NAVAL AIR STATION NORTH ISLAND, Calif. –
Of the many components crucial to the basic performance and safety of an aircraft, perhaps none are more important than the aircraft’s generators and generator control units (GCU), the power behind the electrical systems.
The maintenance and repair of GCUs and generators used in many naval airframes is the job of the Fleet Readiness Center Southwest (FRCSW) generator shop in Building 378.
Among the generators serviced are those of the F/A-18, P-3 Orion, V-22 Osprey, H-53 helicopter and the AV-8B Harrier.
Although the Navy is replacing the Harrier fleet with the F-35B variant of the Joint Strike Fighter, Shawn Willis, MRO deputy program manager for avionics, instruments and rotating electric, said that the shop is completing about 10 to 13 Harrier generators per quarter.
Eventually, the Harrier workload will be limited to Foreign Military Sales customers who are still flying the attack aircraft, he noted.
But as that workload declines, the shop is preparing to accept generators of the E-2D Hawkeye.
“Capability establishment of E-2D generators is expected in Fiscal Year (FY) 23,” Willis said. “A new AVTRON (test) bench has been installed and acceptance is expected in early FY 23.”
Workload in the generators shop is handled by a staff of 34 artisans that include aircraft electricians, instrument and electronics mechanics, electrical equipment repairers and electronic integrated systems mechanics.
The shop repairs two types of generators: Air-cooled generators that use fan blades to cool them and are typically found in helicopters, and oil-cooled generators that are used in aircraft like F/A-18s.
Generators scheduled for maintenance or overhauls are disassembled and evaluated. The unit’s rotors are removed, inspected and repaired if necessary. The bearings are also changed, inspected and tested before the component is returned to the fleet.
The frequency of generator overhauls varies by platform. Many air-cooled generators, like those in the P-3 Orion and H-53, have scheduled repairs—some set at 2,000 hours.
About five years ago the shop’s GCU workload changed when it established capability to modify one of two older versions of the F/A-18 Super Hornet’s GCU.
Artisans began upgrading the older GCU chassis using a kit of 13 new parts.
The workload standard for the upgraded GCUs is 80 man-hours, while the older version is 118 man-hours.
After the chassis’ are stripped, they are sent along with their wiring harnesses for analysis on the Intermittent Fault Detection and Isolation System (IFDIS) in Building 463.
The IFDIS checks the GCU harness connection points for intermittent shorts or opens, and can also simulate the flight stresses and conditions which Hornet aircraft endure. The IFDIS process takes about one day.
GCU components that are inspected include the power supply, the silicon controlled rectifier (SCR) which converts alternating current (AC) to direct current (DC) and shop replaceable assemblies (SRA), or circuit cards.
SRAs are circuit card modules, held in weapons replaceable assemblies, or the containers that house avionic functions.
Willis said that the shop is funded for 57 GCU upgrades in FY 22, and anticipates completing about five every month.
Since 2001, the shop’s GCU workload operates under a Private Public Partnership (PPP). PPP are partnerships between commercial vendors and FRCSW.
Boeing served as the initial PBL agreement holder for the F/A-18 until the General Electric Co. assumed the contract about 13 years ago.
FRCSW artisans provide the labor in disassembly, evaluation and order parts from GE.
Reassembled GCUs are tested on the Aircraft Engine Components Test Stand (AECTS) and following quality assurance and packaging, are returned to GE and distributed to the fleet through the Naval Supply Systems Command.
FRCSW and GE’s Vandalia, Ohio, site are the only facilities conducting depot-level repairs to the GCU.
PPPs are also established with Honeywell for V-22 generators, and Lockheed Martin for E-2D generators.
Three years ago, the shop managed to reduce its turn-around times through Naval Sustainment System (NSS) applications. The NSS was created to bolster production throughout the command and increase fleet readiness.
“In December 2018, there were more than 80 fleet backorders across the GCU platform. By September 2021, the team was able to reduce the fleet backorder count to zero, and continues to maintain a zero back status for going on 12 months,” Willis said.
Last year, the generators shop completed 19 GCU upgrades and repaired or overhauled 64 older GCUs and 239 generators.