Synopsis
Air Florida flight 90 was flight from Washington national airport (located across the Potomac river) to Hollywood International Airport, Fort Lauderdale with an intermidiate stop at Tampa international airport on January 13, 1982. The aircraft was a Boeing 737-222 with 5 crew members and 74 passengers. Washington national airport was closed in the morning due heavy snowstorms, but it was opened later in the afternoon after the snowstorm subsided.
The aircraft was de-iced using the de-icing agent monopropylene glycol .The flight crew experienced several delays due to the bad weather and due to the lack of traction for the ground services tow motor. The pilots used reverse thrust to leave the gate, but to no avail. Eventually a tug ground unit properly equipped with snow chains enabled the plane to leave the gate. The flight experienced another 49 minute delay on the taxiway. Then, at 3:59 p.m., the plane took off in heavy snow and icing conditions.As the plane began its takeoff roll, the first officer noted that the instrument reading were not consistent with reality. The plane took an additional 800m to take off from the runway. As it became airborne, the aircraft reached an altitude of 350 ft before it started sinking again. After being airborne for just 30 sec, the aircraft crashed into a bridge across the Potomac river. After hitting 6 cars and a truck on the bridge, the plane crashed into the freezing Potomac river.
The accident killed 78 people, including 4 civilians on the ground, and caused serious injuries for 10 people, including 5 on the ground. In total, only 5 people survived.
Cause of the crash
This accident provides a great illustration of Reason's Swiss cheese model. There were several latent and procedural errors or mishaps commited by the air-crew which finally "lined up" into one big mishap. The latent failures in this case include:
1) Using reverse thrust to exit the gates, which evidently cause the engine to ingest slush, ice and snow.
2) Not returning to the gate for de-icing after there was a significant build-up of snow and ice on the plane during taxi and holding. This can partially be attributed to organisational pressures forcing the pilots to take off without any further delays.
3) Failing to turn on the anti-icing system during take-off
4) Intentionally following a DC-9 closely during taxi. This caused aditional buildup of snow and ce on the wings
5) Lack of experience of the pilots when it came to flying in cold weather
6) Failing to abort the take-off when the readings coming from the plane were seen to be inaccurate. One of the key reasons why the readings were inaccurate was because of icing on the sensors.
Impact of crash on aviation
This crash is one of the most important accidents in aviation history. This crash led to many regulatory changes when it comes to pilot training and procedural changes. It has also been used as a case study in crew resource management and human factors for many years.
The following videos give a detailed explanation of the crash and its investigation
(Source - Seconds from disaster, Season 3 episode 12)
Part 1
Video embedded from YouTube on 24 September 2009
Part 2
Video embedded from YouTube on 24 September 2009
Part 3
Video embedded from YouTube on 24 September 2009
Part 4
Video embedded from YouTube on 24 September 2009
Want to know more?
- **Air Florida flight 90 **
- This aritcle provides detailed information on the crash.
