Tanker Day: Air to Air Refueling

Tanker Day: Air to Air Refueling

Tanker Day: Air to Air Refueling

RefuelingThere was one F-16C Fighting Falcon receiving fuel from the KC-135’s refueling boom and another waiting. Endurance of the F-16 is limited to about 2.5 hours, even less when engaged in a dogfight. So there was almost always a receiver aircraft in queue, waiting to get tanked up. The 3-4 minutes needed to refuel can seem like an eternity when you’re the one waiting to receive with little fuel in the tanks. Sometimes the fill-ups need to be sequenced, giving the airplanes with the least fuel a chance before everyone else is topped off. Then it’s back to the fight.

Today’s flight was a training mission, with the dogfights rehearsed and strict altitude and conflict limits established to virtually assure no accidents. The two KC-135s and three F-16Cs assigned were dispatched to an anchor point in New Hampshire airspace to fulfill currency requirements, and also to demonstrate capability to community and business leaders from the region. It was Boss-Lift day, a chance for employers to experience the important contribution Air Guard members make, serving the country.

“Boss-Lift”, known internally as Tanker Day, is not just a for-show event, however. The training is real; part of the normal Air Force readiness program, unmatched by any other country. Within hours of the 9/11/2001 attacks, Stratotankers from the eastern USA were on their way to assigned points. While many different forces and weapon systems were employed during the response, KC-135’s were pivotal to making the operation work. Fighter and bomber endurance would have been a real issue without the KC-135, a flying gas station with as much as 200,000 lbs of fuel in its wing and belly tanks. “You can’t kick ass without gas” was the refrain I heard a lot while riding onboard.

The airplanes are old. The specimen I flew on was built in 1962. Over the years, there have been a number of upgrades, including modern Collins FMS/GPS avionics and new International CFM high-bypass engines to replace the original Boeing 707-style Pratt & Whitney water-injected turbojets. This 59 year-old design, designated KC-135R, now operates in global airspace with RNP 4, FANS, CPLDC, and RNAV approaches. Still, much of the KC-135 is original, including the systems used by the boom operator.

Briefing The Plan

Like all training missions, this one began with a thorough briefing. F-16 pilot Major Dan “Tröl” Rissacher lead the discussion of training goals, assets to be deployed, flight plan, weather, allowed maneuvers, acceptable G-forces, emergency procedures, and the general area of operation. He also talked about the combat scenario; who would play the bad guy and how everyone’s score would be tracked. Consistent with aerial dogfighting from all past wars, the winning solution is almost always to get on the enemy’s tail to take the shot. How you get there is another matter. According to Rissacher, “With F-16 against F-16, there’s no aircraft advantage. It’s strictly pilot vs. pilot in a high-speed physically-demanding game of chess where we try to force errors, then exploit them.”

The KC-135R demands its own briefing, especially for the guests (passengers). The airplane is very utilitarian inside, with much of its wiring and ductwork exposed. Entry is via a large cargo door on the left side and seating is bench-style, running along each side of the interior. Although the pilots enjoy a pressurized EROS-style emergency mask system, much like that found in any GA business jet, there is no centralized emergency oxygen for the passengers. Instead, everyone receives an EEBD (Emergency Escape Breathing Device) hood, contained in a small plastic bag. In a case of depressurization, you are to remove the hood from the bag and crack it open, thereby causing the chemically-produced oxygen to flow, then don. We were given a live demonstration; I came away hoping the cabin stayed pressurized.

EMG_1143The KC-135R is also a very mechanical airplane, with cables linking the yoke to the control surfaces with no hydraulic boost except for spoilers, flaps, and rudder. The pilot would be overwhelmed by the control forces had not Boeing linked the yoke to tabs on the inboard and outboard ailerons and the elevators. (The outboard ailerons are neutralized except when flaps are deployed.) The pilot controls the tabs, which in turn move the actual control surfaces. Spoilers also activate to assist with roll when the flaps are deployed. Horizontal stabilizer adjustment is used for trimming the airplane, operated by an electrically-powered jackscrew. One very-seasoned KC-135 captain compared handling to a Piper Navajo; “certainly not the truck-like feel other big Air Force airplanes like the B-52 exhibit”.

There are no leading-edge slats, but the KC-135 does have very-formidable double-slotted Fowler flaps and Krueger leading-edge flaps to provide extra lift. All of this, along with nearly 22,000 lbs of thrust from each engine, is needed to accommodate a MGTOW of 322,500 lbs. The KC-135R can carry almost twice its empty weight in the form of fuel, most of it accessible for provisioning receiver aircraft.

Once airborne, Captain Jamie Blume, the co-pilot, divulged some flight track and holding-position details that were withheld during the briefing. Our destination was AR631 (Air Refueler Route 631), a piece of airspace running east-west from near Kennebunk to Vermont’s southern Champlain Valley. Our holding pattern was defined by four waypoints, used to establish the refueler’s anchor pattern. The clearance was to hold at 22,000 ft while waiting for the receiver aircraft.

Places To Avoid

The air refueler routes and anchor points are public information, but they are different from MOAs and restricted areas, and not typically charted or reported in NOTAMs. Fortunately, most of the operations are conducted in positive-control airspace, where ATC provides separation. “Hot” MOAs should definitely be avoided. It’s legal, but entering a hot MOA VFR can be very risky.

According to Major Rissacher, “it is generally a bad idea unless you have a lot of awareness of what exact military operations are going on and how to stay away from them. Most GA pilots assume that we, particularly fighter aircraft, are all-knowing and that is not the case. For example, many pilots I talk to say ‘well, you have radar so you know where everyone is and can avoid us’ and that’s wrong on many levels. First, that would require that I’m actively working on my radar screen, which is only a fraction of the time, and often not at all in air-to-ground training missions. Second, little, slow airplanes (particularly ones that don’t reflect much radar energy) are difficult to pick up until very close. Third, and most importantly, we cover a lot of ground/altitude in little time… There are often 6-8 aircraft, using every corner of the MOA, and they‘re in an air-to-air fight, traveling 500 knots… even worse, we may change altitude from 45,000 to 500’ in seconds, during which the radar is useless and although we are looking outside it would be difficult to pick up a little airplane.” I was also told that what may appear to be a benign penetration can inadvertently disrupt what is always a very-expensive complex training exercise.

Once anchored, it was game on. F-16Cs, initially invisible, suddenly appeared; one on the port side and the other edging up from below and behind. It’s time to fill’r-up. I was fortunate enough to be stationed next to the boom operator. The two observers and boom operator lay prone, facing rearward toward the boom controls and the receiving aircraft. This gives the operator an excellent view of receiver aircraft and surroundings, the best in the house!

56th Fighter Wing F-16 Fighting Falcons return to base after a successful mission in the skies over Luke Air Force Base, Ariz., Sep 14, 2010. (Photo by Jim Hanseltine)
56th Fighter Wing F-16 Fighting Falcons return to base after a successful mission in the skies over Luke Air Force Base, Ariz., Sep 14, 2010. (Photo by Jim Hanseltine)

The system used to deliver the fuel consists of a boom that carries a long hollow telescoping rod and complex nozzle that connects with the receiver aircraft. The boom extends from the rear belly of the KC-135, raised and lowered using a hydraulically-operated hoist. Two hydraulically-powered joystick-controlled ruddervators, mounted toward the boom’s end, are used to make the boom fly. “It’s a little like flying your own little airplane (in for a landing) and it’s challenging”, according to one boomer.

Part of the challenge is dealing with a multitude of different receiver aircraft. KC-135 customers include B-52 bombers, super-secret drone aircraft, and everything in between. Bigger airplanes, like the C-5, produce a large bow wave that tends to disturb the air around the boom, making it much more difficult to establish correct elevation. Smaller fighter aircraft like the F-22 require a special kind of TLC; even a slight scratch to that fragile stealthy paint can render the airplane tactically useless. The F-16 is particularly tough because the boom has to be flown around the canopy and a nine-inch antenna that is eighteen inches in front of the receptacle. Tricky! And fighter pilots don’t like to wait. I was told that they get very good at quickly lining up with the KC-135’s belly-mounted Pilot Director Lights (PDLs), and expect immediate service!

DSCN1816The actual fueling is an event to behold. Even the relatively-small F-16 fills the entire sighting window. This is the ultimate in close-formation flying. When the boom nozzle securely engages, positive indications are displayed in both airplanes. Fuel can now be safely transferred. Then, almost immediately after being fueled, the F-16 disconnects, and, in our case, launches a battery of high-temperature flares, a demonstration of the airplane’s decoy anti-missile defense against heat-seeking missiles. Spectacular!

Once on the ground, I asked Major Rissacher what the future held for the KC-135 and F-16. Officially, the Air Force has stated that many KC-135s could fly well into the 2030s and beyond. As for the F-16, Rissacher thinks its days are numbered. “The F-16s Vermont has were built in the mid-80s and have around 6,000 hours on them (long past the lifespan they were designed for). The United States isn’t buying any more. The Vermont Air National Guard is designated as the second F-35A unit, giving our skilled airmen the airframe we need to thrive and survive for the foreseeable future.” In Rissacher’s world, the word “survive” means survive as a pilot. “The F-16 is a very capable aircraft, able to perform just about any mission. However, some of these missions assume some of us will be shot down. The F-35A makes it much more likely that the pilots will return to their families and those same pilots/aircraft are around to fly the next mission.”

As for the KC-135, it has already significantly exceeded the original design life Boeing specified. The airplane has outlived many of its customers, including F-100, F-104, F-105, B-58, F-4, SR-71, F-117 and many others. It remains ready to service the next generation of fighters and bombers, most notably the F-35 Joint Strike Fighter. While there are new modern refuelers in the works, including the KC-46 based on the Boeing 767, I would not be surprised to see the venerable KC-135 playing an important role for many years to come. Referring to Boeing’s 1956 design, Joe Patroni, the fictional all-knowing cigar-smoking mechanic in the iconic movie “Airport”, famously said, “Take the wings off this and you could use it as a TANK! This plane is built to withstand anything.” And so it has.


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