IFR communication failure: conditions and timing

When do 7600, 7601 and published SID/STAR procedures apply?

The specific conditions determine the branch.

Current SERA branches

The EU SERA communication-failure provisions introduced by Regulation 2024/404 apply from 1 May 2025. After the specified unsuccessful restoration attempts, the general indication is Mode A 7600 and/or the appropriate ADS-B loss-of-communication indication. It identifies the communication condition; it does not alone determine every route, level or approach action.

An IFR flight on a SID or STAR follows the radio-failure procedure specified on that chart when one is provided. This published procedure must be checked rather than assumed absent. The general IFR profile applies subject to the stated exception. A single memory rule about a number of minutes is not sufficient without checking the branch, applicable chart and minimum-flight-altitude constraint.

7601 has a particular meaning

If an IFR flight encounters VMC and the pilot-in-command decides to continue in VMC, SERA.14083(c)(6) requires Mode A 7601, landing at the nearest suitable aerodrome and reporting arrival by the most expeditious means. It is not a generic diversion code and is not selected merely because some visual conditions briefly appear while the flight continues under another branch.

The laboratory separates “VMC encountered” from “PIC decides to continue in VMC”, so seeing the weather condition alone cannot unlock the 7601 result. It also separates a published SID/STAR procedure from the general IFR profile. These are instructional branch tests, not an emergency checklist or a recommendation to choose a particular branch without the real flight’s facts. Use current charts, national operational publications and approved aircraft/operator procedures; outside the EU SERA context, verify the applicable State rules instead of transferring this lesson unchanged.

What starts the current EU twenty-minute period?

Separate timing, vertical profile, route and approach logic.

Use the correct trigger

Under SERA.14083(c)(4)(i), subject to the published SID/STAR exception, the IFR flight maintains the last assigned speed and level, or minimum flight altitude if higher, for 20 minutes after the specified trigger. In the non-surveillance case this follows failure to make a required report; if surveillance service is provided it follows setting 7600 and/or transmitting the appropriate ADS-B indication.

After that period, speed and level are adjusted according to the filed flight plan as amended by delay and modification messages. Do not replace this with an old seven-minute mnemonic or start a stopwatch at an unrelated remembered event. The route has separate rules: follow the last received and acknowledged route clearance, with the specific rejoining provisions when vectored or offset.

Keep four clocks and paths from becoming one

If vectored or offset with a specified limit, continue to that limit and rejoin the last acknowledged route with the applicable minimum altitude considered. Without a specified limit, rejoin no later than the next significant point. Proceed to the designated aid or fix serving the destination and hold when necessary to meet the descent timing. The twenty-minute profile rule is not permission to fly a vector indefinitely.

Descent starts at or as close as possible to the last received and acknowledged expected approach time; without one, use the applicable ETA. Complete the specified instrument approach and land, if possible, within 30 minutes after the later of the relevant ETA or last acknowledged EAT. In the synthetic timing drill, a 12:10 surveillance indication leads to a 12:30 profile-period endpoint. That arithmetic checks one condition only; it does not validate the route, descent or approach branches.

Can you explain and apply the mechanism?

Four original questions. Work from the stated facts, then compare your reasoning with the explanation.