German investigators have highlighted ambiguity in the regulations for stopping at holding points, after a waiting Korean Air Boeing 777-300ER was struck and badly damaged at Frankfurt by a taxiing Air Namibia Airbus A330-200.

The 777-300ER (HL7204), with 261 occupants, had arrived from Seoul on 16 November last year and was instructed to stop at the hold line of the junction between taxiways M and M8.

German investigation authority BFU states that, owing to the diagonal orientation of the taxiway, the aircraft came to a halt about 32m from the hold line – measured along the 777’s longitudinal axis – or about 25m as viewed perpendicular to the line from the captain’s position.

FRA collision

Source: BFU

Insufficient clearance resulted in the A330’s wing-tip striking the 777’s elevator

This distance meant the 777’s tail was not sufficiently clear of taxiway M, along which the A330 (V5-ANO) was travelling. It had landed 2min after the 777 after a service from Windhoek, with 229 occupants.

BFU says that, according to the A330’s cockpit-voice recorder, the A330 crew saw the 777 and “was aware that the distance [between them] could be close”.

As the A330 passed the intersection, its left winglet struck the 777’s horizontal stabiliser, inflicting serious damage to the control surface.

FRA collision wingtips

Source: BFU

Damage was inflicted on both the 777 (left) and A330 (right)

None of those on board the aircraft was injured.

BFU highlights similar previous ground collisions, including two at Frankfurt in 1998-99, which involved “uncertainty” over the distance at which the aircraft must stop before a holding point.

It says it recommended in its earlier investigations that ICAO-approved “hold short” instructions should be “replaced by a more precise phrase”, but that this recommendation “was not implemented”.