Communication failure

Radio Communications Failure

Radio failure is a common scenario — antenna defect, transmitter defect, power issue. The pilot must react systematically and interpret visual signals.

Source: ICAO Annex 2 Appendix 1 (Light Signals); ICAO Annex 10 Volume II; EASA SERA.11005 Radio Communications Failure; EASA SERA.6005 Class D specifics.

Steps on radio failure

Step 1: Diagnose

• PTT defective?: try another PTT button.
• Frequency correct: check current frequency.
• Squelch: squelch test → squelch off/on.
• Volume check.
• Headset / audio panel: try other combinations.
• Restart radio: master off / on.
• Backup radio try (COM2 if available, handheld radio).

If none of these helps → radio failure confirmed.

Step 2: Transponder

• Squawk 7600 on transponder.
• ATC sees: "Communications failure" on radar.

Step 3: Attempt re-establishment

• Try other frequency: 121.500 MHz (emergency), previous frequency, FIS frequency.
• Handheld if available.

Step 4: If no contact

Pilot applies standard procedures:

VFR radio failure

In uncontrolled airspace

• Continue VFR (see-and-avoid).
• Self-announcement ("blind transmission") at uncontrolled fields:
  • "[Field name] traffic, DEMRA, transmitting blind, joining downwind runway 26."
• Land at the nearest suitable field.

Class C (VFR, EASA SERA.6005)

• Entry into Class C without radio is prohibited — if the failure occurs before entry → avoid Class C and land at an uncontrolled field.
• If the failure occurs inside Class C: continue with the last acknowledged clearance, shortest route out of the airspace, squawk 7600, then land outside the CTR / TMA.

Class D (VFR, EASA SERA.6005)

• Entry into Class D requires prior approval by radio. Without radio → no new entry permitted.
• Failure inside Class D / CTR:
  • Follow the last assigned clearance.
  • Shortest path out of the CTR, land outside (alternate) if not already cleared to land before the failure.
  • If the CTR airport itself is the destination: fly standard pattern, wait for light signals.
  • Squawk 7600 continuously.

IFR radio failure

More complex, based on last clearance + standard procedures:

• Routing: continue last assigned route.
• Altitude: last assigned or standard for route.
• Approach: last expected approach clearance.

Source: ICAO Doc 4444 PANS-ATM, Chapter 15.

Visual signals from tower (light gun)

ICAO Annex 2 Appendix 1 defines standardised light signals:

Aircraft in flight

Aircraft on ground

Priority — radio vs light signals

• Radio instructions take precedence over light signals — as soon as the radio works again, the radio clearance applies, not the latest light signal.
• Exception: a red pyrotechnic flare overrides any earlier clearance (including radio clearance) — the pilot must not land, must go around and request instructions. This is the only light signal that revokes an existing radio clearance.

Pilot signals back

When pilot has understood a light signal:

• By day: wing-rocking (brief aileron wag) = "understood".
• At night: landing-light flashing (3 flashes) = "understood".

Example sequence — radio failure on approach

1. Diagnose: radio dead, ATC not heard.
2. Squawk 7600 immediately.
3. Try 121.500: no answer.
4. Standard pattern flown, approach runway.
5. Await tower signal: steady green → cleared to land.
6. Continue approach, with special caution.
7. Normal landing.
8. After landing: contact tower by phone ("tower phone number" in AIP).

Backup communication in the cockpit

Pre-flight recommendation:

• Handheld radio on board (Yaesu, ICOM).
• Own power source (battery, USB power bank).
• Tower phone number in PLOG.

After flight

• Report incident (aerodrome operator, authority if IFR or CTR involved).
• Radio maintenance carried out.

Summary

Pilot in command (PIC) must on radio failure decide independently:

• Safe landing is priority.
• Standard procedures to be followed.
• Special caution in controlled airspaces (Class C / D without radio = generally avoid).