Engineers' Laurel and Hardy moment caused British Airways 787 to take an accidental knee
- Reference: 1626717670
- News link: https://www.theregister.co.uk/2021/07/19/ba_787_landing_gear_pin_aaib_report/
- Source link:
The Laurel and Hardy-style failure was detailed in a bulletin from Britain's Air Accidents Investigation Branch (AAIB), explaining why the 787's nose landing gear (NLG) was accidentally retracted during maintenance at Heathrow Airport in June.
"To prevent the landing gear from retracting, the procedure required pins to be inserted in the nose and main landing gear downlocks. However, the NLG downlock pin was installed in the NLG downlock apex pin bore which was adjacent to the correct location to install the downlock pin," said the [1]AAIB in its report .
[2]
British Airways Boeing 787 G-ZBJB after the nose landing gear retraction accident (Crown Copyright/AAIB/licensed under [3]OGL )
The 787, G-ZBJB, was scheduled to operate a cargo flight on 18 June. When its pilots arrived early that morning they found ground engineers already working on the aircraft, pushing back its scheduled departure by 40 minutes.
Engineers were trying to clear error messages in the 787's onboard fault recording system about one of the NLG's door-closed solenoid valves. Clearing the message involved fitting lock-out pins to the airliner's undercarriage to prevent it from moving, starting the hydraulic pumps and cycling the gear lever in the cockpit up and down. Without the pins, the landing gear would retract.
[4]
Unfortunately for British Airways, a Laurel and Hardy moment resulted in a very expensive blunder when the NLG unexpectedly retracted during the procedure. Two mechanics were sent to fit the downlock pins to the landing gear before confirming to a colleague in the cockpit that the gear was ready.
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"As [Mechanic] 1 was not tall enough to reach the NLG locking pin hole without steps, he pointed to the location of the hole and [Mechanic] 2 fitted the NLG locking pin," recounted the AAIB. Yet Mechanic 2 had fitted the pin to a very similar hole (the NLG downlock apex bore) next to the correct location.
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Boeing 787 nose landing gear lockout pin location (Crown Copyright/AAIB/licensed under [10]OGL )
An obvious human factors issue, the risk of fitting the downlock pin into the wrong hole had been identified years before [11]after a similar incident [PDF] – yet aviation safety authorities [12]gave airlines a three-year deadline from December 2019 (January 2020 in the UK, then under the EU Aviation Safety Agency) to fit a sleeve to the wrong hole, preventing the downlock pin from being inserted.
Predictably, the modification hadn't been carried out on G-ZBJB and the results of the gear retraction were bad.
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"The aircraft sustained damage to the lower forward fuselage, NLG doors and both engine cowlings, which had also struck the ground. Door 2L had been severely damaged by contact with the stairs positioned at the door aperture as the aircraft sank onto its nose," said the AAIB.
Some of the people aboard the airliner suffered "minor" injuries as the nose crashed to the ground.
[14]
BA's 787s have had fairly uneventful service lives, although in April an in-flight fire was caused aboard one by a Club Class passenger [15]dropping her iPhone XR into her power-operated lie-flat seat . ®
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[1] https://www.gov.uk/aaib-reports/aaib-special-bulletin-s1-slash-2021-on-boeing-787-8-g-zbjb
[2] https://regmedia.co.uk/2021/07/19/ba_787_g_zbjb_nlg_accident.jpg
[3] http://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2YPX2APiTZ07lU9JTxwibdgAAABQ&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[5] https://www.theregister.com/2021/04/08/tui_software_mistake/
[6] https://www.theregister.com/2021/02/19/airspeeder_alauda_drone_investigation_with_photos/
[7] https://www.theregister.com/2021/01/19/sussex_police_drone_crash_crawley/
[8] https://www.theregister.com/2020/10/12/drone_gull_attack_scotland/
[9] https://regmedia.co.uk/2021/07/19/boeing_787_nlg_downlock_pins.jpg
[10] http://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/
[11] https://www.ukfsc.co.uk/wp-content/public_pdfs/Safety_Alerts/ASRS-report-B787-Nose-landing-gear-pin-installation-issue-Jan-2018.pdf
[12] https://www.regulations.gov/document/FAA-2019-0494-0007
[13] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YPX2APiTZ07lU9JTxwibdgAAABQ&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[14] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YPX2APiTZ07lU9JTxwibdgAAABQ&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[15] https://www.theregister.com/2021/04/20/iphone_xr_inflight_fire_british_airways/
[16] https://whitepapers.theregister.com/
The engineer's careers
will take a nose dive.
Re: The engineer's careers
The engineer's careers will take a nose dive.
Maybe, but on the other hand it's a good bet that they would never make that mistake again.
Re: The engineer's careers
Very probably - of course the real fail point resides with whoever did not get around to complying with the 3 year old safety directive.
Re: The engineer's careers
Maybe it's just me, but if I asked someone to do something for me and they weren't sure about doing it properly, I would have watched them do it, or at the very least checked after they had done it. Though as Zenubi said, it should not have been possible to do it wrong in the first place
Re: The engineer's careers
"I would have watched them do it, or at the very least checked after they had done it."
They were too short to do it, so too short to check. I don't want to say anything politically incorrect, but short people are a constant hazard - there is a reason we don't let five year olds drive on motorways.
In the 1970s we used to make short people wear platform shoes to avoid industrial accidents.
Re: The engineer's careers
I agree. But in the interests of accuracy, this isn't (quite) a "3 year old safety directive".
The Safety Bulletin from Boeing was 12 March 2019, so 2 and a quarter years old.
The Airworthiness Directive from the FAA, the regulator who has authority over Boeing, was 16 January 2020, so 1 and a half years old.
The FAA obviously didn't think it was urgent, they gave everyone 3 years to comply. And that time hasn't run out yet.
Boeing-ing-ing
As if the name Boeing didn't have enough troubles. Now it could be coined as a new term for any aviation mishap. Maybe something like, "I Boeinged that one!"
Re: Boeing-ing-ing
I always assumed "Boeing" was the sound made by a part of the aircraft hitting the ground.
BAe 125 Executive Jet
BAe has form. In the late 1970's and on, the BAe 125 executive jet had the 'feature' that if the nose gear was not locked and the engines turned on powering the hydraulics, the nose gear would retract. This was particularly embarrassing when a Middle Eastern 'potentate' arrived to take possession of his flight of 3 BAe 125 aircraft, and they all 'bowed' as soon as the engines were powered up. There was a mandatory modification to ensure the nose gear stayed in place after that incident.
From the photo, it looks like the leading edges of the Roots-Royce engines impacted the tarmac, so maybe not just the nose cone will need replacing. Very expensive if any of the fan blades are damaged, let's hope not.
BAe 125 - https://en.wikipedia.org/wiki/British_Aerospace_125
A per usual the passengers were forced to board the plane a not deplanes while maintenance of indeterminate length was underway.
I've spend many consecutive hours locked in like that.
One would hope they learned a lesson, but insurance will pay the medical claims so I suppose not.
Freight
It was operating as a freight flight as per the article…
Re: Freight
Now now we can't expect people to read the article before commenting That would imply common sense and we know that doesn't exist.
RTFA: "The 787, G-ZBJB, was scheduled to operate a cargo flight on 18 June."...
I shall avoid the temptation
To comment about sticking things into the wrong hole.
This isn't ...
... the joke about the golfer in Japan, is it?
Take an accidental knee
When did we stop saying "kneel"?
Re: Take an accidental knee
When a bunch of racists decided that everyone should kowtow to their political demands regardless of relevance to local needs and issues.
I'm quite surprised there aren't automatic lockouts to prevent this very thing.
There are automatic lockouts to prevent the *pilot* from raising the landing gear on the ground. Probably including weight-on-wheels sensors, and/or checks on altitude and airspeed. However, as part of the maintenance, the *engineers* presumably disabled those safety systems. They're supposed to install the locking pins, so it's physically impossible for the wheel to move, before doing that.
Unfortunately, ground maintenance crews need to do a lot of things that you wouldn't want to be done in normal flight, as a normal part of their repair / diagnosis / maintenance work. So they have the ability to override the system, and safety is supposed to be assured by them following the procedures.
Yes, I could swear there are squat switches that prevent accidental landing gear retraction whilst on ground.
Presumably whatever system reset they were doing must have circumvented that fail safe, hence the requirement to insert the downlock pin.
Lucky there weren't injuries. IIRC in a previous incident of that sort, the sudden change in attitude meant that a pallet rolled forward and caused significant injuries to the loadmaster.
Doh !