United Airlines Flight 624 was an unfortunate incident that occurred almost 75 years ago. The crash of the Douglas DC-6 operating on a flight from San Diego, CA to New York (LaGuardia), NY with stops in Los Angeles, CA and Chicago, IL, led to 43 fatalities, leaving no survivors. After the crash, the Civil Aeronautics Board, the predecessor of the National Transport Safety Board (NTSB), completed a thorough investigation of the incident, and outlined its findings in a final report 14 months after the initial accident.
Aviation in the 1940s
Since aircraft in the 1940s were unable to fly nonstop between the West Coast of the United States and the East Coast due to fuel constraints, airlines often scheduled these intercontinental services with multiple stops along the way. For flight 628, United Airlines chose the cities of Los Angeles and Chicago as refueling stops, probably because this arrangement would allow the aircraft to pick up additional passengers in these cities.
The flight
The first two legs of the flight on June 17, 1948, were uneventful and routine. However, as flight 628 made its final approach into New York’s LaGuardia Airport just after noon, the crew were alerted to a fire in the forward cargo hold as the indicator light illuminated. As a result, the cabin crew and flight crew made the decision to throw carbon dioxide canisters into the cargo hold in hopes of extinguishing the fire.
Standard aviation practice at the time called for the release of relief valves prior to discharging the carbon dioxide bottles to prevent a buildup of the gas in the cabin. However, evidence suggests that the crew did not release these valves, and therefore there was a lot of carbon dioxide in the aircraft, which partially incapacitated the crew, who placed the aircraft on emergency descent. As the aircraft descended, it hit a power line, which led to the plane bursting into flames and ultimately crashing into a…