Under what condition is it permissible to land on a closed runway?

Landing on a closed runway is permitted only in an emergency situation due to the potential hazards that closed runways present. When a runway is marked as closed, it typically indicates that it is unsafe for normal operations, possibly due to construction, maintenance, or other obstructions that have made it unusable. In case of an emergency, such as an engine failure or other critical situation requiring a landing, a pilot may need to use a closed runway if no other options are available. However, this should always be a last resort, as landing on a closed runway can pose significant risks not only to the aircraft but also to any personnel or equipment that might be present on the runway.

Other scenarios, such as routine practice maneuvers or testing aircraft systems, do not justify the landing on a closed runway because they do not involve immediate life-threatening circumstances. Clearance from air traffic control is necessary for safe operations, but it does not apply when the runway is explicitly closed for safety reasons.