This document summarizes a case study on Air Florida Flight 90, which crashed in 1982 shortly after takeoff from Washington National Airport. The crash was caused by ice buildup on the wings due to the pilots not turning on the engine anti-ice system before takeoff in blizzard conditions with 1/4 mile visibility. The crash killed 74 passengers and crew and highlighted issues with crew resource management, communication, decision making, and training at Air Florida that contributed to the accident. A investigation of the flight data and cockpit voice recorders revealed that anomalies in the engine readings caused by ice led the pilots to believe thrust was higher than it was, resulting in a stall during takeoff.

1. Case Study: Air Florida 90
"Larry-we're going down Larry!".
First Officer-Roger Pettit
Gregory C. Stamp
ASCI 604 Human Factors (Prof. Dr. R. Tyler)
Embry-Riddle Aeronautical University 1

2. AGENDA
 Background
 Accident Details
 “How and Why”
 Human Factors Application
 Conclusion
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3. Background
 Date: January 13, 1982
 Bitter winter’s day with blizzard of snow
 Temperature Conditions: as low as -5ºC (? ºF)
 Limited Visibility: ½ mile in snow showers
 Cloud Ceiling: 400ft
 Flight Schedule: 2:15 pm Boeing 737
departure (National Airport to Fort Lauderdale, FL)
 Aircraft flight hours: ?
 Maintenance history: ? www.securiteaerienne.com
 Passengers: 74 /
 Cock Pit Personnel: ill/air-florida-90-b
 Pilot: Captain Larry Wheaton
 First Officer: Roger Pettit
 Both were fairly young pilots/ new at Air Florida
 Airline: Air Florida had rapid growth after Deregulation Act of 1978
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4. Accident Details
 Key Events Leading up to Crash
(Timeline):
 Just Before 1:40pm

Closed airport to plough instrument runway

Captain requested de-icing and then cancelled after
rejection of departure
 2nd de-icing requested after re-opening of airport
 At 3:23pm

Palm 90 cleared to depart gate

Captain mis-used reverse thruster to assist in push off
(violation of company policy)
 Palm 90 taxied into position behind New York Air
DC-9 to melt snow
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5. Accident Details
 At 3:59pm
 Palm 90 was cleared for take-off from Runway36-
visibility down to ¼ mile
 Within less than a minute after take-off- Palm 90
loss airspeed and started descending and
ploughed in 14th Street (“Rochambeau”) Bridge
 Fell into Potomac River with only the tail visible
 After Crash- “The Aftermath”:
 Rescue team impeded by icy conditions
 Only 6 people survived, 4 motorists died
 Recovered both the FDR and CVR from the bottom
of the river
 Critical in solving the puzzle of Palm 90”.
 Discovered captain stated anti-ice switch was off
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6. “How and Why”
 ‘How:’
 Captain Wheaton positioned Palm 90 behind
New York Air DC-9, use exhaust to melt the
ice off fuselage and wings

Counter effect ice melted and blew back over
the wings and re-frozen
 Anomalies in engine instrument readings
 Investigation concluded:

Failure to use engine anti-ice mechanism

Created large amounts of ice and snow to
gather in the engines without being melted.
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7. “How and Why”
 ‘Why:’
 Exhaust from the DC-9 caused a lower than normal
reading on one of the EPR gauges.
 Spectrum analysis of the engine sounds from the CVR
indicated that the anomalies in engines out the takeoff.
 Investigators found that the engine de-ice system was
turned off
 Ice on the compressor inlet pressure probe would cause a
higher than actual thrust reading on the EPR gauges.
 Investigators found that ice build up in the wing
leading edge and slats could cause an abrupt nose up pitch
on takeoff
 First Officer Pettit believed that the engines were producing
max thrust

The throttles weren’t advanced to provide more power to
prevent stall 7

8. Human Factors
Application
 Decision Making:
 Poor decision chain attributed Palm-90 accident
 Determine what must be done
 Pilot judgment error
 Inappropriate procedures
 Crew Resource Management:
 Accident help initiated training in crew resource
management
 Instill professional pilots a positive attitude and skills
 Improve flight crew communication.
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9. Human Factors
Application
 Communications
 Break down in flight crew communication
 First Officer Not assertive with communication to Pilot

Ex: “Pettit remarked several times that "that doesn't
seem right!"
 Training
 Air Florida lacked the necessary infrastructure
 Provide adequate training for flight crew
 Improper supervision of flight operations.
 Lack of experience from both Pilot and Co-pilot
 Selection
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10. Questions???
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