Lack of oxygen explored as possible cause in crash involving Melbourne plane

Aviation experts say the odd, wayward flight of a Melbourne-based Cessna that crashed Sunday into the Virginia mountains, killing a Brevard pilot and the daughter and granddaughter of a Brevard couple, may be an indication that the pilot and passengers lost oxygen before crossing into restricted airspace over the nation's capital.

The air space violation prompted NORAD to send six F-16 fighter jets to intercept the Cessna, leaving in their wake sonic booms that rattled residents across Maryland and Washington, D.C.

The turbine twin-engine aircraft crashed at about 3:30 p.m. Sunday in heavily wooded, mountainous terrain nearly three miles north of Montebello, Virginia.

The pilot, identified by the plane’s owner in a Washington Post interview as Jeff Hefner, and three passengers were aboard the aircraft at impact. The passengers were identified by John Rumpel to the Washington Post as Adina Azarian, 49, and 2-year-old Aria. Additionally, an unidentified nanny was on board. There were no survivors.

Jeff Hefner, 69, of Satellite Beach, was a commercial airline pilot who flew for Southwest Airlines and who was qualified to fly 737 passenger planes. Hefner was also part owner of the Flying Tigers Aviation School based at the Melbourne Orlando International Airport.

His LinkedIn account lists Hefner as having had 30 years of aviation experience. A woman answering the phone at a family member of Hefner's said Tuesday morning that there would be no comment.

John Rumpel would not comment to FLORIDA TODAY.

Cessna pilot reportedly slumped over

The scrambled fighter pilots — from 113th Fighter Wing, out of Joint Base Andrews in Maryland — reported seeing the Cessna Citation pilot slumped over as the plane continued on its course over the nation's capital toward Virginia, according to the Associated Press.

“If you hear this transmission, contact us,” said one of the military jet pilots who identifies herself as being with the Air National Guard, according to recordings of plane-to-plane contact captured on LiveATC.net, a network that records public safety radio traffic.

Another military pilot then radioed the Cessna pilot, saying “You have been intercepted. Contact me.” But the plane flew on before spiraling 30,000 feet down.

What happened: A sonic boom over Washington: Breaking down the Cessna 560 Citation plane crash in Virginia

Rumpel told The New York Times that authorities suggested the plane could have lost pressurization during its flight to New York. The Cessna Citation took off from Elizabethton Municipal Airport in Tennessee at 1:13 p.m. Sunday, and headed for MacArthur Airport in Long Island, New York. Air Traffic Controllers lost contact with the airplane during the aircraft's ascent.

The mysterious civilian crash was eerily similar to an October 1999 flight that killed golfer Payne Stewart. In that case, Stewart was aboard his Learjet flying from Orlando when the chartered flight apparently lost pressure, causing oxygen levels to fall.

Stewart's plane continued to fly before crashing in South Dakota, killing six people, the FAA reported. The NTSB later reported that the pilot likely became incapacitated because of hypoxia, a condition where oxygen levels are restricted, causing those affected to pass out.

NTSB investigating crash site in Virginia

Federal investigators from the National Transportation Safety Board were at the Virginia crash site Monday, looking over the shattered remnants of the plane. "The wreckage is highly fragmented,” NTSB investigators Adam Gerhardt said during a televised press conference. It rests along a sparsely located portion of the George Washington National Forest.

More: Brevard family linked to crashed plane that strayed into restricted airspace over capital

The final report could take up to two years to complete as investigators pore over information, including maintenance records and other avionics that could have retained data about the flight, Gerhardt said Monday.

The airplane is registered to Encore Motors in Melbourne, which is owned by Barbara Rumpel. The Rumpels are prominent in Brevard County business and political life. John Rumpel told the Washington Post that his "entire family" was onboard the Cessna, the Post reported.

The White House, alerted about the aircraft Sunday, expressed its “deepest condolences” on Monday to the Rumpel family and others with connections to those onboard the plane.

“We need to keep them front and center,” National Security Council spokesperson John Kirby said, according to the Associated Press.

Azarian, 49, was well-known in New York City and Long Island real estate, the Associated Press reported. Azarian was described by friends and relatives as a fiercely competitive entrepreneur who started her own brokerage and was raising her daughter as a single parent, according to AP.

“Being a mom was everything to her,” Tara Brivic-Looper, a close friend who grew up with Azarian on the Upper East Side, told the Associated Press. “That they were together (at the end) is fitting."

Could hypoxia have been a factor?

Preliminary information indicates the last communication attempt with the airplane was at approximately 1:28 p.m., when the plane was at 31,000 feet, according to the NTSB. The plane then climbed to 34,000 feet, where it remained for the rest of the flight until 3:23 p.m. when it began to descend and crashed about nine minutes later. The plane was flying at 34,000 feet, when it flew over MacArthur Airport at 2:33 p.m. and then began to loop back toward Washington, D.C, the NTSB said.

The wreckage will be sorted, gathered and later taken to a forensic lab in Delaware to be reviewed. Investigators will focus on determining just when the pilot when unresponsive and why the Cessna looped back toward Washington, D.C., Gerhardt said.

“I want to stress that we are here to not only to figure out what happened but why this happened to prevent future accidents from happening again,” Gerhardt said.

One of the possibilities that NTSB investigators will look into whether the Cessna’s oxygen levels may have dropped, leading to hypoxia. The condition, which causes disorientation and ultimately unconsciousness, can happen if there is equipment failure aboard an aircraft, the FAA has said.

“The slow onset of hypoxia is really, really insidious. It happens so slowly, said Capt. Shem Malmquist, a commercial pilot with 32 years of flight experience and a visiting professor at the Florida Institute of Technology.

Federal investigators will likely be looking for any system failures.

Such a failure would be catastrophic if the pilot is unable to recover, Malmquist said. “They may feel euphoric, and then they pass out” he said.

J.D. Gallop is a criminal justice/breaking news reporter at FLORIDA TODAY. Contact Gallop at 321-917-4641 or jgallop@floridatoday.com. Twitter: @JDGallop.

This article originally appeared on Florida Today: Few answers yet in mysterious crash of Melbourne plane in Virginia