Northwest Airlines ( NWACQ) is planning to retire the last dozen DC10 airplanes in the U.S. that fly passengers, replacing them on prized long-haul routes with newer, more efficient jets that have far more amenities. The airplanes' retirement could also force out several dozen pilots who are over 60. Federal regulations prohibit pilots who are over 60 from flying as captains or first officers, but allow them to fly as second officers. The DC10 is one of the few aircraft that requires what was once common -- three-man crews that include a second officer, also known as a flight engineer. "The DC10 is a reliable airplane, fun to fly, roomy and quiet, kind of like flying an old Cadillac Fleetwood," says Wade Blaufuss, spokesman for the Northwest chapter of the Air Line Pilots Association. "We're sad to see an old friend go." Most of Northwest's roughly 100 DC10 flight engineers are older pilots who chose to extend their careers, "in order to delay retirement or to make up for pensions that were lost" in airline bankruptcies, says Blaufuss, who flew for five years as a DC10 flight engineer. Northwest also flies the 747-200 made by Boeing ( BA), and it, too, requires flight engineers, some of whom could be bumped by DC10 pilots with more seniority. Northwest first flew the DC10 in 1972 after placing an order four years earlier. Its DC10 fleet peaked in 2001 with 45 aircraft, including 24 DC10-30s with 273 seats and 21 DC10-40s with 236 seats. By that year, though, the airplane's time was already passing. "When we landed them in Europe, guys from other airlines would come over and look at them," Blaufuss says. "You don't see them much anymore. They're kind of antiques." Northwest's remaining 12 DC10 aircraft in service are all from the 30 series, including five of the last six to be built at the old McDonnell Douglas Long Beach, Calif., production facility. The last scheduled DC10 passenger flight in the U.S. will be Northwest Flight 98, currently scheduled to depart Honolulu on Jan. 7, 2007, and arrive in Minneapolis the morning of Jan. 8.