A small video camera is saving the Navy and Marine Corps big money.
A new initiative to use video borescopes to inspect engine blades for damage is saving millions of dollars, officials say. In the last year, 35 Marines have gained certification in a common video borescope class for the AV-8B Harrier F-402 Pegasus engine.
“Right now, we have actually saved six to seven engines on wing this year alone and by just a couple engines have saved the Marine Corps millions and millions of dollars’ worth of headache and resources,” said Charles Dowdle, a Rolls Royse field service representative teaching the class.
The Pegasus engine is one of the most complex used by the Navy and the Marine Corps, he said.
“Our engine is very unique. It has the least amount of forward object damage allowed on any of the Navy and Marine Corps engines, so we had to come up with the best possible criteria to actually have a safe aircraft,” Dowdle said.
The two-week, 84-hour course teaches Marines how to locate evidence of impacts on each of the 657 blades in the high-pressure compressor of the engine. They use a miniature camera on the end of a rod to make photographs and measure imperfections between five-thousandths of an inch all the way up to 25-thousandths of an inch. Their measurements must be within three-thousandths of an inch, which is less than the thickness of a dollar bill.
“Since we’ve started doing this, we have made all of the Marines fully award of FOD, the Forward Object Damage on the flight line, on their parking spaces, and they have been very hyper aware of inspecting their low pressure compressors, the blades, where they can actually see inside the intakes,” said Dowdle.
Such inspection is critical to making sure the jets are safe to fly, but the monetary savings is real,” Dowdle said.
“It saves money,” he said. “It’s about $1.5 million to actually change an engine out and 750 man hours.”
The cost per engine is between $3 million and $4 million, which includes shipping, labor and parts.
Marines trained in the operation of the camera system are using it now.
“We have successfully employed them and we have saved six engines so far out in the fleet through this last year,” said Dowdle. “It wasn’t until we got enough qualified Marines in the squadrons that we were actually able to use it. Now they have been employed to Bahrain and on the boats successfully and have utilized the borescope correctly and they have saved engines through our training and they have saved lives.”
The blades on the engines are required to be inspected every 30 hours of flight. Major damage requires replacement of the engine, but minor impacts can be “blended.”
“If it’s really bad, then we’ll go ahead and get the Rolls Royce bore blend team out to their aircraft to blend it out and save the $1.5 million and keep the aircraft in the warfighting shape, or if it is bad, we will go ahead and issue them another engine and keep them safe and flying,” said Dowdle.
He said the process of inspection can take three to five hours, depending on the experience of the Marine.
“So if they have 10 aircraft and each aircraft flies 30 hours, that means they have to do 10 inspections in a month, so if they do that over a year, that’s quite a lot of inspections so they need to be good at inspecting,” Dowdle said.
Stewart Hassell, an aerospace engineer who supports the F-402 engine, said the video borescope first proved its worth in 2013. He said four spare engines were sent to the USS Kearsarge, and upon inspection with the camera, three were rejected with pre-existing damage.
“So that brought this need to light,” said Hassell. “We saw the need for some training to get people certified on how to correctly measure the damage inside the engine.”
Marines in the course have to take three pictures per impact and make measurements. Their accuracy is checked against a master book of all the known impacts on each engine blade.
Cpl. Kyle Rettinger, from Marine Attack Squadron 223, said the work is challenging and tedious.
“You just have to be real precise because they are such small measurements,” said Rettinger.
Cpl. Nolan Brewer, also with VMA-223, said the training was a good learning experience.
“It’s something that I won’t just use in the Corps,” Brewer said. “I plan on doing aviation when I’m out, and this is a nice step for me, a nice learning experience.”
Because of the program, Marine Aviation Logistics Squadron 14 has 14 engines ready for inspection and ready to go out anywhere in the world.
“It is the first time in 20 years that we have had so many engines ready to go at any one time than we have had in the history of Harrier aviation just because of this CBS class, hyper awareness of forward object damage on the flight line and the formal class that we have taught from our FST engineers to our Marines,” said Dowdle. “This is a legacy engine and we don’t make any more of them, so we have to take care of them.”