BA 787 Nosewheel collapse @ LHR

[ImPlaneCrazy]

Looks like G-ZBJB has had an incident this morning whilst (thankfully) on stand at LHR...
https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/750x603/202183680_10165677859390268_1748086562492391633_n_fed979606a 53313e2da006576b01d299a8aae6f9.jpg

[spannersatcx]

Bit more than a 'nose wheel'!

[Richard101]

Can safely say that aircraft is AOG (Aircraft on GROUND)

[Locked door]

I really hope no one was under it.

[NutLoose]

https://www.airlive.net/breaking-british-airways-boeing-787-8-suffered-a-nose-wheel-collapse-at-london-heathrow/

[DaveReidUK]

Aircraft arrived from Domodedovo last night, but was departing from a different stand this morning, so had been towed in the meantime ...

[dixi188]

I wonder if this was during a maintenance procedure.
Remember seeing this at Gatwick with a Northwest 747 when the ground lock pin sheared.

[hoss183]

Looks a lot from the kit parked on the right that they were doing some maintenance on the nose gear.

[DaveReidUK]

AAIB Go team on its way.

[DaveReidUK]

It seems more likely that the Engineering presence was a consequence rather than a cause of the collapse. Looks like there may be some engine cowl damage, too.

[Epsomdog]

hoss183

That bit of kit you refer to is, I think, the FEGP (ground power) basket.

[galanjal]

I think the open cabin door has been badly damaged by the stairs as the nose dropped.

[DaveReidUK]

https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/301x400/g_zbjb_door_b623427bf31dd28e17075238808fae27bb68dce3.jpg

It's the new upward-opening version.

[ROKNA]

Downlock pin in the wrong hole? FAA has something about this for the 787 there is a risk of placing the pin in the wrong place

[SpringHeeledJack]

Am I correct in surmising that because the 787 is made out of mostly composite materials, it will be more challenging to repair the hull, nose wheel assembly housing and door assembly ?

[Station Zero]

Even more so with the 787 due to the barrel method of construction, can’t just replace a panel. Although it is possible to do full thickness (hole) flush repairs, but they are fairly expensive.

[slast]

Very good friend of mine was the dispatcher on board at the time. She just came by after medical checks and initial debriefing. She was standing in the forward cabin talking to the Captain about a departure delay as engineering were still doing something (she wasn't sure what), F/O was (seated?) in the flight deck. No warning of collapse and they were thrown to the floor. Fortunately it seems no persons underneath or loose cargo pallets moved. Door is severely damaged and possible engine damage due ground contact.

[wiggy]

ROKNA

Perhaps this:

https://www.federalregister.gov/documents/2019/07/23/2019-15519/airworthiness-directives-the-boeing-company-airplanes

The FAA proposes to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 787 series airplanes. This proposed AD was prompted by reports that the nose landing gear (NLG) retracted while the airplane was on the ground with weight on wheels, due to the installation of a NLG downlock pin in an incorrect location. This proposed AD would require installing an insert to prevent installation of the pin in the incorrect location.

[J1J]

news reports suggesting a freighter flight? Freight on a new ish 787?

[SpringHeeledJack]

Passenger aircraft used as freighters throughout the covid period. Got to keep that revenue stream flowing what with the horrendous capital costs and banks chasing at their heels.

[dixi188]

Don't we ever learn?
The BAe 146 had a problem where the downlock pin could be placed in a hole in the torque link instead of the downlock. That was fixed with a plastic bung in the wrong hole, 40 odd years ago.
I know it's not Boeing but don't Designers/Engineers learn from others?

[Nightstop]

wiggy

Seems unlikely to me, the hole diameters are totally different:

https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/900x1600/d637a2df_adcf_471a_af89_7aec42e05927_2526848e4915e8073f38cad e8f03aa7142eac72d.jpeg

[slast]

Might "seem unlikely" to you, nevertheless the FAA appears to have a different view...

[wiggy]

No idea whether it's unlikely or not, just quoting verbatim what the FAA published.

[Hatzerim]

Dang...
I would love to see how they repair this composite structure.
Although it was not a big damage (i'm guessing...) it still will be a hard work to do and a big check to get it out of the shop.

[Locked door]

Get a photo from the other side, the diameter of the incorrect hole is smaller on the left and “takes the pin snugly”.

Here’s the relevant FAA narrative.

Narrative 1
New B787 aircraft arrived for post-delivery mod. The NLG drag brace pivot link hollow bolt will accept the gear pin snuggly from LH side while the correct locking hole is 3 inches away and "unmarked." An inexperienced mechanic could accidentally place the locking pin in the wrong hole leading to gear collapse during ground testing damaging the aircraft and potentially injuring or killing persons in the vicinity of the gear.
Apply sealant or similar mitigation to the LH inside bolt hole, mark correct hole with red outline. Has previous Engineering Authorization been implemented on the fleet?


Seems like an accident waiting to happen to me. Except it has happened. Three times. I’d suggest this needs to be a mandatory urgent mod before it happens again.

[Nightstop]

I agree. There should be a placard: “NOT THIS ONE”.

[DaveReidUK]

We should probably wait before hanging a poor mechanic or ground handler out to dry until we have ascertained whether or not BA have embodied the relevant Boeing SB (as far as I'm aware, there is no corresponding EASA AD equivalent to the FAA one).

[kingstonboy]

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/484x338/b787_nlg_downlock_pin_installation_08e729c39a35ca92f2ceed596 b9936590ad27e04.png
Additional info -AD 2019-23-07 introduces an insert for the Apex pin bore and has a compliance time of 3 years from Jan 2020.
Now where is that bloke Murphy ?

[Terry McCassey]

There are aware of the problem as
https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/969x1278/whatsapp_image_2021_06_18_at_17_26_27_245ec21d90cbd51deb93ad 00757fc1ec23a47f59.jpeg
it has happened before.

[PAXboy]

As someone who spent 27 years in IT and Telecommunications trying to make systems fool proof, the idea of a 21st cetury designed pin NOT having a unique notch/detent/angle/single entry point is another indication that Boeing really threw the book on the fire. Possibly on the fire of a 787 lithium battery pack :suspect:

[Lyneham Lad]

Am I missing something here? Notwithstanding that the nosegear ground lock pin was incorrectly positioned, the crew are onboard and the aircraft being made ready for departure so why would hydraulic and electrical selections be made such that the leg is unlocked and starts to retract?

[spannersatcx]

Line maintenance means we could be fixing/testing systems to ensure servicibility of the aircraft right up until departure, nothing unusual in that.

[kingstonboy]

Pure supposition but i would strongly suspect NLG door or gear position solenoid issue and gear function test carried out with the ensuing result . I wonder if the test passed ?

[wiggy]

Wot spannersatcx said...it certainly didn't use to be unheard of to have rectification/maintenance being performed in parallel with pre-departure processes...just for once it probably was just as well this was a freight only service..

[DaveReidUK]

kingstonboy

That configuration bears no resemblance to the photo in post #22.

Which one is actually the 787 NLG ?

[clark y]

I think most types have at least one example of a nose gear collapse/retract and not just Boeing.

It is unnerving seeing the landing gear lever selected up as part of a maintenance check whilst firmly on the ground especially when you feel and hear the gear doors move.

[John4321]

If they had 3 years to modify the aircraft, and we’ve had a year of many cancelled flights, why wasn’t the modification done earlier?

[DaveReidUK]

DaveReidUK

Answering my own question, the photo in post #22 is the MLG - interesting, but no relevance to today's incident.

[Rodney Rotorslap]

Three years to fit a plastic bung?

[tdracer]

dixi188

Boeing did a lot of dumb things during the 787 development, and one of the dumbest was - in order to encourage 'out of the box' thinking and solutions - they took a blank sheet of paper design outlook without bothering to reference the many decades of "lessons learned" experience. While there are certainly gains to be made with 'out of the box thinking', they way they did it resulting in countless cases of 'what the :mad: were they thinking?' design errors. A few well known examples: A structural design error that resulted in a last minute delay of six months in first flight - the design error was known and well understood 'trap' in composite design (the military side of Boeing knew all about it but no one on the 787 bothered to contact them). The L/R fire system hookups were not Murphy proofed - resulting in several aircraft being delivered with the systems switched. The APU Controller (APUC) was designed by a group that had minimal experience with turbine engine control systems - resulting in an APU that was horribly unreliable at EIS - and for years after.
I was involved in a design audit of the APUC about five years ago (at which time they were on the tenth major redesign of the APUC) and I literally had a hard time believing what I was hearing. Some of the design decisions simply defied any sort of logic. Just one example - most APUs use either aircraft power or a dedicated alternator to power the APUC. Modern turbofan FADEC systems have redundancy - a dedicated alternator normally powers the FADEC, but if the alternator fails, the FADEC will switch over to aircraft power for the remainder of the flight (not normally dispatchable that way). So the APUC design team decided to use both a dedicated alternator and aircraft power - but the way they did it didn't provide redundancy, the APUC needed both! Loose the alternator or aircraft power, and the APU shutdown! WTF?

Many of the managers who oversaw the 787 development then took their management technics to the KC-46 development. We all know how well the turned out...:rolleyes:

[DaveReidUK]

To be fair to Boeing, they could be forgiven for not foreseeing that anybody would think sticking a pin through the middle of a hollow pivot bolt (if indeed that's what happened) was going to stop anything moving ...

[Tom Sawyer]

John4321

Because for getting on 18 months many of us who do this type of work (Engineers), are currently stood down/redundant/unemployed/left the industry so not as many manhours available to do the work.

Also, mods like this tend to get done on a planned check in the hangar. If the aircraft is not flying as much and using hours it isn't reaching the hours limit for the check, so checks are getting further apart on a calendar basis. Also, if the aircraft had been put into parking/storage mode at some point, usually no maintenance is carried out apart from those requirements under the parking check regime.

Having said that, if it is a simple mod, no reason it can't be done on the line with a bit of planning, which is probably what will happen now if this is the root cause!

[krismiler]

SQ had a nose gear retraction on an A330 at the gate a few years ago during a maintenance check. Another possible explanation would be damage from a hard landing and the structure fails under the stress of loading. This is less likely as FDM would flag up a landing sufficient to cause the required damage and an inspection would be carried out.

https://www.straitstimes.com/singapore/transport/sia-plane-collapses-at-changi-airport-gate-after-nose-gear-retracts-during

[Station Zero]

Being picky, the AD says do it within the times specific and they are specified in the RB, the RB says 36 months from the issuance of ISS 01 of said RB, that was the 12 March 2019, so should really say three years from March 2019.

So think whoever wrote the safety alert may wish to go re-visit the dates. Not that it would have changed much if indeed this was the root cause of the incident.

[Ngineer]

Aircraft sitting on a gate ready for dispatch do not normally have gear down locks fitted. They are usually only required for testing/maintenance and towing.
The fact that the nosegear has tried to retract on ground points to either a cmc test being run (or other maint or retraction selection) without downlocks fitted, or some serious system malfunction that may cause this to happen. Unless a tractor/tug has tried to drive off in a hurry without disconnecting.

[DaveReidUK]

Ngineer

"Aircraft sitting on a gate ready for dispatch do not normally have gear down locks fitted. They are usually only required for testing/maintenance and towing."

The aircraft had indeed been towed onto the gate.

See earlier posts.

[Flypro]

Stupid question, but don't A/C have 'weight on wheels' switches anymore to prevent undercarriage retraction on the ground ?

[FullWings]

To be fair to Boeing, they could be forgiven for not foreseeing that anybody would think sticking a pin through the middle of a hollow pivot bolt (if indeed that's what happened) was going to stop anything moving ...
I’m not so sure. That task is repeated regularly around the World 24/7/365; if it is possible to do it wrong, it will happen. That’s the point of good mechanical design: to make it very hard to have parts in the wrong configuration.

Thinking about it, we don’t know how many times the pin has been put in the wrong hole as you wouldn’t find out about it unless a) you ran a systems test that actually would retract the gear on the ground without a pin or b) the person who removed it noticed that it wasn’t right. The setup has to be foolproof enough that a short person who is not that familiar with the type can reach in on a dark night and put the pin in the right place, and I don’t think the current arrangement passes this test, hence the AD...

[spannersatcx]

Flypro

Yes but they can normally be overridden, for testing etc.

[Airbanda]

Merely SLF, albeit an enthusiast of 50+ years standing, but how would a weight on wheels switch prevent collapse due to (say) hydraulic pressure dropping over time when engines not running?

[Epsomdog]

Yes they do, but they also have extensive built in test systems (BITE) that enable engineers to simulate the in air condition and thereby override the squat switches. No need to go round fitting slugs to the prox switches when you do this.

[DaveReidUK]

Airbanda

"Merely SLF, albeit an enthusiast of 50+ years standing, but how would a weight on wheels switch prevent collapse due to (say) hydraulic pressure dropping over time when engines not running?"

Once a gear is down and locked, there is no need for hydraulic pressure to be maintained on the extension jacks. Geometry is sufficient.

[Dannyboy39]

tdracer

I don't work on 787s very often, but speaking to people who do all the time say that the aircraft was designed with no input from the engineers who maintain the thing on a day-to-day basis. Jobs that would likely take 1-2 hours on previous types, can often take double that.

[Ngineer]

DaveReidUK

You are missing the point, with the aircraft on gate or in the hangar (ie stationary with no tow in progress) there is no point for having the Downlock pin fitted. The gear is down and locked. And the pins are removed after the tow, they do not take off with them fitted you know.

To say that this incident solely happened as the pin was fitted in the wrong point, without further explanation as to why the gear actually retracted, is a very incomplete explanation of this incident.

Obviously the aircraft had been towed, or did taxi onto gate. But are you saying that the tow commenced without gear pins fitted correctly, and the NLG collapsed with the tow bar and tractor connected during the tow? I see no evidence of this.

I am rated on the B787, and yes I have towed them onto gate many times. The first thing you do after you tow onto gate is remove the gear pins. The 787 is a very complex aircraft, you cannot second guess it, or take any shortcuts when carrying out any maint activity. And that is all I will say without speculating as to what actually happened here.

[DaveReidUK]

Ngineer

"Obviously the aircraft had been towed, or did taxi onto gate. But are you saying that the tow commenced without gear pins fitted correctly, and the NLG collapsed with the tow bar and tractor connected during the tow? I see no evidence of this."

The AAIB are on the scene. It might be best to leave the investigation, analysis and explanation to them.

My comment was purely factual - the aircraft didn't taxi onto the gate, it was towed. As to whether or not that will turn out to be relevant to what happened subsequently, I'm not about to try and guess.

[Deepinsider]

The AAIB are on the scene. It might be best to leave the investigation, analysis and explanation to them.

Quite so. But the very purpose of this forum, is to discuss Rumours. We can all wait a year for the
full facts, but our interest and entertainment is what we read above, isn't it?

[crazyaviator]

Yep, system safety at its finest. They would have the "AD" out quicker if there was a dead body under that fuselage !

[172_driver]

Not 787 rated but I guess the design of the gear lock pins is pretty universal. Do they depressurize the hydraulics in the retract lines or do they physically prevent the down lock from moving (with hyd. pressure on)?

What kind of test would the engineers possibly do with crew and passengers onboard that would pressurize the landing gear retract cycle?

[silverelise]

It was preparing for a cargo flight there were no passengers on board.

[DaveJ75]

Ngineer

I got your point - good post. I also suspect the answer may be up a different tree, especially given the system complexity of the 787!

[OldPilot71]

Lyneham Lad

Reliably informed by Boeing engineer friend that this would have been to test gear solenoid function. Lock pin in, and WOW breaker pulled then gear up selected. Locking pin correctly positioned would have resulted in a non-event. On the plus side, they can now mark the solenoid test "satisfactory".... however.....

[DaveReidUK]

172_driver

"Not 787 rated but I guess the design of the gear lock pins is pretty universal. Do they depressurize the hydraulics in the retract lines or do they physically prevent the down lock from moving (with hyd. pressure on)?"

Downlock pins (as opposed to steering lockout pins) typically don't interact with the hydraulics and simply provide (indirectly) a mechanical resistance to gear retraction.

Here's an example (actually a MLG, but the same principle applies to nose gears):

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/611x546/mlg_downlock_bdfc95929b90fc490eb942576a7633c408429dfb.jpg

The gear isn't quite fully deployed in this shot - when it is, the two highlighted beams pivot so that they are in line with each other and form a geometric lock. You can just see the two holes that will then line up and if needed, accommodate a ground lock pin.

When I first encountered gear pins many years ago, I wondered how a relatively small pin could resist the force of a massive retraction jack - but of course they don't have to, all they need to do is to maintain the geometry of that downlock brace.

See post #22 for the pin in situ.

[172_driver]

Thanks Dave, good picture!

[sycamore]

Seems `bloody` stupid to do this test with crew on board,as Murphy would say....If it can go wrong,sooner or later it willl......

[Tom Sawyer]

Firstly, we have to do a lot with Crew onboard when you are part of a system trying maintain an operation as well as the aircraft. Try turning an A380 on a 90-120 min turn round. The outbound crew are usually on the flight deck by the time I have done my external checks so anything that needs testing will get tested with Flight Deck, Cabin Crew, red caps, cleaners, caterers and even pax all onboard. If I need the Captain or FO to move, I'll ask. I'll gauge what other options I need to consider based on the test I'm running. In this case, assuming the pin was fitted and all other conditions met, I wouldn't have a problem with crew onboard, but would advise them what I was doing, and most of the time the crew are actually interested to see what we do and what the test does. If you want to avoid this situation, then aircraft will need say a scheduled 4 hour turn round time just in case we need to run tests - good luck getting that implemented by an airline. That is the system we work in.

Secondly, I don't think the Engineers were expecting an outcome like this, so why wouldn't they let the crew do their pre-flights as per usual. If the pin was fitted in the wrong hole, they were not aware and carried on potentially "knowing" that they had seen a pin or flag in the NLG & MLG, or had asked one of the engineering team to put the pins in and got confirmation. If we presume the WOW eCB was tripped and collared as per the test procedure mentioned, why would they expect this outcome? So it comes down to holes in the cheese lining up - a design issue which led to a mistake made, and maybe in addition not following the procedure (I'm not 787 licensed but I do work on them occasionally so know it is far from perfect and just plain weird at times, so not sure of the BITE process for satisfaction of pre-conditions prior to the test running i.e, does the WOW eCB need to be tripped to allow the test to continue?).

Note - paragraph 2 assumes this incident is due to the discussed issue of being able to put the locking pin in the apex pin and not the correct locking point.

[Ngineer]

DaveReidUK

Yes, sorry to interrupt the wild speculations and nonsensical theories regarding aircraft towing that was running rife. As you were.

[Alpine Flyer]

I remember similar designs on other A/C where the pins would fit multiple adjacent holes and we were taught never to put the pin in a hole with a collar. Clear markings, blockers and different diameters should be mandatory as some of these pins need to be fitted in locations that are not easily accessible, dark, etc., so possible mixups will occur sooner or later.

Best solution was on the Dash 7/ 8 were you’d have to lie down to insert a pin and pull out a panel on the nose section instead that effects the locking.

[gcal]

If a lot of airlines had not been flying freight for the last 18 months they would not have survived.
Freight can be light in weight and cabin loaded as well as heavy and in the holds.

[Jet II]

Ngineer

I would be very wary of making blanket statements and assuming that what happens in your company is industry wide. For example in my last company it was a regular occurrence for me to arrive at the aircraft to sign off the fuel 15 minutes to departure and find the gear pins still fitted from the tow about 3 hours earlier - I actually preferred that as I ensured that, as the Engineer clearing the Tech Log entry, all pins were physically removed from the gear.

[vs69]

Tom Sawyer

Tom has hit the rivet square on the head (as always)
Its not unusual to end up having to get rid of a status message on departure and the 78 is no stranger to those, with the added bonus that a lot of BITE functions are inhibited with the refuel panel open which doesn't do much for the time pressure factor.
I can picture exactly how this was playing out because it could easily have happened to me or one of my colleagues. From the comfort of my sofa it'd be easy to say "well I would have triple checked the pin was in correctly" but when you are juggling 4/5 aircraft with varying levels of work on them and the distraction of an ever closer departure time, crew, dispatchers etc on your back then it becomes easier to see how the holes line up. (no pun intended)
I sincerely hope those involved are not castigated for this and important lessons are learned.

[H Peacock]

Hmm. If the possibility of a gear pin wrongly fitted was known about and indeed publicised, there’s not much of an excuse for still fitting the pin in the wrong hole? Surely if you are then going to run some checks where the correct fitting of that pin is all that stops the leg retracting when commanded to do so, you’re going to go back outside and check all 3 are correctly fitted!

Irrespective of the various holes present, doesn't simple physics give you a big clue as to where a locking pin should be fitted to do its job?

[vs69]

Well in an ideal world yes, however anyone who has fitted a jumbo downlock fishing pole may disagree with you there!

[Lyneham Lad]

OldPilot71

Thank you (and others) for clarification on the why's and wherefores of likely events leading to the accident.

[Whinging Tinny]

H Peacock

That all depends if the information has been disseminated all the way down the food chain so to speak in the airline concerned.

Who fitted the pin, what level of competency/training they have and which way it was inserted(from the left or from the right)also has a bearing on the outcome due to the differing diameters of the offending hole.

The FAA AD and it's subsequent rectification was raised because it is a known issue.
Not all airlines have embodied the mod yet.

You might like to read up on the EVA B744 nose leg collapse at LHR or a similar occurrence which happened to Lufthansa at FRA.
The nose gear pin was fitted in the correct location in both those incidents.

Also, the B747-100 incident at BAMC where HF came into play big time and resulted in the main body gear partially collapsing.
However before the gear checks began, the U/C pins had been checked by an experienced engineer.

[Nightstop]

Which brings us to the concept of “Just Culture”, which in Western aviation is very well advanced. Here is a link that explains the concept, especially useful for those who believe that punitive action is the only response to an unintentional and non-deliberate offence.

https://www.skybrary.aero/index.php/Just_Culture

[TURIN]

H Peacock

There are five pins. Not much excuse for not knowing something like that as it has been widely published. 😁

Seriously though, there are no excuses but there are reasons that things go wrong. Mitigating those reasons is why we fully investigate and implement corrective action instead of just pointing the finger.

There for the grace of... etc.

[FullWings]

Exactly. I don’t think the engineer(s) involved set out to do this. If it is possible to put the pin in the wrong hole, and by all accounts it can fit quite well, then it’s just a matter of time if this action is taken on a regular basis. Which it is.

A bit like the 320 engine cowls: what are we up to, 45-50 incidences of them not being locked properly? Can’t be anything to do with the design and/or warning systems... :rolleyes:

[fergusd]

PAXboy

Quite . . . the more you see the less impressive aviation safety process is . . . repeatedly, what a shambolically inept design decision, again, how many thousands of issues like this are hiding waiting to kill people I wonder . . . thankfully no plans to return to the safety lottery of aviation travel any time soon . . .

[DaveReidUK]

Update on the aircraft: after the nose had been raised on airbags, the gear was dropped and (presumably after inspection by the AAIB) it was judged secure enough to allow the aircraft to be towed back to the BA Base.

Photos on Twitter show, unsurprisingly, the two forward NLG doors having been ripped off but the two smaller rear doors appear to be more-or-less intact.

[DaveJ75]

H Peacock

Or, to bring the perspective from 1951 to 2021, if the possibility of a gear pin wrongly fitted was known about and indeed publicised, there’s not much of an excuse for it still to be physically possible to fit the pin in the wrong hole?

Humans are intriguing creatures, both under pressure and on a forum...

[QDM360]

DaveReidUK

Photos from when/after it was raised? Do you have a link?

[DaveReidUK]

Twitter link

[procede]

It seems to be missing a door...

[DaveReidUK]

See post #13 for a clue as to why.

[slast]

This should be required reading for any engineer or designer.. originally from the late 1980s, current edition is 2011 I think. Clearly still relevant and strongly recommended. Originally published as "the PSYCHOLOGY of everyday things". Covers exactly the type of design issues that allow people to misinterpret what is intended and/or should be done, such as putting a pin in the wrong hole.
https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/174x270/don_norman_6ced61e76d1bdec305cd566836aaac453df8df65.png

[AerialPerspective]

krismiler

Ansett had the same thing happen in about 2000. A Boeing 767 sitting on a Bay at Sydney Domestic Terminal. The nose gear retracted as a test by an Engineer but no locking pin was present on the NLG so it did what it was designed to do and retracted. Ansett had several incidents and seemed to have a problem with nose gear - 747-312 on arrival at Sydney in 1994 with nose gear retracted. Qantas ended up having to jack it up and tow it for them. Another incident, less well known, failure of Engineer to chock a 767 again at Sydney Domestic Ansett Terminal, aircraft rolled forward and the radome collided with the nose in guidance system box requiring replacement. People wonder why their 767 fleet was grounded a year or so before their eventual collapse following 9/11.

[Uplinker]

H Peacock

I can imagine a number of possibilities:

Publicising the issue does not mean that everybody has read the published document. Those who signed that they had read it might NOT have read it, or they signed but did mot understand or think about the significance, or forgot about it after a month or so.

A very junior engineer might have been told to insert the pin, and got it wrong.

A non-787 engineer, helping out his mates who had a high workload, might have got it wrong.

The tug driver, or another non-engineer ramp worker might have inserted the pin and put it in the wrong hole.

An engineer, asked to check all the pins were in before the test might have seen the pin flag and thought the pin was in - they might not have gone right up to it to check the pin was actually in the correct hole.

Sadly, I don't think that in these days of reduced training and costs that we can assume that everyone - even pilots and engineers - necessarily understand simple physics, nor that everyone can see and understand by looking, how a series of undercarriage struts and levers work.

As a pilot, I was never shown where to fit the locking pins on any of the 7 commercial passenger aircraft types I have flown. Yes, it might be written in the FCOM, but you can't beat actually being shown stuff on the actual aircraft. Have all engineers and tow crews been actually shown exactly where to fit the pins?

It should not be physically possible to insert a ground-lock pin in the wrong hole. If it is, that is very poor design, because with the best will in the World, if something mechanical can be done wrong, it eventually will be.

Engineers only have mandatory duplicate inspections on certain items, such as engine oil caps.

[FlightDetent]

I would assume, yes. All the tow crews and engineers who are responsible for towing aircraft actually have been shown where the pins go.

[TURIN]

AerialPerspective

Were the Engineers responsible for chocks back then? It's not something they do these days.

[aeromech3]

Some many years ago, on one of my types, could have been an L1011, there was an incident caused by a hydraulic leak across the ports in a component which caused the NLG downlock to pressurise to unlock. Of course, for all I know the B787, could be an electrical unlock actuator, as the pin flag in the picture #29, masks the area.

[Capt Quentin McHale]

TURIN

I would say that would depend on the individual operators ground handling procedures.

[dixi188]

It may be someone else's job to put chocks in but if you are doing maintenance procedures it is your job to make sure everything is safe.

[Mr Optimistic]

[Pax]. Looking at the photo in post #22 with the benefit of extensive hindsight, it seems a bit odd that the correct hole was not marked in any way. A red outline around it wouldn't have hurt. In fact, wonder why all such holes aren't marked in some standard way across the industry. Would also visually highlight if a pin wasn't fitted.

[Deepinsider]

We'll all know very soon if it was no pin at all, or wrong hole.
I rather hope the mistake is the former, because if it was the latter;
What a sorry tale of errors that would be.
Boeing... Presumably knew about the risk, but didn't push it out LOUD enough.
FAA..... As above, but even worse being they are the regulator.
Operator.... Well....It's troubled and disrupted times (Covid) with reduced staffing,
changing roles needed, etc, and all the holes line up in the cheese.
Bottom line, this event may well have hurt or worse, ground staff, and shows
that even ground handling threats should never be taken lightly.

[meleagertoo]

TURIN

They'd be irresponsible if they didn't first ascertain they were correctly placed before starting a procedure that relied on them...

[DaveReidUK]

Deepinsider

"We'll all know very soon if it was no pin at all, or wrong hole."

There's a third possible scenario, alluded to in post #7. I've never heard of it happening, but it clearly has, so it might be unwise to rule it out yet.

[Busbert]

Technically the gear didn’t collapse. The gear retracted weight on wheels. The damping in the retraction actuator slows the rate that the aircraft drops. This has the unfortunate effect of generating immense forces into the NLG and retraction actuator attachment, risking punching the actuator through the NLG box before the actuator fails through over pressure.

[golfyankeesierra]

what generates the immense forces? Not the weight I guess? The weight is mostly on the maingears.

[DaveReidUK]

Busbert

"Technically the gear didn’t collapse. The gear retracted weight on wheels. The damping in the retraction actuator slows the rate that the aircraft drops. This has the unfortunate effect of generating immense forces into the NLG and retraction actuator attachment, risking punching the actuator through the NLG box before the actuator fails through over pressure."

I think it's reasonable to infer from the fact that the aircraft was towed off the stand a day or two after the incident, supported on all 3 gears, that there hadn't been any significant internal structural damage.

[Delight]

Stupid question from SLF - is there not a sensor on the landing gear that prevents retraction while there is weight on it?

[TURIN]

Yes, but it can be overridden for the purposes of function checks. Hence why steel ground lock pins are fitted to prevent the gear from moving.

[netstruggler]

See post #62 which I think suggests that the 'Weight on Wheels' interlock would have been disabled as part of the test.

[aeromech3]

In all of 40+ years in maintenance I have put a parked aircraft in air mode perhaps as many times, the electronic wizards nearly daily for auto pilot checks with hydraulics on, older airframes, but if I had anything to do with it I preferred with a tug and tow bar attached and all gears pinned and chocked, but none of these required the gear selected up!
Used the lock solenoid over-ride button on the gear selector panel, perhaps 20 times mostly for unlock indication faults, again hydraulics not needed.
Aircraft are routinely pushed back and towed with only the steering lock-out pin fitted; though I recall on B727's incidents when this was not enough to stop a tow bar shear pin event, if the FE selected hydraulics or started engine motoring; so it begs the question if this was a maintenance caused incident:- what was going on?

[Uplinker]

As a matter of interest, how do gear lock pins work?

Do they operate an electric switch; preventing fluid flow? Do they operate an hydraulic valve; preventing fluid flow? Do they prevent movement of a side stay, which in turn prevents hydraulic pressure being applied to the main jacks?* Or do they physically withstand the full force of 3000psi hydraulic pressure?

*Airbus A320 main gear locks consist of a sleeve which prevents retraction of a side-stay ram. So they must withstand full hydraulic force. The nose gear is a pin, if I recall.

[Deepinsider]

Good explanation, with pics.... posting #63

[Uplinker]

So... there is a hydraulic valve kept shut until the side stay moves? By locking the side stay - which presumably has much less pressure fed to it - a small pin can prevent activation of the main jack?

[TURIN]

The Lock pins physically prevent the side brace/drag brace from moving. The side/drag brace forms a geometric lock that prevents the gear collapsing even without hydraulic pressure applied. The A320 uses sleeves around the down lock actuator that prevents the side stay from moving.
When the gear is selected 'up' on the ground, hydraulic pressure is still applied to the actuators but they are prevented from moving by the pins and/or sleeves.

[DaveReidUK]

Uplinker

"Do they operate an electric switch; preventing fluid flow? Do they operate an hydraulic valve; preventing fluid flow? Do they prevent movement of a side stay, which in turn prevents hydraulic pressure being applied to the main jacks?* Or do they physically withstand the full force of 3000psi hydraulic pressure."

None of the above.

See the response in post #63 to the previous poster who asked the same question.

[slacktide]

It was mentioned earlier in the thread, but to prevent rehashing the issue, the hollow pivot bolt necks down internally and can accept the lockpin fairly snugly.

But - the 777 has this exact same configuration, with a hollow pivot bolt right next to the lockpin location. (Sorry, can't find a good photo online.) I'm curious why this has not been an enough of an endemic issue on the 777 to issue an AD. There have certainly been inadvertent 777 nose gear retractions that you can find on Google.

[Redlands]

Image posted on Reddit by @jonsky7
https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/2000x1124/h754yirwo6671_2e2394f6bcfbb6ca07fde8577a31a62053934150.jpg

[DaveReidUK]

slacktide

"It was mentioned earlier in the thread, but to prevent rehashing the issue, the hollow pivot bolt necks down internally and can accept the lockpin fairly snugly.

But - the 777 has this exact same configuration, with a hollow pivot bolt right next to the lockpin location. (Sorry, can't find a good photo online.) I'm curious why this has not been an enough of an endemic issue on the 777 to issue an AD. There have certainly been inadvertent 777 nose gear retractions that you can find on Google."

The gear pin is a bog-standard pip pin that any engineer from the last 50 years or more would recognise. It is indeed the same part number for the 777 and 787:

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/800x600/777_787_nlg_downlock_pin_b5cafdf2214af3836c02a0c8e0f1130adc3 a0f16.jpg

Judging from the photo of the nose bay, I suspect that a "snug fit" inside the (larger diameter) pivot bolt would only occur if the pin were inserted up to and including the shoulder.

It would (should?) then be obvious to the user that the pips were not engaged with anything and that the pin could be pulled out without having to depress the button to release it.

While I agree that it's not 100.00% Murphy-proof, any engineer or ground handler who doesn't understand something so basic is in the wrong job.

(with the caveat that the "pin in the wrong hole" scenario just a theory so far and has yet to be confirmed by the AAIB)

[Whinging Tinny]

https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/747x425/pin_09f1df423492f8ac130053a645fb69a067e16050.jpg
The 'offending stepped hole' and the mod.

[TURIN]

https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/2000x1307/_20210625_130727_e10613f07ea16546fe904e9802a9da7117c8f230.jp g
A modified version.

[BDAttitude]

Being a fan of that Murphy guy:
- The upside of the RBF flag on this pin is: it lowers the chance of going airborne with a pin locking down the gear.
- The downside of it is: a cursory look will confirm that a pin is in place, when it is in fact in the hole next door, and above happens.
Doing a traffic circuit with gear locked down might be the cheaper option :}.

[EEngr]

How much leeway is there in pinning/unpinning landing gear between operators? Might some pin the gear only when necessary (towing, maintenance) and others pin the gear and leave it until pushback and uncoupling the tug?

How might this situation be exacerbated by new hiring to fill vacancies created by Covid?

[Out Of Trim]

I have to say, the incorrect reinforced looking hole does look like it should be the one to be used. The correct one looks quite insignificant in comparison! I can’t believe that it was not marked properly. Very poor engineering from Boeing…. 🤭

[Deepinsider]

BDAttitude

Yes. But a 788 departing at max weight still has to burn off/dump 55 tonnes before it's light enough to land. (77W about 100 tonnes)
so it's a pretty big circuit!

[TURIN]

EEngr

From my experience the pins are only used for maintenance tests as required or for long term parking. Even towing between stands these days seems to be operator choice. Some insist, some just want the nose pin, some directly mandate that they're not used for towing at all to avoid any unpleastness. The risk of them being left in out ways the risk of a gear collapse during towing.
If you are only ever working with one operator then there is no real excuse for not knowing their procedure. If you are working multiple airlines and aircraft types then it is more likely that an incorrect procedure could be used.

[Compton3fox]

Deepinsider:
Yes and quite expensive.. But not as expensive as having the NLG retract at the gate :}

[OldPilot71]

There is. But you can deactivate it via virtual breakers on the 787 for ground maintenance in order to "cycle" the gear and carry out various tests. Of course, the aircraft should be jacked up for this or gear appropriately pinned.

[Nige321]

AAIB report out... (https://www.gov.uk/government/news/aaib-special-bulletin-g-zbjb-inadvertent-nose-landing-gear-retraction-during-pre-flight-maintenance)

The DDG procedure required the cockpit landing gear selection lever to be cycled with hydraulic power applied to the aircraft. 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. When the landing gear selector was cycled the NLG retracted.

[Snyggapa]

An Airworthiness Directive had been issued, with a 36-month compliance from 16 January 2020, to install an insert over the apex pin bore to prevent incorrect installation of the downlock pin, but this had not yet been implemented on G-ZBJB.

I wonder how many airlines will now have had a "oh hell" moment and be rushing to complete this presumably simple maintenance task to block up the wrong hole to prevent reocurrence. Cost per aircraft to rectify is less than $2K and takes 2 hours, according to this:

https://www.federalregister.gov/documents/2019/07/23/2019-15519/airworthiness-directives-the-boeing-company-airplanes

Seems like the exact same problem has happened at least three times now...

[DaveReidUK]

From the report:

"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."

Oops.

[golfyankeesierra]

Classic Murphy, great design.

[601]

$2K and takes 2 hours,
for a bit of plastic and 5 minutes work?

[Tom Sawyer]

Snyggapa

As I've said previously - it maybe a simple job, but a lot of us Engineers, including maintenance planners have been stood down/furloughed/redundant/left the industry over the past 18 months. Factor in also that this job would normally be carried out as part of hangar check package which are usually scheduled on flying hours and with the reduced flying hours of aircraft the hangar checks have gotten further apart on a calendar basis, it shouldn't be hard to see that a lack of Engineers and manhours, and planned maintenance events have compounded this situation. During aircraft parking, the Aircraft Maintenance Program is also suspended and in most cases no maintenance activities are carried out apart from those required under the parking/storage requirements. I would think a lot of operators are now starting to plan this work out on the line on their active airframes, if they have enough Engineers available.

Just like pilots, we have to got through recurrent training packages, and due to the current extended stand down situation possible re-qualification. Some companies may also have to go through a recruitment process before they get enough Engineers on-line, so don't expect Engineering support to be fully back to normality for a while yet. I'm forever hopeful that eventually companies will see the value of maintenance and Engineering, rather than the cost.

[Alanwsg]

https://www.theregister.com/2021/07/19/ba_787_landing_gear_pin_aaib_report/

[DaveReidUK]

Thanks.

The AAIB report linked in post #122 inexplicably omitted the reference to Laurel and Hardy ...

[Icarus]

Out of simple curiosity, does anyone know how many of the 32 787s in the BA fleet had the AD completed prior to this incident?

[Uplinker]

It seems we cannot assume that all engineers read their notices, or airworthiness directives, nor that they know, or can work out just by looking, where a ground lock pin must go?

And this at a company that failed to notice that the engine cowl locks on both engines were not closed prior to departure on an Airbus out of Heathrow.

What a sorry state of affairs.

How difficult is it for engineering to print a label and stick it on the leg; pointing to the ground lock pin hole? Would take about 2 mins per aircraft with a portable label printer.

:ugh:

[Sygyzy]

If Only....

I'm pleased to imagine Uplinker that you have an approved portable label-printer about your person, all ready to print approved labels. I wonder how long it took you to get the required approval and how much each printer costs. From my experience, said printer would cost ten times (at least) the cost of a similar/identical unappoved printer available in your local Staples (other stationers are available). I also hope you have your credit card handy for when the label that you stuck on comes unglued and lodges on the forward weight switch and prevents the gear from retracting (other scenarios are available). A great (simple idea) but not for the real (bureaucratic, or read [misguidedly] 'safety conscious') world.

'This at a company that failed to notice the engine cowl locks were not closed prior to departure'. Which company would that be, cos many worldwide operators of Airbus aircraft also fell into the same trap. A problem first with design (both problems) and then with training and finally with manpower currency/shortages in the current situation.

I'm not saying you're wrong. If only it were that simple...

[lancs]

Approved stencil, approved spray paint, approved technique. Go.

[TURIN]

I was reading on another thread about pilots not retracting the landing gear after takeoff. How difficult is it to print off and follow a checklist, physically lift a lever and move it up, observe the green lights extinguish.

We are all human. :mad: happens.

[dixi188]

Whilst a full safety assessment for a label might be required, some simple things only need a bit of common sense.
The A300 freighters I was on had a CB for the main deck cargo door that would sometimes pop for no known reason, and at 3am when tired, trying to find it in the electronics bay under floor could cause a delay.
Someone came up with the idea of painting a red ring around the CB and a label saying "This One". Never had a problem finding it after that.
Simple common sense solutions used to be approved by the CAA in a thing called a "Minor Modification".

[tdracer]

601

Given there is an AD associated with it - 2 hours to do the paperwork is about right.

[Yeehaw22]

Sygyzy

I wouldn't say 3 engineers on a 787 turnaround is short on manpower. Currency/experience maybe.

Although myself personally raising the gear lever to UP for any ground procedure is the biggest butt puckering task for me. And this may seem self righteous but when it comes to it I trust no one to make sure the pins are in. I get off my arse and go and put them in or check they're in. Just force of habit.

[kiwi grey]

I read that the FAA estimated cost - parts & labour - is $2,000 per aircraft.
Which looks kinda cheap compared to the cost of delaying the flight of the "Oops" aircraft, let alone the (?100 times as much?) cost of fixing it

[esscee]

Of course if that area at the top of the nose u/c was designed by an engineer and not by CAD, then it is a fairly good example of no Murphyism occurring! Also, who authorised/signed off on the final design of that area where the Very important nose u/c ground locking pin is fitted? Human Factors again, preventing possible "cock-ups".

[Uplinker]

Hi Sygyzy, point taken. Every engineering facility I have ever worked in has a portable label maker in the test room. Used to be Dymo, now they are electronically printed. Or if not a label, what about a ring of red paint round the correct hole, or a red arrow?

Regarding approval, do the company decals and paint colours on the fuselage have to be approved by the manufacturer and the XAA before an aircraft is sprayed with paint? Many aircraft have the last two letters of the registration painted somewhere on or around the nose gear leg. Are these specifically approved? Genuine question.

Speaking of company decals, there are lots of pictures on this thread showing photos of the aircraft, so the airline involved can clearly be seen, to answer your last question :ok: That airline is supposed to be one of the very best, I thought?

Hi Turin, yes fair point, hence my views elsewhere on pilot training and practise - seems the rot has now started to reach other areas of operations too? This incident did not involve an aircraft in flight - so there was no immediacy required and the nose gear pin was checked by more than one engineer on three separate occasions, if I've read the report correctly !

[DaveReidUK]

Uplinker

"This incident did not involve an aircraft in flight - so there was no immediacy required and the nose gear pin was checked by more than one engineer on three separate occasions, if I've read the report correctly !?"

The report is a tad ambiguous on that point.

The engineer confirmed several times to the flight deck that the pins had been fitted. Given that he had fitted the MLG pins himself, watched his colleague fitting the nose pin, and could see all 5 streamers dangling, it's by no means certain that each confirmation was preceded by an additional check.

[sycamore]

And they had used steps to fit the MLG PINS,so why not the NLG...Mech1 obviously did not check M2 had put the pin in the correct hole.....!

[TFE731]

DaveReidUK

One plus point. After the incident the short mechanic no longer needed the assistance of a taller friend to reach the pin!

[Tom Sawyer]

All I've got in my mind at the moment a picture of a number of Engineers reading this thread, rolling their eyes at some of the comments of non-Engineers about how perfect they would be at doing our job and they would never make this mistake, or have the solution. If any of you are 787 pilots, why have you never noticed this Murphy factor on your aircraft when you check the pins are removed? Did you actually look at the right hole, or just check there was no flag hanging down? To be honest, I've fitted the down lock pins to B787 NLGs numerous times and it has made me wonder if I got right 100% of the time as I wasn't aware of this issue until this event, despite over thirty years line maintenance experience! There by the grace of God/imaginary being go I????

"Blame is better to give than to receive" - Neil Peart, Freewill.

[TURIN]

Spot on Tom.
As I alluded to above, anyone is capable of making the simplist of mistakes.

[boguing]

As an outsider I'd suggest a green painted pin and a green hole. (And I'm obviously prepared to hear that it's red because it's been done this way since the Wright Flyer got retracts).

[Mr @ Spotty M]

With regards to the steps being used for putting in the MLG pins and not not the NLG pins.
The reason is most likely that the steps were to tall for the NLG.

[TURIN]

I've got to be honest, I don't use steps for either the mains or nose. 😏

[Uplinker]

"Tom Sawyer: All I've got in my mind at the moment [is] a picture of a number of Engineers reading this thread, rolling their eyes at some of the comments of non-Engineers about how perfect they would be at doing our job and they would never make this mistake, or have the solution."

Agreed, (am not a 787 pilot), but I don't think we are claiming that we never make mistakes, (I've made some howlers).

It just seems rather foolhardy of the manufacturer and operator that; knowing about the problem, an indication of some sort was not applied to all the aircraft until the wrong hole could be blocked off by the official mod. Or a photo and a warning printed in the engineer's notes for this procedure. Or even simply a photo emailed to all engineers. Do engineers receive an equivalent to our NOTAMS and Ops notices?

[FlightDetent]

God bless them, deserve much better than that!

[Tom Sawyer]

We don't get anything directly from the manufacturer of the aircraft. Most companies will issue Tech Notices or some variation on this title to provide us information for awareness based on Service Bulletins, Incidents, Trends, Airworthiness Notices, Modifications and the suchlike. The problem comes that whoever receives that information in Tech Services or Engineering will deem how important it is for it to be highlighted and disseminated. Urgent information should be put out within days, or stuff could take weeks. There is also the issue that different operators will have a different view to one another. Last year I had a notice from one operator regarding B773 centre fuel tank gauging that required the panel door cycling post refuel. I got another notice from a different operator with the same information probably 2 months later as they had assessed it as not as urgent or took longer to process it.

It isn't really viable for us to get the information direct from the OEM as, in my case for example, I'm licensed on 6 types with about 10 engine combinations and 4 authorities, so I'd probably be snowed under with notices and information, some of which could be irrelevant depending on aircraft mod status, config, line or base maintenance info and duplicate information from multiple sources.

[WHBM]

The AD came out in January 2020, before the pandemic, when the industry was still running full speed. The 787 has been the most used type in the fleet in the intervening time. In fact the issue was originally described in a Boeing Service Bulletin in March 2019. I wonder how many other 2019 Service Bulletin's the airline has not yet got round to.

The AD also came out when Alex "Every day I think of ways to save money" Cruz was still CEO at the airline. I suspect any AD with 36 months to comply was under instructions from the top not to even order the parts until July 2021. Note the accident took place less than a month before the final compliance date. It's a shame the AAIB did not ask to see the forward maintenance schedule for this aircraft (and all the other 787s) in the days ahead for when it was scheduled to be fitted.

[Jet II]

TURIN

I dont think I have ever used steps to put gear pins in on any aircraft - perhaps I was doing it wrong all those years..

[Uplinker]

Thanks Tom. Licensed on 10 types would be all the more reason for a warning to be added to the procedure notes, I would have thought?, (but not up to you personally, I realise).

I remember when I was a new F/O; very innocently asking an engineer if they followed check-lists like us pilots. The guy said, "No, we use common sense"................I hoped he was joking !

@WHBM, Ah, yes, the classic case of a CEO seeing just numbers on a spreadsheet. "If we don't do X, this number will get smaller. Therefore we will spend less money and the airline* will get better..........."

Fantastic - "Safety is our number one concern", yeah, right.

*for 'the airline', substitute 'my bonus'.

[DaveReidUK]

Jet II

"TURIN

I don't think I have ever used steps to put gear pins in on any aircraft - perhaps I was doing it wrong all those years.."

To use the terminology of the report, you clearly (both) belong to the "Mechanic 2" category, rather than that of "Mechanic 1".

[Magplug]

In every company there is relentless pressure to de-skill at every level so that salaries can be kept as low as possible. Those who have technical skills and legal maintenance permissions become thinly spread, supervising more and more less-skilled workers. They cannot be everywhere at once. Sooner or later someone working for them makes a major boo-boo and this a fine example.

Meanwhile the company PR will continue to chant 'Safety is our first priority' and 'We are an industry leading centre of excellence'. It was very lucky no-one was under that 787 when it hit the ground.

[TURIN]

DaveReidUK

Nah, average height, but sprightly and good at climbing.

[DaveReidUK]

Magplug

You don't ever stand under an aircraft when someone is planning to cycle the gear lever, pins or no pins.

[Easy Street]

Just out of interest, what exactly is tested by cycling the gear handle if the intent is for the legs not to move? I thought doors could be operated separately for access purposes, and presumably the electrics could be put through some kind of self-test routine without signalling retraction? Cycling the gear handle on the ground has always involved jacks in my experience, admittedly on much smaller aircraft.

[TURIN]

It can be something as simple as resetting a glitch.

[DaveReidUK]

Easy Street

"Just out of interest, what exactly is tested by cycling the gear handle if the intent is for the legs not to move?"

According to the AAIB report (see earlier link), cycling the gear handle was the approved procedure to clear a number of maintenance messages related to a snag that the aircraft was carrying.

Why that was being done on the ramp just prior to departure, some 36+ hours after the aircraft had arrived at LHR, is a mystery.

[Magplug]

Dave... To a pilot or engineer you are of course stating the blindingly obvious!

However, as you are aware, the ramp is an open area that is notoriously difficult to control. There are many workers carrying out many different roles from different departments and companies. The only thing they know is that.... 'When the beacon is on you do not approach the aircraft'. You appear to presume that the engineers conducting the check were sufficiently numerous as to prevent others approaching - In this day & age that is pretty unlikely!

[Uplinker]

Hi Magplug, (responding to your post #156), Quite so. Here we have one of the two leading aircraft manufacturers, and one of the leading operators - in terms of high standards, supposedly.

A manufacturer with years of skill and experience of aircraft design and construction behind it. A very experienced operator who would have us believe they are the best and who is not a LoCo, so charges high prices for tickets.

They are both supposed to be setting an example of quality and safety, with no need to cut corners and de-skill its workforce. Absolutely shameful.

[Yeehaw22]

DaveReidUK

If the aircraft was being prepped for dep, then there's every chance the messages reappear on power up or even power changeover from gpu to apu. The 787 is renowned for this. Hence why they need clearing before departure and not on arrival.

[DaveReidUK]

Yeehaw22

"If the aircraft was being prepped for dep, then there's every chance the messages reappear on power up or even power changeover from gpu to apu. The 787 is renowned for this. Hence why they need clearing before departure and not on arrival."

Except that the AAIB report makes it clear the snag was already in the Tech Log as an ADD from a previous sector. If it wasn't considered acceptable to dispatch the aircraft from LHR carrying the ADD (which is understandable), then WTF had BA been doing since the aircraft's arrival a day-and-a-half previously ?

[Yeehaw22]

Who's to say its not a pre departure procedure for despatch for that particular defect?

[gas path]

"Except that the AAIB report makes it clear the snag was already in the Tech Log as an ADD from a previous sector. If it wasn't considered acceptable to dispatch the aircraft from LHR carrying the ADD (which is understandable), then WTF had BA been doing since the aircraft's arrival a day-and-a-half previously?".....
You might just find waiting for the spare pressure switch for a drop dead ADD is the answer!
AND 3 previous incidents. It is a shame though that they hadn't carried out the mod to plug the apex pin. Incidentally the 777 has the similar design but it hasn't happened to one of those.

[DaveReidUK]

Yeehaw22

That would make sense, so every flight since the ADD was raised would involve cycling the gear handle prior to pushback.

As the saying goes, what could possibly go wrong ... ? :O

The account of the aircraft's maintenance history in the final report will be interesting reading.

[TURIN]

Magplug

Actually, having performed this procedure quite recently, we waited until all ground equipment and personnel were clear of the aircraft before selecting gear up. Even the crew were kept in the terminal building. It caused a delay but we considered it prudent to do so. It can be difficult sometimes trying to explain to operators that this is the correct way to behave and it can mean the LAE in charge has to be quite firm with airline station managers, MOCs and airport duty managers that need the stand ASAP. Pressure for an on time departure should never trump safety.

[Easy Street]

cycling the gear handle was the approved procedure to clear a number of maintenance messages related to a snag that the aircraft was carrying.

Hindsight is always 20/20 but that just strikes me as bizarre. Why not put a maintenance switch in the system to reset whichever electrical signals clear the messages, avoiding the need to cycle the gear handle and the obvious potential accident which has resulted?

[Tom Sawyer]

A lot of the tests we run via the CMC do actually do this by configuring the system "electronically" to simulate the required condition. In some cases however a physical change is required. In this case maybe there is a mechanical switch or prox sensor in LG lever module that needs to be physically made to get a suitable response? The other issue of course is how far do you go with maintenance switches? How many would be required to simulate every potential test mode? What is the risk if a switch is left in the incorrect position prior to flight, or fails? Remember the A320 that had spoiler problems on take off (at LGW?) because the ground maintenance safety selector on the spoiler actuator had been left in the wrong position? Putting it in another context, this kind of incident has happened maybe 3-4 times now on B787s, how many times has the test been carried out successfully in the same period? Putting more complexity into the system when there is a known simple preventative fix available is not the solution.

[swh]

Has the airframe been scrapped ?

[Mr @ Spotty M]

There is no way that it would be scrapped with that small amount of damage.

[gas path]

The airframe is currently being repaired by Boeing. After strip out and assessment they make up a surrogate repair and bond it in. This is then subject to NDT. If all is good it is removed and the final repair made up and bonded. It will be totally invisible and will not need any further inspections later in the life of the aircraft..

[Waterworld]

The airframe is currently being repaired by Boeing. After strip out and assessment they make up a surrogate repair and bond it in. This is then subject to NDT. If all is good it is removed and the final repair made up and bonded. It will be totally invisible and will not need any further inspections later in the life of the aircraft..
Any idea how much longer until it flies again?

[Liffy 1M]

G-ZBJB is flight-planned from LHR-DUB this afternoon, according to Flightradar24. https://www.flightradar24.com/data/aircraft/g-zbjb

[DaveReidUK]

Flight number indicates non-revenue (Engineering) movement.

[CAEBr]

Final AAIB report now issued

Link (https://assets.publishing.service.gov.uk/media/6346baf78fa8f53465d139bb/Boeing_787-8_G-ZBJB_12-22.pdf)

[Capn Bloggs]

Designed by Murphy.

[hunterboy]

And operated by the most penny pinching bunch of chisellers you can imagine…..

[wiggy]

And operated by the most penny pinching bunch of chisellers you can imagine…..

Not saying anything about chiselling but some of the comments with regard to the behaviour of some of the post incident onlookers is interesting...who'd have thunk it....:oh:

[Magplug]

De-skilling is a creeping malaise in both engineering and piloting. The less you have to train someone, the less you have to pay them. You could call it the ISO9000 disease. You give an idiot a written procedure that he may never deviate from and you can pay that idiot as little as you like because the job requires no skill. The fewer LAEs you employ, the cheaper your operation. With the reduced number of LAEs those that remain come under intolerable pressure of work and naturally start to make mistakes. Incorporate a 'Murphy' element in the NLG hinge mechanism then you have the required recipe for disaster.

Interesting AAIB comment that the SB for modifying the 'Murphy' NLG to remove the possibility for confusion was 'prioritised' to some undetermined date in the future.... What does that tell you about the World's Favourite Airline?

When the UK was in the EU British registered aircraft eventually fell under the governance of EASA. The UK CAA were not slow to capitalise on that situation and promptly made redundant all those CAA personnel previously responsible for safety oversight. Unfortunately after Brexit those personnel have not been replaced. Instead the CAA relies heavily on individual airlines carrying out their own oversight via approved safety management systems. In one particular airline ASRs routinely go uninvestigated unless AAIB participation is expected. The net result is that pilots don't bother to file ASRs any more. There is a huge difference between 'monitoring for trends' and simply kicking dangerous issues into the long grass.

With airlines now 'self-investigating' incidents we are quickly moving towards the situation experienced in the US where the FAA relaxed governance over Boeing which allowed the 'self-certification' of the 737 Max. As we know that did not end well.

[Capn Bloggs]

It does make you wonder what was going on, given the issue was known-about for over two years prior, with the initial quick-fix suggestion by Boeing: a pretty simple "fill the hole up with silicon".
You give an idiot a written procedure that he may never deviate from and you can pay that idiot as little as you like because the job requires no skill.
I particularly felt sorry for the Mech 2 checking the "40" new memos on his ipad, one of which was the wrong-hole alert.

[happybiker]

When the UK was in the EU British registered aircraft eventually fell under the governance of EASA. The UK CAA were not slow to capitalise on that situation and promptly made redundant all those CAA personnel previously responsible for safety oversight.

When the EASA regulations were adopted and came into force in the UK, EASA became the "competent authority" for initial airworthiness (certification) matters. The CAA did downsize the number of certification staff, a number of these taking up posts with EASA. The CAA were the "competent authority" for continuing airworthiness matters and were required to carry out oversight of all organisations maintaining aircraft and components as specified by the EASA Regulations. At that time CAA did not reduce the staff numbers who carried out these oversight duties and CAA still retain responsibility for safety oversight of continuing airworthiness and operational matters.

[Ancient Observer]

Happybiker is 100% correct.

[Magplug]

So where did all the Flt Ops inspectors go?

Either way, nothing is being investigated and airlines are now both Poacher & Gamekeeper. Where will it end?

[hoistop]

This design was an accident waiting to happen. However, once the problem came to light, it took way too long thru all boards, committees, etc. to be sorted out, and COVID measures did not help with that. Turkish Airlines DC-10 near Paris (decades ago) comes to mind: -known design problem, SB was out, only timing was such that before the airplane was modified, it crashed, killing all aboard. I am also working in Quality stuff for years, now SMS etc. but sometimes I feel that thru all the benefits of orderly processess etc. a simple common sense has evaporated. Instead of having people aware, what they are doing, we give them procedures, loads of warnings, cautions, memos... everything, except proper education. (and money that goes with it).
When I did maintenance licence 30 years ago, I was paid (near inimum wage) to sit in the classroom to listen to the best and most experienced guys in the company for more than a year for basic training theory only. Now, future AMTs just click a,b,c answers on a bunch of exams, study at home on their free time, (if they study at all, some just try to get sample questions on the web to memorize) and collect practical experience on the go, often without any serious coaching. Then we have frozen water in AOA sensors and/or in NLG steering electronics, pushed there with high pressure cleaning, 40 times too much biocide in fuel tank, leaking oil filters as they were squeezed obviously incorrectly into the housing and other hard to believe events. It seems to me that modern airplanes take considerable wrongdoing due to excellent design, but this is obviously changing now-designs not so brilliant anymore. Hope Airbus will not follow the suit.

[Bidule]

... but sometimes I feel that thru all the benefits of orderly processess etc. a simple common sense has evaporated. Instead of having people aware, what they are doing, we give them procedures, loads of warnings, cautions, memos... everything, except proper education. (and money that goes with it).


:ok::D

[WideScreen]

This design was an accident waiting to happen. However, once the problem came to light, it took way too long thru all boards, committees, etc. to be sorted out, and COVID measures did not help with that. Turkish Airlines DC-10 near Paris (decades ago) comes to mind: -known design problem, SB was out, only timing was such that before the airplane was modified, it crashed, killing all aboard. I am also working in Quality stuff for years, now SMS etc. but sometimes I feel that thru all the benefits of orderly processess etc. a simple common sense has evaporated. Instead of having people aware, what they are doing, we give them procedures, loads of warnings, cautions, memos... everything, except proper education. (and money that goes with it).
When I did maintenance licence 30 years ago, I was paid (near inimum wage) to sit in the classroom to listen to the best and most experienced guys in the company for more than a year for basic training theory only. Now, future AMTs just click a,b,c answers on a bunch of exams, study at home on their free time, (if they study at all, some just try to get sample questions on the web to memorize) and collect practical experience on the go, often without any serious coaching. Then we have frozen water in AOA sensors and/or in NLG steering electronics, pushed there with high pressure cleaning, 40 times too much biocide in fuel tank, leaking oil filters as they were squeezed obviously incorrectly into the housing and other hard to believe events. It seems to me that modern airplanes take considerable wrongdoing due to excellent design, but this is obviously changing now-designs not so brilliant anymore. Hope Airbus will not follow the suit.
While I agree with your general reasoning, we should realize the amount of aircraft (-flavors), the amount of systems on an aircraft, the complexity of these systems (Ehhhh, software), the speed with which things get updated as well the hugely increased amount of regulations, no longer fits a teaching schedule you describe. Once the experience guy "knows" everything needed to teach, that knowledge has become old. So, yeah, there is no way any longer, each airline does have these knowledgeable people (often multiple) and the nowadays teaching needs to come from a central teaching location. Which is what has become the norm. Unfortunately.

Let alone, be able to make distinctions between "regular" and "important" stuff, everything tends to get the same importance classification, which in itself is a dangerous aspect.

Add to that the amount "new" technicians need to learn has become that much, these learners no longer can absorb all they are considered to get known, old-school style. So, curriculum selections need to be made, as well drip-feeding this knowledge in a consumable way.

Compare that with countries, where a significant amount of educational time is spent on imprinting "religion" items. When children spent 50% of their available learning time on religion items, they will stay (significantly) behind their mates in other world-parts, who spent all their learning time on subjects that matter for economic prosperity. There are reasons why religion based authoritarian countries are economically very weak (and often survive on Gas/Oil sales), this is one of them.