The National Transportation Safety Board (NTSB) published their final report after looking into a plane crash in June 2023 that resulted in the deaths of four people.
On Wednesday, May 14, the NTSB announced that the probable cause of the crash was “pilot incapacitation due to loss of cabin pressure for undetermined reasons.” Another factor mentioned was the “pilot’s and owner/operator’s decision to operate the airplane without supplemental oxygen.”
According to the NTSB, it seems that the people on the airplane suffered from hypoxia, which means they didn’t have enough oxygen during the flight and became unable to function. The NTSB mentioned that the signs of hypoxia from high altitude “are often vague and are experienced differently by different individuals,” but if not addressed, it can result in death.
At the time of the crash, there were four people on board: Adina Azarian, 49, her 2-year-old daughter Aria, Aria’s live-in nanny, Evadnie Smith, 56, and the pilot, Jeff Hefner, 69.
Investigators could not figure out what caused the loss of cabin pressure or whether it happened suddenly or gradually.
The NTSB reported that the pilot got in touch with the Atlanta Air Route Traffic Control Center soon after taking off from Elizabethton Municipal Airport in Tennessee, just before 1:15 p.m. on June 4, 2023. About 15 minutes later, the pilot stopped answering air traffic control, even after “repeated attempts.”
Investigators believe that the pilot probably lost the ability to fly while climbing to the cruising altitude. They think the plane was on autopilot for the rest of the flight, until it could no longer stay in control.
After reaching 34,000 feet, the plane stayed at that height. About an hour later, it passed its target destination in Long Island and turned back, flying over Washington, D.C.
About two minutes before the crash, United Air Force pilots were allowed to connect with the plane, which caused a “sonic boom” that many people nearby could hear. They noticed the pilot slumped over in his seat. Also, no other passengers showed any movement.
Then, at 3:22 p.m., the plane “went into a quick downward spiral” and landed in a wooded area close to Montebello, Va.
An investigation showed that in the days and weeks before the crash, maintenance workers reported several problems, including “several related to the pressurization and environmental control system” and a missing oxygen mask on the pilot’s side.
The report stated that there was no proof showing these problems were resolved before the flight.
The NTSB reported that the pilot had health issues, like high blood pressure and high cholesterol, and was given medications that might cause impairment. They found “no evidence” that the pilot was at an “exceptionally high incapacitation risk” or had misused his medications when the crash happened.
The NTSB stated, “Based on the accident circumstances, it is likely that all airplane occupants were incapacitated due to a common environmental condition, such as loss of cabin pressurization.”