Lost Comms Procedures IFR – Essential Guide
Understanding Lost Comes in IFR Flights
Losing two-way radio contact with Air Traffic Control (ATC) during an Instrument Flight Rules (IFR) flight is a critical challenge every instrument-rated pilot must be prepared to handle. The IFR system itself relies on this constant communication for traffic separation, clearances, and safe navigation, especially in low-visibility conditions. When that communication link is broken, a clear, pre-defined plan is essential to maintain safety and order in the skies.
Pilots aren’t left to improvise; Federal Aviation Regulation (FAR) 91.185 provides precise lost communication procedures. The goal is to make a pilot’s actions predictable, enabling ATC to anticipate the aircraft’s flight path and maintain traffic separation.
Steps to Re-establish Communication
Before following official lost comes procedures, attempt to re-establish contact:
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Check Equipment: Verify radio volume is up, the correct frequency is selected, and the headset is properly connected. Check the audio panel and scan for popped circuit breakers.
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Try Other Frequencies: Attempt to transmit on your previous frequency. If equipped, switch to a secondary radio.
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Use Emergency Frequency: Try to make contact on 121.5 MHz, as another aircraft or facility may be able to relay a message.
If all attempts to restore communication fail, set your transponder to code 7600. This non-verbal signal immediately alerts ATC to your predicament and shows you are following official lost comes procedures.
With communication confirmed lost, and the transponder set to 7600, your next step is to follow a predictable flight path governed by specific rules for route and altitude.
To determine your route, follow the AEF mnemonic in order of priority:
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Asigned: The route last assigned by ATC.
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Vvectored: If being vectored, fly directly to the fix, route, or airway specified.
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Eexpected: The route ATC advised you to expect in a further clearance.
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Fled: The route filed in your flight plan.
For your altitude, you must fly the highest of the following three for any given flight segment:
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Mminimum IFR Altitude (MEA) for the route.
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Eexpected altitude for a subsequent leg.
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Asigned altitude from your last clearance.
Proceed along the established route and altitude until you reach your clearance limit. If you were given an Expect Further Clearance (EFC) time, hold at the limit until that time arrives. If not, hold until your filed Estimated Time of Arrival (ETA). At the correct moment, you can begin your descent and instrument approach.
Emergency Procedures in VFR Conditions
The major exception to these IFR rules is encountering Visual Meteorological Conditions (VMC). If the radio fails while you are in VMC, or if you later fly into it, the complex procedures for route and altitude no longer apply.
Instead, you must continue the flight under VFR and land as soon as practicable. While squawking 7600 is still required, your new priority is to navigate visually to a suitable airport for a safe landing.
Upon arriving at a towered airport, look to the control tower for light gun signals to receive your landing clearance. A steady green light clears you to land; a flashing green means you should circle and return for landing.
