A Boeing 787 Dreamliner being operated by British Airways for a dedicated cargo-only flight to Frankfurt, Germany, fell on its chin last week during preflight maintenance when a procedural mistake caused the nose landing gear to collapse at London Heathrow Airport. Two persons were slightly injured and the plane was damaged, according to the incident report.
The U.K. Air Accidents Investigation Branch said the accident happened because a mechanic in charge of inserting a locking pin into the landing gear was too short to reach the necessary hole without a ladder and let a co-worker do it instead. He pointed to the location of the hole, but the second mechanic put it in the wrong one.
As part of the maintenance check during cargo loading, engineers had to clear codes from the system by putting the cockpit landing gear selector through an up-down cycle. The first mechanic notified engineers on the flight deck that the pin was in place, but his visibility was limited. When the hydraulic power was applied and the locking pin wasn’t in the proper place to prevent the landing gear from retracting, the plane collapsed.
A member of the ground crew who was operating the pallet loader and under the open cargo door was slightly injured when the plane dropped. The co-pilot, who was in the cockpit, received a minor injury and the three people standing in the forward cabin and galley fell to the floor but were uninjured, investigators said.
The aircraft’s nose came to rest on the articulated arm of a ground power unit, crushing the cable arm. The aircraft sustained damage to the lower forward fuselage, nose landing gear doors and both engine cowlings, which also struck the ground. The upstairs door was severely damaged by contact with the stairs positioned at the door opening as the aircraft sank onto its nose.
In 2018, another Boeing 787 experienced a similar retraction of the nose landing gear when the downlock pin was accidentally installed in the wrong bore in the lock assembly.
The U.S. Federal Aviation Administration in January 2020 issued a directive for 787 operators to install within 36 months a special insert in a locking assembly bore to prevent the downlock pin from being inserted in the incorrect hole.
The British Airways (CXE: IAG) plane involved in last Tuesday’s incident had not been retrofitted with the part.