Faulty Nose Gear Door Actuator Examined

The National Transportation Safety Board has released an updated factual report on the Northwest Airlines Flight 74 landing accident at Guam International Airport (GUM) on August 19, 2005.

As ANN reported, the NWA Boeing 747-200 experienced trouble extending the landing gear on approach to GUM, indicated by a red light on the landing gear indicator and a warning horn. After aborting the initial approach and consulting a cockpit operations manual, the flight crew concluded the landing gear was "down and locked."

Soon after touchdown, the nose gear collapsed, and the plane skidded to a stop on the runway. The 340 persons aboard evacuated the stricken jet via inflatable slides, with only two minor injuries reported. The aircraft, damaged beyond all repair, was eventually scrapped, the Guam Pacific Daily News said.

Subsequent examination and testing of the aircraft's nose gear components revealed several problems with the landing gear door actuator: one of two "lock keys" was found to be installed backward; strands of metallic material were found in different areas of the actuator; the "manual override crank gland was found lightly torqued with safety wire installed"; the "lock ram and lock ring" were damaged; and the piston rod seal was "installed with non-standard backup rings," according to the report.

Unknown to the flight crew of Flight 74, the same aircraft had experienced similar problems just 10 days prior, but the captain of that flight failed to make note of it in the plane's maintenance log.

The NTSB's final report on the accident and determination of probable cause has not yet been released.

FMI: www.nwa.com, www.ntsb.org