Wing historian relives joys, trials of old Fairchild KC-135 airframe Published Sept. 8, 2006 By Dan Simmons 92nd ARW historian FAIRCHILD AIR FORCE BASE, Wash. -- "Start the water!" When I was a copilot in the KC-135A model here at Fairchild back in 1979, that order from the aircraft commander filled me with excitement and anxiety -- excitement because we were starting our takeoff roll and anxiety because I never knew if the aircraft's water injection system was actually going to work. The A model, or "steam jet" as it was known, had a water injection system to increase thrust on the old Pratt and Whitney J57 engines. When the temperature was above 20 degrees Fahrenheit, demineralized water was injected into the air inlet and diffuser section of each engine. The water increased the density of inlet and combustion air, which resulted in an increased thrust of about 2,000 pounds for each engine. This was very important during heavyweight takeoffs on hot days because the anemic J57 engine only produced 10,500 pounds of thrust during a "dry thrust" takeoff. Compare that to the KC-135R model engine that produces 22,000 pounds. Water injection not only produced incredible noise heard for miles around, but it also produced a cloud of black smoke that looked like a small thunderstorm on the runway. Everybody on base knew when a KC-135A was taking off. One of my most important jobs as the copilot was to throw the switch that started this whole process, and what a process it was. After I activated the switch, the aircraft kind of moaned, and all of the cockpit lights dimmed as the water-injection pumps came to life and put a surge on the aircraft's electrical system. At the same time, the navigator started the timer on his watch because he would be making an important call over interphone in about two minutes. As the aircraft started its takeoff roll, the pilot advanced the throttles and the whole crew kept its collective fingers crossed that all four engines would "take water." All eyes were on the gauges as the pilot advanced the throttles forward. Everybody looked at the fuel flow and engine pressure ratio to see if we had extra power. Inability to get water on any engine required us to abort the takeoff because of the control problems caused by engines producing uneven thrust. All too often the water didn't work, but that didn't mean we weren't going to fly. We always had some tricks up our sleeves to get the system to work. The first thing the pilot would do is bang his fist on the throttle quadrant. The relays to the water pumps were routed through this area and sometimes they just needed a little "wake-up call." If that didn't work, I would stop the water, the pilot would advance the throttles near the takeoff setting, then I would activate the pumps once again. Sometimes this shock to the system would get it going and we would be on our way. Once the water activated, the aircraft started lumbering down the runway, but the anxiety wasn't over. Sometimes water would stop flowing to an engine during the takeoff roll. If it happened before the takeoff-decision speed, the pilots had to abort. After decision speed, the takeoff was continued with reduced performance. The loss of water was a serious thing. Losing water on all four engines was almost the equivalent of losing thrust from an entire engine. The Air Force lost a number of KC-135 aircraft due to water injection problems on takeoff. Even with good water, the KC-135A was grossly underpowered during heavyweight takeoffs on hot days. On a 13,000 foot runway, we would often rotate with only 1,000 feet remaining on the airfield. After flying the "souped up" KC-135R model, I now realize that the A model was extreme flying. It was always amusing to have a fighter pilot passenger sit in the center seat behind the pilots to watch the takeoff. After we passed the 10,000-foot point on the runway he would usually lean forward with eyes as big as compact discs and a very concerned look on his face. Apparently he had never seen the departure end of the runway on a takeoff roll, and he didn't like the view. Once we did manage to get airborne, the water saga continued. The 670 gallons would "burn" for about two minutes. When water ran out, the aircraft experienced a sudden loss in performance. By that time it was critical to have the flaps up, accelerating to climb speed. This is where the navigator had a key role. At 110 seconds after water initiation, the navigator had to announce over the interphone, "110 seconds on water." For the pilots, the call meant that if the flaps were not up, they had to raise them now before the water ran out. There are so many other water stories, particularly about Strategic Air Command alert aircraft and how the maintainers had to heat the water, and dump the water or refill it depending on the outside temperature. When the temperature dropped below 20 degrees, water wasn't needed anymore because at these cold temperatures the engines produced enough power to enable "dry thrust" takeoffs. The problem lay in that gray area of temperatures--between 20 and 40 degrees. Maintainers would often dump water in the evening, when it was cold, and load it back on in the morning after the temperature rose. At some temperatures, they were out at the aircraft for hours late at night, heating the water to prevent it from freezing. I always admired and respected the crew chiefs for doing this day in and day out when the temperature wouldn't cooperate. This was before the Air Force had articulated its core values, but these maintainers practiced "Service before Self" before the phrase was commonplace around the service. I flew the R Model for a number of years before I retired. My personal opinion is that the R Model conversion and the subsequent Pacer CRAG modifications are probably among the greatest aircraft success stories in the history of the Air Force. Although I think the R model is wonderful, I will always have special feelings for my first love--that old steam jet. I think I feel that way because it was a quirky, needy aircraft that required extra attention. But as long as you understood its limitations and treated it right, it didn't let you down very often. If you didn't understand its limitations and didn't treat it right, it could be very unforgiving. I think that fact led to a special relationship between a crew and an aircraft. While the R model is helping us fight the Global War on Terrorism today, we should never forget that the A Model, along with the B-52, were the real metal heroes of the Cold War. I grew up with the KC-135A, and I will never forget the great experiences I had with it, whether it was in the air or sitting on alert. Happy 50th birthday you old beloved tanker. You have served our nation well for half a century.