Editor's note: This story was first published at 8:04 p.m. EDT on August 3, 2016.

The head of Marine Corps aviation has ordered all non-deployed aircraft to stand down for 24 hours following three recent F/A-18 crashes of F/A-18s​, two of which were fatal.

Lt. Gen. Jon Davis told wing commanders on Wednesday that non-deployed squadrons must take "an operational pause" within the next seven business days, said Marine Corps spokeswoman Capt. Sarah Burns. The move is different than grounding aircraft, she said.

Commanders can decide which day to take the pause, during which aircraft are typically inspected, Burns said on Wednesday​.

She

Burns

​could not say what specifically

exactly

​prompted Davis' decision, which was approved by Marine

Corps

​Commandant Gen. Robert Neller.

Three Marine Corps F/A-18s have crashed in the last two months.

when Blue Angels pilot

​Marine Capt. Jeff Kuss, a Blue Angels pilot, was killed on June 2 when his Hornet crashed shortly after takeoffin Smyrna, Tennessee. On July 28, Marine Maj. Richard Norton, a graduate of the Navy's TOPGUN school, was killed when his F/A-18C crashednear Marine Air Ground Combat Center Twentynine Palms, California.

Then on Tuesday, a Navy pilot safely ejectedfrom an F/A-18C that was on loan from the Marine Corps. The Hornet went down near Naval Air Station Fallon, Nevada.

Marine Corps aviation is suffering from a perfect storm that has caused the number of flyable aircraft to plunge in the last five years. Budget cuts have postponed maintenance for aircraft that have been flown hard during 15 years of combat and led to a shortage of spare parts, especially for CH-53E Super Stallion helicopters.

Several CH-53E Super Stallion helicopters from Marine Heavy Helicopter Squadron 772, Special Purpose Marine Air-Ground Task Force - Southern Command, standby on the flight line aboard Marine Corps Air Station New River, North Carolina, before departing for Soto Cano Air Base, Honduras, June 8, 2016. SPMAGTF-SC is a temporary deployment of Marines and sailors throughout Honduras, El Salvador, Guatemala, and Belize with a focus on building and maintaining partnership capacity with each country through shared values, challenges, and responsibility. (U.S. Marine Corps photo by Sgt. Adwin Esters/Released)
Several CH-53E Super Stallion helicopters from Marine Heavy Helicopter Squadron 772, Special Purpose Marine Air-Ground Task Force - Southern Command, standby on the flight line aboard Marine Corps Air Station New River, North Carolina, before departing for Soto Cano Air Base, Honduras, June 8, 2016. SPMAGTF-SC is a temporary deployment of Marines and sailors throughout Honduras, El Salvador, Guatemala, and Belize with a focus on building and maintaining partnership capacity with each country through shared values, challenges, and responsibility. (U.S. Marine Corps photo by Sgt. Adwin Esters/Released)

Several CH-53E Super Stallion helicopters from Marine Heavy Helicopter Squadron 772 sit on the flightline ahead of a deployment to Central America.

Photo Credit: Sgt. Adwin Esters/Marine Corps

The service is also in the process of transitioning to the F-35

J

​joint

S

​strike f

F

​ighter, but delays in the program have forced the service

Marine Corps

​to fly its

their

​Hornets, AV-8B Harrier II jump jets and

their

​EA-6B Prowlers longer than anticipated.

Last summer, only 378 of the Marine Corps’ required flightline inventory of 1,065 fixed- and rotary-wing aircraft could fly, Davis said at an Aug. 1

event at a

​think tank event in Washington

, D.C

​. Since then, roughly 80 more aircraft have become flightworthy, he said.

With fewer aircraft flying, Marine pilots are not getting the flight hours they need, but the service is slowly improving, Davis said. The Marine Corps is trying to get pilots the appropriate number of flight hours by 2020.

At the Aug. 1 event, Davis was asked if Marine pilots’ lives were in danger as a result of the drop in flight hours.

"I do not think we’re unsafe, but we’re not as proficient as we should be," he

Davis

​said. "We don’t let units fly that are unsafe."

Davis

He

​added that he tracks all Marine squadrons' weekly

the how many

​flight hours

all units get per week

​, noting that

and

​Norton’s unit, Marine Fighter Attack Squadron 232, was "doing OK."

On Jan. 14, two CH-53E helicopters from Marine Heavy Helicopter Squadron 463 crashed off Hawaii, killing 12 Marines. Davis has said the CH-53E helicopter crews had enough training for the mission they were doing, but they probably needed more training before they could fly in combat.

"We don’t know what happened out there — I won’t know until that investigation that comes out," he told reporters on July 6. "I grieve for every one of the families. That’s the hardest part for me. I’m the deputy commandant for aviation and I lost 12 great Marines. That’s what I think about every day."

About four months before that crash, another CH-53E Super Stallion made a hard landing in North Carolina. One Marine was killed and 11 others injured. In May 2015, an MV-22B Osprey crashed in Hawaii, leaving two Marines dead and 20 more injured.

Marine aviation deaths

in September 2015.