MEMPHIS, APRIL 7 -- An off-duty Federal Express pilot armed with two claw hammers, a knife and a spear gun attacked the crew of a company cargo jet in midair today, critically injuring three people including himself.

Auburn Calloway, 42, was a passenger on FedEx Flight 705, when he burst into the cockpit of the DC-10 and attacked the plane's pilot, co-pilot and engineer about 50 miles west of Memphis, authorities said.

A bloody struggle ensued before the crew was able to overpower the man, who has worked for Federal Express since 1989.

Flight Capt. David Sanders, 49, radioed for help at about 4:45 p.m. EDT, and the plane returned to Memphis International Airport where it was boarded by police and emergency medical technicians.

"The captain was the only one with significant strength. He stopped the plane on the runway and deployed the emergency chutes so the police and EMTs could get inside," said Larry Cox, president of the Memphis Shelby County Airport Authority.

"The others were bloodied from head to foot. It was gruesome. They looked like victims of an automobile crash or an explosion," Cox said.

The Federal Bureau of Investigation said Calloway, who was hospitalized, will be charged Friday under U.S. air piracy statutes and could face life in prison if any of his victims dies of injuries from the attack.

Co-pilot James Tucker, 42, and flight engineer Andre Peterson, 39, were hospitalized in critical condition. Sanders was listed in noncritical condition.

Assistant special FBI agent Richard Marquise declined to speculate about the reason for the attack, but said the plane had been impounded at the airport and was being checked for explosives.

Federal Express said in a statement that Calloway tried to take control of the DC-10 while the plane was en route to San Jose, Calif. The company provided few other details.