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More details emerge in plane crash investigation

Office of Rep. Gary Knopp

Rep. Gary Knopp had impaired vision caused by glaucoma when his private plane collided with a charter plane last summer, according to a medical report released Monday by the National Transportation Safety Board.

The report is among hundreds of pages of documents released by the board on the mid-air crash that killed Knopp and six others July 31. It's an interim step — the board's final report is still likely months away.

In its preliminary report last year, NTSB said Knopp was flying illegally because he had been denied a medical certification eight years prior, due to vision problems. The Federal Aviation Administration requires a medical certification to fly.

The updated medical report said Knopp was denied that certification because he had glaucoma in both eyes that led to a reduced field of vision. Glaucoma is caused by a buildup of fluid in the eye and can lead to blindness, starting with a loss of peripheral sight.

It can be treated with surgery but surgery doesn’t restore vision that’s already been lost.

Knopp had laser surgery to treat glaucoma in both eyes in 2010. By then, his glaucoma had caused irreversible damage to his optic nerves, particularly in the right eye, according to the report.

Pilots with glaucoma can qualify for medical certification on a case-by-case basis or if they meet certain criteria. But the FAA denied Knopp’s medical certification in June 2012 because of his vision problems. Knopp appealed that decision and was again denied certification in July 2012.

At his last optometry visit in May 2020, Knopp said his vision seemed “fine.” But his optometrist noted he still had severe glaucoma and made a plan to refer him back to his ophthalmologist for re-evaluation, according to the report. 

Greg Bell, who was flying the charter plane from High Adventure Air, received his most recent aviation medical certification a month before the crash. The report found no significant issues with his exam.

Other documents in the report include interviews with eyewitnesses, photos of logbooks and systems data from both planes. But NTSB’s investigation is still far from completed, said Clint Johnson, the board’s Alaska chief.

“The investigation has gotten to a point where we’ve reached 51 percent of those reports from those different specialists, and they’ve been reviewed, they’re ready for release," he said.

Credit High Adventure Air Charter
Greg Bell

He said the board is waiting to do a visibility study to see whether the pilots would have seen each other before crashing.

To do that, specialists will lay out the wreckage of both planes to see how they collided. They’ll also use scans from similar planes to determine whether there were any visual obstructions inside the aircrafts.

That part of the process has been delayed by the pandemic. The planes are sitting in a hangar in the Mat-Su but restrictions have made it hard to get specialists up from Washington, D.C.

Johnson said once they’ve done the study, they can work backward to determine the probable cause of the accident.

“This is not the final report by any stretch of the imagination," he said. "But it allows the public a chance to see what has been done to date and, again, allows them a chance to digest the work that has been done.”

Brice Banning, who’s leading the investigation, said he hopes to have a final report between 18 to 24 months after the crash.

Also released in the report is an interview with Matthew Dahl, an FAA investigator.

Dahl had accompanied Bell on a checkride two weeks before the crash. He said the Bell family, who owns High Adventure Air Charters, were meticulous about safety and didn’t cut corners when it came to taking precautions.

But he does note that the charter plane involved in the crash did not have an Automatic Dependent Surveillance-Broadcast, or ADS-B.

That technology allows aircrafts to send and receive three-dimensional data about where planes are in the airspace. It was not a requirement for either plane involved in the crash. But analysis from the NTSB’s systems report did say that it could have helped the planes be aware of each other before crashing.

Dahl said in the interview that he suggested Bell look into purchasing ADS-B technology. He said Bell was concerned about the cost, since ADS-B can run thousands of dollars. Knopp’s plane had a system with ADS-B capabilities, the report said.

There are three lawsuits in process from the families of the crash victims, against Knopp’s estate and his widow, Helen Knopp. Two of those lawsuits also target charter pilot Bell and High Adventure Air Charters.

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