787 Gear Collapse

[Magnum 475]

Just saw this in my news feed.



Apparently several airport workers injured.

[48k]

Very lucky that the injuries were not a lot worse. That's going to be a meeting without tea and biscuits.

[fooman]

If it's Boeing I ain't going.

[Marshall878]

That guy had a lucky escape! Where are the chocks and I'm guessing the ground pin!

[alangla]

Not the first time either. A member of ground crew is going to get flattened by one of these things falling on them at some point. A couple of them had a pretty narrow escape this time
https://www.gov.uk/government/news/aaib-report-boe...

Edited by alangla on Friday 5th June 13:39

[48k]

alangla said:

Not the first time either. A member of ground crew is going to get flattened by one of these things falling on them at some point. A couple of them had a pretty narrow escape this time
https://www.gov.uk/government/news/aaib-report-boe...

Edited by alangla on Friday 5th June 13:39

That BA incident (on a 787-800) was 5 years ago though, and this 787-900 aircraft is only a year old - you'd hope that the locking pin hole design and standard maintenance procedures had long been updated in line with the AD and SB that were in place so that it's not possible for the mistake to happen again.

AAIB Bulletin said:

The design of the aircraft nose landing gear downlock assembly created an opportunity for error when inserting the NLG locking pin, with two holes located so close together that the pin could be inadvertently inserted in the incorrect location. A Service Bulletin and Airworthiness Directive was available that would have prevented the accident, but this had not yet been completed on G-ZBJB.

Also - and this is a MASSIVE point of pendantry so please excuse me for it - the landing gear hasn't collapsed. It has been deliberately retracted whilst the aircraft is on the ground.

[Mr Pointy]

48k said:

Also - and this is a MASSIVE point of pendantry so please excuse me for it - the landing gear hasn't collapsed. It has been deliberately retracted whilst the aircraft is on the ground.

I must admit I'm surprised you can even get an aircraft to do this; I would have thought once you have weight on the wheels then there's no reason to be able to retract the gear. Obviously a very convoluted procedure for maintenance would be required but nothing that could be triggered unless the aircraft was propped up.

[borcy]

Traditionally unless you had hyds on nothing would happen. U/C locks are mechanically locked and hydraulically unlocked.
Then with the WoW switches made, that would be another barrier.

So yes, you'd have to have the a/c on jacks with power and hyds on to get the U/C up.

Unless the 787 works differently or there's some workaround.

[Master Bean]

Story from the avherald.

https://avherald.com/h?article=53a14f7c&opt=0

[48k]

borcy said:

Traditionally unless you had hyds on nothing would happen. U/C locks are mechanically locked and hydraulically unlocked.
Then with the WoW switches made, that would be another barrier.

So yes, you'd have to have the a/c on jacks with power and hyds on to get the U/C up.

Unless the 787 works differently or there's some workaround.

787 has a lock override button on the landing gear panel which will override the lock and allow the gear lever to be moved.

[borcy]

48k said:

borcy said:

Traditionally unless you had hyds on nothing would happen. U/C locks are mechanically locked and hydraulically unlocked.
Then with the WoW switches made, that would be another barrier.

So yes, you'd have to have the a/c on jacks with power and hyds on to get the U/C up.

Unless the 787 works differently or there's some workaround.

787 has a lock override button on the landing gear panel which will override the lock and allow the gear lever to be moved.

Override which lock?

[48k]

borcy said:

48k said:

borcy said:

Traditionally unless you had hyds on nothing would happen. U/C locks are mechanically locked and hydraulically unlocked.
Then with the WoW switches made, that would be another barrier.

So yes, you'd have to have the a/c on jacks with power and hyds on to get the U/C up.

Unless the 787 works differently or there's some workaround.

787 has a lock override button on the landing gear panel which will override the lock and allow the gear lever to be moved.

Override which lock?

The lock on the landing gear lever.

[borcy]

48k said:

The lock on the landing gear lever.

I thought that was what you meant, there usually is.

I assume the 787 has fewer hydraulic systems compared with previous aircraft though.

[48k]

borcy said:

48k said:

The lock on the landing gear lever.

I thought that was what you meant, there usually is.

I assume the 787 has fewer hydraulic systems compared with previous aircraft though.

Well, I don't believe there is a physical lock on Airbus landing gear levers it's software controlled.

You said "the a/c has to be on jacks...to get the U/C up unless the 787 works differently or there is a workaround"

I'm saying it clearly doesn't have to be on jacks, as can be seen by the BA incident 5 years ago and this one. And the "works differently / workaround" is to press the lock override button which allows the gear lever to by physically moved. If there is no locking pin in the nose gear lock hole and you press that button and select gear up - the gear is going to retract and you're having a meeting without tea and biscuits.

[borcy]

48k said:

borcy said:

48k said:

The lock on the landing gear lever.

I thought that was what you meant, there usually is.

I assume the 787 has fewer hydraulic systems compared with previous aircraft though.

Well, I don't believe there is a physical lock on Airbus it's software controlled.

You said "the a/c has to be on jacks...to get the U/C up unless the 787 works differently or there is a workaround"

I'm saying it clearly doesn't have to be on jacks, as can be seen by the BA incident 5 years ago and this one. And the "works differently / workaround" is to press the lock override button which allows the gear lever to by physically moved. If there is no locking pin in the nose gear lock hole and you press that button and select gear up - the gear is going to retract and you're having a meeting without tea and biscuits.

I'm not suggesting you're wrong. I was wondering how the u/c works.
I'd be surprised if there weren't any locks on the u/c, by that i don't mean the lock in the cockpit on the u/c lever or the ground locks (pins), I mean on the u/c itself.

[48k]

borcy said:

48k said:

borcy said:

48k said:

The lock on the landing gear lever.

I thought that was what you meant, there usually is.

I assume the 787 has fewer hydraulic systems compared with previous aircraft though.

Well, I don't believe there is a physical lock on Airbus it's software controlled.

You said "the a/c has to be on jacks...to get the U/C up unless the 787 works differently or there is a workaround"

I'm saying it clearly doesn't have to be on jacks, as can be seen by the BA incident 5 years ago and this one. And the "works differently / workaround" is to press the lock override button which allows the gear lever to by physically moved. If there is no locking pin in the nose gear lock hole and you press that button and select gear up - the gear is going to retract and you're having a meeting without tea and biscuits.

I'm not suggesting you're wrong. I was wondering how the u/c works.
I'd be surprised if there weren't any locks on the u/c, by that i don't mean the lock in the cockpit on the u/c lever or the ground locks (pins), I mean on the u/c itself.

Gotcha You're right there would be a hydraulic lock. But if the gear has been selected up the lock is released to allow the gear to move. Which is why the lock pin is supposed to be inserted.

[eccles]

On a lot of Aircraft there is a geometric lock on the U/C. While the weight is on, you can't physically move the U/C without raising the aircraft. The exception being the nose gear.

[borcy]

48k said:

Gotcha You're right there would be a hydraulic lock. But if the gear has been selected up the lock is released to allow the gear to move. Which is why the lock pin is supposed to be inserted.

So I'm assuming hyds were on. Yes i know why ground locks are fitted.

Then there's the wow switches. I assume they were either bypassed in some way or the gags were fitted.

[croyde]

I wonder what this lever does?

[Fat Fairy]

Can anyone give a reason as to why anyone would need to move the Landing Gear handle while the jet is sat in a parking bay, awaiting its crew and passengers?

I've never needed to go further than a 'Lamps Test' of the 'Gear handle in the last 40 years of (admittedly military) aircraft maintenance?