Synopsis
On 18 June 2021, a Boeing 787-8 (registration G-ZBJB) was being prepared for a cargo flight from London Heathrow to Frankfurt. A ground maintenance team was addressing three fault messages related to the nose landing gear (NLG) doors. The dispatch deviation guide allowed deferral of the defects if the NLG doors were recycled to confirm correct function. To prevent gear retraction, downlock pins were fitted. However, when the lead engineer selected the landing gear lever to up, the NLG retracted, causing the aircraft's nose to strike the ground. The lower front fuselage, door 2L, and forward lower engine cowlings were damaged. The co-pilot and a cargo loader sustained minor injuries.
History of the Flight
The aircraft was scheduled to operate a freighter flight from London Heathrow to Frankfurt with two pilots and an overseas engineer (OSE). The pilots arrived at the crew reporting centre at about 0520 hrs and collected the briefing pack. The briefing pack noted an outstanding technical issue with the NLG door solenoids. The pilots consulted the Minimum Equipment List and confirmed no operational issues. After routine procedures, the crew arrived at the aircraft at approximately 0625 hrs. Three ground engineering personnel were on the flight deck. They informed the crew they were addressing EICAS status messages related to the NLG door solenoids. The OSE offered assistance but was declined. The commander asked for an estimated time and was told about 40 minutes, then left for walk-around checks, during which he did not recall seeing any landing gear locking pins installed.
Two ground engineers left the flight deck; the licensed aircraft engineer (LAE) remained in the left seat working on a laptop. The co-pilot sat in the right seat and began pre-departure checks. He recalled the LAE pressurising a hydraulic system. At 0650, the co-pilot received departure clearance by datalink, and shortly after, the LAE raised the gear lever to up. The co-pilot heard the gear system actuate and felt the aircraft nose strike the ground. The co-pilot sustained a minor injury; the engineer was unhurt. After the retraction, the co-pilot noted loss of AC electrical power and APU shutdown. He moved the APU selector to shut off but left the battery on for communications. The commander, upon reboarding, was in the galley with the OSE and Turn Round Manager (TRM) when the NLG retracted; none were injured, though hot drinks spilled. A cargo loader standing on a Unit Load Device loader next to the forward cargo door was struck on the head by the cargo door as the aircraft fell, suffering minor injuries and taken to hospital.
After checking for injuries, the commander and OSE went to the flight deck. The commander and co-pilot left to check egress routes. The OSE turned off the inertial reference system and electrical power. Airport RFFS arrived and entered through the L2 door, which had been damaged by contact with access stairs. The commander suggested using the R1 door due to concerns about the escape slide. When crew exited, they were confronted by many people seeking information, which they described as "mayhem".
Ground Maintenance Actions
The maintenance shift started at 0530 hrs. The ramp management assigned an experienced LAE, a technician, and two mechanics. The technician was not experienced on B787 maintenance. One mechanic (Mech 1) was experienced on the B787 and had worked with the LAE before; the other (Mech 2) was seconded from the Cabin Excellence Team. The team reached the aircraft at 0605 hrs. After external checks, they went to the flight deck. Mech 1 plugged in the maintenance laptop. The LAE found three NLG solenoid faults plus an existing Acceptable Deferred Defect from 13 June 2021. Consulting the Aircraft Maintenance Manual and other documentation, he judged insufficient time to rectify before departure. The Dispatch Deviation Guide indicated deferral was possible if the NLG doors were recycled. This required fitting downlock pins, applying hydraulics, and cycling the gear lever.
During the LAE's assessment, the flight crew arrived, so the technician and both mechanics moved to the galley. The LAE sat in the left seat with a laptop and tablet; the co-pilot was in the right seat. The LAE asked Mech 2 to put in the downlock pins. Mech 2 relayed this to Mech 1, who asked if Mech 2 had done this before; Mech 2 had not. Mech 1 retrieved five downlock pins from flight deck stowage and exited with Mech 2. The technician also left to sit in the team's vehicle. Mech 1 looked for small steps to reach the NLG lock link hole but found none; Mech 2 was tall enough. Both crouched to the left side of the NLG; Mech 1 pointed to the downlock pin hole and asked Mech 2 to insert the pin. Mech 2 reached up and inserted the pin; Mech 1 heard a click and saw the pin inserted but did not consciously check the position. He pulled on the pin warning flag to confirm it was held firmly. Both mechanics then fitted the main landing gear downlock pins using large steps. They returned to the flight deck and informed the LAE that the pins were in. Mech 1 collected a headset to communicate with the LAE. The LAE instructed him to ensure the cargo loading team were clear because the landing gear moves slightly when hydraulic power is applied.
Injuries and Damage
The aircraft sustained damage to the underside of the forward fuselage, door 2L, and forward lower engine cowlings. The co-pilot and one cargo loader suffered minor injuries. No other persons were injured.
Probable Cause
The source does not state a probable cause. However, the investigation noted that the downlock pin had been inserted in the downlock link assembly apex pin bore instead of the downlock pin hole, and that the design of the NLG downlock assembly created an opportunity for error due to two holes being close together. A Service Bulletin and Airworthiness Directive that would have prevented the accident had not been completed on G-ZBJB.