MD-11
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Departure Airport; General Maintenance Action
Procedure; Aircraft
During post C-Check maintenance flight refueling panel detached and lodged in slats mechanism. Excess roll noted when retracting slats at speed 260 KIAS. This is a normal post maintenance flight check profile. Return to maintenance practice of placing speed tape over the panels prior to test flight.
This was a Part 91 Test Flight of a MD-11. During the Flight Test profile while the 260 KT Slat Check was being accomplished; normal slat extension was performed with no roll observed. However; during slat retraction the aircraft rolled 20 to 30 degrees left. Had observers go back to the cabin area and observed the left outboard slat mechanism was slow to retract. The remainder of the Test Flight was accomplished and uneventful. After landing and parking back at the vendor's location; post flight inspection revealed that the refueling panel on the underside of the left wing had come loose in-flight and lodged in the respective left outboard slat mechanism causing damage to both. Until just two and half years ago; the approved Vendor that accomplishes the Heavy Maintenance 'C' checks were allowed to use Speed Tape to seal and protect panels from coming loose during Flight Test profiles. Due to recent changes to Maintenance Policies and procedures; use of Speed Tape for the sole purpose of protecting these panels from coming loose is no longer authorized. The policies need to be changed to give the Vendor the authority to use Speed Tape for this specific purpose and mitigate the threat of these panels coming loose during flight test profiles and damaging the aircraft.
MD11 Maintenance crew reports the refueling panel door coming loose during a 260 knot slat check and jamming the slat. Previously speed tape had been used to prevent the door from coming off during this rigorous test.