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WayexTDI
Posts: 2554
Joined: Fri Sep 21, 2018 4:38 pm

Re: BA 787-8 Nosewheel collapse at LHR

Wed Aug 11, 2021 4:48 am

zeke wrote:
WayexTDI wrote:
An aircraft seeing its nose gear retract is no indication of the lack of airworthiness of the aircraft: it has happened many times before when there was no maintenance being performed, just by not following the proper procedures.


I can guarantee you that an aircraft like the 787 sitting on its nose is not airworthy.

That's POST accident; PRE accident (nose gear collapse), many of those aircraft were airworthy.
 
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Crosswind
Posts: 2681
Joined: Sat Nov 25, 2000 4:34 am

Re: BA 787-8 Nosewheel collapse at LHR

Wed Aug 11, 2021 10:50 am

zeke wrote:
Crosswind wrote:
Incorrect. It was being loaded for a flight to Frankfurt, with pilots on board at the time of the occurrence on stand 583. Lots of routine maintenance goes on during turnaround.


Routine maintenance be is a transit check, a 72 hr check, or clearing defects means the aircraft is unairworthy at that time, those tasks need to be formally completed following the published procedures and then the aircraft is released for flight, only after the aircraft is released for flight can the captain accept the aircraft. The presence of loading or pilots does not make it is airworthy. The fact that is ended up on its nose during a maintenance procedure is very strong evidence that is it not airworthy.


I'm sorry but you are overstating the point, it was routine maintenance associated with an existing ADD. Happens all the time, every day at airports worldwide during the normal turnaround.

The aircraft was no more un-airworthy because of that than it was because of the doors being open. It's part of a routine of turnaround. You know as well as I do that even an aircraft with no defects is still not legal to fly until the Captain signs the final acceptance in the techlog. So the fact the engineers were working on an existing ADD doesn't alter the legal status of the aircraft. With or without the ADD the aircraft wasn't legal to fly until the techlog is closed by the Captain. The existing ADD did not render the aircraft incapable of flight, but the DDG procedure had to be completed between each flight to comply with the ADD.

I was responding to the very specific point that the aircraft was not at a gate (it was) was not between flights (it was) and was undergoing maintenance (which it was in terms of a DDG procedure associated with an existing ADD)

The aircraft wasn't in a maintenance area, or out of service. The pilots were onboard, freight was being loaded and the aircraft was being prepared for imminent flight.

To claim that it was un-airworthy or out of service is totally disingenuous. It was a routine turnaround. The AAIB is quite clear on the circumstances.

https://www.gov.uk/aaib-reports/aaib-special-bulletin-s1-slash-2021-on-boeing-787-8-g-zbjb
 
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zeke
Posts: 16432
Joined: Thu Dec 14, 2006 1:42 pm

Re: BA 787-8 Nosewheel collapse at LHR

Thu Aug 12, 2021 4:37 am

Crosswind wrote:
To claim that it was un-airworthy or out of service is totally disingenuous. It was a routine turnaround. The AAIB is quite clear on the circumstances.


It was unairworthy at the time, according to the AAIB (https://assets.publishing.service.gov.u ... G-ZBJB.pdf) it was undergoing a maintenance procedure for NLG door-closed solenoid valve, under MEL 32--31-02-03 it required a maintenance procedure (M) to be performed.

(M) May be inoperative on one system channel provided:
a) Inoperative relay is deactivated, and
b) Opposite system channel is verified to operate normally.

The Part 145 delegate advised the crew "the rectification work would take approximately 40 minutes to complete."

According to the AAIB

"The lead ground engineer sat in the left seat on the flight deck was working through the NLG status messages on the ground maintenance laptop. In order to defer the three defects highlighted by the status messages, the DDG for the aircraft required hydraulic pressure to be applied and the cockpit landing gear lever to be cycled from down to up then returned to down. The Lead Engineer instructed the lead mechanic (Mech 1) and another mechanic (Mech 2) to fit the landing gear locking pins. This would prevent the landing gear retracting when the landing gear lever was cycled. They were also instructed to attach the ground communications headset to the external connection in the NLG bay. Mechs 1 and 2 located the five landing gear locking pins and proceeded to the NLG to fit the first pin. As Mech 1 was not tall enough to reach the NLG locking pin hole without steps, he pointed to the location of the hole and Mech 2 fitted the NLG locking pin. As Mech 1 and 2 proceeded to the right main landing gear (MLG), Mech 1 informed the load team member on the pallet loader that they were going to apply hydraulic power to the aircraft and he should stand clear of the aircraft and lower the pallet loader to prevent contact with the cargo door. The application of hydraulics causes the aircraft to move slightly and can result in control surfaces and landing gear doors moving suddenly as the system is pressurised.

With the aid of some portable steps, Mech 1 fitted the two right MLG downlock pins before repeating the process on the left MLG as Mech 2 observed. Mech 1 returned to the flight deck to inform the Lead Engineer that the pins had been fitted. Mech 1 and Mech 2 then walked to the left of the NLG and Mech 1 plugged in the ground headset. The Lead Engineer requested further confirmation from Mech 1, through the headset, that the landing gear pins were fitted. Mech 1 confirmed that the pins were fitted. Mech 2 then stepped away from the aircraft and walked to nearby vehicles to observe.

The Lead Engineer was reading the appropriate section of the Aircraft Maintenance Manual (AMM) on the maintenance laptop when he received confirmation that the landing gear pins were fitted. The Lead Engineer applied hydraulic power but before selecting the landing gear lever he requested final confirmation, through the headset, from Mech 1 that the ground locking pins were in place and the aircraft loading team was clear of the aircraft. From his position next to the NLG on the left side of the aircraft, Mech 1 visually checked that he could see the warning flags for each of the landing gear locking pins. His view of the pallet loader was limited to just above the load platform, so he checked that no feet were visible to indicate the load team were clear. He then confirmed to the Lead Engineer that the pins were fitted and that the pallet loader was clear of personnel. On pressing lock ovrd and selecting the landing gear lever to up, the NLG retracted, and the aircraft nose struck the ground."

Where I work, even installing gear pins requires a separate log entry, and renders the aircraft unairworthy. This is to prevent the aircraft getting airborne with gear pins installed with a costly return.

If you look at the language in FAR 43.11 (similar appears in EU OPS), this is the style of wording that is used when an aircraft is released for flight “I certify that this aircraft has been inspected in accordance with (insert type) inspection and was determined to be in airworthy condition.” After every flight some form of inspection is carried out, where I work this includes engine oils, water servicing, and a 36hr/72hr/Weekly/EDTO check.

from 14 CFR § 43.11 - Content, form, and disposition of records for inspections conducted under parts 91 and 125 and §§ 135.411(a)(1) and 135.419

"(4) Except for progressive inspections, if the aircraft is found to be airworthy and approved for return to service, the following or a similarly worded statement - “I certify that this aircraft has been inspected in accordance with (insert type) inspection and was determined to be in airworthy condition.”

(5) Except for progressive inspections, if the aircraft is not approved for return to service because of needed maintenance, noncompliance with applicable specifications, airworthiness directives, or other approved data, the following or a similarly worded statement - “I certify that this aircraft has been inspected in accordance with (insert type) inspection and a list of discrepancies and unairworthy items dated (date) has been provided for the aircraft owner or operator.”

(6) For progressive inspections, the following or a similarly worded statement - “I certify that in accordance with a progressive inspection program, a routine inspection of (identify whether aircraft or components) and a detailed inspection of (identify components) were performed and the (aircraft or components) are (approved or disapproved) for return to service.” If disapproved, the entry will further state “and a list of discrepancies and unairworthy items dated (date) has been provided to the aircraft owner or operator.”

(7) If an inspection is conducted under an inspection program provided for in part 91, 125, or § 135.411(a)(1), the entry must identify the inspection program, that part of the inspection program accomplished, and contain a statement that the inspection was performed in accordance with the inspections and procedures for that particular program."
 
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Crosswind
Posts: 2681
Joined: Sat Nov 25, 2000 4:34 am

Re: BA 787-8 Nosewheel collapse at LHR

Thu Aug 12, 2021 11:16 am

Well done. You’ve proved my point.

They engineers were complying with a legal terms of the existing ADD, the same as the Captain signing the techlog. All the maintenance procedure was doing was verifying the opposite channel was operative. Then they would sign off the continuation of the ADD. The aircraft would have flown in the same physical state that it was in prior to the incident.

So the aircraft was airworthy, it wasn’t going to be repaired or physically altered from the state it was in prior to the incident before flight. It didn’t need a tyre change, a component change or other type of repair.

Legally it wasn’t allowed to fly until the procedure had been completed, same as it’s not allowed to legally fly until a pre flight inspection is complete, the fuel is signed off, all ADDs and OOPs are compliant and the Captain signs the final acceptance of the aircraft.
 
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zeke
Posts: 16432
Joined: Thu Dec 14, 2006 1:42 pm

Re: BA 787-8 Nosewheel collapse at LHR

Thu Aug 12, 2021 1:02 pm

Crosswind wrote:
They engineers were complying with a legal terms of the existing ADD, the same as the Captain signing the techlog.


Who said it was an existing ADD ? The AAIB specifically stated "In order to defer the three defects highlighted by the status messages, the DDG for the aircraft required hydraulic pressure to be applied and the cockpit landing gear lever to be cycled from down to up then returned to down."

The AAIB stated they had yet to defer 3 defects.

Who said the captain signed the techlog, they had not event completed their preflight checks, according to the AAIB report the commander was in "forward cabin along with the dispatcher and a ground technician" What flight crew signs a techlog that is not released for flight.

Crosswind wrote:
All the maintenance procedure was doing was verifying the opposite channel was operative.


How do you know that ? The AAIB stated "In order to defer the three defects highlighted by the status messages"

You do realize for a maintenance procedure to be done, it is by definition unairworthy and then has to be returned to service, if and only if, the maintenance procedure is successful (this case the procedure was unsuccessful). In the process of conducting the maintenance procedure, the aircraft remains unairworthy.

Crosswind wrote:
it wasn’t going to be repaired or physically altered from the state it was in prior to the incident before flight. It didn’t need a tyre change, a component change or other type of repair.


A part change has no bearing on if an aircraft is unairworthy, any maintenance task (that includes installing gear pins, adding oil, adding fuel), a 36 hr/72hr/Weekly/ ETDO check needs to completed successfully and signed off by a Part 145 delegate before then the aircraft is released for flight by a Part 145 delegate, i,e. they “certify that this aircraft has been inspected in accordance with (insert type) inspection and was determined to be in airworthy condition.”

Pilots do not have a Part 145 licence to return an aircraft to service.

Crosswind wrote:
Legally it wasn’t allowed to fly until the procedure had been completed


Because it was unairworthy and not released for flight, the give away in the AAIB report was the "lead ground engineer sat in the left seat on the flight deck was working through the NLG status messages on the ground maintenance laptop." The other give away was the "On pressing lock ovrd and selecting the landing gear lever to up, the NLG retracted, and the aircraft nose struck the ground". There is no reason for an airworthy aircraft to override safety locks select gear up whilst still on the ground.
 
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Scoreboard
Posts: 25
Joined: Sat Jan 16, 2021 4:06 pm

Re: BA 787-8 Nosewheel collapse at LHR

Tue Aug 24, 2021 8:23 am

From a friend who is an engineer with BA at Heathrow (yes, I know...)
The aircraft is in a hangar, the Boeing team have scoped the work to be carried out and are ready to start work next month. The only issue is to check the finances to make sure it is worth spending the money.
 
celestar345
Posts: 78
Joined: Wed May 08, 2013 5:35 pm

Re: BA 787-8 Nosewheel collapse at LHR

Tue Aug 24, 2021 8:52 am

zeke wrote:
There is no reason for an airworthy aircraft to override safety locks select gear up whilst still on the ground.


To override you just press a button in the cockpit next to the landing gear lever. With hydraulic power and no downlock pit it will retract.
Actually it won't be airworthy if it doesn't retract... and you will be on the news as soon as you take off.

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