Sir - In response to the letter "Make recorders easier to recover" (Flight International, 11-17 September, P60), I would point out that there have been automatically deployable flight-data/cockpit-voice recorders on the market for more than 25 years.
They have been fitted to every type of airframe - from large transports, through patrol, fighter and carrier-based aircraft, to helicopters - almost exclusively in military service.
The recorder is contained in an externally mounted fairing, which also incorporates a search-and-rescue beacon to locate the recorder, along with survivors. Upon impact, the unit is released automatically (without an explosive charge), flies clear and either lands away from the immediate crash site, or floats. This Canadian-developed technology has been successful in many instances, providing almost immediate access to accident data without costly recovery.
While, for instance, in the case of the 17 July Trans World Airlines Boeing 747 crash, this would not have eliminated the need to salvage the aircraft, the system can, in some cases, increase the ease of recorder retrieval and assist in determining costly salvage decisions.
The reason that this technology has not been more widely used is that deployable systems are significantly more expensive to install than non-deployable systems. As has been the case with other safety-system improvements, until a requirement is established (possibly as part of a dual-redundant-recorder capability), or a clear economic advantage can be identified, this technology will remain under-utilised by the aviation-safety community.
DAVID GODFREY
Coronado, California, USA
Source: Flight International
