Sir Isaac and the Airbus
Newtonian physics – which a professor of fond memory tried to teach me in freshman year of college – prescribes laws that are immutable. Dr. Fred Furst used to say, “The laws of physics are the same wherever you go, and bad things happen when you try to break them.” For that reason alone, I’m confident neither Sir Isaac nor Prof. Furst would choose the Airbus 330 tanker for the US Air Force.
I never promised you there would be no math, but trust me: this won’t be too bad. We’ve got to do a little math and a little physics.
Newton’s Second Law of Motion defines the relationship between mass (roughly what something weighs), acceleration (not the speed of an object, but the rate at which an object gains speed) and the force required to move a mass at a rate of acceleration: Force equals mass multiplied by acceleration. As Freddie Furst said over and over again, “F=mα.” About which more in a moment.
The Air Force has a lot of guidelines, manuals and regulations. Pilots – at least those who live to ripe old age – usually go by the book. The book on air refueling operations requires that tanker aircraft be able to perform maneuvers called “breakaways” and “overruns” in just the way the Air Force specifies.
As I described on the Rush Limbaugh Show on July 17, a “breakaway” is a vital safety maneuver which is performed often in training and in flight operations. There’s an imaginary envelope around the tanker “boom,” the controlled crane-like device projecting from the rear of the tanker that pipes fuel into the receiving aircraft. If you go outside the envelope – say a gust of wind hits, or the fighter is going too fast, or even if it pitches or yaws, twisting away — the “boomer” (the guy sitting in the back of the tanker who “flies” the boom), the receiving pilot or the tanker driver can call “breakaway,” which is supposed to result in several near-simultaneous events.
The boomer pops the boom off the receiving aircraft which then decelerates rapidly and drops about 1000 feet of altitude. The tanker is supposed to be able to accelerate rapidly (to a specified higher speed that varies by type of receiving aircraft) and climb away from the receiver. So now we’re back to F=mα.
According to the General Accountability Office decision overturning the contract award to Northrop-Grumman/EADS for the Airbus 330 tanker, “…there is no documentation in the record setting forth an analysis of whether Northrop Grumman’s proposed aircraft has sufficient operational airspeed when refueling the [deleted by GAO] to initiate an emergency breakaway procedure.”
What the GAO is saying, in its lawyerly language, is that the facts show that the Airbus 330 cannot reach a sufficient speed to pull away from one or more aircraft it’s supposed to refuel. And if it can’t, there could be a mid-air collision. That may also mean that the huge weight of the Airbus isn’t compensated by comparable engine power to enable it to accelerate fast enough to get out of the way. You need an awful lot of “F” to push that much “m” fast enough to get enough “α” for a breakaway, and the Airbus apparently just doesn’t have it.
Another part of the Airbus’ inability to perform the mission is the “overrun” problem. No, Virginia, we’re not talking about cost overruns (those will come but only after the contract is begun). We’re talking about how a tanker and a receiving aircraft join up.
Tankers usually orbit above a set position – flying a racetrack-shaped oval that may be thirty miles or more in length – waiting for whatever fly guys are coming by to gas up. When one or more do – say an F-16 – the tanker swings out of its orbit to theoretically come up ahead of the F-16 on the F-16’s original course. But sometimes (according to the tanker guys, it’s always the fighter jock’s fault: you can imagine what the fighter jocks say) the tanker comes out behind.
At that point, the fighter is supposed to drop speed and altitude and – again, that old F=mα thing – the tanker is supposed to climb and accelerate past the fighter to get in position for the boomer to plug into the fighter’s nose. But the Airbus weighs too much and apparently can’t even go fast enough even if its engines could push it to the required speeds.
According to the GAO decision, despite the fact that the Air Force had told Northrop Grumman that the Airbus apparently couldn’t accelerate quickly enough and reach the speed set by Air Force standards to perform an overrun, the Air Force disregarded its own mandatory guideline to keep the Airbus eligible for the contract. And, as the GAO decided, they had no reasonable basis to do so: “…the record does not establish that the [Air Force] had a reasonable basis for concluding that Northrop Grumman’s proposed solution would allow its aircraft to obtain the requisite overrun airspeeds to satisfy this…requirement.”
So not only can’t it accelerate quickly enough, the Airbus apparently has too low a top-speed. Again, this is a problem that cannot be overlooked. Or, as the GAO put it, it was unreasonable for the Air Force to say that the Airbus 330 can refuel all USAF tanker-compatible aircraft in accordance with Air Force procedures.
The Airbus cannot be eligible for the contract award if it can’t fly the mission. That’s what the Air Force documents said and that’s one of the big reasons GAO tossed out the contract award.
And there’s a third problem. This one is simple geometry.
Most airfields don’t have runways as wide as Dulles International. The NATO standard runway is 147.6 feet wide. When an aircraft breaks down, or if another aircraft has to take priority landing or taking off, a tanker will have to be able to be turned around on the runway.
To do that, one of those small tractors you see at airports is attached to the nose gear, the pilot turns the nose wheel all the way over, and the tractor pulls the bird around 180 degrees. According to Boeing, their 767 tanker can turn around in about 129 feet, which can be done fine on a 147-foot wide runway.
There is no public data we could find on the Airbus’ turning radius but one source says that the Airbus website used to state that the turning radius of the A-330 was 143 feet. If the runway is a few feet narrower than the NATO standard, if the Airbus isn’t lined up with its right wheels on the farthest edge of the runway and if a lot of other ifs, the U-turning Airbus gets its nose off the runway and probably gets stuck.
Which means you have a runway out of operation until – minutes or hours later – the too big, too heavy aircraft gets unstuck.
It’s just like good old Freddie Furst used to say: the laws of physics are the same wherever you go. If F still equals mα (and it surely does) the Airbus 330 can’t perform the Air Force tanker mission.