This article provides general information on conditional clearances and additionally identifies possible reasons and factors that explain how a conditional clearance can contribute to a runway incursion. It also includes advice on potential risk mitigation actions and measures. The safety relevant effects of conditional clearances used during enroute phases, e.g. time or position-based climb/descent clearances are explained in the article CPDLC-General Safety Considerations.
The conditional clearance
A conditional clearance is a clearance issued by an air traffic controller which does not become effective until a specified condition has been satisfied.
Example of conditions that may be included in a conditional clearance include: