Comms & Mandatory Reports

Two communications topics that intersect at the hold: what to do if your radio quits while you're in the pattern, and what events you must report to ATC even when comms are working. The lost-comm procedure is what the EFC time in your DFRATE clearance is for. The MARVELOUS VFR C500 mnemonic catches every pilot-initiated mandatory report — much of which the radar environment makes redundant, but the responsibility never moves to the controller.

Diagram of ATC holding instructions. A charted holding pattern at PINNE Intersection needs three items — direction to hold from the fix, the holding fix, and an expect-further-clearance time — with the matching clearance quoted. An uncharted pattern at HORST Intersection needs those plus the holding course, the outbound leg length, and whether the pattern is nonstandard, again with the clearance quoted. Both chart excerpts are watermarked NOT FOR NAVIGATION. — What a holding clearance must contain, and how that changes when the pattern is not charted. For a **charted** hold it is three items and “as published” does the rest; for an **uncharted** one ATC has to give you the course, the leg length and any nonstandard turns as well. Read back the EFC time either way — it is the clock you fly to if the radios then quit. FAA Instrument Procedures Handbook (FAA-H-8083-16B) — US Government work, public domain

Lost communications at a holding fix

If you reach a clearance limit (the holding fix) without onward clearance, ATC expects:

Maintain the last assigned altitude.
Begin holding in accordance with the depicted holding pattern (if charted on the approach plate or en-route chart).
If no pattern is depicted, enter a standard hold on the course you approached the fix on.
Immediately request further clearance — try 121.5, the previous frequency, the destination tower frequency, etc.
Always report time and altitude on reaching a holding fix — this is the single most important position fix you can give ATC.

The EFC time from your DFRATE clearance is the lost-comm safety net. If everything goes silent and you reach EFC time without further clearance, you proceed onward as the original clearance contemplates (typically per AVE-F: continue along the route Assigned, Vectored, Expected, or Filed; descent per AVE-F minimum altitudes; arrival at destination at the original or amended ETA).

MARVELOUS VFR C500 — mandatory reports

Even with comm equipment working, certain events must be reported to ATC. The mnemonic catches every one of them. Some apply only in non-radar environments (where ATC can't see your position); others apply everywhere.

M — Missed approach
A — Airspeed change of ±max(10 kts, 5%) of filed TAS
R — Reaching a holding fix (time + altitude)
V — VFR-on-top altitude change
E — ETA changed ±2 min (3 min in the North Atlantic) — non-radar only
L — Leaving a holding fix or holding point
O — Outer marker (or fix used in lieu of) — non-radar only
U — Unforecast weather
S — Safety of flight (emergencies, urgency situations)
V — Vacating an altitude or flight level
F — Final approach fix — non-radar only
R — Radio / nav / approach equipment failure
C — Compulsory reporting points (depicted as solid triangles on charts) — non-radar only
500 — Unable to climb or descend at least 500 fpm

In a radar environment ATC sees most of these directly, so reports like Outer Marker / FAF / Compulsory points become redundant. But the responsibility to report doesn't shift to the controller — if you're flying somewhere where radar coverage is intermittent, expect to be back to non-radar reporting without warning.

Squawk codes during a comm-loss event

If your radios fail entirely, set the transponder to 7600 immediately. ATC sees the lost-comm flag instantly and starts coordinating with controllers downstream. Continue the lost-comm procedure (maintain altitude, hold per pattern, EFC time logic) until you can re-establish communications or arrive at destination.

If the lost-comm event is also a true emergency (engine, fire, etc.), 7700 takes precedence over 7600. ATC handles 7700 differently and will assume your inability to communicate is part of the larger emergency.