Flap loss on 747 undetected after night landing

Aviation

German investigators probing the loss of a Boeing 747-400ER freighter’s flap on landing at Frankfurt Main have indicated that previous incidents on the type have been the result of corrosion and inadequate lubrication of parts.

The Turkish-registered MyCargo Airlines aircraft (TC-ACM) had been operating a service from Dammam on behalf of Saudia’s cargo division.

German investigation authority BFU says an alert was received on 16 September last year that an aircraft parked at stand S506 had sustained substantial damage to the leading edge of its vertical fin as well as punctures and scratches to the right side of its fuselage.

Extension of the flaps showed that an inboard fore flap from the starboard wing was missing.

This flap is around 8m in length and was subsequently found along with guide and mounting components, several hours later, close to the touchdown zone of runway 07R, where the aircraft had arrived at 05:07.

Three occupants had been on board the jet, comprising two pilots and a mechanic. The pilots told the inquiry that the landing had appeared normal and that, in the darkness, no damage to the jet had been noticed. The alert over the damage came some 3h later.

BFU says that “several” events have occurred involving the loss of such flaps on the 747, including two at Frankfurt in 2009 and 2014.