What happened
On 25 February 1998, a Boeing 747-436, registration G-BNLA, arrived at London Gatwick Airport following a scheduled passenger flight from Harare, Zimbabwe. During the post-flight engineering check, technicians discovered damage to both the inboard and outboard right-hand elevators. The aircraft was operating a public transport flight carrying 18 crew members and 267 passengers, with no injuries or fatalities reported.
While the damage was identified at Gatwick, the flight crew had not noticed any issues during the flight or the pre-flight inspection in Harare. The first officer, acting as the handling pilot, noted a slight, unexpected yaw during the takeoff rotation, though flight data from the Quick Access Recorder (QAR) did not confirm any significant lateral acceleration or control surface discrepancies.
The investigation
Investigators examined the aircraft's movement at Harare International Airport. The commander noted that during engine start-up, an Airbus A340 had taxied past the right side of the Boeing 747 and stopped in close proximity behind it. The A340 crew had specifically requested that the G-BNLA use minimum breakaway thrust due to their close position.
Physical examination of the damage revealed that a narrow, blue-painted object had struck the underside of the outboard elevator, causing skin damage, and subsequently impacted the inboard elevator, resulting in a piece of honeycomb structure breaking away. A search of the taxi route at Gatwick yielded no debris, and airport authorities at Harare had no records of any unusual incidents or debris retrieval. While a local representative for the operator found a small piece of blue fibregably-type debris on the ramp at Harare, its origin could not be definitively linked to the aircraft's structure.
Findings
- The damage to the right-hand elevators was caused by an impact from a narrow, blue object.
- Calculations indicated that the winglet of the Airbus A340 would have been at a height capable of striking the elevators.
- The exact source of the blue object could not be determined, as all ground equipment at the departure airport was white, and the only blue vehicle present showed no signs of damage.