The US government has proposed to substantially increase the length of time that conversations in airline cockpits can be recorded, a change promoted by safety advocates but greeted cautiously by pilots who want tighter controls on how the information is used.
The Federal Aviation Administration proposal for airlines and manufacturers to adopt the latest "black box" digital technology would require that two hours of cockpit audio be preserved, up from the current maximum of 30 minutes.
It would also extend the range of another system on commercial jetliners that records data on the performance of aircraft systems, like engines, wing flaps and rudder pedals.
The changes, some of which would require retrofits on nearly 10,000 planes over several years, would cost the industry an estimated USD$256 million, the FAA estimated.
A final regulation is not expected until 2006 at the earliest, with changes phased in over periods of between two and four years after that.
The FAA did not, however, embrace a controversial recommendation from the National Transportation Safety Board for cockpit video recorders.
"We're looking at that question," said Marion Blakey, the FAA administrator.
Airline pilots vehemently oppose cockpit video recorders as an unwarranted intrusion.
Cockpit voice recorders, which run continuously in loops of up to 30 minutes, are usually analyzed after a serious in-flight incident or near accident. They are always reviewed after a crash, if they are recovered, and have provided accident investigators with insight about crew performance.
Investigators have complained that recordings are too short and crucial information earlier in a flight might have yielded valuable clues had it not been recorded over.
But pilots' unions are fiercely protective of the cockpit recordings and are wary about what information gets reviewed and who listens to the tape.
Conversations can range from mundane verbal equipment checks to sensitive personal or company matters, banter, and, in rare circumstances, the last moments of an ill-fated flight.
The Air Line Pilots Association, the largest commercial pilots' union, says current rules extend only limited protection for how recorder information is used by airline management. No rules prevent companies from using data for disciplinary action.
"We know that recorded safety information has been misused and abused in the past and that these practices continue today -- the need for decisive action to secure the information so that it used exclusively for safety purposes could not be more urgent," said Terry McVenes, a pilot and chairman of the union's air safety group.