Conditional Line-Up Cancelled Near the Stop Bar
At a controlled airport, VT-SGA, a Piper Archer, is holding at A1 for runway 09. A landing A320 is on 1 NM final. A maintenance vehicle has just been cleared to cross at A3, beyond A1. Tower transmits: 'VT-SGA, behind the landing A320, line up runway 09, behind.' The pilot reads back the conditional clearance and begins to move. When the nose is about 2 m short of the stop bar, tower says: 'VT-SGA, cancel line-up, hold position, vehicle crossing.' The landing aircraft is still on final, and the pilot cannot see the vehicle from the holding point. The aircraft's tail is clear of the taxiway, but another aircraft is waiting behind. The pilot must decide how to stop and what to report.
1. What does the conditional clearance mean, and what should the pilot have done before moving?
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The phrase 'behind the landing A320, line up runway 09, behind' is a conditional line-up clearance. It authorises the aircraft to enter the runway only after the landing A320 has passed and the runway is clear. It is not a take-off clearance, and it does not authorise crossing the hold short line while the landing traffic is still on final.
Before moving, the pilot should have identified the landing A320, confirmed that it had passed, and checked that the runway and approach path were clear. The readback must include the callsign, the conditional element, and the runway, for example: 'Behind the landing A320, line up runway 09, behind, VT-SGA.' A readback alone does not make the condition satisfied. If the pilot cannot see the landing traffic or is unsure whether it has passed, the aircraft should remain behind the stop bar and ask the tower to confirm.
2. What should the pilot do after hearing 'cancel line-up, hold position'?
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The pilot should stop immediately and remain behind the stop bar, because the nose is still short of it. Do not continue moving while reading back. The priority is to stop the aircraft in a controlled way, keep the tail clear of the taxiway if possible, and then acknowledge with a full readback:
'Holding position, VT-SGA.'
The pilot should not cross A1, not enter the runway, and not reverse unless instructed. Reversing near a stop bar can create a collision risk with the aircraft behind. After stopping, report the exact position if it differs from the holding point, for example: 'VT-SGA holding position at A1, stop bar not crossed.' Keep monitoring the tower because the vehicle crossing and the landing A320 may affect the next clearance.
3. Suppose the nose had already crossed the stop bar when the cancellation was received. What should the pilot report, and what should not be done?
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If the nose had already crossed the stop bar, the pilot should stop immediately and report the situation clearly:
'VT-SGA, stop bar crossed, holding position.'
The report should state whether the whole aircraft is past the stop bar, whether any part is on the runway, and whether the aircraft is clear of the approach path. Do not continue onto the runway, and do not attempt to reverse without a specific instruction, because the aircraft behind may be close and the tower may need to protect the runway. The controller can then decide whether to cancel the landing traffic, instruct the vehicle to hold, or give alternative instructions. The pilot should be prepared to evacuate the runway if instructed, but only after a clear clearance and a full readback.