Western Airlines Flight 366

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Western Airlines Flight 366
Western Airlines Boeing 720 Volpati-1.jpg

An identical Boeing 720-047B from Western Airlines
Accident summary
Accident type Loss of control after mechanical failure of
the rudder
place Ontario International Airport , California , United StatesUnited StatesUnited States 
date March 31, 1971
Fatalities 5
Survivors 0
Aircraft
Aircraft type United StatesUnited States Boeing 720-047B
operator United StatesUnited States Western Airlines
Mark United StatesUnited States N3166
Departure airport Los Angeles International Airport , California , United StatesUnited StatesUnited States 
Destination airport Ontario International Airport , California , United StatesUnited StatesUnited States 
Passengers 0
crew 5
Lists of aviation accidents

The Western Airlines Flight 366 (flight number WAL366 ) was a training flight of Western Airlines from Los Angeles International Airport to Ontario International Airport in California , on 31 March 1971 a Boeing 720-047B was performed. When taking off at the destination airport, the Boeing crew lost control of their aircraft, which resulted in the crash and death of all five occupants.

plane

The aircraft that crashed was the 154th and last Boeing 720 ever built . The Boeing 720 was a shortened version of the Boeing 707 with a modified wing structure. Modified in this way, this type of aircraft should be positioned on the market as a medium- haul aircraft . Production was discontinued due to the lack of commercial success and the launch of the much more efficient Boeing 727 , which served the same market segment, in 1967.

The aircraft concerned was three years and seven months old at the time of the accident and had the type designation Boeing 720-047B . The machine was finally assembled at the Boeing plant in Renton , Washington, and made its maiden flight on August 27, 1967. The machine had the serial number 19439 , it was the 621st Boeing of the types 707/720 from ongoing production. The machine was then delivered to Western Airlines on September 7, 1967 , which approved it with the aircraft registration number N3166 . The four-engine medium-range narrow-body aircraft was equipped with four turbofan engines of the type Pratt & Whitney Jt3d-3B equipped. By the time of the accident, the machine had completed 11,521 flight hours, which accounted for 7,011 take-offs and landings.

Occupants and purpose of the flight

The machine was to be used for test flights on that day, which is why there were only five crew members on board:

  • The 49-year-old captain Raymond E. Benson sat in the right pilot's seat on the flight. He was piloting the machine at the time of the accident. Benson was licensed as a test captain and had been with Western Airlines since November 1945. He had type ratings for the aircraft types Convair CV-240 , Convair CV-340 , Convair CV-440 , Douglas DC-3 , Douglas DC-6 , Douglas DC-7 , Boeing 707 and Boeing 720. He had the type rating for the Boeing 720 Acquired on March 24, 1965. From his accumulated flight experience of 19,714 hours, Benson had completed 3,780 flight hours in Boeing 707 and Boeing 720 aircraft.
  • The 40-year-old captain Henry L. Coffin sat in the left pilot's seat on the flight. He had type ratings for the aircraft types Lockheed L-188 Electra , Douglas DC-3, Douglas DC-4 , Boeing 707, Boeing 720 and Boeing 727 . On July 24, 1964 he was admitted as first officer on board the Boeing 720B, and on March 21, 1969 as a flight captain. Coffin had 15,767 hours of flight experience, of which he had completed 3,840 flight hours in the cockpits of Boeing 707 and Boeing 720 machines.
  • The 32-year-old Second Officer Kent M. Dobson flew for Western Airlines since June 1968. In addition to the Boeing 707 and Boeing 720, he had a type rating for the Lockheed L-188 Electra. On September 30, 1968, he had qualified for the position of flight engineer on board the Boeing 720B. In his pilot career, Dobson had gained 3,988 hours of flight experience by the time of the accident, 1,740 of them in Boeing 707 and 720 aircraft.
  • In addition, there were two flight captains on board, 53-year-old Richard Ernst Schumacher and Howard A. McMillan, who were also trained to pilot the Boeing 720, but were not entrusted with this task at the time of the accident.

the accident

Flight 366 was carried out as a routine test flight to check the ability of the pilots present. The aircraft was used to make an ILS approach on runway 25, with engine no. 4 being idled in order to simulate an engine failure. The air traffic controller in charge gave the master clearance to land the machine at his own discretion or to make a missed approach . About 100 feet above the runway, and thus at the decision height, a simulated go- around was initiated in the event of an engine failure. The machine rose to 500 feet as it rolled and yawed to the right. While the roll and yaw movement continued, the machine fell on a south-easterly course with the aircraft nose pointing almost vertically downwards towards the ground. The machine shattered on impact, killing all five occupants.

root cause

The National Transportation Safety Board is investigating the incident. The investigation revealed that the support attachment of the hydraulic drive of the rudder had failed, which led to a complete loss of control of the rudder shortly after the start of the go-around maneuver. The support fixture failed due to a combination of stress corrosion cracking and high tensile loads.

swell

Coordinates: 34 ° 3 ′ 0 ″  N , 117 ° 36 ′ 0 ″  W.