The crash of a private jet, which occurred after a sonic boom was heard, was due to pressure loss, a report indicates

An unresponsive private aircraft that drew a response from military jets in 2023, causing a sonic boom in and around Washington, D.C., most likely suffered a loss of cabin pressure before it crashed in Virginia, the National Transportation Safety Board said in a report released on Tuesday.

All four people on board were killed when the private business jet went down near Montebello, Va., in June 2023. The N.T.S.B. said in its report that the plane most likely suffered a loss of cabin pressure, leading to a lack of oxygen and incapacitating the pilot and the three passengers.

The board also found that the pilot operated the plane without supplemental oxygen, contributing to the accident.

The cause of the pressure loss was unclear, the report said.

The plane, a Cessna 560 Citation V, had a number of maintenance issues that were flagged, including several related to the pressurization and environmental control system, according to the report. Two days before the flight, maintenance crews noted that there was no pilot-side oxygen mask, and that the supplementary oxygen levels were so low that oxygen masks would not have been deployed if the cabin lost pressure.

There was no evidence that these issues were addressed before the flight, the report said.

The plane took off from Elizabethton Municipal Airport in Elizabethton, Tenn., around 1:15 p.m. on June 4, 2023, and was headed to Long Island MacArthur Airport in Ronkonkoma, N.Y. The pilot stopped responding to commands from air traffic control about 15 minutes after taking off, the report said.

The pilot probably became incapacitated as he climbed to a cruising altitude of 34,000 feet, the report said.

Rather than land on Long Island, the plane, which appeared to be on autopilot, turned around and flew over Washington. Military jets sent to make contact with the plane traveled at supersonic speeds that produced a loud boom heard across the region.

The pilots of the military jets, who used radio transmissions, flight maneuvers and flares to try to intercept the private aircraft, observed that the pilot of the Cessna was “completely slumped over” and “motionless,” according to the report.

At around 3:22 p.m., the plane began “a high-velocity, near vertical descent” into mountains just north of Montebello, Va., the report said.

The impact of the crash created a crater, and wreckage was scattered around the accident site.

The victims were identified as Adina Azarian; her 2-year-old daughter; her nanny and the pilot.

The jet was owned by Encore Motors of Melbourne, a company in Florida. The company’s management could not immediately be reached for comment on Tuesday night.