Steve Riethof did a very informative impromptu presentation today on runway incursions and safety.
One of the tidbits that I took away from this presentation:
Q: How long is an aircraft allowed to stay on the runway once it has been cleared for takeoff?
A: Basically forever, there is no legal limit. While we may expect an aircraft to make an immediate departure once it has been cleared for takeoff, it may fail to do so for a variety of reasons. And losing track of such an aircraft can have dangerous consequences.
The story: Recently at KTEB, a Piaggio on an IFR flight plan radioed the tower that it was ready to go. Tower cleared it for takeoff on 24. 40 seconds later, a Cirrus was cleared for takeoff on 19. The controller apparently failed to notice that the Piaggio had not taken off in the 40 second interval. (The controller also failed to notice that he had not handed the Piaggio off to departure control---something he would have done on an IFR flight.) The Cirrus began its takeoff roll, and the Piaggio blew out its tires braking to avoid a collision at the intersection of the two runways.
40 seconds is a really long time. Most aircraft start their takeoff roll within 10 seconds, probably less, of being cleared. But, at least legally, the Piaggio was entirely within its rights to take 40 seconds, if it needed 40 seconds. Sure, the controller screwed up. And perhaps the Piaggio should have radioed the cause of its delay, if it could not take off immediately after having radioed that it was ready to go. But it also seems to me that the pilot of the Cirrus should have been more aware of what was going on.
1. Monitor both the tower and ground frequencies during run-up for better situational awareness.
2. Once you have been cleared, you should depart immediately. If you experience any delays, you should radio the tower with an explanation.
3. Just because the tower clears you to, doesn’t mean you should go. (Though, if you are not going to go, you should radio and tell them why.) Stanley Sanders related the case in Providence, RI, where an aircraft got lost taxiing on the ground, failed to comply with taxi instructions, and ended up on the active runway without the tower's knowledge. Disaster was narrowly averted when a clear-headed pilot who sensed the confusion in the radio transmissions, refused a takeoff clearance, saying they were going to stay put until the tower sorted things out.