Description

Whilst a departing Piper PA-42 light aircraft was lined up but not cleared for take off on runway 21 at Perth in normal day visibility, an airport authority ground vehicle operating airside to check RVR failed to comply with an ATC TWR instruction and entered the same runway. There was no actual risk of conflict since, although LVP were still in force after earlier fog, the visibility had substantially improved such that the TWR controller had been able to see the vehicle incursion and therefore withhold the imminent take off clearance.

Investigation

An Investigation was carried put by the Australian Transport Safety Bureau (ATSB). It was noted that at Perth, the standard method of determining RVR for LVP purposes was for a vehicle driven by an Airport Operations Officer (AOO) to drive along the active runway from the threshold to a designated intermediate observation point (marked ‘4’ on the diagram below) and report the number of runway edge lights visible. When standing by for this duty, the AOO was required to park their vehicle a specified location (marked ‘9’ on the diagram below).