Fuel cell Airmen plug leaks, keep fleet flying
By Senior Airman Ryan Lackey, 92nd Air Refueling Wing Public Affairs
/ Published January 23, 2018
FAIRCHILD AIR FORCE BASE, Wash. -- The Airman’s mask fogs up slightly from breathing too hard from the exertion of shimmying across the metal ribs of a KC-135 Stratotanker wing’s confined interior. The ever-present odor of jet fuel is distracting as the Airman grunts while moving a mere ten feet of distance from the tiny entrance hatch to the area needing repair; the cave-like interior of the fuel tank seeming more at home to a spelunker than a mechanic.
Making such efforts to repair an aircraft’s fuel systems is a vital part of maintaining Fairchild’s rapid global mobility, mid-air refueling mission.
Aircraft fuel is stored in special ways to maximize efficient use of space and overall balance; both important factors for flying due to the significant stress aircraft endure as flight hours accumulate. This stress can cause any number of maintenance issues, but few are more serious than a fuel leak.
Aircraft aren’t completely rigid and are designed to have some pliability, but when a fuel tank’s seals degrade under the strain of flying, leaks can occur and a minor annoyance can quickly become a major hazard if not addressed.
"A KC-135 Stratotanker could become a giant fireball in the sky, or it wouldn't get sufficient fuel pressure to keep the engines running enough to leave the ground if we weren’t here," said Tech. Sgt. Joseph Gonzales, 92nd Maintenance Squadron Aircraft Fuel Systems section chief. “We are responsible for all aspects of aircraft plumbing, keeping the most vital part of Fairchild’s mission functional: its ability to handle fuel.”
Airmen of the 92nd MXS Aircraft Fuel Systems Flight have one of the more dangerous jobs in the business of keeping aircraft flying.
In a lone hangar at the edge of the flight line, these airmen tackle the delicate operation of repairing leaking aircraft and repairing faulty fuel plumbing systems.
"We are separated from the rest of the base because this job is inherently dangerous,” Gonzales said.
These Airmen face more than potentially explosive conditions; they handle other hazards such as toxic chemicals, fumes, claustrophobic confines and lack of oxygen.
“We are entering spaces that were recently filled with jet fuel, so the air inside is pretty bad,” said Master Sgt. Zach Kuno, 141st Maintenance Squadron Aircraft Fuel Systems supervisor. “These areas were designed to hold fuel, not accommodate people. There is one way in and one way out and it doesn't have life support of any kind. The biggest wing interior space is like an uncomfortable, metal coffin and we must work in much smaller spaces than that.”
Before anyone can enter the fuel areas of an aircraft, it must be completely de-fueled by Petroleum, Oil and Lubricants or POL specialists. Using specialized safety gear, fuel systems Airmen will then pump out and vacuum up the remaining puddles of fuel, ventilating the confined space continuously to ensure the environment is safe to work within.
“We have to keep the fuel vapor level below 10 percent to lower the fire hazard risks,” Gonzales said. “We can't enter the fuel areas with an oxygen level of less than 19.5 percent or greater than 23.5 percent. The low end is immediately dangerous to life and health, while an oxygen-rich atmosphere can be a major fire hazard and potentially explosive.”
Static electricity remains a huge safety concern and fuel cell Airmen are very careful about it at all times while working on aircraft, added Gonzales.
The majority of aircraft store fuel in the wings to free up space in the fuselage for cargo and passengers. Unlike passenger aircraft; the KC-135 is a flying gas depot dedicated to carry as much fuel possible to refuel other aircraft, with eight tanks in the wings and 16 internal fuel bladders housed along the bottom of the fuselage that can hold up to 200,000 pounds of fuel.
“Each cell is a rubber fuel bladder within the body of the aircraft and the whole bottom of the KC-135 has them,” Gonzales said. “The largest cell is in the rear of the craft by the boom operator. It's large enough that you could seat four people at a poker table and have a bit of extra room inside.”
Working within the smelly confines of a fuel tank may not be a job for everyone, but fuel systems Airmen believe all it takes is some confidence, patience and a willingness to learn.
"Any Airman can potentially do this,” said Tech. Sgt. Jeremy Blackwell, 92nd Maintenance Squadron Aircraft Fuel Systems NCO in-charge. “We put them through the paces by having them deal with the vapors, the safety equipment and confined spaces. If they can manage to excel through that gauntlet and understand that this job is something of an art more than just a skill; we can make them excellent fuel systems Airmen.”
These nimble aircraft plumbers are responsible for fuel tanks and everything that goes with them, such as the pumps, gauges, probes, hoses, lines and seals. It’s vital to keep it all in working order and with a seasoned fleet, those skills are more valuable and in demand than ever before.
"Fairchild has a reputation as the best tanker base, with some of the best maintainers for those tankers too,” Blackwell said. “We’re requested to send our Airmen to all kinds of places that don't have the abilities we have here, sometimes performing patch repairs in order to get it to a base with full facilities.”
The fuel cell Airmen’s abilities were recently put to the test, when several aircraft had significant fuel system failures the week before a mission.
“We were through in fixing it all correctly the first time, finding all problems expediently and returning them back to service the same week,” Gonzales said. “All the flights proceeded without delay. That success was in no small part due to our partnership with our 141st counterparts; backing us up and putting in the time and expertise to accomplish the extensive repairs.”
“That's what's called Total Force Integration and Rapid Global Mobility. We contribute to it every time we put an aircraft back on mission,” Gonzales added.