Investigation Summary
The investigation focused on why a highly experienced crew, led by a captain with over 28,000 hours, flew a functional aircraft into the water. The crew was using the autopilot in 'heading mode' to fly the approach, which was not a recommended procedure for the final segment. During the descent, the First Officer was calling out altitudes, but both he and the Captain were likely misled by the new drum-type altimeters, which were harder to read than the older three-pointer style. The crew failed to cross-check their altitude against the drum altimeter's small digits, and a possible missetting of the Captain's altimeter by 0.12 inches of mercury (representing about 125 feet) further eroded their safety margin. The lack of high-intensity approach lights at LaGuardia's Runway 22 meant the pilots had no visual cues to correct their descent in the foggy, rainy conditions until impact.
Final Conclusions
The Civil Aeronautics Board determined the probable cause was a premature descent below landing minimums due to crew preoccupation with aspects of the new aircraft and environment, leading to the neglect of essential flight instruments. Contributing factors included the crew's limited experience on the Electra, faulty autopilot approach technique, an erroneous altimeter setting, marginal weather, and sensory illusions caused by inadequate approach lighting.
Video Analysis
American Airlines Flight 320 News Report & Aftermath Footage — Archival newsreel and aftermath footage showing the recovery of the Lockheed Electra wreckage from the East River in February 1959.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Albert Hunt DeWitt, aged 59.
First Officer
Frank Hlavacek, aged 33. Survived.
Flight Engineer
Warren Cook, aged 36. Survived.
Systems & Failure Modes
Drum-type Altimeter
A new style of altimeter that used a rotating drum for thousands of feet and a single pointer for hundreds; suspected of being misread by the crew.
Autopilot (Heading Mode)
The crew used the autopilot to fly the approach course rather than hand-flying, which contributed to their lack of tactile awareness of the descent.
Interesting Facts
- 01The aircraft was a brand-new Lockheed Electra delivered to American Airlines only months prior.
- 02The Captain had over 28,000 hours of flight time but only 48 hours on the Electra type.
- 03The crash occurred on the same day as the 'Day the Music Died' Beechcraft Bonanza crash in Iowa.
- 04Runway 22 at LaGuardia lacked high-intensity approach lights and a glideslope at the time.
- 05The First Officer, Flight Engineer, and one stewardess survived the impact and were rescued from the water.
Safety Actions & Advisories
Flight Data Recorder Mandate
The CAB recommended that all large turbine-engine aircraft used in air transportation be equipped with a flight recorder to assist in accident investigations.
Simulator Training Requirements
Recommended that air carriers establish simulator training programs for aircraft requiring significantly different operational techniques before they enter service.
Autopilot Approach Criteria
Recommended establishing specific autopilot approach limitations and criteria for all air carriers.
Known Controversies & Unanswered Questions
Altimeter Design Dispute
Reference ↗There was significant debate regarding whether the new drum-type altimeters were inherently prone to misinterpretation or if the crew simply failed to monitor them correctly.