United Airlines Flight 624

United Airlines Flight 624, a Douglas DC-6 airliner, registration NC37506, was a scheduled passenger flight that originated in San Diego, California with stops in Los Angeles and Chicago en route to LaGuardia Airport in New York City. The four-engine propeller-driven airplane crashed at 1:41 p.m. Eastern Daylight Time on June 17, 1948 outside of Aristes, Pennsylvania, killing all 4 crew members and 39 passengers on board.[1]

United Airlines Flight 624
A DC-6 similar to the aircraft involved in the accident
Accident
DateJune 17, 1948
SummaryIn-flight fire (false warning) followed by crew incapacitation
SiteConyngham Township, Columbia County, near Aristes, Pennsylvania
40.820427°N 76.361042°W / 40.820427; -76.361042
Aircraft
Aircraft typeDouglas DC-6
Aircraft nameMainliner Utah
OperatorUnited Airlines
RegistrationNC37506
Flight originLindbergh Field, San Diego
1st stopoverLos Angeles Airport
Last stopoverChicago Municipal Airport
DestinationLaGuardia Airport, New York City
Occupants43
Passengers39
Crew4
Fatalities43
Survivors0

Accident sequence

Flight 624 from San Diego had just completed a routine initial descent as part of its approach into the New York area, when the forward cargo hold fire indicator light illuminated, leading the flight crew to believe there was a fire in that cargo hold. Although this later turned out to be a false alarm, the crew decided to discharge CO
2
bottles into the forward cargo hold, to try to extinguish the possible fire.

While proper operating procedure called for opening the cabin pressure relief valves prior to discharging the CO
2
bottles, to allow for venting of the CO
2
gas buildup in the cabin and cockpit, there was no evidence the crew opened the relief valves. Consequently, the released CO
2
gas seeped back into the cockpit from the front cargo hold and apparently partially incapacitated the flight crew. The crew then put the aircraft into an emergency descent, and as it descended lower it hit a high voltage power line, bursting into flames, then smashing through the trees of a wooded hillside.[1]

Ed Darlington of radio station WCNR at nearby Bloomsburg said "there was no sign of life and apparently everyone was killed." The scene of the wreck was in a sparsely wooded area about five miles from Mt. Carmel, a small town 135 miles from Philadelphia where delegates are gathering for the Republican National Convention. News of the crash brought excited whispering from the delegates. No one knew for certain whether any high Republican officials were on the plane.

Ira F. Roadarmel of Mt. Carmel, one of the first persons on the scene, said "everything was scattered. The largest piece of the plane left was an engine. The rest of the plane was in small parts — so small they could be carried."

George Minnich, an employee of Midvalley Colliery No. 2, which the plane missed by only 100 yards in its descent, said that he saw the plane bank. "Suddenly there was a horrible crash," he said. "All you could see was a mass of flames. It sounded as though the end of the world was coming."[2]

The plane's logbook, found near the scene of the crash in a thickly wooded area, identified the plane's pilot as Captain George Warner.

The Sheboygan Press, June 17, 1948.


Notable victims

Among the passengers were Broadway theatre impresario Earl Carroll and his girlfriend, actress Beryl Wallace, plus Henry L. Jackson, men's fashion editor of Collier's Weekly magazine and co-founder of Esquire Magazine.

Investigation and final report

The Civil Aeronautics Board investigated the crash and published a narrative describing the following sequence of events in its final report:[1]

The airplane, named Mainliner Utah, arrived in Chicago at 09:52 en route from Los Angeles to New York. After a 52-minute turnaround, the DC-6 departed for New York. The airplane climbed en route to its planned altitude of 17,000 feet. At 12:23, and at 12:27 the crew made a routine acknowledgment of a clearance to descend en route to an altitude between 13,000 and 11,000 feet. A little later a fire warning led the crew to believe that a fire had erupted in the forward cargo hold. They then discharged at least one bank of the CO
2
fire extinguisher bottles in the forward cargo hold. Because they did not follow the correct procedure, the cabin pressure relief valves were closed. This caused hazardous concentrations of the gas to enter into the cockpit. These concentrations reduced the pilots to a state of confused consciousness probably resulting in loss of consciousness. An emergency descent was initiated until it described a shallow left turn, heading towards constantly rising terrain. Five miles east of Shamokin the airplane, flying only 200 feet above the ground, entered a right climbing turn. As it passed to the north of Mt. Carmel, the climbing turning attitude increased sharply. The airplane then crashed in a power line clearing on wooded hillside at an elevation of 1,649 feet. The airplane struck a 66,000 volt transformer, severed power lines and burst into flames.

Investigation revealed that the fire warning in the cargo compartment had been false.

— CAB File No. 1-0075-48

The CAB concluded with the following probable cause for the accident: "The Board determines that the probable cause of this accident was the incapacitation of the crew by a concentration of CO
2
gas in the cockpit."

See also

References

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