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."