Incident Overview
On 8 February 2003 at 0708 hrs, a Boeing 777-236 (registration G-VIIU) and a Boeing 747-400 made contact while being manoeuvred on the ground at London Heathrow Airport. The B777, operating a scheduled passenger flight from Chicago to Heathrow, had landed and taxied to Stand W5. The stand's Azimuth Guidance for Nose-In Stand (AGNIS) was initially not operational, causing the commander to stop short. After the AGNIS was activated, the aircraft was moved forward approximately 10 to 12 metres to the correct parking position.
Sequence of Events
Earlier, at 0705 hrs, a Boeing 747-400 was given clearance by ATC to tow from Block 123 through Block 96 (adjacent to the W stands) to Stand X9. The tow crew were not advised of any potential obstructions. At 0708 hrs, while both aircraft were moving forward, the B777's left horizontal stabiliser made contact with the upper surface of the B747's port winglet. Neither the flight crew of the B777 nor the tow crew of the B747 were aware of the contact.
Discovery of Damage
Later that day, the B777 was towed from Stand W5 to Stand TF1, and then to Stand S3. A pre-flight inspection prior to a scheduled departure at 1855 revealed damage to the left elevator trailing edge and left stabiliser skin. The aircraft was inspected by an engineer and removed from service for repair. The B747 departed for Narita Airport, Japan, where upon arrival, missing static wicks and damage to the top of the left winglet were noted. Engineering inspection found relatively minor damage, and the aircraft remained in service.
Contributing Factors
The source does not provide a probable cause. However, it notes that visibility was in excess of 10,000 metres, weather was dry, and sunrise was due at 0731 hrs. The W stands were all occupied. ATC did not inform the tow crew of the B777's position, and the tow crew could not see the stand markings from their position on the taxiway centreline due to a slight camber. They did not observe that the B777 had not positioned fully forward on the stand.