United Air Lines Flight 629

United Air Lines Flight 629
	A United Air Lines DC-6
Accident summary
Accident type	Bomb explosion
place	near Longmont , Colorado , United States
date	November 1, 1955
Fatalities	44
Survivors	0
Aircraft
Aircraft type	Douglas DC-6B
operator	United Air Lines
Mark	N37559
Surname	Mainliner Denver
Departure airport	LaGuardia Airport , New York City , New York United States
1. Stopover	Chicago Municipal Airport , Illinois United States
2. Stopover	Stapleton International Airport , Denver , Colorado United States
3. Stopover	Portland International Airport , Portland , Oregon United States
Destination airport	Seattle-Tacoma International Airport , Seattle , Washington United States
Passengers	39
crew	5
	Lists of aviation accidents

On November 1, 1955, a Douglas DC-6B crashed on United Air Lines Flight 629 (flight number: UA629 ) after a bomb exploded on board. All 44 people on board were killed in the accident. The perpetrator was Jack Gilbert Graham , the son of a passenger, who had acted out of revenge and greed.

Machine and occupants

The aircraft used on Flight 629 was a Douglas DC-6B, which had made its maiden flight in 1952. It was the 224th final assembled DC-6 from current production with the work number 43538th The machine was equipped with four radial engines of type Pratt & Whitney R-2800 equipped. She was christened Mainliner Denver and carried the aircraft registration N37559 .

There were 39 passengers and 5 crew members on board. The youngest passenger was 13 months old, the oldest 81 years old.

Flight history

The plane had started at LaGuardia Airport in New York City and had made a scheduled stopover at Chicago Municipal Airport en route . The plane landed at Stapleton International Airport at 18:11 with an 11-minute delay. After the stopover, the machine was refueled with 3400 gallons (approx. 13,000 liters) of fuel, and a new crew was added. Captain Lee Hall, a fighter pilot from the Second World War , should control the machine on their next destination. The late arrival in Stapleton also had an impact on the aircraft's onward flight. The DC-6 took off at 6:52 p.m. local time. At 6:56 p.m. the crew gave a final radio message, reporting that they had passed the beacon over Denver.

the accident

At the bottom right the torn off rear tail of the DC-6

Seven minutes after take-off, air traffic controllers in Stapleton noticed two sources of light on the horizon, which fell to the ground at roughly the same speed within 35 to 40 seconds. Immediately afterwards, they saw a flash of light in the same direction, so bright that it illuminated the cloud cover hanging at 10,000 feet (about 3000 meters).

The pilots tried to contact all the machines in the area to check whether there was an emergency. The DC-6 of United Air Lines flight 629 was the only one that did not answer.

After the crash, numerous emergency calls were received from residents of the Longmont area . Callers reported loud explosions and burning debris that had fallen from the sky.

Salvage work

The rescue teams could only determine the deaths of all 44 occupants of the machine. The debris of the machine was scattered over an area of six square miles (about 15.5 square kilometers), falling on sugar beet fields .

A breakup of the machine could be determined in the air. Large pieces of debris from the wings, engines and central fuselage sections were recovered from two craters 150 feet (46 meters) apart. The fire patterns suggested that the large amounts of fuel on board had ignited upon impact. The fires were so violent that they lasted three days despite all attempts to extinguish them.

Accident investigation

Due to the immense force of the explosion, there was speculation early on that the machine had crashed as a result of a bomb attack and not a technical problem or a pilot's error. On November 2, the New York Times quoted witness Conrad Hopp, a farmer who lived near the crash site. Hopp claimed that he and his family had heard a huge explosion that sounded like a bomb went off. Hopp ran out of the house and saw a large fire in the sky above his stable.

The debris was gathered in a warehouse in Denver

The aircraft accident was investigated by the Civil Aeronautics Board . Investigators found that the explosion had occurred near the tailplane. It was so strong that it had torn the fuselage in the rear area into many small parts and one could rule out that it was caused by one of the aircraft's own assemblies. Items from cargo compartment No. 4 in the rear of the machine also had a strong smell of explosives.

The suspicion that a bomb had exploded on board the machine was also supported by the discovery of metal pieces of unusual thickness, which could not belong to any component of the machine and were covered with gray soot. Laboratory examinations of structural fragments in the rear cargo compartment revealed contamination with chemical substances known to be by-products of dynamite explosions . It has been suggested that the explosion originated in the baggage of one of the passengers.

FBI investigation

As the evidence of a crime intensified, the FBI joined the investigation into the case. The investigation focused on the living environment of the passengers boarded in Denver; the question was investigated whether they might have enemies. Some passengers had taken out life insurance at Denver Airport prior to departure , including 53-year-old businesswoman Daisie Eldora King, who was on her way to Alaska to visit her daughter. After identifying her suitcase, investigators found newspaper clippings in it reporting the conviction of her son, Jack Gilbert Graham , of forging documents related to counterfeit checks . Graham held a grudge against his mother for having sent him to a children's home as a child . He was registered as the beneficiary in both her will and life insurance.

The insurance policy purchased at a machine was for an amount of US $ 37,500 in the event of the death of Ms. King (adjusted for inflation, that would be US $ 357,000 today). Investigators discovered that some time before the crash, an unexplained explosion had occurred in a Denver drive-in restaurant owned by Ms. King that devastated the place. Investigators found that Graham initially insured the restaurant and then took out the insurance after the explosion.

Investigators eventually ransacked Graham's house and car. They found cables and other materials for building a bomb, as well as a duplicate of the life insurance policy taken out at the airport in which Jack Gilbert Graham had been entered as the beneficiary, and two other policies for $ 6,250, in which the beneficiary was the daughter and one Sister of Daisie Eldora King were specified. When comparing written samples, it was also found that Ms. King had not signed any of these policies, or the policy acquired at the airport. The documents were therefore worthless.

Graham testified that Mrs. King packed her travel bag herself. However, his wife Gloria stated that her husband had packed a Christmas present in his mother's bag the morning before the flight.

In light of the overwhelming burden of proof and contradictions in his testimony, Graham finally confessed on November 13, 1955, that he had placed the bomb in his mother's trunk. He said he tied a couple of sticks of dynamite around two detonators with 3-4 feet of twine. Graham used two detonators to ensure that even if one detonator fails, it will explode.

For his deed, Graham was inspired by the mass murderer Joseph-Albert Guay , who blew up a Douglas C-47 of Canadian Pacific Air Lines in the Canadian province of Quebec in 1949 . The modus operandi of Graham was the same as Guay.

Legal processing

Excerpt from the TV broadcast

After the confession was obtained and the judicial authorities looked into the matter, they were amazed to find that there was no law criminalizing causing an explosive explosion on board a commercial aircraft . In order to forestall a possible acquittal of Graham in the case, they ultimately only charged him with premeditated murder of his mother. As a result, despite the number of fatalities in the crash on Flight 629, the charges were only first degree murder. It was the first Colorado trial to be televised, and it was broadcast on KLZ and KBTV .

One of the defense strategies at the trial was to request that Graham's confession be annulled as he had not been informed of his rights before signing the confession. The request was rejected. During the 1956 trial, the defense was unable to rebut the massive burden of proof from the physical evidence presented by the prosecution and from the testimony of witnesses.

Graham was eventually sentenced to death in the gas chamber . The death sentence was carried out on January 11, 1957 at the Colorado State Penitentiary in Cañon City , Colorado , after some postponements . In a final statement prior to the execution, Graham said he felt no remorse for what he had done and no pity for the victims.

The case was the second bomb attack on an airliner in the United States and the first in which the perpetrator was convicted. The investigation into the bombing of United Air Lines flight 23 in 1933 had fizzled out. In response to the incident on Flight 629, US President Dwight D. Eisenhower signed a law making bombing airliners a criminal offense.

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Individual evidence

↑ ^a ^b Accident report in the Aviation Safety Network
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u Jack Gilbert Graham , FBI
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u A Byte Out of History - The Case of the Mysterious Mid-Air Explosion , FBI , December 9, 2005.
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q Philip Jett: United Flight 629: America's First Mass Murder in the Sky , Criminalelement.com , March 21, 2019.
↑ This figure was taken with the template: Inflation Determined, rounded to a full US $ 1,000, and relates to January 2020.

40.200142 -104.9561Coordinates: 40 ° 12 ′ 0.5 ″ N , 104 ° 57 ′ 22 ″ W.

[asn-1] Accident report in the Aviation Safety Network

[fbi-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u Jack Gilbert Graham , FBI

[fbi2-3] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r ^s ^t ^u A Byte Out of History - The Case of the Mysterious Mid-Air Explosion , FBI , December 9, 2005.

[jett-4] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q Philip Jett: United Flight 629: America's First Mass Murder in the Sky , Criminalelement.com , March 21, 2019.

[Vorlage-Inflation-5] This figure was taken with the template: Inflation Determined, rounded to a full US $ 1,000, and relates to January 2020.