By JOHN MILLIMAN
Aging Aircraft Integrated Product Team

PATUXENT RIVER NAVAL AIR STATION, MD-Blasting the old paradigm of "You'll take what we give you and like it," the Fleet Technology Transition Team here is working closely with several Fleet squadrons to field a small, but effective "weapon" in the war against aircraft corrosion.

The team, part of the Naval Air Systems Command Organic Coatings Lab at Pax River, is breaking new ground by including Fleet maintainers in developing spot corrosion removal kits, including a new Bristle Disk, right from the beginning.

The Bristle Disk, made by the 3M Corporation, may be a relatively small item, but it's a vital part of a coordinated effort to fight aircraft corrosion, according to Bob Ernst, head of NAVAIR's Aging Aircraft Integrated Product Team.

"Aircraft corrosion was a $1.4 billion problem for the Navy and Marine Corps last year," Ernst stated. "By far, it's our largest single cost driver.

"Corrosion in aircraft takes many forms and there isn't one panacea for it all - corrosion has to be tackled step by step and piece by piece," Ernst added. "Individual technology advances like this are what's helping us keep these aging and corroding platforms from overwhelming us, and the way this technology is being developed and fielded is an excellent example of the solid work being done to control these costs."

"Traditionally, we develop new technology and force feed it to the Fleet," explained Tom Doughty, engineering technician and Fleet support representative for the Organic Coatings Lab here. "They typically either like it and use it, or they dump it over the side."

All too often, it's the latter as technology gets developed with the end user brought in at the end of the process as an after thought.

"They seem to like being involved and having a say in the process right from the beginning," Doughty explained.

With a focus on airframe corrosion maintainers, the team's project du jour is the Radial Bristle Disk - a possible replacement for flap brushes and abrasive wheels currently used to remove spot corrosion.

Merely replacing the current technology will be a challenge in itself as it has been around a long time and is generally accepted by Fleet maintainers.

"I came in the Navy in '67," said Doughty, "and we were using it then."

The problem with the current, and dated, technology is that it removes much more than just corrosion.

"Out in the Fleet, I've seen where guys would grind away while (holding a conversation) and they would be grinding valleys in the metal," he explained. "The panels we're grinding aren't usually stress panels, but over time you could grind right through them."

Removing excess paint as well as generating a lot of heat in the metal are also adverse effects of using the old technology, according to Doughty.

So what to do? Turn to chemical strippers and derusting agents?

"Chemicals have been phased out due to toxicity and environmental concerns," Doughty said.

Another big drawback of current methods is that maintainers usually strip more metal and reapply more paint than is actually needed.

"If you had an area the size of a fingernail," explained Doughty, "by the time you were done, you've stripped several square inches."

Recoating that bare metal also entailed reapplying an area of primer and top coat - a process requiring the aircraft to be roped off, isolated from other maintainers and wasteful amounts of paints and primers mixed.

Ever on the lookout for new ways to fight corrosion and minimize waste, team members kept an eye out for possible replacements.

"Steve Spadafora, head of NAVAIR's Materials Protection Branch, saw bristle disks while on a tour of 3M's lab," explained Doughty. "They were developed as a sealant removal tool. They generated very little heat, didn't damage the substrate and removed what it was supposed to without taking all day.

"Steve brought some back and asked us to investigate them as possible corrosion removal tools," he continued. "So we worked with 3M to develop two disks we'd like to see out in the Fleet."

Extensive lab work by the team led to the refinement of the bristle disks and the creation of a spot corrosion kit containing everything a maintainer needs to tackle spot corrosion. It should not be confused with a similar product available commercially that is intended for automotive use and is much more aggressive.

The disk itself is made of plastic containing aluminum oxide and a proprietary element that gives it a grit equivalent of 400, according to team leader Kevin Kovaleski.

"The bristles provide a continuous supply of abrasive material to the work surface. To use it, you only need to apply very little pressure to strip a surface," Kovaleski said. "A great feature of the disk is if too much pressure is applied, say two pounds or more, the bristles just fold over. At that point, they're not doing anything."

So far, testing in the lab and evaluations by several Fleet squadrons are promising, according to Kovaleski.

"We did a surface roughness test on some panels using a profilometer (tests roughness of metal)," he said. "The bristle disks were close to baseline."

In other words, the sections ground clean with the bristle disk were virtually undiscernable from untreated bare metal.

"We also ran temperature profiles," Kovaleski continued. "Bristle disks produced about 100 degrees F surface temperature, as compared to the abrasive wheel which produced about 200 degrees. Big difference."

To tweak the kits and validate the new technology, the team is working with NAVAIR PMA-260 (Common Support Equipment), GSA and several squadrons (VAQ-129, VP-40, VP-9 and VAW-120) to evaluate the kits.

So far, the results are promising.

"I tasked VAW-120 to evaluate and test (the disks)," explained AMC(AW) Ronald Higham, maintenance adviser to the commander, Airborne Early Warning Wing, Atlantic. "They are doing their normal corrosion work using the disks. The crew really likes the material and can't say enough about them."

"These kits are coming, we just need to know what, if any, modifications to make," stated Kovaleski. "We don't want to just shove this down the Fleet's throat."

"The philosophy is to take the technology to the ultimate end users in the Fleet to get their input," Doughty added.

"Let them see it, work with it right there in their own work spaces and on their own aircraft and give us their input right on the spot.

"We'll take that input and make changes to the technology as needed so that when it does transition to the Fleet, it will be effective."

"In six months, we should have something we can send out to the Fleet," Higham added. "And, it's so much better than those old flap brushes we've used for all these years."

The spot corrosion kit is being developed along with an associated corrosion control touch-up kit, which includes one of the teams other success stories - "SemPen" spot primers and one and two-component topcoats that can be sprayed with an aerosol sprayer (included in the kit), brushed on or applied like correction fluid.

"The kits contain everything a technician needs to treat corrosion discrepancies," said Doughty. "The intent is to reduce the hazmat stream and hazardous air pollutants, as well as allow other shops to work on the aircraft at the same time. Maintainers using the kits will still need to wear personal protective equipment, though."

Following an anticipated thumbs-up from the Fleet in September, Doughty anticipates another year before all of the logistics associated with the transition of the new technology is completed and the kits arrive out in the Fleet.

-USN-