Emergencies & lost comms
How to declare MAYDAY or PAN-PAN and what ATC will ask, the emergency squawks and 121.5, minimum fuel, what to do when the radio dies (VFR and IFR, 14 CFR 91.185), light-gun signals, blocked frequencies, and traffic and TCAS alerts. Examples use the Cirrus SR22 flight from IFR departure and IFR en route & arrival; the alphabet and squawk basics are in fundamentals.
Terms
| Term | Meaning |
|---|---|
| distress | serious and/or imminent danger, needing immediate help: say MAYDAY |
| urgency | a safety concern needing timely but not immediate help, a possible distress: say PAN-PAN |
| emergency | either of the above (P/CG). Declaring one gives you priority and lets you break rules as needed (91.3(b)) |
| minimum fuel | you can accept little or no delay at the destination; an advisory, not an emergency, no priority |
| fuel remaining | always said as time (minutes) including reserves, not gallons |
| souls on board | everyone aboard, crew included |
| NORDO | no radio |
| two-way radio failure | you can't both send and receive with ATC; covered by 91.185 under IFR |
| guard | 121.5 MHz, the VHF emergency frequency |
| TA / RA | TCAS traffic advisory (look for traffic) / resolution advisory (climb or descend now) |
Declaring: MAYDAY and PAN-PAN
The distress or urgency message, in AIM 6-3-2 order. Say as much as time allows; the first three lines matter most.
| Order | Item | Example |
|---|---|---|
| 1 | MAYDAY ×3 (distress) or PAN-PAN ×3 (urgency) | "MAYDAY, MAYDAY, MAYDAY" |
| 2 | station called | "NorCal Approach" |
| 3 | call sign and type | "Cirrus four five charlie delta, SR22" |
| 4 | nature of the problem | "engine failure" |
| 5 | weather | "in the clouds" |
| 6 | intentions and request | "request vectors to Livermore" |
| 7 | position and heading | "over SUNOL, heading three five seven" |
| 8 | altitude | "five thousand five hundred descending" |
| 9 | fuel remaining in minutes | "fuel two hours" |
| 10 | people on board | "two souls on board" |
| 11 | anything else useful | "ELT on", aircraft color |
| When | Who / freq | You say | Expect from ATC | You read back / do |
|---|---|---|---|---|
| distress, already talking to ATC | the frequency you are on | the message above | "Cirrus four five charlie delta, roger MAYDAY, Livermore is your nearest airport, twelve o'clock, five miles, say intentions." Or: "say souls on board and fuel remaining." Or: silence on the frequency while other traffic is moved off. | keep your assigned squawk (ATC already sees you); answer in a few words; fly first |
| distress, not talking to anyone | last assigned frequency, else 121.5 | squawk 7700, then the message, addressed to "any station" if needed | "Cirrus four five charlie delta, squawk MAYDAY on seven seven zero zero." Later: "radar contact (position), if feasible squawk four two one three." | set 7700; change back to a discrete code only if it's easy |
| urgency (rough engine, unsure of position, weather closing in, sick passenger) | current frequency | "PAN-PAN, PAN-PAN, PAN-PAN, NorCal Approach, Cirrus five charlie delta, rough-running engine, request vectors to the nearest airport, five thousand." | "Cirrus five charlie delta, nearest airport Livermore, one o'clock, one zero miles, turn right heading zero four zero." Or: "do you want to declare an emergency?" | read back; say "affirmative" if the situation is getting worse |
| problem solved, or on the ground | same, or tower | "Cirrus five charlie delta, engine running normally, no further assistance needed." | "roger" and normal service; fire trucks may still meet you on landing | ATC may ask for a report within 48 hours if they gave you priority (91.123(d)) |
- If you don't say MAYDAY or PAN-PAN but ATC thinks you're in trouble, they handle it as an emergency anyway (7110.65 10-1-1). The minimum ATC needs first: call sign and type, the problem, and what you want (10-2-1).
- An aircraft in distress has the right of way over all other traffic (7110.65 2-1-4).
- You're in at least an urgency condition the moment you doubt your position, fuel or weather (AIM 6-1-2). Ask then, not later.
If ATC says…
- "Say intentions." One line: "Landing Livermore" or "Returning to San Jose."
- "Say souls on board and fuel remaining." "Two souls, fuel two hours" (fuel as time, reserves included).
- "Say nature of the emergency." Short: "Engine failure" or "smoke in the cockpit."
- "Do you want to declare an emergency?" If you have to think about it, the answer is yes.
- "Cirrus five charlie delta, the MVA in your area is two thousand." A terrain warning: climb or turn as needed.
- A long list of questions while you're busy. "Stand by" is fine; fly, then answer.
Transponder codes
| Code | Meaning | When to set it | ATC reaction |
|---|---|---|---|
| 7700 | emergency | not in contact with ATC, or told to | alarm at every radar position; data block shows EMRG / EM |
| 7600 | radio failure | you've lost two-way radio | data block shows RDOF / RF; ATC applies lost-comms handling |
| 7500 | unlawful interference (hijack) | only for a real hijack | "verify squawking seven five zero zero"; no reply means they assume a hijack |
| assigned discrete code | normal | already talking to ATC: keep it through an emergency unless told to change | — |
- The other codes, and how to change codes without passing through 75xx–77xx, are in fundamentals.
- 7500 is not a joke. If you set it by accident, ATC will ask you to verify; answer in the clear that you are not being hijacked, then set your code. ATC never assigns 7500 unless you've told them of a hijack; refuse it otherwise (AIM 6-3-4).
Guard (121.5) and getting help
| Situation | Where to call |
|---|---|
| in contact with ATC | stay on that frequency; ATC won't move you without a reason (7110.65 10-2-2) |
| lost, no contact, or the frequency is dead | 121.5, "any station" |
| no answer on 121.5 from a center | call the nearest tower on 121.5; center coverage on 121.5 doesn't reach every part of its radar area (AIM 6-3-1) |
| can't reach ATC at all | an FSS, San Francisco Radio or New York Radio (relay services), or another aircraft |
| far from anyone, at low altitude | climb if you safely can: VHF range is line of sight (AIM 6-3-2) |
121.5 is monitored by direction-finding stations, military and most civil towers, radar facilities, and many aircraft (AIM 6-3-1). KSJC's Chart Supplement notes 121.5 is not available at that tower: use the approach frequency.
Fuel: minimum fuel vs emergency
| Declaration | Say | What it means | What ATC does |
|---|---|---|---|
| minimum fuel | on initial contact, after your call sign: "NorCal Approach, Cirrus five charlie delta, minimum fuel." | you can take no undue delay at the destination; an emergency is possible if delayed | passes it to the next controller, watches for delays; no priority (AIM 5-5-15) |
| emergency for fuel | "MAYDAY, MAYDAY, MAYDAY … low fuel, fuel remaining one five minutes …" or "declaring an emergency, fuel" | you will land short of your reserve, or might not make it | priority handling, the shortest route to a runway |
| ICAO wording (outside the US) | "MINIMUM FUEL" / "MAYDAY MAYDAY MAYDAY FUEL" | the same idea, with fixed-reserve definitions | see fundamentals for ICAO differences |
Minimum fuel gets you nothing except attention. If a delay would leave you below your planned reserve, declare an emergency instead.
Priority, deviations and asking for things
| Phrase | Who says it | Meaning / use |
|---|---|---|
| "say request" | ATC | you called without a request; give it in one line |
| "unable (reason)" | you | you can't comply: "Unable, climb performance" or "unable, icing". Required when you won't comply (91.123) |
| "stand by" | either | wait; it's neither yes nor no |
| "(request) approved" / "unable (request), (reason)" | ATC | the answer to your request (7110.65 2-1-18) |
| "immediately" | ATC | act now: an imminent conflict (7110.65 2-1-5) |
| "expedite" | ATC | quick compliance to prevent a conflict from developing |
- In an emergency you may break any Part 91 rule as needed (91.3(b)). Tell ATC as soon as possible about any deviation from a clearance (91.123(c)) and get an amended clearance (AIM 6-1-1).
- Afterward the FAA may ask for a written report (91.3(c)); if ATC gave you priority they may ask within 48 hours (91.123(d)).
- Equipment failures under IFR must be reported: call sign, what failed, how it limits IFR flight, and what help you want (91.187). For example: "Cirrus five charlie delta, lost GPS, request vectors for the ILS."
Radio trouble: first checks
Most "lost comms" is a knob. Work down this list before squawking 7600.
| Check | Why |
|---|---|
| volume, squelch, headset plug, audio panel selections | the most common cause |
| the frequency you typed; try the previous one | wrong digit, or you left too early; the previous controller can give a new one (AIM 5-3-1) |
| a stuck mic: yours (constant sidetone, TX light) | a stuck push-to-talk blocks the frequency for everyone (AIM 4-2-2) |
| the other radio (COM2), or the hand mic | a failed radio or headset |
| wait a minute on a center frequency | a center's backup transmitter usually takes over within 60 seconds (AIM 5-3-1) |
| 121.5, then FSS / San Francisco Radio / New York Radio, or another aircraft | any of these can relay (AIM 6-4-3) |
| VOR audio turned up | ATC can broadcast on a VOR's voice channel (AIM 6-4-3) |
| a phone, after landing | call the ATC facility (Chart Supplement number) or Flight Service so they stop looking for you |
Frequency congestion and stuck mics
- Listen before you key the mic. On a busy frequency, keep the first call short and wait for "go ahead".
- A stuck mic sounds like an open carrier, cockpit noise or someone's intercom on the frequency. Check yours first.
- If the assigned frequency is completely blocked, treat it as a frequency outage: go back to the previous frequency or another one for the same facility and ask for instructions (AIM 4-2-2, 5-3-1).
- A blocked frequency can hide a holding clearance. If you reach a clearance limit without holding instructions, hold standard (right turns) on the inbound course and keep calling (AIM 5-3-8).
Lost comms: VFR
If the radio fails in VFR conditions, or you reach VFR conditions after it fails, stay VFR and land as soon as practicable, even when on an IFR flight plan (91.185(b)). "As soon as practicable" is not "as soon as possible": you don't have to land somewhere unsuitable or stop a few minutes short of your destination (AIM 6-4-1).
- Squawk 7600 (AIM 6-4-2).
- Towered airports: follow the steps below and watch for light signals.
- Untowered airports: fly a normal, well-announced pattern; you may still be able to transmit.
| When | Who / freq | You say | Expect from ATC | You read back / do |
|---|---|---|---|---|
| receiver dead, before reaching the Class D | tower frequency | "Executive Tower, Cirrus four five charlie delta, SR22, receiver inoperative, one zero miles south at two thousand, landing Sacramento Executive, request light signals." | light signals only; you won't hear anything | stay outside or above the Class D until you've seen the traffic flow |
| 3–5 miles out | same | "Cirrus four five charlie delta, four miles south, joining left downwind runway two." | light signals | join the pattern; watch the tower |
| downwind and base | same | "… left downwind runway two", "… left base runway two" | steady green = cleared to land | land on steady green only |
| transmitter dead (you can hear) | listen on tower | nothing | spoken instructions, or light signals | acknowledge by rocking the wings (day) or flashing landing or nav lights (night) |
| both dead | watch the tower | nothing | light signals | as above |
Light-gun signals (AIM 4-3-13)
| Signal | Aircraft on the ground | Aircraft in flight |
|---|---|---|
| steady green | cleared for takeoff | cleared to land |
| flashing green | cleared to taxi | return for landing (steady green will follow) |
| steady red | stop | give way to other aircraft, keep circling |
| flashing red | taxi clear of the runway in use | airport unsafe, do not land |
| flashing white | return to starting point on the airport | — |
| alternating red and green | exercise extreme caution | exercise extreme caution |
Acknowledge in flight by rocking the wings (day) or blinking landing or nav lights (night); on the ground by moving ailerons or rudder (day) or blinking lights (night). If the radio fails on the ground before taxiing, phone the tower and ask to depart without a radio (AIM 4-2-13).
Lost comms: IFR
In IMC, 91.185(c) tells you which route, which altitude and when to leave the clearance limit. ATC plans on you doing exactly this (AIM 6-4-1, 7110.65 10-4-4).
| Route: the first that applies (AVEF, an instructor mnemonic) | Example on KSJC → KSAC |
|---|---|
| Assigned: the route in the last clearance | SUNOL ONE, Sacramento transition, then as filed |
| Vectored: direct from where the radio failed to the fix, route or airway in the vector clearance | "vector to join V334" → join V334 and fly it |
| Expected: a route ATC said to expect ("expect further clearance via …") | fly it |
| Filed: the route in your flight plan | SAC VORTAC, then KSAC |
| Altitude: the highest of these, for each route segment (MEA, an instructor mnemonic) | Example |
|---|---|
| Minimum IFR altitude for the segment (MEA, MOCA and so on) | V334 SUNOL → SAC: 5,000 |
| Expected altitude, once the time or fix to expect it has passed | "expect six thousand one zero minutes after departure": climb to 6,000 at takeoff + 10 minutes |
| Assigned altitude in the last clearance | "except maintain five thousand": 5,000 |
Re-check the altitude at each segment: climb for a higher MEA ahead, and after it return to the highest of the three. An "expect" altitude only counts after its time or fix; if the radio fails after that time, it no longer applies (AIM 6-4-1).
| Leaving the clearance limit | Do |
|---|---|
| the limit is a fix where an approach begins | start descent or the approach as close as possible to your EFC, or without one, to your ETA (filed or amended ETE) |
| the limit is some other fix | leave it at your EFC, or on arrival without one; go to a fix where an approach begins; start the approach as close as possible to your ETA |
| the limit is the destination airport (the usual case) | fly the route to an approach fix (SAC VORTAC here), hold there if early, and start the approach at your ETA |
- Squawk 7600, keep trying the frequencies in the first-checks table, and monitor VOR voice.
- If you break out into VFR conditions at any point, the VFR rule takes over: stay VFR and land as soon as practicable.
- ATC plans around your route and altitude. If you don't turn up, it restricts other IFR traffic that could conflict for 30 minutes past your approach clearance, EFC or ETA (7110.65 10-4-1).
What ATC does
- Calls on the frequency, 121.5, VOR voice, via FSS or relay radios, and may broadcast your clearance "in the blind" (7110.65 10-4-4).
- Tests whether you can hear: asks you to ident, squawk 7600, or turn, then says "ident observed" or "reply not received". If you can hear but not speak, do exactly what they ask.
Receiver or transmitter only
| What failed | Signs | What to do |
|---|---|---|
| receiver (you can still transmit) | silence on every frequency, but your transmit light and sidetone work | keep transmitting in the blind ("… transmitting in the blind"), position, altitude and intentions at key points; ATC may hear you; squawk 7600 |
| transmitter (you can still hear) | ATC keeps calling you; your calls are never answered | squawk 7600, follow what you hear; answer ATC's questions with IDENT or turns when asked |
| both | nothing in or out | 7600, then 91.185 (IMC) or land as soon as practicable (VMC) |
Traffic, terrain and TCAS alerts
| You hear | Meaning | Do, then say |
|---|---|---|
| "Traffic alert, Cirrus five charlie delta, twelve o'clock, one mile, advise you turn left immediately" | a collision risk seen by ATC (7110.65 2-1-6) | turn now; "Turning left, Cirrus five charlie delta, looking" |
| "Low altitude alert, Cirrus five charlie delta, check your altitude immediately, the MVA in your area is three thousand" | you're close to terrain or obstacles | climb or correct at once, then report |
| "Traffic, two o'clock, three miles, eastbound, altitude indicates five thousand five hundred" | an advisory, not an instruction | "Looking" → "traffic in sight" or "negative contact" |
| your TCAS II RA | an avoidance climb or descent command | follow it at once, then "NorCal, Cirrus five charlie delta, TCAS RA"; when done, "clear of conflict, returning to assigned altitude" (7110.65 2-1-28) |
| a TA (or an ADS-B / TAS traffic alert) | look for traffic | don't leave your clearance on a TA alone (AIM 4-4-16) |
- An SR22's traffic display (ADS-B In or a TAS) gives advisories only, never an RA.
- Deviating for an RA is allowed and must be reported as soon as possible (91.123(a), (c)). ATC won't issue instructions that contradict an RA you've reported.
MSFS and online networks
- MSFS 2024 built-in ATC: there's no menu option to declare an emergency, and squawking 7700 or 7600 doesn't change how it treats you (reported, Microsoft Flight Simulator forums; still on the wishlist). Practice the calls aloud and fly the 91.185 logic yourself.
- Failures: Settings → Assistance → Failure and Damage has Crash Damage, Aircraft Stress Damage and Engine Stress Damage. They make abuse consequential; they don't schedule random failures (reported, third-party guides). Some add-on aircraft have a failures page on their own tablet.
- VATSIM: emergencies may only be declared while under ATC; if a controller asks you to stop the emergency, do so or disconnect; never squawk 7500 (Code of Conduct B6). 121.5 is used as in the real world (A16).
- PilotEdge and other human-ATC services are the way to practice lost-comms and emergency calls with a real controller.
Recipes
MAYDAY: engine failure en route
Level at 6,000 passing SUNOL northbound, in the clouds. Fly first: best glide, nearest airport, then the call.
YOU "MAYDAY, MAYDAY, MAYDAY, NorCal Approach, Cirrus four five charlie delta, SR22, engine failure, in the clouds,
request vectors to the nearest airport, over SUNOL, heading three five seven, five thousand five hundred descending,
fuel two hours, two souls on board."
ATC "Cirrus four five charlie delta, roger MAYDAY. Livermore airport is your nearest, twelve o'clock, five miles.
Livermore altimeter three zero zero two. Say intentions."
YOU "Three zero zero two, landing Livermore, Cirrus four five charlie delta."
ATC "Cirrus four five charlie delta, Livermore runway two five right is in use, report the airport in sight."
YOU "Airport in sight, Cirrus four five charlie delta."
ATC "Cirrus four five charlie delta, Livermore Tower is expecting you, contact tower one one eight point one."
(Livermore Tower has limited hours; when closed, ATC keeps you on frequency and you use the CTAF)PAN-PAN: rough engine
The engine still makes power, but you want the nearest runway.
YOU "PAN-PAN, PAN-PAN, PAN-PAN, NorCal Approach, Cirrus five charlie delta, rough-running engine, request vectors to the
nearest airport, six thousand, two souls, fuel two hours."
ATC "Cirrus five charlie delta, roger PAN. Nearest airport Livermore, one o'clock, one two miles. Turn right heading zero
four zero, descend at pilot's discretion, maintain four thousand."
YOU "Right zero four zero, pilot's discretion four thousand, Cirrus five charlie delta."
(if it gets worse: "Cirrus five charlie delta, now declaring an emergency.")Minimum fuel, then an emergency
Tell them early; upgrade when the numbers stop working.
YOU "NorCal Approach, Cirrus five charlie delta, six thousand, minimum fuel."
ATC "Cirrus five charlie delta, roger, expect vectors ILS runway two, expect no delay."
... told to hold for 20 minutes; fuel at the field would be under your reserve ...
YOU "NorCal, Cirrus five charlie delta, unable holding, declaring an emergency for fuel, fuel remaining three zero minutes,
request direct to the approach."
ATC "Cirrus five charlie delta, roger, cleared direct COUPS, cross COUPS at or above two thousand, cleared ILS runway two
approach."Lost comms in IMC after takeoff (KSJC → KSAC)
Clearance: SUNOL ONE, Sacramento transition, then as filed; climb via SID except maintain 5,000; expect 6,000 ten minutes after departure. Radio dies passing 3,000 in cloud; takeoff was at 1800Z, filed ETE 40 minutes.
1800 takeoff
1803 radio silent. Check volume, frequency, COM2, headset. Squawk 7600. Try 121.3, 121.5, the tower.
ROUTE Assigned: continue the SUNOL One, Sacramento transition, then as filed (SAC VORTAC → KSAC).
ALTITUDE highest of: assigned 5000, MEA 5000 on V334, expected 6000 (only from 1810). → 5000 now.
1810 climb to 6000 (the "expect" time has passed and 6000 is the highest).
1830 SAC VORTAC reached early. KSAC is the clearance limit; SAC is the IAF. ETA = 1800 + 40 = 1840.
Hold at SAC (the published hold for the approach) at 6000 until 1840.
1840 leave the hold, descend in the hold-in-lieu to 1500 and fly the ILS or LOC RWY 2.
Tower light signals if it's open; land. Phone NorCal after landing.
If you break out VFR at any point: stay VFR, land as soon as practicable.Receiver failure: towered VFR arrival (KSAC)
Your transmitter works, the receiver doesn't. Squawk 7600.
[EXEC TOWER 119.5, 10 miles south, outside the Class D]
YOU "Executive Tower, Cirrus four five charlie delta, SR22, receiver inoperative, one zero miles south at two thousand,
landing Sacramento Executive, request light signals."
(circle outside the Class D, watch which runway traffic uses)
YOU "Cirrus four five charlie delta, four miles south, joining left downwind runway two."
YOU "Cirrus four five charlie delta, left base runway two."
steady green from the tower → land; steady red → give way and keep circling; flashing red → don't land here.
(day: rock the wings to acknowledge)Traffic alert or RA
Respond first, then talk.
ATC "Traffic alert, Cirrus five charlie delta, twelve o'clock, one mile, opposite direction, altitude indicates six
thousand, advise you turn right immediately."
YOU (turning) "Turning right, Cirrus five charlie delta, looking."
YOU "Traffic in sight, Cirrus five charlie delta."
TCAS II aircraft:
YOU "NorCal, (call sign), TCAS RA."
YOU (after) "NorCal, (call sign), clear of conflict, returning to six thousand."Stuck mic or blocked frequency
When the frequency has an open carrier and you can't get through.
1. Check your own PTT and the TX light first.
2. Go back to the previous frequency: "NorCal, Cirrus five charlie delta, one two five point two five is blocked, request
another frequency."
3. No luck: another frequency for the same facility, 121.5, or Flight Service.
4. Keep flying your last clearance; hold standard at a clearance limit if you reach it without instructions.References
- AIM chapter 6: Emergency procedures (opens in a new tab): 6-1 pilot authority, 6-2-2 transponder, 6-3-1 and 6-3-2 distress and urgency messages, 6-3-4 code 7500
- AIM 6-4: Two-way radio communications failure (opens in a new tab): 91.185 explained with examples, 7600, re-establishing contact
- AIM 4-2-13 and 4-3-13 (opens in a new tab): radio failure at a towered airport, light-gun signals
- AIM 4-4-16 TCAS (opens in a new tab) and AIM 5-5-15 minimum fuel (opens in a new tab)
- FAA Order JO 7110.65BB (opens in a new tab): chapter 10 (emergencies, 10-2-1 information needed, 10-2-6 hijack, 10-4-4 lost comms), 2-1-4 priority, 2-1-6 safety alerts, 2-1-8 minimum fuel, 2-1-28 TCAS, 5-2-3 emergency codes
- Pilot/Controller Glossary (opens in a new tab): distress, urgency, emergency, minimum fuel, fuel remaining, MAYDAY, unable, stand by
- 14 CFR 91.185 (opens in a new tab), 91.3 (opens in a new tab), 91.123 (opens in a new tab), 91.187 (opens in a new tab): lost comms, PIC authority, compliance and deviation reports, malfunction reports
- SKYbrary: Minimum fuel (opens in a new tab): the ICAO MINIMUM FUEL and MAYDAY FUEL wording
- VATSIM Code of Conduct (opens in a new tab): B6 emergencies and 7500, A16 guard
- Fly Away Simulation: damage and failures in MSFS 2024 (opens in a new tab) and MSFS forums: Declare Emergency wishlist (opens in a new tab): secondary, for the sim notes marked (reported)