Synopsis
A Boeing 777-200 (N781AN) and an Airbus A340-300 (TC-JDK) collided in the Holding Area for Runway 27L at London Heathrow Airport on 6 November 2005 at 1238 hrs. The A340 was instructed to taxi to N2E. As it passed behind the B777, the A340's right winglet made contact with the B777's left elevator and left wing tip. The A340 had not reached the section of the yellow taxiway centreline parallel to the parked B777. This collision occurred at the same location as a previous collision between similar aircraft types reported in AAIB Bulletin 9/2005.
Flight History
At the time of the accident, it was daylight with visibility in excess of 10 km and rain. The B777 was cleared to taxi from Stand 320 at Terminal Three to Holding Point LOKKI for Runway 27L. Four minutes later, the A340 was cleared to taxi from Stand 335, also at Terminal Three, to the same holding point.
As the B777 approached LOKKI, it was instructed to hold at N2W, behind a Boeing 737-800, in the holding area. The Air Departures Controller (ADC) then instructed the A340: “When you can, taxi forward to hold N2E.” The crew replied “OK, taxi N2E.” The ADC later transmitted “Just caution, the B777 will be moving up shortly,” which was not acknowledged.
After the A340 had passed behind the B777 and was nearly in line abreast, the pilot of the B777 advised the ADC that he would have to return to stand, stating that the A340 had collided with him. Airport Rescue and Fire Fighting Services and ground operations personnel were dispatched. They reported damage to the right winglet of the A340 and the left elevator and left wing tip of the B777. Both aircraft were advised to taxi back to a stand for inspection.
Crew Comments
The B777 crew initially thought the jolt was an engine surge but quickly realized they had been hit by another aircraft. They felt two jolts; the first was firmer than the second.
The A340 crew had a slot time of 1250 hrs. They did not remember hearing the ATIS broadcast warning about wing tip clearance but had read similar notes on their airfield plates. They recalled the ADC instruction as “Taxi N2E” and did not register the phrase “when you can,” interpreting it literally. They did not hear the caution call about the B777 moving. They discussed the B777’s position and decided to taxi slightly left of the yellow line to give themselves more room. As they passed behind the B777, the co-pilot checked the right wing tip, but assessment was difficult due to the obtuse angle and rain on the window. After passing the rear of the B777, the aircraft turned parallel, and a second jolt occurred.
ATC Communications and Procedures
The ADC stated that he used “when you can” to emphasize that the decision to proceed safely rested with the crew. Both the ADC and the On-the-Job Trainer (OTJT) noted that such non-standard R/T phrases are not uncommon. The CAA’s CAP493 indicates that an air traffic control service assists in preventing collisions between aircraft on the apron and maneuvering area.
Aircraft Examination
Damage to the B777’s left elevator and left wing tip appeared to have been inflicted by the upper part of the A340’s winglet. The A340 was temporarily repaired and dispatched. The B777 was equipped with a replacement wing-tip fairing and was awaiting a replacement elevator at the time of examination.
Recorded Data
ATC radio transmissions and ground radar data were recorded. The flight data recorder from the A340 showed that the ground speed at impact was 6 kt and that the collision occurred at approximately 1238 hrs.