Every so often the Legal Services Plan receives a call from a pilot who, while taxiing to the active runway at the local towered airport, casually crossed a closed runway. As a result, ground control quickly advised the pilot of a deviation as no clearance had been issued to cross the closed runway. Having reviewed the notam in effect for the runway closure prior to the flight, the pilot tells us that while taxing the aircraft, he or she concluded that no clearance was necessary to cross the closed runway because there was no doubt that the runway was in fact closed.
However, the federal aviation regulations do not make any distinction between a closed runway and an active runway when it comes to clearance requirements. For example, with respect to takeoff, landing, and taxi clearances at Class D airports, 14 CFR 91.129 states that “no person may, at any airport with an operating control tower, operate an aircraft on a runway or taxiway, or take off or land an aircraft, unless an appropriate clearance is received from ATC.”
Additional insight can be gained from FAA Order JO 7110.65W, which prescribes ATC procedures and phraseology and states that for taxi and ground movement operations, “Aircraft/vehicles must receive a clearance for each runway their route crosses. An aircraft/vehicle must have crossed a previous runway before another runway crossing clearance may be issued. NOTE−A clearance is required for aircraft/vehicles to operate on any active, inactive, or closed runway except for vehicles operating on closed runways in accordance with a Letter of Agreement (LOA).”
Likewise, the FAA's best-practice guide for runway safety states that pilots must "never cross a hold line, including inactive or closed runways, without explicit ATC instructions." With this in mind, never hesitate to query ATC to be certain that you are cleared to cross or enter a runway.