Incident Description
On 2 September 2021 at 02:55 UTC, a Boeing 787-8 operated by LOT Polish Airlines (registration SP-LRD) was landing at Incheon International Airport (RKSI) in Seoul, South Korea. During the landing roll, the flight crew attempted to deploy both thrust reversers but was unable to do so despite multiple attempts. The aircraft decelerated safely using wheel brakes and vacated the runway via a taxiway.
Investigation Findings
The Polish State Commission on Aircraft Accident Investigation reviewed documentation from the maintenance organization and a technical inspection conducted by Korean Airlines at the operator's request. The investigation determined that maintenance personnel failed to follow procedures when deactivating and reactivating the thrust reversers on both engines. Locking pins used during deactivation were installed without flag markers as required by procedure. When access panels were closed, the unmarked pins went unnoticed by personnel and were left installed in the reverser modules, preventing their deployment during landing. Additionally, after completing the scheduled maintenance tasks, the full activation procedure (Trust Reverser for Ground Maintenance – Activation DMC-B787-A-R78-31-00-20G-730BA) was not performed, nor was the recommended functional test of the reversers, which could have revealed that the locking pins were still installed.
Contributing Factors
The investigation identified two contributing circumstances: (1) the absence of a permanently assigned person to coordinate work on aircraft, and (2) inadequately prepared maintenance documentation.
Preventive Actions
Several preventive measures were implemented by the investigating entity: the incident materials will be used in periodic training for the aircraft type; a safety bulletin has been placed on the e-learning platform for mandatory review by maintenance personnel; the maintenance documentation for deactivation of thrust reversers will be revised to prevent the use of inappropriate tools and to require an independent inspection after completion of work; and the certifying privileges of personnel involved in the incident have been suspended pending clarification of all circumstances. No additional safety recommendations were issued by the commission.