A Boeing 747-422, operated by United Airlines, was taxiing for departure at Melbourne Airport, Australia. At the same time, a Boeing 767-338ER operated by Qantas was stationary on taxiway Echo and waiting in line to depart from runway 16. The tail section of the 767 was protruding into taxiway Alpha while it was stationary on taxiway Echo awaiting a clearance to enter the runway. The pilots of the 747 received a clearance to taxi, which included a taxi route from the international apron to the holding point on taxiway Bravo, for a departure from runway 16, via taxiways Uniform then Alpha. The pilot in command of the 747 deviated from the taxi clearance issued by the surface movement controller and turned the 747 right into taxiway Echo, to pass behind the 767. The left wing tip of the 747 collided with the right horizontal stabiliser of the 767 as the 747 crew attempted to manoeuvre behind the 767. The taxiway dimensions and markings at Melbourne Airport complied with international standards and were suitable for use by the aircraft types involved in the occurrence. The 747 crew was aware of the 767, and chose to pass behind it rather than wait on taxiway Alpha until the 767 was no longer obstructing the taxiway. The decision by the pilot in command of the 747 to deviate off the centreline of taxiway Alpha and taxi behind the 767 did not comply with the taxi clearance issued by the SMC. It was based on his assessment that it was safe to do so. The pilot in command of the 747 misjudged the distance between the wingtip of the 747 and the right horizontal stabiliser of the 767, which resulted in the collision.