulated public utility.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[dik]

or maybe just properly regulated...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[waross]

or maybe just properly regulated...

Isthat a typo?
Did you mean "just poorly regulated?"
No problem with poor regulation.
The agency is already in place.
The FAA.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[dik]

then maybe they should do their job then...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Alistair_Heaton]

Dominic Gates article

https://www.seattletimes.com/busine...lam-the-agencys-oversight-of-boeings-737-max/

I didn't realise there was an auto throttle issue as well.

 

[1503-44]

I banned 737s from my personal space. Not important to me if govs do, or don't agree with my policy.

 

[GregLocock]

Ex FAA safety engineer has a few observations.

https://www.seattletimes.com/busine...lam-the-agencys-oversight-of-boeings-737-max/

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[Alistair_Heaton]

There may also be a link to the 737-500 Indonesian crash with the auto throttle issue.

They have had issues with the AT since the 737-200. But mainly its the crew alerting system which is the issue. The fact it doesn't and the save is that the pilots have to recognise the issue and disconnect it from memory inside the magical boeing reaction time assumption.

 

[Alistair_Heaton]

FAA just approved the 737 MAX 8200 variant.

This is for Ryanair think its a max 8 but with 200 seats.

 

[Alistair_Heaton]

Seems double figures worth of them are grounded again due to them having an electrical issue with grounding.

 

[Lou Scannon]

Bugger!

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[Alistair_Heaton]

wee the second issue is of course electrical grounding

 

[waross]

Bugger
(The devil made me do it.)

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Alistair_Heaton]

If your interested someone changed the method of securing power control units to racks from rivets to fast fasteners on the production line. These fasteners don't give a grounding bond to the airframe.

Don't have a clue what the implications of that are with the electrical system, I am sure Lou and Bill does though.

 

[RedSnake]

Well if the electrical system is built with the same principle as a car, which it seems to bee looking at this picture.
Where all minuses goes via the ground and not via separate cables back to the power source.
Then the problem becomes the same as having a a bad minus pole or earthing in a car.
Anything can happen and things just stopp working.
What this "fast fasteners" are I am not shore, the word can probably be used for a lot of different rivets, screws etc.

Best Regards A


“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

They are push and turn to lock type clip there is a T on the end of the shaft which goes through a hole with a slot. You then push against a spring and turn and the T then has metal under it and holds them in.

Well that's what they usually are for cowls and fairings. Avionics Usually has threaded lock bars which get tightened to keep the connections good in the rack then wire locked so they can't move.


I think the anything can happen is the reason why they have stopped them flying before the FAA has had time to produce the official paper work requiring it.

To note this is the power distribution not the flight control system although as you say it may screw up everything.

 

[RedSnake]

Okey I know what you mean, we have those kind of fasteners on some electrical cabinet doors.
There was talk about a fire hazard.
So my guess is that if the unit isn't tightened enough, there can be discharges and light arcs, causing fire.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Alistair_Heaton]

No clue. I presume that they are not certified for electrical purposes and changing them by production line kangaroo court has certification and QA issues.

The actual issue itself is one thing, the corporate mentality that anyone on the construction hanger production line can anyway consider it acceptable to change anything without it going through a QA checking process is completely another. If the QA process has signed it off acceptable then that another colossal issue.

 

[Lou Scannon]

Bill,

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[waross]

Boeing may still have culture issues.
Again;
"If it's Boeing, I'm not going."

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!