Boeing took another step toward putting active radio frequency identification tags onto airplane parts by beginning a 120-day test of the tags on board a FedEx plane. Boeing wants to test potential electromagnetic interference from the battery-powered tags, which the FAA has not approved yet.

The tags were installed on the flight deck, avionics compartment, cargo compartment and wheel wells. They operate at 915 MHz and transmit a signal every three seconds, making them readable from as far as 1,000 feet away.

Ken Porad, Boeing Commercial Airlines' RFID program manager, says the active tags will allow checks on aircraft inventory without opening access doors. Boeing has been promoting the use of RFID tags with its suppliers, saying the airline industry will benefit by being able to track and manage parts more effectively if they have chips holding information such as maintenance history.

But questions remain about how tagging numerous parts will affect airplane assembly, and whether active tags will be considered safe by the FAA. Last year the FAA approved the use of passive tags, which do not transmit signals independently, on airplane parts.