Incident Overview
On 10 June 2016, during a scheduled maintenance check (designated D2+C14+CPCP+12KHRS+A155+EO+R/I) on a Boeing 737-400 at the LOTAMS technical base at Warsaw Chopin Airport (EPWA), damage occurred to the forward passenger door skin near the upper hinge. The maintenance tasks involved installation and adjustment of the forward passenger doors in accordance with work cards 52-11-00-705-007 rev.83 and 52-11-00-520-003 rev.83.
Performed by
The work was carried out by maintenance personnel who held general qualifications but lacked specific training on the B737 type and had no experience in such tasks. They were supervised by personnel holding B1 certification.
Damage Description
The door skin was torn approximately 13 mm below the upper hinge as a direct result of failing to remove a hinge cover strip before adjusting the door. The strip caught on the door skin, causing the tear.
Causes Identified
The investigation identified two causes:
1. Human error: misinterpretation of the Aircraft Maintenance Manual (AMM) by the personnel performing the installation and adjustment of the door.
2. Organizational error in maintenance management: assigning the door installation and adjustment tasks to personnel without appropriate training and experience for this type of work, and a lack of proper supervision over the executing staff by the B1 supervising personnel.
Preventive Actions Taken by the Operator
- Notified the operator of the incident.
- Cascade notification of maintenance area managers to inform staff.
- Information forwarded to the Technical Personnel Training Section (TQQT) for use in recurrent training on human factors and aircraft type.
- The area manager (TTB) was tasked with conducting on-the-job training for the involved personnel regarding technical documentation usage and supervision duties for B-level personnel.
- Topics related to this type of incident were included in the periodic Human Factors (HF) course program.
- The incident was recorded in the LOTAMS event database for inclusion in aviation safety indicators.
Safety Recommendations
None.