Lost Communications: What to Do and Say

First, make sure it is the radio

A quiet radio is not always a broken one. The AIM's radio technique paragraph tells you to stay alert to a lack of sound in your receiver: check the volume, recheck the frequency, and make sure your microphone is not stuck in transmit (AIM 4-2-2). Before you decide you have lost communications:

• Check the volume and the frequency. One wrong digit puts you on a silent frequency.
• Check the headset plug and the audio panel. A loose plug or the wrong radio selected sounds exactly like a failure.
• Look for a stuck microphone. A mic stuck in transmit blocks the frequency, and nobody can answer you.
• Go back to the last frequency that worked. It is one of the places the AIM tells you to try (AIM 6-4-3).
• Try another radio, the second COM or a handheld if you carry one. The emergency frequency, 121.5, is also an option (AIM 6-4-3).

If nothing works, set your transponder to 7600 (AIM 6-4-2). It tells radar controllers that you have lost two-way radio communication.

Where to land

Whether a radio failure is an emergency depends on the situation, and the decision is yours (AIM 6-4-1). On a VFR flight, stay in VFR conditions and choose an airport:

• An airport without a tower. Procedures at non-towered airports generally do not require a radio (AC 90-66C 9.12.2). Work out the runway in use from the wind and landing direction indicators before you join the pattern, and keep a sharp lookout.
• An airport with a tower in Class D airspace. After a radio failure under VFR, you may continue and land if the weather is at or above basic VFR minimums, you keep visual contact with the tower, and you receive a clearance to land (14 CFR 91.129(d)(2)). Without a radio, that clearance is a steady green light.
• Class B and Class C airspace. Class B needs an ATC clearance and Class C needs two-way radio communication before you enter (AIM 3-2-3, 3-2-4). With a dead radio, avoid them if you have a better choice. The Class D radio-failure rule above also applies in Class C (14 CFR 91.130(a)).

Landing at a towered airport without a radio

The AIM describes three cases (AIM 4-2-13):

The calls at the top of this page are the receiver-inoperative case. You are transmitting in the blind: talking without being able to hear a reply, in the belief that the tower can still hear you (Pilot/Controller Glossary). The pilot in this example heard the ATIS before the radio failed, so already knows the runway in use. Without that, work out the traffic flow first, from outside or above the Class D surface area, and call after.

The example calls leave out two things the AIM asks for: your aircraft type, and a request to be controlled with light signals. A call with everything AIM 4-2-13 lists, aircraft type, position, altitude, intention to land and that request, sounds like this:

Springfield Tower, November One Two Three Alpha Zulu, transmitting in the blind, receiver inoperative, Cessna 172, ten miles southwest, three thousand five hundred, landing Springfield, request light signals.

At about 3 to 5 miles, give your position again and join the pattern (AIM 4-2-13). The second call plans to fly over the field first: doing that above the Class D surface area is one way to see the wind and the traffic before you join.

Reading the light signals

The figure above has every signal, from the FAA's table of light gun signals (AIM 4-3-13). On the way in, these are the ones to know:

• Steady green: cleared to land.
• Flashing green: return for landing. A steady green follows at the proper time.
• Steady red: give way to other aircraft and continue circling.
• Flashing red: airport unsafe, do not land.
• Alternating red and green: exercise extreme caution.

After landing, a flashing green clears you to taxi, a steady red means stop, and a flashing red means taxi clear of the runway in use. On the ground, acknowledge by moving your ailerons or rudder by day, or blinking your landing or navigation lights at night (AIM 4-2-13).

If the radio fails before takeoff

Get it fixed if you can. If not, phone the tower and ask for authorization to depart without two-way radio. If the tower agrees, you will get departure information and be told to monitor the tower frequency or watch for light signals (AIM 4-2-13).

On an IFR flight

Different rules apply. 14 CFR 91.185 sets the route, the altitude and when to leave the clearance limit if the radio fails in instrument conditions, and AIM 6-4-1 explains them. If the failure happens in VFR conditions, or you reach them, you continue VFR and land as soon as practicable. The AIM notes that this does not mean as soon as possible (AIM 6-4-1).

Common mistakes

• Deciding too soon. A wrong frequency or a turned-down volume knob can look exactly like a failure. Work through the checks first.
• Forgetting 7600. It is how a radar controller learns what has happened.
• Joining the pattern before you know the flow. The AIM asks you to wait outside or above the Class D surface area until you do.
• Landing without a steady green. At a towered airport, without a radio, the steady green is your landing clearance.
• Stopping the calls. If only your receiver has failed, the tower can still hear you. Keep calling your position.

FAQ

Is losing the radio an emergency?

It depends on the circumstances, and the AIM leaves that decision to you (AIM 6-4-1). In an in-flight emergency requiring immediate action, 14 CFR 91.3(b) lets the pilot in command deviate from any Part 91 rule to the extent required to meet it, and the AIM says not to be reluctant to use that authority when the situation calls for it (AIM 6-4-1).

What does NORDO mean?

An aircraft that cannot or does not communicate by radio when radio communication is required (Pilot/Controller Glossary).

Can I land at a towered airport without a radio?

After a radio failure under VFR, yes, in Class D airspace, and in Class C too (14 CFR 91.130(a)): the weather must be at or above basic VFR minimums, you must keep visual contact with the tower, and you need a clearance to land, which comes as a steady green light (14 CFR 91.129(d)(2), AIM 4-3-13). An aircraft with no radio at all needs the tower's authorization in advance (14 CFR 91.129(b)).

What should I squawk if the radio fails?

7600 (AIM 6-4-2). 7500 and 7700 are the other two codes you set only when something has gone wrong.