The FAA should require that all emergency locator transmitters in general aviation aircraft must be upgraded, the NTSB said (PDF) on Wednesday. The newer 406 MHz transmitters have significant advantages, the NTSB says, including longer range, better accuracy, and the ability to encode identification information, so rescuers know exactly what airplane is in distress. The safety board cites two accidents: In one airplane equipped with an older ELT, 16 hours elapsed before rescuers found the survivors, and when an airplane with a 406 MHz ELT crashed, the wreckage was located within an hour. The FAA should require an upgrade to the 406 MHz units before February 2009, when a change in satellite services will make the older units even less reliable, the NTSB says. “This [change in service] will necessitate U.S. search and rescue authorities reverting to older, less effective search methods and techniques, which would greatly decrease the likelihood of finding downed aircraft in a timely manner,” the NTSB said. AOPA has opposed mandatory ELT upgrades, citing costs. The new units can cost from $1,000 to $1,500. The 406 MHz units activate in about 81 to 83 percent of crashes. The older units, which operate on the 121.5 MHz frequency, have an activation rate of 73 percent in actual crashes, AOPA said.