MIAMI, FL, USA
N751MA
Boeing 707-323C
One hour after departure, the aircraft lost all hydraulic fluid from the utility hydraulic system. On approach to Miami, the flight engineer manually extended the main landing gear. Attempts to manually lower the nose landing gear were unsuccessful. A fly-by of the tower indicated the nose gear doors were open and the gear was retracted. The aircraft was landed in this configuration. After the incident, the aircraft was raised, and the nose landing gear was extended using the normal manual extension system. After the aircraft was taken to a hangar, the nose landing gear was retracted and manually extended 4 more times with no evidence of failure or malfunction. The utility hydraulic system relief valve housing failed due to fatigue cracking, resulting in the loss of all hydraulic fluid. The flight engineer had been flying for 21 days as a flight engineer at the operator and had accumulated 25 flight hours. He reported he had 54 total flight hours as flight engineer in the Boeing 707 and 3,800 flight hours as flight engineer in the Douglas DC-8.
On February 22, 1996, about 1618 eastern standard time, a Boeing 707-323C, N751MA, registered to Wilmington Trust Company and operated by Millon Air, Inc., landed with the nose gear retracted at Miami International Airport, Miami, Florida, while on a 14 CFR Part 121 nonscheduled international cargo flight. Visual meteorological conditions prevailed at the time and an instrument flight rules flight plan was filed. The aircraft received minor damage and the airline transport-rated captain, first officer, second officer, and extra pilot were not injured. The flight originated from Manaus, Brazil, on the same day about 1040. The flightcrew stated that about 1 hour after departure from Manaus, the flight engineer noticed the utility hydraulic system fluid level was going down. He attempted to isolate the source of the fluid loss, but this was unsuccessful, and all fluid was lost. On approach to Miami, the flight engineer attempted to manually extend the nose landing gear. This was unsuccessful. He then successfully lowered the main landing gear. Further attempts to lower the nose landing gear, with the help of a fourth crewmember and directions from Millon Air personnel on the ground in Miami, were unsuccessful. The flightcrew performed a fly-by of the Miami Air Traffic Control Tower, and controllers confirmed the nose landing gear was retracted and the nose landing gear doors were open. The aircraft was landed with the nose landing gear retracted and the nose landing gear doors open. After landing the flightcrew evacuated the aircraft via the cockpit windows. After the incident, the aircraft was lifted and the nose landing gear was extended by NTSB, FAA, and Millon Air personnel using the normal manual extension system. After the aircraft was moved to a hangar, the nose landing gear was retracted and manually extended four more times, with no evidence of failure or malfunction of the nose landing gear and manual extension system. Postincident testing of the utility hydraulic system indicated the pressure relief valve housing had failed, allowing loss of all hydraulic fluid from the system. Metallurgical examination of the failed pressure relief valve housing was performed by Frank P. Zakar, Materials Engineer, NTSB, Washington, D.C. The housing failed as a result of fatigue cracking which emanated from internal threads of the housing. (See attached Metallurgist's Factual Report) Company records indicated the flight engineer was hired by Millon Air in August 1995. He completed ground training and took an initial aircraft proficiency check on October 27, 1995. Records showed he completed initial operating experience on February 1, 1996, although the record did not have the signature of the Check Airman who certified the experience. The flight engineer received a line check on February 1, 1996. At the time of the incident the flight engineer had accumulated 25 flight hours as flight engineer on the Boeing 707 at Millon Air and reported he had 54 flight hours as flight engineer on the Boeing 707. He reported he had 3,800 flight hours as flight engineer on the Douglas DC-8.
failure of the flight engineer to follow the appropriate emergency procedure to manually extend the nose landing gear. Factors relating to the incident were: fatigue failure of the utility hydraulic system relief valve, which resulted in an inoperative normal gear extension system; the flight engineer's lack of total time in the incident aircraft; and inadequate training given by the aircraft operator.
Source: NTSB Aviation Accident Database
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