Sen. John McCain John Sidney McCainCrenshaw looms large as Democrats look to flip Texas House seat Analysis: Biden victory, Democratic sweep would bring biggest boost to economy The Memo: Trump's strengths complicate election picture MORE (R-Ariz.) is concerned the Air Force has not identified the cause of oxygen deprivation issues with F-35A fighter jets in his home state, despite an investigation and a pause on flights that will be lifted this week.

“It is clear that there are broader problems with this program that the Air Force must fully investigate and remedy,” said McCain, the chairman of the Senate Armed Services Committee, said in a statement.

“The Senate Armed Services Committee will continue its focused oversight of this important program to make certain our troops are equipped with the most effective and sophisticated aircraft, and ensure the American people get the best value for their tax dollars,” he added.

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The 56th Fighter Wing at Luke Air Force Base near Phoenix will resume local F-35A Lightning II flight operations on Wednesday, according to officials.

The Air Force suspended the F-35A flights on June 9 after five incidents since May 2 in which pilots experienced symptoms similar to oxygen deprivation.

“No specific root cause for the physiological events was identified” after experts and engineers from the Joint Program Office, Lockheed Martin, the Air Force Research Laboratory and several other organizations investigated the aircraft, base spokeswoman Maj. Rebecca Heyse said in a statement.

Heyse noted that specific concerns were eliminated as possible causes for the oxygen deprivation, “including maintenance and aircrew flight equipment procedures.”

The Air Force will temporarily apply five criteria when flights resume to gather more data, including avoiding the altitudes where all five events occurred, modifying ground procedures, expanding physiological training and increasing minimum levels for backup oxygen systems for each flight.

Brig. Gen. Brook Leonard, the 56th Fighter Wing commander, said in the Air Force statement that the team of investigators “has worked tirelessly to better understand the physiological events.”

“This is a complex challenge that necessitates multidimensional solutions across a series of steps to get back to a full operating capability,” Leonard said. “We are confident that this initial step with the criteria our team developed will allow us to return to flying F-35s safely and to continue building the future of airpower.”