Accident Details
On 13 December 2000, a Cessna 152, registration G-BHPX, was en route from Inverness to Benbecula. The time of the accident was corrected from 1500 to 1600 UTC in an AAIB bulletin corrigendum.
Emergency Locator Transmitters Information
The AAIB replaced the original paragraph on emergency locator transmitters (ELTs) with a comprehensive description of radio distress beacons. ELTs are aviation beacons generally fitted to aircraft. Other categories include emergency position indicating radio beacons (EPIRBs) for maritime use and personal locator beacons (PLBs) for land or person-carried use.
ELTs are of four basic types: Automatic Fixed (ELT(AF)), Automatic Portable (ELT(AP)), Survival (ELT(S)), and Automatic Deployable (ELT(AD)). ELT(AF) are permanently attached and operate automatically; ELT(AP) are attached before a crash but removable; ELT(S) are removed by survivors; ELT(AD) are ejected and deployed.
These beacons are compatible with the COSPAS/SARSAT satellite system, which detects distress beacons on 121.5 MHz, 243 MHz (NATO frequency), and 406.0-406.1 MHz. Beacons on 121.5 and 243 MHz transmit a modulated carrier wave detectable by satellite and homed by SAR aircraft. 406 MHz beacons transmit a half-second data pulse every 50 seconds containing unique identification information. They should be registered on a database with owner and contact details.
As of 1 February 2009, COSPAS/SARSAT will cease satellite processing of 121.5 and 243 MHz, detecting only 406 MHz transmissions. Homing equipment for the 406 MHz band is being fitted to SAR aircraft. 406 MHz beacons typically include a lower-powered 121.5 MHz auxiliary transmitter for final homing.
The CAA requires all ELTs to comply with EUROCAE Standard ED62.