// Emergency alerting
Crash alarm
The crash alarm in Prestwick tower: how ATC alerts the fire service, the UK emergency categories, fire category A7 and the fire-to-aircraft frequency 121.605.
What it is
- CAP 670 requires an audible primary means of alerting the aerodrome emergency services plus an independent standby, and a way to talk to other emergency services (IAS01.42–.43).
- CAP 168 requires a discrete communication system linking the fire station, tower and vehicles, and an alerting system at both the fire station and the tower.
How controllers use it
- ATC normally alerts the emergency services, immediately and with the fullest information, confirms the aircraft type, and passes the surface wind when there is a fire on the ground (CAP 493 S5 Ch 7).
- 121.605 MHz is for fire service to flight deck, on the ground during a declared emergency only; it is recorded and kept 30 days (CAP 168).
UK rules and practice
- Categories (CAP 493): Aircraft Accident / Accident Imminent; Aircraft Ground Incident; Full Emergency; Local Standby; Weather Standby; Unlawful Acts; Off-aerodrome; Domestic.
At Prestwick
- Rescue and firefighting category A7, with Cat 8/9 at short notice (AIP AD 2.6). Cat 7 covers aircraft 39–49 m long with fuselage width up to 5 m (CAP 168).
Typical UK practice: The make of Prestwick’s crash alarm is not public (the “Omnicrash” name is unsourced). The button here is a silent illustration of a typical UK panel.
// Through the eras
| Era | Status | Notes |
|---|---|---|
| 1930s–40s | Typical UK practice | A crash bell or klaxon to the fire section is typical of the period. |
| 1950s–60s | Typical UK practice | A push-button alarm and direct line to the fire station are typical. |
| 1980s–90s | Typical UK practice | A push-button panel with a standby is typical. |
| Modern | Typical UK practice | Required (CAP 670 IAS01.42); the make at Prestwick is not public. Fire category A7 (AIP). |