(NewsNation) — Nearly 5,000 pilots licensed to operate in the U.S. were investigated for allegedly falsifying medical records to hide conditions that could deem them unfit to fly, according to the Federal Aviation Administration.

The pilots under investigation, who are military veterans, are accused of intentionally omitting or submitting inaccurate and false details about medical conditions to the FAA. These conditions could potentially negatively impact eligibility to continue to fly.

The FAA has collaborated with the Veterans Administration and determined that about 4,800 out of the more than 6,000 certified pilots in the U.S. are under scrutiny. An anonymous U.S. official familiar with the investigation told The Washington Post, “About 600 of the pilots under investigation are licensed to fly for passenger airlines.”

“Like any other high-performing industry and occupation, pilots are very concerned about seeking medical care when they need it because they are worried it could reflect on something like a medical certification which they need for their livelihood,” said emergency room physician Dr. Amy Ho.

The investigation by The Washington Post revealed that these pilots informed the FAA that they were fit to fly, but they neglected to report, as required by law, that they were receiving veterans’ benefits for disabilities that could bar them from being in the cockpit.

“Of those 600, the majority were cleared by the FAA to continue flying,” said Laura Einsetler, who is a commercial airline pilot. “So, there’s only I think, a small 60 of them, that actually had ramifications that way.”

The FAA has stated that out of those pilots, 60 of them posed a threat to aviation safety and they have been advised to stop lying while their records are under investigation. The majority of the other pilots with ongoing cases are allowed to continue flying as the FAA examines their documentation.

“The FAA has been transparent with the public on our work. Finally, any veteran who may have a disqualifying condition has been told they cannot fly. There are many disabilities that a pilot could have and still be able to fly,” the agency wrote in a statement to NewsNation.

Commercial pilots undergo extensive routine medical assessments that include evaluations of their eyesight, hearing, blood pressure, urine, cognitive abilities, and any indicator of mental disorders.

However, these examinations are allegedly brief, sometimes lasting only five or 10 minutes and pilots are allowed to self-report their media al history through paperwork.

Dr. Robert Noven, an aviation medical examiner, says the FAA has long relied on pilots to report their own health history. He adds people underreporting their medical records is “nothing new.”

Noven emphasizes that his intention is not to stigmatize; he says that there are even more pilots on the civilian side who aren’t disclosing their medical histories. He believes a substantial solution to this problem would involve granting examiners complete access to medical and medication records, rather than solely relying on the honor system among pilots.