Circumstances At 0341 hours the driver of Qantas tug Red Charlie requested permission to tow a Qantas B767 aircraft from the Qantas Maintenance Area to the International Terminal Bay 30. The driver was cleared by ATC to tow the aircraft via taxiway foxtrot and hold short of runway 16. This instruction was acknowledged by the driver. VH-AMB was arriving at Sydney on a flight from Armidale and was on final approach to runway 16. As the tug approached the holding point for runway 16 the Aerodrome Controller [ADC] issued the hold short instruction a second time which was again acknowledged by the driver. The ADC had decided that VH-AMB would land before the tug would be given permission to cross runway 16 and issued a landing clearance to that aircraft at 0345 hours. It had been common practice during the night shift, for tug drivers to receive a clearance to cross runway 16 at the point at which the ADC issued the second hold short instruction. With this expectancy in mind, the tug driver thought he had received a clearance to cross runway 16 when he acknowledged the second hold short instruction. The holding point for runway 16 on taxiway foxtrot is not easily recognised from the tower at night and controllers therefore had to rely on pilots/drivers complying with any instruction received. As Red Charlie was approaching this holding point, it was not possible for the ADC to accurately determine the position of the tug and aircraft. At 0346.10 hours the pilot of VH-AMB informed the tower that he had an aircraft in front of him on the runway. The ADC immediately cancelled the landing clearance and established that Red Charlie was clear of runway 16, having crossed that runway. As VH-AMB was still in a position to land, a second landing clearance was issued at 0346.55 hours. VH-AMB continued the approach and landed safely. Significant Factors 1.The driver of Red Charlie had an expectation that he would be given a clearance to cross runway 16 at the time the second hold short instruction was issued. 2.The position of the taxiway foxtrot holding point is difficult to visually judge at night from the control tower. 3.The driver of Red Charlie did not read back the instruction to hold short of runway 16. 4.There is no ATC requirement for the read back referred to in 3 above. Safety Actions The Bureau of Air Safety Investigation issued a Safety Advisory Notice [SAN930310] to Qantas Airways, the Civil Aviation Authority and the Federal Airports Corporation. It stated that: The Bureau of Air Safety Investigation advises that formal radio procedures instruction should be included in all airside driver training and suggests that ATC could have an input into such training.