090 CommunicationsChapter 8
| Code | Meaning |
|---|
| H24 | Continuous day and night |
| HJ | Sunrise to sunset |
| HN | Sunset to sunrise |
| HO | Operating hours |
| HS | Scheduled operational hours |
| HX | No specific hours |
| Item | Value |
|---|
| No reply wait time | 10 seconds |
| Radio check max length | under 10 seconds |
| Time format | 4-digit UTC |
| Heavy wake category | over 136,000 kg |
| Flight number abbreviation | Not allowed |
| Code | Meaning |
|---|
| QFE | Height (airfield pressure) |
| QNH | Altitude (MSL pressure) |
| QDM | Magnetic track TO station |
| QDR | Magnetic bearing FROM station |
| QTE | True bearing FROM station |
| QUJ | True track TO station |
| Item | Value |
|---|
| Long final | 4–8 NM |
| Short final | under 2 NM |
| EAT given if delay | over 10 min |
| EAT revised if change | over 5 min |
| Signal square viewing | 2,000 ft AAL |
| Deadside descent | 1,000 ft AAL |
| Code | Meaning |
|---|
| 7500 | Hijack |
| 7600 | Radio failure |
| 7700 | Emergency |
| Condition | Hold time |
|---|
| No radar | 20 min after missed CRP report |
| With radar | 7 min (latest of level reached, 7600, or missed CRP) |
| Landing window | ±30 min of EAT/ETA |
| Item | Value |
|---|
| ATIS update interval | 30 min |
| RVR reported when vis | under 1,500 m |
| CAVOK visibility | 10 km+ |
| CAVOK cloud base | no cloud under 5,000 ft or MSA |
| METAR wind update | direction over 60° or speed over 10 kts |
| Braking: Good | coefficient over 0.4, code 5 |
| Braking: Poor | coefficient under 0.25, code 1 |
| Item | Value |
|---|
| VHF aeronautical band | 117.955–137 MHz |
| VHF channels | 118–136.975 MHz |
| Channel spacing | 8.33 kHz (25 kHz backup) |
| HF band | 2.85–22 MHz |
| Range formula | 1.23√(h₁ + h₂) ft → NM |
| Wave equation | 3 × 10⁸ = f × λ |
| # | Type |
|---|
| 1 | Distress (MAYDAY) |
| 2 | Urgency (PAN PAN) |
| 3 | Direction finding |
| 4 | Flight safety |
| 5 | Meteorological |
| 6 | Flight regularity |
| Phrase | Use |
|---|
| MAYDAY × 3 | Distress |
| PAN PAN × 3 | Urgency |
| PAN PAN MEDICAL | Protected medical transport |
| STOP TRANSMITTING, MAYDAY | Impose silence |
| CANCEL DISTRESS | End distress (aircraft) |
| DISTRESS TRAFFIC ENDED | End distress (ATC) |