NADEP North Island: demystifying the depot. North Island's hangars in San Diego - Naval Air Depot NADEP

0 Comments | Naval Aviation News, Sept-Oct, 2002 | by Mike Hammond

Somewhere in the fleet, the following conversation might be taking place: Pilot to mechanic, "My plane's headed for the depot at North Island. What happens to it there?" Mechanic to pilot, "Sir, you got me. It just goes away and a few months later it comes back all clean and shiny." So what really happens to the F/A18 Hornets, E-2C Hawkeyes, C-2A Greyhounds, H-60 Seahawks, AH-1 Cobras and S-3 Vikings that disappear into Naval Air Depot (NADEP) North Island's hangars in San Diego, Calif? The answer is: plenty!

Part of the Naval Air Systems Command, NADEP North Island is the Navy's largest aviation industrial facility on the West Coast. Its civilian and military personnel refurbish naval aircraft and components, utilizing a unique capability to test, disassemble, repair, manufacture, rebuild and calibrate much of the U.S. Navy's aircraft and parts inventory.

When an aircraft arrives at NADEP North Island, whether under its own power or by truck, the first step is to induct it into the depot. Paperwork is completed to turn the airplane over to the depot, and the squadron and depot versions of the Aviation Discrepancy Book are checked for repair and modification requirements to be performed. Next, depot artisans begin the examination and evaluation (E&E) process to determine what needs to be done in order to get the aircraft back to the fleet as quickly and cost-effectively as possible. The depot's work center process then begins, outlining all of the work necessary in minute detail and estimating the costs, parts and labor charges. The work may be scheduled maintenance or unscheduled work that was found to be needed during the E&E process, modifications and upgrades, or work done in response to squadron requests based on their unique knowledge of how the aircraft is flying.

The depot and the squadron or air wing negotiate a completion date that takes into account the depot's need to give the aircraft the best maintenance and repair possible and the fleet's need to get the airplane back for training or to meet critical deployment schedules. "Throughout the process," said AE1(NAC) Stephen Dyson, a C-2 crew chief, "we may be in contact with maintenance control at the squadron to ask if certain things were already done, or if paperwork is available that we don't have, and we keep the squadron abreast of what's happening with their plane."

A stop in the paint hangar comes up next, where paint is removed by plastic media blasting (PMB), a more environmentally friendly and timesaving method than the customary chemical stripping, which is still used in some applications. Tom Sapien, Aircraft Paint/PMB supervisor, explained that "the depaint process is crucial to the fleet because it's our job to identify corrosion on aircraft and arrest it before the aircraft is repainted and reinducted into the fleet." However, this step can he a challenge due to the amount of paint on the aircraft when they arrive at the depot. The specification calls for only a 9mm coating, but aircraft have arrived with 30mm of paint, adding up to 600 pounds to aircraft weight and requiring as much as an additional six days at the depot for removal. Once all the paint is removed, an anticorrosive or primer coating is applied to protect the stripped surfaces from exposure to the saltwater environment if the aircraft will remain at North Island for a lengthy period.

Disassembly comes next, allowing the aircraft frame and its component parts to take different paths to completion at the depot. The airframe gets work on corrosion, stress damage, cracks and an array of other maintenance and repair activities. It may be x-rayed to find hidden damage and surfaces may be ground, heat-treated or examined nondestructively for honeycomb or other internal damage. With a composite material facility that was the first of its kind in the Department of Defense, NADEP utilizes specialized materials of extraordinary strength and light weight to repair and replace surfaces that only a few years ago would have needed to be bought new.

Component parts that need work are removed and sent to shops that specialize in that type of part, such as avionics, landing gear, stabilizers and flaps, instruments, fuel cells, ordnance systems, canopies, parachutes, and hydraulic and pneudraulic systems. This element comprises the largest portion of the depot's workload; in FY 2001 NADEP North Island completed more than 63,000 component parts.

Once the complex dance of moving parts and assemblies around the depot for maintenance and repair is completed, reassembly of the aircraft begins. Then, it's another visit to the paint complex, where the aircraft get a new coat of paint, decals, stencils and all the required critical safety of flight markings.

The last stop is the depot test line where depot artisans and military crews perform a series of ground tests and checks until they deem the aircraft ready to fly. NADEP North Island pilots and crew then take to the air and perform another series of checks to ensure the airworthiness of all the aircraft's systems. If any discrepancies are found or problems develop, they're corrected, and depot pilots and crew again do a check flight.