While it may look easy to the casual observer, air-to-air refueling is an endeavor that can be wrought with peril. Even so, it is a capability developed over decades that allows American airpower to be anywhere in the world at a moment’s notice. Whether or not you’re training at home or have just pulled off a target downrange and are in need of fuel, the process of linking up with your “flying gas station” is pretty much the same.
Even though the day’s Air Tasking Order has been briefed and re-briefed, there’s a number of forces determining when and where you rejoin on the tanker. The “frag” lays out the plan for the day’s flying, to include the general location of the air refueling track.
In the AOR, location is subject to change as often times tankers will leave their original orbit to place themselves closer to a fight where air assets may be expending large amounts of fuel. Receivers will generally use their radar to determine the position of the tanker, establishing radio communications approximately twenty to thirty miles out.
Once positive comm is established, the tanker will clear the receiving aircraft to join. If there are already “chicks in tow,” meaning other aircraft are receiving their assigned off-load of gas, the inbound aircraft will be cleared to the wing–either left or right.
As the fighters approach, they will be asked to “check nose cold and switches safe.” That simply means that all emitters are off, to include the IFF system, any ECM pods, and the radar is placed in standby mode. If the approaching receivers were in a fight prior to the rejoin, it’s critical for them to have their Master Arm switch to the OFF position and thereby safing any remaining stores aboard.
This particular video deals specifically with the Boeing F-15D. With the Eagle and its twin Pratt & Whitney F-100 motors, there is a surplus of power, giving the pilot a fair amount of speed and maneuvering leeway as it applies to the rejoin. The intercept geometries, power settings, and airspeed are important in the Light Gray, though not as critical as they would be for a Block 25 or 32 Viper with a “small mouth” intake and poor higher-altitude performance. Other factors weighing in are whether or not it’s night, and how much–if any–weather you’re going to encounter.
Once the tanker clears you to “pre-contact,” you position your jet in trail to the tanker at a distance of approximately one mile. Because the tanker aircraft are so large and have multiple engines, there are several key factors that help determine your approach parameters. For example, the shape of the Boeing KC-135 Stratotanker‘s wing naturally generates a lot of down-force than that of the KC-10. It also has four engines, which greatly disturbs the air and creates a bumpy ride for the aircraft moving into position to take on fuel.
On the approach to the pre-contact position, at roughly three-quarters to half a mile, you’ll find yourself in a position where you need to fight your way through the chop caused by the downwash of the wings, as well as the exhaust of the four motors. If things get really sporty because of winds or other environmental factors, the receiver may request the KC-135 pilots to pull back the two inboard engines, creating a smoother approach with less turbulence.
At about five hundred feet in trail, the boomer will clear you to contact. As the receiver, you are driving straight at the tip of the boom in such a way that if the canopy weren’t there, the nozzle would hit you right in the face. All of the fighters have centerline refueling points, with the exception of the Eaglejet. In the F-15 you need to offset slightly right, since the air refueling receptacle is in the left wing-root area.
Your visual reference at this point is the belly of the tanker. As the pilot, you’re watching the director lights, which are actuated by the boomer’s control stick as you approach. Then the lights stop flashing at you, it means you’re in a good spot. At that point, you need to modulate your power so you freeze your position as much as possible. A common error is cutting the power too much and falling behind, or you add too much and end up driving forward too far.
In a nutshell, you want as stable of a platform to take on gas as possible, making life much easier for the boomer. In the Eagle, once you actuate the door for the air-to-air refueling receptle, a green “READY” light illuminates on the top canopy bow. Once good contact between the tanker and receiver is established, the little light goes out.
If you as an Eagle Driver are getting out of the fight to take on gas, it’s not uncommon to need anywhere from eight to ten thousand pounds of fuel. However, if the tanking sequence does NOT include you being in a fight and instead just need a top-off, the off-load will generally be around four thousand pounds.
In this video, we have the opportunity to see the air refueling sequence from the crew of a NASA F-15D Eagle as it supports test missions over southern California. Pay careful attention to the pilot’s approach to the tanker, as well as the actual plug-in. If you’ve ever wondered what the process was like, here is your answer!
No One Kicks Ass Without Tanker Gas!!