United Air Lines Flight 629

United Air Lines Flight 629
A United DC-6B similar to the aircraft involved
Bombing
DateNovember 1, 1955
SummaryBombing
Site8 miles east of Longmont, Colorado, U.S.
40°12′0.51″N 104°57′21.96″W / 40.2001417°N 104.9561000°W / 40.2001417; -104.9561000
Aircraft
Aircraft typeDouglas DC-6B
Aircraft nameMainliner Denver
OperatorUnited Airlines
Call signUNITED 629
RegistrationN37559
Flight originLaGuardia Airport, New York City, New York
1st stopoverChicago Midway International Airport, Chicago, Illinois
2nd stopoverStapleton International Airport, Denver, Colorado
Last stopoverPortland International Airport, Portland, Oregon
DestinationSeattle-Tacoma International Airport, Seattle, Washington
Occupants44
Passengers39
Crew5
Fatalities44
Survivors0

United Air Lines Flight 629, registration N37559 and dubbed Mainliner Denver, was a Douglas DC-6B aircraft that was blown up on November 1, 1955, by a dynamite bomb placed in the checked luggage. The explosion occurred over Weld County, Colorado, 8 miles east of Longmont, Colorado, United States, at 7:03 p.m. local time, while the airplane was en route from Denver to Portland, Oregon, and Seattle, Washington. All 39 passengers and 5 crew members on board were killed in the explosion and crash.

Investigators determined that John Gilbert Graham was responsible for bombing the airplane in a bid to kill his mother as revenge for his childhood and to obtain a large life insurance payout. Within fifteen months of the explosion, Graham—who already had an extensive criminal record—was tried, convicted, and executed for the crime.