Ethiopian plane crash

[JuniorD]

I’m not even an IT dork like you lot but all this shop talk is getting me slightly aroused

[Mattt]

Can you imagine Norton Antivirus Airplane edition?

God help you if you ever wanted to change AV supplier, you’d probably have to write the plane off.

[George Smiley]

frisbee said:

Most processors used in avionics struggle to do the basic avionicy stuff, let alone adding overhead from signed communications or other additional security.

Indeed, and processor overload makes it much easier to break in.

Most DoS attacks are designed to cause system overload not to deny access but to enable access.

[Vaud]

Mattt said:

Can you imagine Norton Antivirus Airplane edition?

God help you if you ever wanted to change AV supplier, you’d probably have to write the plane off.

No.. just send it back to have the wings re-installed...

[Lemming Train]

https://www.seattletimes.com/business/boeing-aeros...

Good on EASA, although I suspect there are some politics at play here to demonstrate that they aren't the FAAs European puppet.

FAA said:

On Wednesday, the FAA declined to clarify if the EASA requirements are stricter or in line with its own.

“We aren’t going to comment on specific details about ongoing discussions,” the FAA said in a statement. “The FAA has a transparent and collaborative relationship with other civil aviation authorities as we continue our review of changes to software on the Boeing 737 MAX … Each government will make its own decision to return the aircraft to service based on a thorough safety assessment.”

The FAA appear to be a bit.. rattled.

Edited by Lemming Train on Thursday 5th September 19:13

[MartG]

https://www.bbc.co.uk/news/business-49591363#

The FAA certified it safe to fly in the first place, then it crashed twice - they need to rebuild trust in their certification procedures before other authorities accept their recommendations at face value.

[bitchstewie]

I don't know whether this is a regular kind of occurrence but christ

https://komonews.com/news/local/door-blows-off-boe...

[George Smiley]

From the same page.

http://komonews.com/news/nation-world/boeing-767-b...

http://komonews.com/news/nation-world/debris-from-...

[eliot]

bhstewie said:

I don't know whether this is a regular kind of occurrence but christ

https://komonews.com/news/local/door-blows-off-boe...

I thought the cabin doors are plug doors and therefore impossible to blow open under pressure. Maybe it was a cargo door?

[eharding]

bhstewie said:

I don't know whether this is a regular kind of occurrence but christ

https://komonews.com/news/local/door-blows-off-boe...

A Boeing Test Engineer and Manager undergoing a debrief shortly after the event:

[anonymous-user]

bhstewie said:

I don't know whether this is a regular kind of occurrence but christ

https://komonews.com/news/local/door-blows-off-boe...

It’s a static load test where they test the wings and the structure on the ground in a test aircraft on a big test rig. Sometimes it gets tested to destruction, sometimes it’s just to the test limit.

During the test the wings get bent upwards to (I think) 150% of the normal load. In some tests they keep bending them to see when they fail, other times they go to 150% and then stop.

They also over pressurise the cabin so it depends on when the door actually failed and what caused it. My understanding is that it was a cargo hold door.

The articles don’t actually say if the door failed the test. I’ve never heard of one coming off in a test. From Boeing’s usual guarded press release, it sounds like it failed below the test target and failed the test. I would expect that if it failed we’ll beyond the test target, then that would be in the press release. That’s what the tests are for though.

Some good wing test videos here.

https://www.popularmechanics.com/flight/g2428/7-ai...

Edited by anonymous-user on Saturday 7th September 10:11

[bitchstewie]

I prefer not to watch them as being slightly addicted to Aircrash Investigation on National Geographic tends to backfire whenever I find myself sitting on a plane

I know when I've watched them in the past I'm in awe of the things they can do.

[anonymous-user]

bhstewie.

Isn’t it odd that when you post your name doesn’t get censored buy if you get quoted it does?

[wc98]

El stovey said:

It’s a static load test where they test the wings and the structure on the ground in a test aircraft on a big test rig. Sometimes it gets tested to destruction, sometimes it’s just to the test limit.

During the test the wings get bent upwards to (I think) 150% of the normal load. In some tests they keep bending them to see when they fail, other times they go to 150% and then stop.

They also over pressurise the cabin so it depends on when the door actually failed and what caused it. My understanding is that it was a cargo hold door.

The articles don’t actually say if the door failed the test. I’ve never heard of one coming off in a test. From Boeing’s usual guarded press release, it sounds like it failed below the test target and failed the test. I would expect that if it failed we’ll beyond the test target, then that would be in the press release. That’s what the tests are for though.

Some good wing test videos here.

https://www.popularmechanics.com/flight/g2428/7-ai...

Edited by El stovey on Saturday 7th September 10:11

even then the way the loading is being applied looks to be the initial cause of failure in some of the tests, where the attachment points of cables/rods actually damage the part they are fixed to, leading to failure of the entire structure. they really are incredibly well designed and built.
my grandfather was in a boeing 707 flying through a big storm where he reckoned the wings were deflecting 30 feet from the centre line. there were lots of crease/stress marks near the inboard end of the wing when they landed.
might still be a photo in my dads place, both he and my grandfather took lots of pictures of the damage aircraft that had gone through storms sustained over the years.

[Lemming Train]

Not the first time it's happened. A China Airlines 747-400F blow off its entire front nose section 15 years ago when undergoing the pressure leak test in the factory before roll out.

[jshell]

eliot said:

I thought the cabin doors are plug doors and therefore impossible to blow open under pressure. Maybe it was a cargo door?

Used to be but not now. Now many rely on locking mechanisms rather than interference fit!!!

[anonymous-user]

jshell said:

eliot said:

I thought the cabin doors are plug doors and therefore impossible to blow open under pressure. Maybe it was a cargo door?

Used to be but not now. Now many rely on locking mechanisms rather than interference fit!!!

Which doors? The ones with locking mechanisms I’ve seen are still held closed by positive cabin pressure differential. I.e. once locked and pressurised they still can’t be opened.

[IanH755]

El stovey said:

jshell said:

eliot said:

I thought the cabin doors are plug doors and therefore impossible to blow open under pressure. Maybe it was a cargo door?

Used to be but not now. Now many rely on locking mechanisms rather than interference fit!!!

Which doors? The ones with locking mechanisms I’ve seen are still held closed by positive cabin pressure differential. I.e. once locked and pressurised they still can’t be opened.

The door didn't "open" as such as that is impossible in the pressurised A/C. Instead the door was blown out of the airframe. This used to be difficult as the door was shaped as an interference fit so it couldn't be physically pushed out of the airframe as an extra safety measure but this design style has been replaced by simply "locking" the door into the airframe with a latch mechanism.

With all the extra flexing and pressure during the test a latch was probably compromised and the lack of a door interference fit meant that, once the latch failed there is nothing to prevent the internal pressure pushing the door out of the airframe.

[M4cruiser]

IanH755 said:

With all the extra flexing and pressure during the test a latch was probably compromised and the lack of a door interference fit meant that, once the latch failed there is nothing to prevent the internal pressure pushing the door out of the airframe.

So we still haven't learnt anything from Turkish Airlines 981 crash in Paris, caused by this. Surely all doors should be larger than the hole. And windscreens (Southampton landing incident, but luckily not a crash).

[anonymous-user]

IanH755 said:

El stovey said:

jshell said:

eliot said:

I thought the cabin doors are plug doors and therefore impossible to blow open under pressure. Maybe it was a cargo door?

Used to be but not now. Now many rely on locking mechanisms rather than interference fit!!!

Which doors? The ones with locking mechanisms I’ve seen are still held closed by positive cabin pressure differential. I.e. once locked and pressurised they still can’t be opened.

The door didn't "open" as such as that is impossible in the pressurised A/C. Instead the door was blown out of the airframe. This used to be difficult as the door was shaped as an interference fit so it couldn't be physically pushed out of the airframe as an extra safety measure but this design style has been replaced by simply "locking" the door into the airframe with a latch mechanism.

With all the extra flexing and pressure during the test a latch was probably compromised and the lack of a door interference fit meant that, once the latch failed there is nothing to prevent the internal pressure pushing the door out of the airframe.

Wasn’t it a hold door?