What happened
On August 18, 2015, at Warsaw Chopin Airport (EPKT), licensed maintenance personnel performed an engine removal procedure on a Boeing 73CO-400. The task required the engine to be removed under the EASA Form 1 (Inspected/Tested) category, which necessitated a high-power engine test to verify operational integrity. The airport operations officer was notified of the intent to perform the test and designated a specific area for the procedure.
During the execution of a takeoff power test, the crew gradually increased the engine thrust to 98% N1. Once the thrust exceeded 90% N1, ground personnel monitoring the test ordered an immediate abort of the procedure. Following the engine shutdown, an inspection revealed that a fragment of the pavement surface had detached during the high-power run. The loose debris struck the right horizontal stabilizer, the leading edge, and the rear section of the fuselage near the APU.
The investigation
The investigation focused on the conditions of the designated testing area and the sequence of events leading to the detachment of the pavement fragment. The investigation established that the engine test was being conducted according to the operator's requirements for engine certification.
Findings
- The primary cause of the incident was the improper condition of the pavement surface in the area designated for the engine test.
- The detachment of the pavement fragment occurred as a direct result of the high thrust levels applied during the takeoff power test.