GUY NORRIS / LOS ANGELES
An advanced arc fault circuit breaker (AFCB) designed to protect aircraft from wire-related accidents, including fuel tank explosions, has started test flights. Manufacturer Eaton Aerospace hopes the devices will be available for retrofit in the first quarter of next year, following the establishment of an industry certification standard.
The AFCB is one of two prototypes being tested under a joint Naval Air Systems, Office of Naval Research and Federal Aviation Administration contract to improve safety by detecting and preventing electrical arcing caused by wiring damage or faults. The programme is one of several safety efforts prompted by the crash of TWA flight 800 in 1996, and builds on earlier electrical safety initiatives launched by the US Navy to counter the rising number of wiring-related mishaps. An FAA Boeing 727 and a US Navy McDonnell Douglas C-9 will be used in testing.
Eaton's AFCB is being flight tested first, while one developed by a Hendry Telephone/Texas Instruments team is several months away. Eaton's AFCB project manager Jim McCormick says the design is based on a domestic electrical appliance already in production. Algorithms analyse the current passing through the circuit breaker and detect anomalies while preventing false alarms tripping the breaker, a technical challenge that has prevented earlier development.
Ground tests have been completed and initial flights recently conducted on Boeing's 737-900 testbed, says McCormick. The US Navy six-month trial, which started on 24 August, will initially involve seven new breakers. The AFCBs will replace present circuit breakers on non-critical, duplicated systems like anti-collision beacons. It is hoped the FAA trial will lead to a supplemental type certificate for the installation of the AFCBs.
AFCBs are expected to complement other wiring safety initiatives such as the embedded wire integrity monitoring system being studied by Honeywell and Goodrich.
Source: Flight International
