Thermal Sprayed Non-Skid (TSN) coatings, specifically created to meet the performance conditions for vertical take-off aircraft from ships’ surfaces are also now being used on US Navy aircraft carriers, some of which will carry similar jets to the UK’s new carriers. The coatings being used there were developed by the US Navy.
Blast Cleaning for Aviation in the US Navy
We get an insight into how the applications of these performance-based coatings are applied to the aircraft carriers through Johnny Sanchez, Flight Deck Non-Skid Specialist for California-based South Bay Sand Blasting & Tank Cleaning (SBSBTC) has been directly involved in supervising applications. He says: “We are using titanium & aluminium on the Landing Helicopter Dock (LHD) class of ships due to the new type of aircraft that put out higher heat signatures than the previous vertical Harrier jets. This sacrificial coating is only applied to the spots on the flight deck where the deck is impacted by high heat, where the deck would buckle and crack the traditional non-skid coatings system.
With 21 years’ experience of non-skid and other multiple coatings application, Sanchez ensures all non-skid and coatings application meets NAVSEA standards, and trains and supervises coatings inspectors. He continues: “Coatings for aircraft carrier decks have come a long way from general epoxies with high solvent content. Due to environmental regulations non-skid coatings have gone up in percent solids to 90% resin & binder. With new resins like polysiloxane non-skids now have good heat resistance & colour retention.
“The most commonly used non-skid chemical makeup is polyamide primers and polyamine, due to their high resistance to solvents, chemicals, hydrocarbons – and of course they do not break down in a highly corrosive environment like salt water.
“Here in the States, the most common surface prep requirement is meeting the cleanliness standard of SSPC-WJ-2L (Ultra High Pressure Water Jetting) with allowable light flash rust. If a profile needs to be implemented then the surface prep would be SSPC-SP-10 near white blast, but this is rare in flight deck preservation operations.”
The Function of Arresting Gear in Aircraft Carrier Landings
Nuclear-powered aircraft carriers, known as CVN carriers, use arresting gear cables to enable aircraft landings. Due to their design the non-skid in the landing area must be non-abrasive, and the aggregate must not be hard or as dense. It must be capable of breaking down or ‘giving’ to the arresting gear cables as aircraft tail hooks catch them and cause them to slap against the deck. Sanchez explains: “Non-skid for CVN use is broken into two composition types, Abrasive & Non-Abrasive.
“Normally the aggregate used is aluminium, which is a softer alloy. It’s used in the non-abrasive areas and identified as Limited non-skid, versus the General non-skid which uses very hard and dense aluminium oxide aggregate.”
Coating Application techniques
Sanchez says the application is mostly by roller: “For non-skid application with a life expectancy of 1 or 3 years we use a hard-core phenolic roller with a smooth surface which peeks up the non-skid, giving it its anti-slip surface.
“The main requirement is spread rate. The non-skid range is ¼ inch to 3/8-inch thick, but that’s not how we calculate thickness – we calculate by spread rate as square footage divided by gallons. So the minimum allowance is 18 sqft per gallon to a maximum 30 sqft per gallon.”
“Not much maintenance can be accomplished when the ship is out to sea. Due to the vast square footage, you would need the equipment and product to accomplish the preservation, and experience in operating the equipment. The Navy can only accomplish spot repairs.
“We can accomplish full removal and replacement on helicopter carriers during a drydocking. CVN Carriers have too many moving parts so we can usually accomplish anywhere from 50% to 70 % of the flight deck while other work gets done on the catapults, elevators, and other equipment.”
A fascinating understanding of how blast cleaning is undertaken on aircraft carriers and how its performance is integral to its longevity. If this article is of an interest to you, then do subscribe to our PCE International Magazine. What’s more, receive all the latest industry news and opinions directly to your inbox.