WASHINGTON — Government documents showed today that the crew of the Northwest Airlines jetliner that crashed in Detroit on Aug. 16, killing 156 people, made a series of mistakes.
The National Transportation Safety Board released documents that indicated the jet's automatic throttle was not set properly, but that the crew fixed the error.
According to the cockpit voice recordings, there is no evidence the crew went through a mandatory equipment checklist during taxiing to takeoff position. It is during that checklist that settings are checked for wing flaps, which give the plane lift on takeoff.
Flaps Found Retracted
A factual report completed by board investigators and an examination of the crash wreckage found that the MD-80's flaps, which are supposed to be extended during takeoff, were in a retracted position.
The safety board has not completed its investigation yet--and the cause of the crash is still undetermined--but an improper flap setting could cause a crash.
A failure by the pilot and co-pilot to run through the verbal checklist is considered a serious lapse by aviation experts.
The plane, bound for Phoenix, stalled and crashed shortly after takeoff in the nation's second worst air disaster.
"Examination of the available trailing edge flap actuators revealed dirt and soot marks that indicated the actuator positions at the time that the sooting occurred," safety board investigators said in the report.
"Measurement of the actuators that were intact at both attachments revealed consistent indications of a retracted flap position," they said.
There was a stall warning and the crew discovered that the automatic throttle would not engage, apparently because the thrust computer indicator--TCI--had not been set properly.
"Won't stay on," Capt. John Maus said, referring to the automatic throttle. "Won't go on," co-pilot David Dodds said.
"But they won't stay on," Maus said.
"OK, power's normal," Dodds said.
There was a sound of laughter recorded on the tape and Dodds said, "Vee one."
Seconds later two stall warning devices were sounded. The plane crashed in a ball of fire. The tape shows there were seven impact recordings--the last one recorded at 24 seconds after 8:45 p.m.