Investigation Summary
The investigation focused on the Boeing 707's rudder control system, specifically the Bendix-made rudder servo unit. Investigators discovered that during the manufacturing process, workers had used tweezers to bind wire bundles, which inadvertently damaged the insulation of the wires. This damage led to a short circuit that bypassed the pilot's inputs and commanded a hard-over rudder movement. The sudden yaw and roll occurred at a low altitude of approximately 1,600 feet, leaving the crew with insufficient time or altitude to diagnose the electrical failure and regain control. The crash was particularly significant as it was the deadliest single-aircraft accident in U.S. history at the time.
Final Conclusions
The Civil Aeronautics Board (CAB) determined the probable cause was a rudder control system malfunction, producing yaw, sideslip, and roll leading to a loss of control from which recovery action was not effective. The malfunction was traced to a short circuit in the rudder servo caused by damaged wiring insulation during assembly.
Photographic Evidence (1)
Video Analysis
Quality Control | American Airlines Flight 1 — A detailed look at how a minor manufacturing defect in the rudder servo wiring led to the catastrophic loss of American Airlines Flight 1 in 1962.
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Airframe & Maintenance
Crew Experience
Captain
James Heist
First Officer
Michael Barna Jr.
Second Officer
Robert Pecor
Flight Engineer
Robert Cain
Systems & Failure Modes
Rudder Control System
The system responsible for yaw control; a short circuit in the servo unit caused an uncommanded hard-over deflection.
Autopilot Servo
The Bendix-manufactured unit contained the damaged wiring that triggered the fatal rudder movement.
Interesting Facts
- 01At the time, it was the deadliest commercial aviation accident involving a single aircraft in the United States.
- 02The crash occurred only two minutes after takeoff.
- 03Investigators found that tweezers used during the assembly of the rudder servo unit had damaged wire insulation.
- 04The impact was witnessed by passengers on a Mohawk Airlines flight that took off immediately after Flight 1.
Safety Actions & Advisories
Rudder Servo Inspection
The FAA and Boeing implemented stricter quality control and inspection protocols for the assembly and maintenance of rudder servo units to prevent wiring damage.