Air Transport

The FAA has issued new phraseology rules in an effort to "avoid confusion" over the identification of Northwest Airlines and Delta Air Lines aircraft for pilots and controllers as the companies combine operating certificates and more than 350 Northwest aircraft are painted in Delta colours over the next 12 to 14 months.

Until the merging operating certificates under the Delta banner is complete, pilots and controllers handling Northwest flights will continue to use the "Northwest" aircraft call sign and the "NWA" three-letter identifier in flight plan, regardless of the paint scheme of the aircraft, says the FAA.

The policy calls for pilots of flights carrying Northwest call signs but painted in Delta colours to include the phrase "Delta colours" at the end of certain radio calls and on written flight plans.

FAA says the temporary policy, effective for one year starting 14 December, is required to avoid confusion when Delta and Northwest aircraft "are communicating with air traffic control but are not painted in the colours of the airline matching the call sign they are using."