Investigation Summary
The Wingfoot Air Express was conducting a series of promotional and test flights on its maiden voyage day, intended to showcase the future of passenger air travel. During its final leg of the day, returning to the White City aerodrome, the airship experienced a sudden ignition of its hydrogen envelope. As the craft buckled, the crew and passengers attempted to parachute to safety. Pilot Jack Boettner and chief mechanic Harry Wacker survived the jump. However, mechanic Carl Emery Weaver died when his parachute ignited, and photographer Milton Green Norton died from injuries sustained during his landing. Passenger Earl Horton Davenport attempted to parachute, but his equipment became tangled in the gondola cables, leaving him suspended fifty feet below the burning craft; he was killed instantly when the airship crashed into the bank building. The wreckage, including two rotary engines and gasoline tanks, crashed through a large glass skylight into the Illinois Trust and Savings Bank. The subsequent explosion of the gasoline tanks trapped employees within the bank's central rotunda, leading to a high ground casualty count.
Final Conclusions
The exact cause of the fire was never definitively determined, though several theories were proposed. These included sparks from the rotary motors igniting the hydrogen, the sun's rays causing gas expansion and a subsequent burst, or the accidental mixing of oxygen into the hydrogen supply during the charging process. The disaster directly led to the city of Chicago adopting new aviation regulations, the closure of the Grant Park Airstrip, and the establishment of Chicago Air Park, which later became Midway International Airport.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Systems & Failure Modes
Hydrogen Envelope
The lift for the Type FD dirigible was provided by highly flammable hydrogen gas, which ignited during flight, leading to the total loss of structural integrity.
Rotary Engines
The craft was equipped with two heavy rotary engines; investigators theorized that sparks from these motors may have ignited the leaking or venting hydrogen.
Parachutes
Early aviation parachutes were used by the five occupants; three deployments were successful in terms of opening, but only two individuals survived the descent and landing.
Interesting Facts
- 01The accident was the first major civil aviation disaster in United States history.
- 02Ten of the thirteen fatalities were bank employees working on the ground.
- 03In addition to the fatalities, 27 bank employees were injured in the crash and subsequent fire.
- 04The crash occurred in full view of thousands of spectators, including fans at a Chicago White Sox game at Comiskey Park.
- 05The airship was 150 feet long and powered by two rotary engines.
- 06The fire department required 30 minutes to recover bodies from beneath the heavy engine wreckage.
Safety Actions & Advisories
Chicago Aviation Ordinances
The city of Chicago adopted a new set of rules and regulations for aviation over the city to prevent similar disasters over populated areas.
Grant Park Airstrip Closure
The Grant Park Airstrip was closed to aviation activities due to its proximity to the downtown Loop.
Establishment of Chicago Air Park
The disaster spurred the creation of Chicago Air Park, which later became Chicago Midway International Airport, to move aviation operations away from the city center.
Known Controversies & Unanswered Questions
Undetermined Cause of Ignition
Reference ↗Despite multiple investigations, the exact cause of the hydrogen ignition remained a subject of debate. Theories ranged from sparks emitted by the rotary engines to static electricity or the expansion of gas due to solar heat, but no single cause was ever proven.