Northwest Orient Airlines Flight 6231
| Northwest Orient Airlines Flight 6231 | |
|---|---|
 A Northwest Orient Boeing 727-200 |
|
| Accident summary | |
| Accident type | Loss of control |
| place |
Stony Point in Harriman State Park ( New York , United States )
 |
| date | 1st December 1974 |
| Fatalities | 3 |
| Survivors | 0 |
| Aircraft | |
| Aircraft type | Boeing 727-251 |
| operator |
Northwest Orient Airlines
|
| Mark | N274US |
| Passengers | 0 |
| crew | 3 |
| Lists of aviation accidents | |
The crash of a Boeing 727 on Northwest Orient Airlines Flight 6231 took place on December 1, 1974 in the vicinity of Stony Point in Harriman State Park ( New York State ). The plane was chartered to host a football team in Buffalo, New York . The accident happened before the landing in Buffalo, the three crew members were killed.
The cause of the accident was a stall caused by the fact that the pilots reacted incorrectly to an unreliable airspeed display. The values were incorrectly displayed because the crew had forgotten to switch on the pitot tube heater before take-off , which led to the icing up and thus blocking of this pitot tube .
The accident
The Baltimore Colts (now Indianapolis Colts ) were supposed to start their flight in Buffalo, New York, after a snowstorm in Detroit prevented their actual aircraft from taking off.
The replacement aircraft, a Boeing 727-251 with the air vehicle registration N274US, started at 19:14 from John F. Kennedy International Airport for the flight to Buffalo. When the aircraft reached 16,000 feet (4876 m), the warning signal for excessive airspeed sounded, which was replaced ten seconds later by a stick-shaker warning.
The plane then climbed further to 24,800 feet (7315 m), where it spun and lost altitude. A maximum acceleration of +5 g acted on the aircraft. At 19:26, the aircraft hit the ground on a slightly positive slope, right wing pointing down. The aircraft lost 24,000 feet in altitude in just 83 seconds, which translates into a rate of descent of 17,350 feet / minute (320 km / h).
The scene of the accident was only found on the day after the accident. Police described the crash site as a thickly forested swamp, and access was made even more difficult by wind and sleet.
The crew
Since it was a transfer flight, only three crew members were on board. Captain John B. Lagario had been with Northwest Airlines for eight years; First Officer Walter A. Zadra and Second Officer James F. Cox Jr. had both been with Northwest six years.
The cause of the accident
The National Aircraft Accident Investigation Board , the National Transportation Safety Board (NTSB), led the investigation into this accident and published the final report on August 13, 1975. The Federal Aviation Administration (FAA), Northwest Airlines, Boeing , and the Air Line Pilots Association were also involved and the International Association of Machinists and Aerospace Workers and the engine manufacturer Pratt & Whitney .
The authorities found that the pitot tubes, which measure the airspeed (indicated airspeed), were clogged with ice and the pilots were thus given incorrect speed information. The pilots assumed they were going too fast and pulled the plane up to quickly reduce speed. In fact, the plane was traveling at a normal speed, so the speed was too slow after it was pulled up. A stall occurred at a high angle of attack and the aircraft went into a spin.
From the accident report of the NTSB:
The accident was caused by the fact that the crew lost control of the aircraft because they did not recognize the high angle of attack, the stall at low speed and the spin. The stall was caused by the incorrect reaction of the pilots to the unreliable airspeed information. This in turn happened because the pitot tubes iced up during the flight.
The examination of the cockpit voice recorder (CVR) showed that the pilots considered the shaking of the control stick to be an indication of an approach to the speed of sound ("mach buffet"). In fact, however, the “stick shaker” warns of a stall and thus of a too low airspeed.
Similar events
- Alas Nacionales Flight 301 on a Boeing 757 on February 6, 1996
- Aeroperú flight 603 with a Boeing 757 on October 2, 1996
- Austral Líneas Aéreas flight 2553 on a Douglas DC-9 on October 10, 1997
- Air France Flight 447 on an Airbus A330 on June 1, 2009
- Air Algérie flight 5017 with a McDonnell Douglas MD-83 on July 24, 2014
- Saratov Airlines Flight 703 with an Antonov An-148 on February 11, 2018
Web links
- Final Accident Report Report by the NTSB on the accident (PDF; 1.1 MB)
- Aircraft accident data and report in the Aviation Safety Network (English)
Coordinates: 41 ° 12 '53 " N , 74 ° 5' 40" W.