National Airlines Flight 2511

National Airlines Flight 2511 was a United States domestic passenger flight from New York City to Miami, Florida. On January 6, 1960, the Douglas DC-6 serving the flight exploded in midair. The National Airlines aircraft was carrying 5 crew members and 29 passengers, all of whom perished. The Civil Aeronautics Board investigation concluded that the plane was brought down by a bomb made of dynamite. No criminal charges were ever filed, nor was the blame for the bombing ever determined, though a suicide bombing is suspected. The investigation remains open.

One of the victims was retired U.S. Navy Vice Admiral Edward Orrick McDonnell, a Medal of Honor recipient and veteran of both World Wars.

Flight history

National Airlines' New York-Miami route was usually flown by a Boeing 707 as Flight 601. On January 5, 1960, the 707 aircraft scheduled to fly to Miami was grounded due to cracks that were discovered in the cockpit windshield. The windshield replacement procedure would take eight hours to perform, so National Airlines transferred the passengers of Flight 601 to two propliner aircraft it had in reserve.

Passengers were boarded on these two replacement planes on a first-come, first-served basis. Seventy-six passengers boarded a Lockheed L-188 Electra. This aircraft flew to Miami and arrived safely.

The remaining 29 passengers boarded a Douglas DC-6B, which departed Idlewild Airport for Miami as Flight 2511. The crew consisted of stewardesses Mary O'Dell (24) and Valery Stewart (25), pilot Dale Southard (45), copilot Richard L. Hentzel (31), and flight engineer Robert R. Halleckson (34). The plane departed New York at 11:52 p.m. and was scheduled to arrive in Miami at 4:36 a.m. on January 6.

The aircraft, registration N8225H was described as being in good condition. It had four Pratt and Whitney R-2800 CB-16 engines and had accumulated 24,836 hours of flight time.

2511's flight plan called for it to fly south from New York to Wilmington, North Carolina, where it would continue south over the Atlantic Ocean. It would fly south 550 mi over the ocean to Palm Beach, Florida. The crew maintained radio contact with National Airlines' radio controllers and air traffic control, reporting clouds and instrument flying conditions. The crew checked in with Wilmington Airport at 2:07 a.m., and later reported flying over the Carolina Beach radio beacon at 2:31 a.m. This was the last radio contact with the airplane.

Crash and recovery

After losing contact with the DC-6 aircraft, National Airlines, the United States Coast Guard, and the United States Navy began an intensive search along the southeastern coast of the United States. The search was called off the following day, when National Airlines received word that there was a plane down in North Carolina.

At about 2:45 a.m. a farmer, Richard Randolph, heard the sound of an engine cutting in and out, followed by tearing metal and an explosion. Later that morning, after his teenage son McArthur Randolph found airplane wreckage in one of his father's fields, Richard Randolph drove to Bolivia, North Carolina, which had the nearest phone. He called Wilmington Airport to report the downed plane at approximately 7:00 a.m. When Highway Patrol officers responded, he led them to the crash site.

Bodies and wreckage were scattered over an area of 20 acre covering farm fields, marshland, and pine forests.

During the first day of search and rescue, investigators located 32 bodies of the 34 persons on board. One of the missing bodies was later found at the main crash site. The remaining body was found at Snow's Marsh, approximately 16 miles from the main site.

Initial reports speculated that the aircraft had disintegrated in mid-flight. One newspaper reporter indicated that the largest piece of wreckage he observed was a portion of the wing. A fragment of aluminum, believed to be a piece of the airplane's skin, was found on Kure Beach, 25 mi from the rest of the wreckage.

Bombing

The crash of National Airlines Flight 2511 came shortly after the crash of another National Airlines plane. National Airlines Flight 967 exploded over the Gulf of Mexico on November 16, 1959. The cause of the explosion was believed to be a bomb in the luggage of one of the passengers, Robert Vernon Spears, who enlisted a substitute to board the plane in his place. Spears was heavily insured, and the FBI indicated that his motive was insurance fraud. Similarly, Julian Frank was covered by almost $900,000 (roughly equivalent to $ million in dollars) in life insurance policies, including some purchased the day of the crash.

The CAB sent the material recovered from Frank's body to the FBI laboratories for testing and analysis. Analysis determined that the many wire fragments that were found embedded in Frank's body, in the seats on the right-hand side, and in the carpeting, were low-carbon steel wire, 0.025 in in diameter. One of the dismembered fingers recovered from the wreckage had been embedded in the face plate of a travel alarm clock. A life jacket from Kure Beach, found with parts of a flight bag embedded in it, tested positive for nitrate residue. A black "crusty" residue on Frank's right hand was found to be manganese dioxide, a substance found in dry cell batteries.

In addition to the evidence collected from Frank's body, there were also samples of residue taken from the air vents and hat rack located on the right side of the aircraft near the leading edge of the wing. These samples contained sodium carbonate, sodium nitrate, and mixtures of sodium-sulfur compounds.

The Civil Aeronautics Board concluded the severity of Frank's injuries and the numerous particulates found embedded in his body could only be attributed to his proximity to an explosion. Furthermore, the chemical compounds detected in the area around the explosion's point of origin were consistent with those generated by a dynamite explosion. The manganese dioxide samples collected from the seats near the focal point and from Frank's body indicated a dry cell battery was located very near the explosive. The CAB determined, based on the blast pattern, a dynamite charge had been placed underneath the window seat of row 7.

The CAB's chief investigator, Oscar Bakke, testified before the Senate Aviation subcommittee to this effect on January 12, 1960. The same day, the FBI formally took over the criminal aspects of the investigation.