Fighter Wing: A Guided Tour of an Air Force Combat Wing tcml-3

by Tom Clancy

  The first operational tankers, the KB-29, the KB-50, and the KC-97, were derived from the Boeing B-29 bomber. Their shortcomings were obvious. Because of their four piston engines, the early tankers simply could not keep up with the new generation of jet fighters and bombers that were quickly becoming the primary customers for these aerial gas stations. The solution, clearly, was going to be a jet tanker capable of integrating itself with the new jet combat force of the USAF.

  The problem was that until someone developed a jet transport with sufficient payload capacity, this idea was going to stay just that — an idea. Fortunately, in the early 1950s there was an international race to produce the first commercially viable jet transport, and the USAF was able to pick their new tanker from the winners. The British Comet was first into service, but an unforeseen problem with metal fatigue around the window frames led to the loss of several aircraft in flight through explosive decompression. In the United States, Boeing's long experience with designing pressurized high-altitude aircraft like the B-29 paid off in the design of a tremendously strong airframe that would become the basis for both the military C-135 transport and the 707 commercial passenger liner. In 1954, soon after the first flight of Boeing's first jet transport prototype, the Model 367-80, the Air Force ordered a fleet of Boeing tankers to support the bomber force of the then-Strategic Air Command.

  Boeing's project number for what became known as the Stratotanker was Model 717. It differed from the basic 707 airliner in having smaller overall dimensions, a somewhat narrower fuselage, no cabin windows, and, of course, an extendible, finned refueling boom and tiny compartment for the boom operator under the tail. The tankers, constructed more simply, to military standards, than their commercial cousins, actually went into service before the Boeing 707 completed final commercial certification.

  Now, you should understand that if the whole fuselage barrel section were filled with fuel, the plane would be too heavy to take off. Thus, the fuel carried is actually contained in a relatively small volume, leaving the inside of the cabin available for other uses. All of the tanker-related equipment is below the main deck, leaving seating space for passengers or an equivalent volume of cargo — up to 83,000 lb./37,650 kg.

  Over the years, more than two dozen variants of this versatile airframe have been built, including a bewildering collection of "deep black" intelligence collection platforms, going by such names as Rivet Joint and Cobra Ball. A small number of all-cargo versions were built as C-135 Stratolifters. The -135 has also enjoyed some modest success in the export market; a dozen C-135F models were sold to France in 1964 to support that country's tiny but potent nuclear strike force of Mirage IV bombers. Canada and Israel also purchased tanker/cargo aircraft from the 707/KC-135 family, and continue to operate them today.

  If you take a walk around one of the big tankers, the first thing that strikes you is how much it looks like an old Boeing 707, but with fewer windows. This absence of viewports is one of the reasons for the Stratotankers' longevity, since each hole that you put in a pressurized airframe is just another place for structural fatigue cracks to start.

  The entire KC-135 fleet was originally equipped with the noisy and fuel-guzzling Pratt & Whitney J-57 engine, which also put out a lot of smoke on takeoff. Fortunately, most of the aircraft remaining in service have been re-engined with more efficient and powerful General Electric/SNECMA CFM- 56 turbofans, creating the KC-135R variant. The engine change reduces noise by 85 % and pollutant emissions by 90 %, and the increased power allows for a much shorter takeoff run. The biggest benefit, though, is the vastly improved fuel efficiency, which allows a KC-135R to offload up to 50 % more fuel than one of the earlier J-57-equipped birds. While most aircraft in the USAF fleet are equipped to take fuel from tankers, most KC-135s are not themselves equipped with flight-refueling receptacles. The few that are so equipped are known as KC-135RTs, and are highly coveted assets by the new Air Mobility Command (AMC), which controls most of their operations, maintenance, and use. Thus, unlike the small fleet of McDonnell Douglas KC-10 Extenders (the newest USAF tanker, based on the commercial DC-10), most KC-135s can only be refueled on the ground. This makes for an interesting set of decisions for the operators of the -135. Unlike the Extender, they can either off-load fuel or deploy to an overseas area, but not both at the same time.

  You get into the KC-135 through an entry hatch in the bottom of the fuselage, on the left side of the nose. It requires a bit of a climb to get up the ladder and into the cockpit, something like the climb into the conning tower of a submarine. Once there, the first thing you will probably notice is that by the standards of current commercial airliner cockpits, the -135 is decidedly ancient. The four-person flight crew usually includes three officers (aircraft commander, pilot, and navigator/radar operator) and one enlisted airman (the crew chief/ boom operator), each with a seat in the tight little workspace up front. Very little of the modern computer age is evident, other than a digital flight management system and the throttle controls for the four CFM-56 engines. The fit of communications and navigation gear enables the tanker to maintain station precisely and talk to its customers, though the navigation gear is also a bit dated. Until the planned installation of a GPS receiver later in the 1990s, the navigator has to depend on the old standbys of shooting the sun and stars with a sextant, and the old-style LORAN and TACAN navigation beacon systems. The nose-mounted radar is a Texas Instruments APQ-122(V) weather and ground-mapping radar, which is capable of assisting in the navigator's tasks. All USAF tankers are unarmed; and indeed, they are not even equipped with basic self-protection radar warning receivers, chaff or flare dispensers, or jamming pods. As a result, they can only survive and operate under conditions of total local air supremacy. It is not hard to understand why, when you consider that a tanker is nothing but a relatively slow and unmaneuverable bag of fuel, requiring just one cannon shell or "hot" warhead fragment from an AAM to turn it into a very large fireball.

  As you move aft, you encounter the lavatory compartment on the left side, just aft of the cockpit. You are struck again by the rather spartan nature of this most necessary of aerial conveniences; it does not even flush! Instead, they use the same kind of chemical toilet "packs" found on the B-1B. Also, for the male crew members, there is a "whiz tube" urinal. While convenient, this can be deadly during rough flights, as the spring-loaded lid tends to snap shut when "bumped." Just across from the lavatory is the galley — or more precisely, the place where box lunches and the thermos bottles for coffee and water are kept. There are no microwave ovens or refrigerators, just a bare aluminum rack, looking for all the world like an airline food/drink cart with no wheels. Just aft of the lavatory compartment on the aircraft's left side is a large pressurized cargo door, big enough to load large items like bulk cargo, duffel bags, or other personal equipment. These can be strapped down or placed in large crate bins tied to the floors. The original floors are made of impregnated plywood, and are kept lovingly cleaned and painted by the ground crews. Other than the planned GPS receiver upgrade, these floors are the next major planned upgrade for the -135 fleet. The plan, if money is available, is to replace the existing floors with hardened metal Roll-On/Roll-Off (Ro/Ro) floors, so that items like palletized cargo and small wheeled vehicles like ramp service carts can be loaded and tied down. This should help alleviate some of the airlift problems Air Mobility Command (AMC) has been having with their fleet of heavy airlift aircraft.

  Along the side walls of the KC-135 are passenger seats made of aluminum tubing and synthetic webbing. These are surprisingly comfortable, if you aren't packed in too tightly. That means eighty people can travel in mild discomfort, and 160 in total unpleasantness! Except during actual deployment, most tankers fly with few passengers, and are actually quite comfortable. While I'm always a reluctant flier, other people I know generally enjoy their time in the -135s, and even find that the webbing seats make passable bunks if there is enough room to spread out. In fact, the main cargo compartment is la
rge and open. You feel like you're in a wide-body commercial jet, with none of the annoying overhead bins or narrow seat aisles to bump yourself on.

  In the rear of the compartment is the environmental control system, with large green bottles of oxygen mounted to the after bulkhead. Just above these are several very comfortable bunks, though a pair of severely lettered signs make it clear that these are for members of the crew to rest in, and not for mere passengers. Overall, the pressurized cabin of the KC-135 is quite comfortable, though the heating system, which occupies a large part of the after cabin, is somewhat inadequate to warm the entire interior. Thus, it is advisable on long flights to wear something warm, preferably a leather flight jacket, which also has the advantage of looking good around the officers' club!

  At the far after end of the cargo compartment, on either side of the environmental control system, are the entrances to the refueling pod. To get into this, the business end of the KC-135, pick one side or another, step down onto what looks like a very comfortable cushion, and lie on your stomach. At this point, you are on one side or another (observers' stations actually) of the "boomer" position, so named because this is where the refueling boom is actually "flown" and mated to other aircraft. The boomer lies on a similar couch between the two observers' stations and faces a thick window (with two smaller side windows) with a small control panel below it. This position is a favorite of aerial photographers who want to take really spectacular pictures; you never forget the view. Just below the boomer's couch is a control stick, which flies the boom. This stick controls a pair of fins on the telescoping refueling boom just in front of the boomer's window, and these respond to control inputs from the operator. The stick is surprisingly simple to use. To conduct a refueling, the boomer flips a switch which deploys the boom from its stowed position up against the KC-135's tailcone down into its "flying" position. The boomer then sets the telescoping boom to a "neutral" length position and alerts the flight crew that he is ready to have an aircraft take on fuel. What happens next borders on the bizarre if you are not familiar with it.

  From behind will come a small formation of aircraft, having flown to the tanker track in complete radio and emissions silence (which limits the ability of an enemy to read whether something is coming at them or not). Even in peacetime, this is a skill practiced whenever the restrictions of weather and the exercise rules allow. After establishing formation on the tanker (either on the wing or behind), the first recipient moves up behind the KC-135, aligns itself with a series of colored position lights located under the tail of the tanker, and opens its refueling receptacle door. Most aircraft designs have this placed behind the flight crew position, over their shoulder and to the left side. Once the boomer sees that the receiving aircraft is stable and in its proper refueling position (this varies with different aircraft types), the real fun begins.

  Using the control stick to fly the refueling boom into position over the receiving aircraft's receptacle, the boomer activates a switch which stabs the refueling probe of the boom into the receptacle, causing it to "hard latch." This last part of the operation can be tough, especially in rough air, and may require several attempts to get it right. The two aircraft are now joined, flying just a few yards/meters apart, and the boomer relays this fact to the flight deck, where the flying crew actually controls the pumping of fuel down the boom to the receiving aircraft. Though the pumping is fairly rapid, fully refueling a tactical aircraft like the F-15E Strike Eagle or the F-16 Fighting Falcon does take a few minutes. Meanwhile, both aircraft are flying an oval "racetrack" course at about 300 knots/545.5 kph. at an altitude of 20,000 to 25,000 feet/6,060.1 to 7,575.8 meters. One of the more interesting features of this aerial dance is that once the two aircraft are hooked up, they can talk plane-to-plane over a special intercom link, which allows the pilot of the receiving aircraft to report battle damage or other problems, and to receive updates on targeting and scheduling changes. For many pilots during the early hours of Desert Storm in 1991, the last thing they heard before going into combat was the reassuring voice of a Boomer on the intercom, wishing them well and a safe return. Since the two aircraft are only about 35 feet/10 meters apart, the receiving aircraft can take a severe buffeting from the tanker's wake turbulence. It's tough to maintain a position, even for a skilled pilot, especially at night, in bad weather, when you are low on gas.

  To the aircrews of combat aircraft returning to base, shot full of holes and leaking fuel all over the sky, every drop on a tanker is precious. Happily, the KC-135R tanker can carry a lot of fuel — some 203,288lb./92,210kg., which translates to a capacity of about 25,411 gallons/95,890.6 liters. Since an airborne tanker can do two things with the fuel, burn it or off-load it to another aircraft, there is a tradeoff between the range and endurance of the tanker on the one hand and the amount of fuel available for off load. For example, with 120,000 lb./54,545 kg. of transfer fuel, the range of the KC-135R is 1,150 nm./2,090.1 km. On the other hand, with 24,000 lb./10,909.1 kg. of transfer fuel, the range is 3,450 nm./6,309.4 km.

  So, how does all of this come together in the real world of combat operations? In an intervention scenario, a KC-135R tanker can either deploy to an overseas base (carrying high-priority personnel and cargo), or support the deployment of other aircraft by tanking them — it can't do both. This means that planners have to be careful to make sure that enough tankers are available to do both. Unfortunately, this is getting tougher all the time. During 1994, the tanker force took a 25 % personnel cut and moved almost three quarters of its U.S.-based tankers and people from former SAC bases to three main AMC bases, as well as reassigning many aircraft to USAF Reserve and Air National Guard units. Tankers also are increasingly used to transport cargo, because metal fatigue and other problems with the C-141B Starlifter fleet have forced planners to assign cargo missions to the hard-working tankers.

  As long as combat aircraft need to burn fuel, there will be a requirement for tankers. Eventually the KC-135s and the force of about sixty wide-body KC-10 Extenders will have to be replaced. To some extent, the tanker mission can be performed by tactical aircraft fitted with extra fuel tanks and refueling gear mounted in removable "buddy packs." But for really long hauls, there is no substitute for specialized and dedicated aerial tankers, based on economical, standardized commercial airframes. Just what that replacement will be exactly is anyone's guess, but rest assured that when fuel is low and tensions are running high, the tanker crews will be the most popular folks in the skies.

  BOEING E-3C SENTRY AIRBORNE WARNING AND CONTROL SYSTEM

  Ever since our simian ancestors learned to climb trees, we have known instinctively that the higher you climb, the farther you can see. Later, many ancient cultures devoted considerable labor to building hilltop watchtowers. Spotting an approaching enemy even a few minutes sooner can make the critical difference between victory and defeat. The development of radar in the 1930s provided proof that nature is consistent. Generally speaking, radar works much like light — it travels in straight lines and usually cannot bend to peer over the local horizon. While a mountaintop is a good spot for a radar station, a mountain is rarely located where you need it, and it's hard to move. However, if you could put a big radar antenna on a high-flying airplane, your radar horizon could theoretically reach out to two or three hundred miles. Also, if you put an air battle control staff on the same airplane and provide them with powerful computers, situation displays, and secure communications, you have what is called an Airborne Warning and Control System (AWACS) — the king on the chessboard of the modern air battle. Its status also makes it the most prized target in the sky, making the Sentry the sort of high-value airborne asset that will normally be protected by a hefty escort of fighters.

  AWACS aircraft had their start at the end of World War II, when the U.S. Navy was desperately trying to fight off the hordes of Japanese Kamikaze suicide aircraft that were trying to stop the invasion and battle fleets of the Americans. The Navy's solution to the relative vulnerabil
ity of their surface ships was to convert TBM Avenger torpedo bombers into primitive AWACS aircraft. These early AWACS aircraft would have been available for the invasion of Japan in late 1945, had it taken place. Later, purpose-built AWACS aircraft were built by both the Air Force and Navy to their specific needs, usually on transport or airliner airframes. For many years, the USAF birds were based upon the classic Lockheed C-121 Super Constellation airliner /transport. Called the EC-121 Warning Star, it served in the AWACS mission for over twenty years before being replaced by the current AWACS aircraft, the E-3 Sentry, in the later 1970s.

  The Boeing E-3C Sentry AWACS looks like a large jet airliner being attacked by a small flying saucer. The airliner is the old reliable Boeing 707- 320B airframe, with a flight deck crew of four (pilot, copilot, navigator, and flight engineer) and a "mission crew" of thirteen to eighteen controllers, supervisors, and technicians back in the main cabin. Using an airframe similar to the venerable KC-135 and all the other Boeing Model 320 derivatives has proven quite popular with the U.S. military, and quite practical for the taxpayers. The saucer, or "rotodome," is 30 feet/9.1 meters in diameter, 6 feet/1.8 meters thick at the center, and is supported 11 feet/3.35 meters above the fuselage on two streamlined struts just aft of the trailing edge of the wings. It is designed to generate enough aerodynamic lift to support itself, and does not place any stress, other than drag, on the wings or airframe. Mounted back-to-back with the main APY-2 radar antenna (upgraded from the original APY-1 version) inside the rotodome is an antenna array for the APX-103 IFF/ Tactical Digital Data Link (IFF/TADIL–C) system. This is a highly sophisticated IFF system, capable of interrogating virtually any IFF transponder in the world within 200 nm./365.7 km. (It reportedly has some sort of NCTR capabilities as well.) When transmitting, the rotodome, powered by hydraulic motors, makes one complete revolution every ten seconds. When it is not transmitting, it makes one revolution every four minutes, to keep the bearings lubricated. Considering the flight stresses it has to support and the complex of wave guides, power cables, and signal lines that must pass through it, the saucer's rotary slip joint is a marvel of mechanical engineering. The radar transmitters and their elaborate power supplies and cooling equipment are located under the floor of the aft cabin, where conventional 707s stow the passengers' luggage.