TYNDALL AFB — A Monday letter from U.S. Sen. Marco Rubio to Secretary of the Air Force Heather Wilson provides a first official accounting, of sorts, of the number of F-22 fighter jets left behind as Hurricane Michael bore down on Tyndall Air Force Base earlier this month.

The primary purpose of the letter is to urge Wilson to ask Congress for funding to repair all F-22s damaged in the hurricane, while reminding her that Secretary of Defense James Mattis called last month for an increase in the percentage of military aircraft that are mission-capable at any given time. Mattis wants the nation's fleet of military aircraft, including the F-22, to achieve an 80 percent mission-capable rate during the 2019 federal fiscal year, which began Oct. 1.

But also in his letter, Rubio notes that "31 percent of F-22 aircraft at Tyndall Air Force Base were designated Non-Mission Capable (NMC) and were sheltered in place" as Hurricane Michael approached. Rubio's letter also indicates that 55 of the fifth-generation fighter aircraft are assigned to the 325th Fighter Wing at Tyndall. Thirty-one percent of that fleet would comprise 17 aircraft.

The Air Force hasn't yet provided official information on the numbers of F-22s evacuated from Tyndall, but various reports have indicated that at least 33 jets were sent elsewhere to ride out the hurricane. That could mean as many as 22 of the jets remained behind.

The Air Force version of the F-22 has a particularly low mission-capable rate. According to the latest Air Force figures from 2017, less than half of the service's F-22 fleet — 49.01 percent — is ready to perform their missions at any given time. That is the lowest mission-capable rate among aircraft across the Air Force fleet.

Before the hurricane, Tyndall had been the largest single base, in terms of numbers of aircraft, for the Air Force's 186 F-22s.

In his letter, Rubio acknowledges, as the Air Force has previously indicated, that an assessment of the condition of the F-22s left at Tyndall during Hurricane Michael is ongoing. But Rubio goes on to say "the facts are clear that any damage sustained could have been avoided if the NMC (non-mission-capable) rate for the F-22 was lower."

"As you finalize damage assessments of the aircraft that endured Hurricane Michael," Rubio tells Wilson, "I urge you to begin implementation of the framework laid out by Secretary Mattis starting with all Tyndall AFB fighter aircraft."

"Additionally," Rubio wrote, "I ask you waste no time or effort in providing a supplemental funding request to Congress to repair and restore these aircraft to mission capable status as soon as possible."

A new F-22 has a basic construction cost of $143 million, but when research and development costs are factored in, the cost bumps up to about $330 million.