How to Cross a Runway on the Radio

The rule: no runway without a clearance

At an airport with an operating control tower, you need a clearance to cross any runway, and ATC issues an explicit clearance for every runway crossing (AIM 4-3-18, 2-3-5). A taxi route that continues on the other side of a runway does not include the crossing. Neither does a clearance to taxi to your departure runway (AIM 4-3-18).

Controllers clear you across one runway at a time: you must have crossed one before they clear you across the next. The exception is runways whose centerlines are no more than 1,300 feet apart along your taxi route, at airports approved to clear you across several such runways with a single clearance (JO 7110.65 3-7-2).

How the clearance sounds

The clearance usually follows the pattern “cross (runway) at (runway or taxiway)”, sometimes followed by a hold short (JO 7110.65 3-7-2).

Ground: November One Two Three Alpha Zulu, cross runway three six at Alpha, hold short of runway two seven.

You: Cross runway three six at Alpha, hold short of runway two seven, November One Two Three Alpha Zulu.

The clearance has to name the runway you are crossing, normally with the word “cross”. A route that merely leads across a runway is not a clearance: hold short and ask.

In the exchange at the top of this page, Ground adds “remain this frequency”: after you cross, stay on Ground's frequency rather than changing to another one.

Before you cross

1. Stop at the hold short markings, with no part of the airplane past the solid yellow lines (AIM 2-3-5).
2. Hear a clearance that names the runway. A route that happens to go across, without one, means hold.
3. Read it back: the runway and where to cross, then your callsign.
4. Look both ways along the runway. A clearance is not a reason to stop looking.
5. Cross promptly, and keep going until the whole airplane is past the hold short markings on the far side.

Who clears you: Ground or Tower

Tower, the local controller, is in charge of the active runways. Before Ground can clear you across one, Ground must get Tower's approval for that crossing point (JO 7110.65 3-1-3). That is why you sometimes wait at the line even when the runway looks empty.

Common mistakes

• Crossing on a taxi clearance. “Taxi via Alpha” across a runway is not a clearance to cross it.
• Crossing on someone else's clearance. With similar callsigns on the frequency, make sure the call was yours. If you are not sure, ask before you move.
• A readback without the runway number. “Cross at Alpha” leaves out the part that matters most.
• Treating a clearance for one runway as a clearance for the next. Cross only the runways the controller names. If the next one is not named, hold short of it (JO 7110.65 3-7-2).
• Stopping on the runway, or just past it with the tail still over the markings. Keep moving until you are clear.

If Ground says something you did not expect

• “Hold short of runway three six”: stay where you are and read it back with the runway number.
• “Cross runway three six at Alpha without delay”: the controller needs you across quickly. Read it back, cross promptly and do not stop on the runway (JO 7110.65 3-7-2).
• “Contact Tower”: at some airports the crossing is handled on Tower's frequency. Change, and call Tower holding short.

FAQ

Do I need a clearance to cross a runway that is not in use?

Yes, at an airport with an operating control tower. The AIM says a clearance is required before crossing any runway (AIM 4-3-18), and controllers issue a crossing clearance for each runway on your route (JO 7110.65 3-7-2).

What if I am not sure whether I have crossed the runway yet?

You are clear of a runway only when every part of the airplane is past the holding position markings on the far side (AIM 2-3-5). If you might still be on the runway, keep moving until you are sure you are past them: never stop on a runway. Then, if you are unsure where you are, stop and tell Ground. The AIM asks pilots who become disoriented while taxiing to tell ATC right away (AIM 4-3-19, 4-3-20).

How do I cross a runway at an airport without an operating control tower?

There is nobody to clear you, and that includes a towered airport after the tower has closed. Stop at the hold short markings, make sure you have adequate separation from other aircraft, vehicles and people, including aircraft on final or taking off, and cross (AIM 2-3-5). Announce it on the CTAF: the AIM's self-announce procedure covers ground operations too (AIM 4-1-9).