An aircraft’s crew depends on a variety of tools to ensure their survival in the event of an emergency: fire extinguishers, ejection seats and Halon-filled fire bottles, to name a few.
As aircraft are inducted into Fleet Readiness Center Southwest (FRCSW), much of this life-saving equipment is turned over to the Ordnance Egress/Ejection Seat shop in Building 399 for overhaul or maintenance.
The shop works on the equipment of F/A-18 legacy and Super Hornets, Growlers, CH-53 and H-60 helicopters, the E2/C2 airframe, and the V-22 Osprey as that workload expands at the command.
Several types of ejection seats are serviced including the SJU-5 and SJU-6 that are used in the legacy F/A-18 Hornets, and the newer SJU 17 Naval Aircrew Ejection Seat (NACES), created in the late 1980s, that is found in the Super Hornets.
“We also overall and repair the components to ejection seats, which total about 20 components,” said Ordnance/Ejection Seat shop supervisor Quenton Robins.
Introduced in World War II by SAAB, a Swedish military manufacturing company, early ejection seats were originally powered by compressed air. Today’s seats are powered by any combination of rocket motors, explosive cartridges, or high-pressure gas.
The ejection process from a NACES is quick: less than one second.
When the ejection control handle is pulled, the inertia retractor positions the pilot in the seat. The retractor is designed to keep the pilot’s spine in alignment, so that during the ejection phase, the back is not injured.
The catapult is the next mechanism to fire and moves the seat up a guide rail, activating emergency oxygen for the pilot. Afterward, a rocket pack fires forcing the seat from the aircraft.
The fate of the pilot lies with the Time Release Mechanism (TRM) and the drogue gun that controls operations from this point.
The TRM releases the pilot from the seat, as the smaller parachutes, or drogues, vertically stabilize the seat while slowing it down. These are activated by “drogue guns” which fire a cartridge.
The main chute is deployed between 11,500 and 14,500 feet by the g-limiter of the TRM.
The NACES is computer-controlled with electronic sequences. A probe measures wind speed, pressure and altitude that tells the computer, which acts as a sequencer, when to activate the seat.
The SJU-5, on the other hand, is manually activated by trip rods.
“We disarm the seats in the shop, and it averages about one to two weeks for an overhaul, depending on what components are involved,” Robins noted.
“We push out approximately 25 to 40 single and two-seaters annually. But that’s not including what we may bring in on the disassembly side, so we could push 50 to 100 annually.”
He added that about 80 ejection seats and their components are currently preserved in-house awaiting parts.
Common to all ejection seats are the seat pans that contain survival kits.
Seat pans hold a variety of survival gear including life rafts, distilled water, batteries and radios. A fully loaded unit weighs about 20 pounds.
“Overhaul of the seat pans and parachutes is performed at Naval Air Station Lemoore, MCAS Miramar, and NAS Joint Reserve Base Ft. Worth. But we’re in the process of standing up the capability to do that at the depot level,” Robins said.
The shop also removes the Hornet’s guns and missile launchers and re-installs them during the aircraft’s assembly phase. Maintenance or repairs to these are handled by the fleet and made ready-for-issue (RFI).
In addition to servicing liquid oxygen bottles, fire extinguishers and their related regulators and valves, the shop also maintains an inventory of the expiration dates of the service and shelf lives of the explosives and cartridges that activate ejection of seats, an aircraft’s “black box,” and initialize fire extinguishers.
As its workload increases, Robins said the shop is looking forward to expanding its staff of 25 ordnance systems mechanics.
“Many of the artisans here have a military background and are former aviation structural mechanics,” he said. “We’ll have about five more on the way as we go to multiple shifts to spread out our work.”