Lost Comms: What to Do When the Radio Dies, and Why the Light Gun Still Matters

The flight was almost over. A student pilot, only a few solos into his training, was turning base at Herzliya, a busy training airfield on Israel's coast. Then the radio went quiet. No tower, no other traffic, nothing.

That pilot was Allon Mason, who now builds ZuluCheck. What happened next is what this article is about. It covers the lost-comms procedures every pilot learns and few ever fly, and the light gun that controllers still keep in the tower. It looks at real events, from Cessnas to Boeing 777s, where an airplane went silent. And it sets out what the FAA, EASA, the UK, Israel, Canada and Australia actually tell you to do, plus the backup most procedures were written too early to mention: the phone in your pocket.

Key takeaways

• Radio failures are common, and usually human. NATO counted more than 900 lost-comms reports over Europe in 2018 and put more than 75% down to human error. NASA's ASRS found mis-set radios and audio panels caused over half of all interruptions to communication.
• Light aircraft lose the radio when it hurts most. ASRS reports show general aviation comms losses cluster in the approach and landing phases.
• The core procedure is the same almost everywhere. Squawk 7600, stay in visual conditions, land at the nearest suitable aerodrome, and watch the tower for light signals.
• In the US, the VFR rule is 91.129(d), not 91.185. To land at a towered airport without a radio you need VFR weather, visual contact with the tower and a clearance to land, which can come from a light gun.
• Light signals only say yes or no. A steady green in the air means cleared to land. A steady red means give way and keep circling. Flashing red means the airport is unsafe. The FAA and ICAO tables differ in small but important ways.
• Europe now names the phone. Since 1 May 2025, the EU rule SERA.14083 tells pilots to try "all available means," including mobile phones. Israel's procedures say the same, and Herzliya publishes its tower's numbers. The FAA's rules have not caught up.
• When the electrics die, the transponder dies too. Squawking 7600 then does nothing, and a phone call may be the only way to tell anyone who you are.

What "lost comms" really means

"Lost comms," "NORDO" (no radio) and, for airliners, "PLOC" (prolonged loss of communication) all describe the same situation: the pilot and air traffic control can't talk to each other. But the cause matters, because it decides what you can still do.

• The radio is fine, but you're on the wrong frequency. A digit misheard or mis-dialled on a handoff. This is the most common cause by far.
• The volume, squelch or audio panel is set wrong. You're transmitting, but you can't hear the answer.
• A stuck microphone. Your push-to-talk switch is jammed, so you're blocking the frequency for everyone. NASA's ASRS found stuck mikes caused about 60% of blocked-frequency incidents.
• The headset, jack or push-to-talk failed. Common in rental and training aircraft.
• The radio itself failed. Transmitter, receiver or both.
• The electrical system failed. The alternator quits, the battery runs down, and the radios, the transponder and often the landing gear lights go with it.

The numbers back this up. A 1993 NASA ASRS study of lost-communication reports found that mis-set radios or audio selectors caused over half of all interruptions, with radio failure next. Light single-engine pilots were more likely than others to lose comms through an actual equipment failure. The average loss lasted 7.6 minutes, and general aviation events clustered in approach and landing, exactly when the pilot is busiest.

The first 60 seconds

Before you declare the radio dead, check the things that most often turn out to be the real problem. This is a generic sequence, not taken from any aircraft's POH. Your handbook's own procedures come first.

The UK CAA's 2026 radiotelephony guide for general aviation pilots uses the same idea, with an 11-item radio-failure checklist that includes making sure the push-to-talk switch isn't stuck. The CAA's Skyway Code also recommends carrying a handheld radio as a backup.

What the rules say: FAA, EASA, UK, Israel, Canada and Australia

Every country starts from the same ICAO standard. For a flight in visual conditions, ICAO Annex 2 has three steps. Keep flying in visual conditions. Land at the nearest suitable aerodrome. Then report your arrival to air traffic services "by the most expeditious means." The details differ from country to country.

United States. Two rules matter, and they're often confused:

• 14 CFR 91.185 is for IFR flights. In VFR conditions, "continue the flight under VFR and land as soon as practicable." The FAA's Aeronautical Information Manual (AIM 6-4-1) adds that "as soon as practicable" doesn't mean "as soon as possible."
• 14 CFR 91.129(d) is the VFR rule for towered airports. If your radio fails, you may 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. Without a radio, that clearance is a light signal.

AIM 4-2-13 spells out the arrival. If the receiver is dead, "remain outside or above the Class D surface area until the direction and flow of traffic has been determined." Then join the pattern and "watch the tower for light signals." If both transmitter and receiver are dead, "join the airport traffic pattern and maintain visual contact with the tower to receive light signals." And squawk 7600, though AIM 6-4-2 warns you "may not be in an area of radar coverage."

European Union. Commission Implementing Regulation (EU) 2024/404 rewrote the radio-failure rule, SERA.14083, from 1 May 2025. First, the pilot must try to re-establish contact "using all available means," which the rule says include data link, satellite voice and mobile phones. In the traffic pattern of a controlled aerodrome, keep a watch for visual signals. Squawk 7600, or set the ADS-B transmitter to show the loss of communication. A VFR flight shall "land at the nearest suitable aerodrome, and report its arrival by the most expeditious means." For IFR flights, the old 7-minute rule became 20 minutes.

United Kingdom. The UK kept its own procedure when the EU changed. The UK AIP (ENR 1.1, 3.4.2.3.1) says to squawk 7600 with Mode C and land at the nearest suitable aerodrome. Watch for visual signals from the ground, and report your arrival to ATC "as soon as possible." It also warns that ATC "might not be aware of the loss of communications," so watch for vehicles or traffic on the runway. The CAA's Skyway Code suggests it "may be advisable to divert to a quiet aerodrome outside of controlled airspace," then overfly, read the signal square and circuit, and land when you believe it is safe.

Israel. Israel's domestic AIP has a general procedure, ג-01, "loss of radio communication." Squawk 7600. Try the previous frequency, 121.5, other aircraft or a mobile phone, and transmit blind twice. Then continue in visual conditions and land at the nearest suitable aerodrome, using that field's own lost-comms joining procedure. Code 7600 is permanently monitored in the Tel Aviv FIR. Each airfield publishes its own join. At Ben Gurion, VFR pilots fly over the tower to see the runway in use, join downwind at 2,000 feet, land after a green light and, "if able," phone the tower.

Canada. Transport Canada's AIM tells a pilot who loses the radio in a control zone to land at the aerodrome, squawk 7600 and inform ATC as soon as possible. A NORDO arrival approaches from the upwind side and joins the crosswind at circuit height. If you cross the airport first, do it "at least 500 feet above circuit height."

Australia. Airservices' ERSA says to stay in visual conditions, broadcast "transmitting blind," and land at the nearest suitable aerodrome. In controlled airspace, squawk 7600. Some Class D aerodromes publish their own communications-failure procedures.

Joining the pattern without a radio

So you're coming home with no radio. How do you get into the pattern without surprising anyone?

The idea is the same in every procedure: find out what everyone else is doing before you join them. Read the windsock, the runway in use and the traffic from above, then descend somewhere nobody is flying, and join at pattern altitude in a predictable place.

The FAA's Airplane Flying Handbook describes checking traffic and wind "from a distance or altitude well above the traffic pattern," and, for an entry from the upwind side, crossing midfield "at least 500 feet above pattern altitude (normally 1,500 feet AGL)." Canada uses the same 500-foot margin. Many European and Israeli procedures say it more simply: fly over the tower. The tower sees you, you see the runway, and nobody has to guess.

Once you're in the pattern, your job is simple and hard at the same time: fly a normal, predictable pattern and keep looking at the tower. The AIM's own list of the light gun's weaknesses starts with this one: the pilot may not be looking at the tower when the signal comes.

A first solo, a dead radio and a green light at Herzliya

Herzliya (LLHZ) is one of Israel's busiest general aviation airfields, just north of Tel Aviv, where flight schools fly circuits all day. Its circuit altitude is 800 feet, and its published lost-comms join is precise. The pilot tries to phone the tower on one of its two published numbers, flies in on the published entry route at 1,200 feet with the landing lights on, passes over the tower, joins the circuit for the runway in use while descending to 800 feet, and lands after a green light. A note adds that the tower will keep transmitting instructions, in case only the transmitter has failed.

That's the procedure Allon flew. After one of his first solo flights, returning to the field, he lost communication on base. He flew Herzliya's lost-comms procedure 400 feet above the circuit, the same 1,200 feet the procedure publishes for joining. He entered at the beginning of the crosswind leg and flew the circuit watching the tower. On final, the light came: steady green, cleared to land.

While he was in the circuit, he saw another airplane go around. Nobody on the ground told him why, but the timing said it all: the tower had apparently sent it around to clear the airfield for the student with no radio.

There are three lessons in that landing. The procedure works, if you've read it before you need it. ATC adapts around you: other traffic waits or goes around so the silent airplane can land. And it happens when you least expect it: on base, at the end of a routine flight, to a pilot with only a few hours of solo time.

Light gun signals, explained

The light gun, a signal lamp, is a narrow, powerful spotlight with a sight and a trigger. The controller aims it at your airplane and shows a colour: steady or flashing, green, red or white. It's old technology, and control towers still keep one, because it works with no radio at all.

Here's what each signal means in the United States, from 14 CFR 91.125 and AIM 4-3-13.

ICAO's table, used across Europe (as SERA Appendix 1), Israel and most of the world, is almost the same. Three differences matter:

• Flashing white in the air means nothing in the US, but under ICAO it means "land at this aerodrome and proceed to apron." You might see it if you're diverting to a field you didn't plan on.
• The red flare exists only in the ICAO table: whatever you were told before, don't land yet.
• Alternating red and green ("exercise extreme caution") exists only in the FAA table.

Other countries add their own twists. Australia's ERSA says a steady green means authorised to land "if pilot satisfied no collision risk exists." Canada's red pyrotechnic is used only at military towers.

How to acknowledge a light signal

The tower needs to know you saw it.

• By day, in the air: rock your wings. ICAO adds: except on the base and final legs, when wing-rocking is a bad idea close to the ground.
• At night, in the air: flash the landing light or the navigation lights. ICAO says twice; Canada says a single flash of the landing light; the FAA says to blink the landing or navigation lights.
• On the ground: move the ailerons or rudder.

The light gun has real limits. The AIM notes it can only give "approval or disapproval of a pilot's anticipated actions." In 2016, NATCA, the US controllers' union, reported that controllers at 14 facilities had filed safety reports saying their light guns were hard to see. One said no aircraft could see them in daylight. Many units dated from the 1950s, and the FAA updated its specifications in 2015 and made new units available. If you can't see a light, don't assume you've been cleared. Keep flying the pattern and keep looking.

When it really happened: lost comms in the record

Investigation reports are full of radio failures. Most end quietly. The interesting ones show what works, what doesn't, and what goes wrong next.

Light aircraft: the phone and the light gun

Grand Junction, Colorado, November 2002. A Piper Arrow's alternator failed, and all electrical power was gone about 35 miles out. According to the NTSB, "the pilot used his cell phone to call GJT Tower and he was given clearance to land." On rollout, the left main gear collapsed.

Myrtle Beach, South Carolina, March 2016. A Cessna 210 lost all electrical power after takeoff; the NTSB traced it to a corroded alternator wire. The NTSB report says: "The adult passenger then called the control tower via a cell phone and was cleared to land." The gear wouldn't extend fully, and it collapsed after touchdown. Nobody was hurt.

Dallas Love Field, October 2015. A Piper Lance had a total electrical failure after takeoff at night, and its transponder return vanished from the controllers' screens. According to NATCA's account of the event, the pilot dialled 911. The dispatcher alerted the tower, and on the pilot's second call he was patched through. One controller talked to him by phone while a second took every other frequency and asked a waiting Boeing 757 crew, a King Air and an airport vehicle to check visually whether his gear was down. He landed with the engine off and stopped within the first 1,700 feet of the runway.

Opa-Locka, Florida, November 2017. At night, on an instrument approach, a Cessna 172RG lost electrical power and its radios at about 500 feet. The safety pilot squawked 7600, and "after receiving a green light gun signal from the tower, the pilot continued the approach," the NTSB wrote. The right main gear collapsed; the gear warning horn and low-voltage light had both gone dark with the electrics.

Billings, Montana, March 2024. A Beech King Air B200 had a total electrical failure shortly after departure. The tower "cleared the pilot to land by using a green light gun signal." The NTSB found the generators had never come online after an improper engine start, and the battery lasted 18 minutes. The manual gear extension wasn't complete, and the gear collapsed on landing.

Bern, Switzerland, July 2025. Swiss media reported that a propeller aircraft with serious electrical problems lost radio contact and disappeared from radar. Military radar found it again. The tower cleared the airspace, sent blind calls on every frequency and guided the pilot in with a hand-held light gun. The pilot recognised the signals and landed safely. This one comes from press reports citing unnamed sources, not an official investigation.

Look at the pattern in those reports. The radio was rarely the real danger. An electrical failure takes the landing gear lights, the gear motor or the warning horn with it, and the pilot lands not knowing whether the gear is down and locked. In Dallas, the controllers on the phone could ask other crews to look. A light gun can't do that.

Airliners that went silent

Northwest 188, October 2009. An Airbus A320 from San Diego to Minneapolis was out of contact for, in the NTSB's words, "about 1 hour 17 minutes" at 37,000 feet. The first officer had probably never finished dialling in a new frequency, and both pilots were working on their laptops. They flew past Minneapolis and finally called from over Eau Claire, Wisconsin: "roger, we got distracted and we've overflown Minneapolis." Controllers told the NTSB that silent airliners happen "as often as several times during an 8-hour shift."

Air Canada 795, November 2009. Two weeks later, an A320 from Toronto to Los Angeles was out of contact for 37 minutes. The crew had been getting static on 121.5 and had turned the volume down. Another aircraft relayed the call that finally got through.

Jet Airways 9W118, February 2017. A Boeing 777 from Mumbai to London lost contact at a handoff over central Europe. According to NATO, it flew on into Germany for almost an hour without talking to ATC, and two German Eurofighters were launched to intercept it. Press reports put the silence at closer to half an hour. Either way, fighters were alongside a widebody full of passengers because of a radio frequency.

The UK's sonic booms. In January 2021 and March 2023, RAF Typhoons were authorised to fly supersonic over England to reach civil aircraft that had stopped talking to ATC. Both aircraft were escorted to Stansted, and the booms were heard across several counties.

When silence turns deadly

Gol 1907, Brazil, September 2006. An Embraer Legacy business jet and a Gol Boeing 737 collided at 37,000 feet over the Amazon, killing all 154 people on the 737. The NTSB's factual report records that "between 3:51 pm and 4:26 pm, there were no attempts to establish radio communications from either the crew of N600XL or ATC," and the Legacy's transponder signal stopped being received at 4:02. Neither airplane's collision-avoidance system gave an alert. Later, the Legacy crew made a dozen calls, and heard a frequency change without all its digits. A lost-comms situation that nobody treated as one ended in the worst accident in Brazilian aviation at the time.

How often does this happen?

• Over Europe: NATO's air command counted more than 900 lost-comms reports in 2018. Fighters launched for almost one in ten. More than 75% were down to human error, 15% technical. Loss of communication is the main reason NATO scrambles its alert fighters, and EUROCONTROL says 90% of interceptions in Europe are attributed to it.
• Earlier European data: a study EUROCONTROL cited found that 40% of loss-of-communication events became prolonged losses. Among equipment causes, "sleeping" receivers that stopped receiving without warning came first, at 53%.
• In the US: NORAD said in 2012 that general aviation aircraft made up the majority of its more than 1,500 intercepts since 2001. AOPA's intercept procedures card lists the number one reason as "entering restricted airspace and not talking to ATC."

When the transponder dies too

Every one of the procedures above starts with the same step: squawk 7600. That step assumes something no checklist card says out loud: that your transponder still has power.

In most light aircraft, the transponder and the radios share an electrical system. When that system fails, they fail together, and so does ADS-B Out. There is nothing left to squawk. To the controller you're at best an unlabeled blip on primary radar, and down low, outside primary radar coverage, you may not be there at all. That's what happened in Dallas: the Lance's return simply vanished.

That's where the phone comes in. We wrote about the transponder problem in our article on how pilots really use checklists. Here, let's look at whether the phone is allowed, and whether it works.

Can you call ATC on your phone?

The record says yes, it works. Grand Junction, Myrtle Beach and Dallas all ended with a phone call and a clearance. A 2020 NASA ASRS bulletin describes a pilot with a total electrical failure in cloud who called Flight Service on a cellphone and asked them to relay to approach control.

The rules are catching up, unevenly:

• The EU says yes. SERA.14083, since May 2025, tells pilots to try "all available means," naming mobile phones. And a VFR flight must report its arrival "by the most expeditious means," which on the ground is a phone call.
• Israel says yes. The national procedure lists the mobile phone among the ways to re-establish contact, and Herzliya, Ben Gurion and Haifa publish tower numbers in their lost-comms procedures.
• The UK tells you to report your arrival "as soon as possible," and its AIP gives a telephone line for the London Distress and Diversion cell (for approved aircraft installations).
• The FAA hasn't caught up. AIM 4-2-13 tells you to "call the tower by telephone" to request a departure without a radio, but says nothing about calling from the air. The FCC's rule 47 CFR 22.925 says cellular phones "must not be operated" while an aircraft is airborne. AOPA put it plainly in 2022: FAA rules and policies "have not been updated for the use of cellphones," and advised pilots to record tower numbers and rely on the pilot in command's emergency authority (14 CFR 91.3). In 2013, a proposal to publish ATC phone numbers in the FAA's Airport/Facility Directory (now the Chart Supplement) noted they could enable NORDO communication "in certain situations."

Use the phone the way every procedure uses everything else: aviate, navigate, communicate. Fly the airplane first and keep flying the published procedure. Call when the airplane is stable and you can do it safely. Coverage is usually better low and near towns. And remember the Dallas lesson: a call to emergency services works, but a call straight to the tower is faster.

The hard part is the number. It's printed somewhere: in the Chart Supplement, in your country's AIP, on a page you photographed before the flight. None of that helps at 1,200 feet with a dead panel, both hands busy and a student's heart rate.

ZuluCheck: the comms backup in your pocket

That's exactly the problem ZuluCheck was built to solve.

• One tap to call the tower. The frequency bar at the bottom of every checklist screen shows your local frequencies and 121.5. Tap it, and the radio-failure sheet opens with the phone numbers you need: the nearest aerodrome's tower or operator, a backup ATC unit such as approach or the area control centre, and the rescue coordination centre. Each is one big button that dials with a single tap.
• The right numbers for where you are. ZuluCheck picks the nearest aerodrome from your location, or uses your home field. Where an AIP publishes dedicated radio-failure lines, like Herzliya tower's two numbers, ZuluCheck marks them in red.
• Built in, offline, sourced. More than 5,000 aerodromes so far: every public-use airport in the United States, plus the UK, France and Israel. The numbers are stored in the app, so the list appears with no data signal, along with its source and date.
• Your headset, your phone. If your headset pairs with your phone over Bluetooth, as many current aviation headsets do, the call comes through your ear cups, over the engine. Most Bluetooth headsets run on their own batteries, so they keep working when the panel doesn't.
• Every emergency checklist, one tap away. A red button on every screen opens the emergency procedures, transcribed from the aircraft's own POH, with memory items first and best glide in view. Bigger type, one item at a time, and nothing to flip through. Emergency checklists are free for everyone.

A laminated card can't dial a phone. Neither, as far as we know, can any other checklist app.

ZuluCheck is free forever for two aircraft, with every feature included. ZuluCheck Pro adds unlimited aircraft for clubs, rental pilots and instructors.

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ZuluCheck is for reference only and is not a substitute for the aircraft's approved flight manual or the procedures published in your country's AIP. Phone numbers can change: check them before flight, and always fly the airplane first.