Wilmington, North Carolina —
In the early hours of January 6, 1960, National Airlines Flight 2511, a Douglas DC-6 traveling from New York City to Miami, was torn apart midair by a powerful explosion, killing all 34 people on board.
The plane, carrying five crew members and 29 passengers, disintegrated over North Carolina near Bolivia and Kure Beach. The crash scattered wreckage across two main sites and left investigators grappling with what caused the catastrophic event.
The Investigation
The Civil Aeronautics Board (CAB), the primary investigative body for aviation accidents at the time, quickly launched a detailed inquiry. Wreckage was painstakingly collected and reconstructed inside a hangar at Wilmington Airport using wooden frames and chicken wire.
Investigators determined that the explosion originated just ahead of the leading edge of the plane’s right wing. Portions of the aircraft recovered from Kure Beach were traced to this area, while an irregular triangular section of fuselage was entirely missing, pointing to a violent in-flight detonation.
A Notable Victim
Among the victims was retired U.S. Navy Vice Admiral Edward Orrick McDonnell, a highly decorated veteran of both World Wars and a Medal of Honor recipient. Other passengers included a vice president of the Continental Bank of Cuba, a University of Miami student, a pharmacist, and an insurance adjuster. Several victims were standby passengers who had boarded the flight at the last minute.
A Suspicious Passenger
Investigators found one passenger’s injuries particularly alarming. The body of Julian Frank, a New York City lawyer, was discovered away from the main crash site in Snow’s Marsh on the west side of the Cape Fear River.
Unlike other victims, Frank’s body showed severe trauma consistent with being at the center of an explosion. Both legs were severed, his muscle tissue was torn, and fragments of metal, wire, and debris—including a hat ornament—were embedded in his flesh. The coroner also noted blackened areas on his skin similar to gunshot residue.
Frank underwent two autopsies to extract fragments lodged in his body. Forensic tests revealed manganese dioxide—commonly found in dry cell batteries—on his hands and nearby debris, suggesting a bomb’s electrical detonator.
Adding to suspicions, Frank was under investigation for running a charity fraud in New York and allegedly misappropriating up to one million dollars. He had purchased nearly $900,000 in life insurance (equivalent to around $7.1 million today), including some policies taken out on the day of the flight.
Forensic Evidence Points to Bomb
Further investigation revealed small wire fragments, sodium nitrate, and other chemicals associated with dynamite in the cabin’s carpeting and air vents near seat 7.
One of the most chilling pieces of evidence: a human finger bone was discovered embedded in the metal face plate of a travel alarm clock recovered from the wreckage—strongly suggesting a bomb with a timing mechanism.
By early 1960, the CAB had ruled out other potential causes, such as structural failure, propeller explosions, engine fires, oxygen bottle explosions, lightning strikes, and midair collisions.
Other Theories
Despite strong evidence pointing to a bomb, some experts proposed alternative explanations, such as an engine fire causing explosive decompression. Some speculated that Frank, known to fear flying, may have panicked and damaged a window, although forensic evidence largely discounted this theory.
Some pilots suggested repeated stress on aircraft during training flights could have weakened the DC-6’s structure. However, investigators found no signs of metal fatigue or prior structural issues with the aircraft.
Official Conclusion
On January 12, 1960, Oscar Bakke, the CAB’s chief investigator, testified before the Senate Aviation Subcommittee that the explosion was the result of a dynamite bomb placed beneath seat 7 on the right side of the passenger cabin.
“The probable cause of this accident was the detonation of dynamite within the passenger cabin,” the CAB’s final report concluded. However, the report did not assign responsibility for planting the explosive, leaving the question of who placed the bomb—and why—unanswered.
On January 20, 1960, the FBI assumed control of the criminal investigation. Over six decades later, no one has been charged in connection with the bombing, and the case remains officially open and unsolved.
A Lingering Mystery
The tragedy of National Airlines Flight 2511 remains one of aviation’s haunting unsolved mysteries, underscoring the vulnerability of civil aviation to acts of sabotage. It also highlighted how life insurance fraud had become an emerging criminal motive for bombing commercial aircraft during the mid-20th century.
For the families of those lost, the lack of closure continues to cast a shadow over this shocking chapter in aviation history.
