USAF Shows The Way

For almost a quarter century the KC-135 family of aircraft have been the pre-eminent tanker aircraft. The most numerous version, the KC-135A, made its initial flight on August 31, 1956, at Renton. When production had been completed 732 aircraft had been delivered. This aircraft is of fundamental importance to USAF around the globe. The KC-135A has a maximum fuel capacity of 31,200 US gallons and the maximum transfer rate to another aircraft is approximately 1000 gallons per minute. The fuel carried is a common supply for both tankers and aircraft to be serviced. Consequently, good management is needed to ensure that not too much fuel is transferred leaving the KC-135A in a precarious position.

The options for the RAAF would appear to revolve around three possibilities. The first would be the acquisition of some USAF KC-135A aircraft which the USAF may be prepared to part with. The second would be to obtain the modified KC-135RE version which would be re-engined with CFM56 powerplants and have some refined performance and aerodynamic attributes. Although desirable from an environmental and performance viewpoint, the US$? million cost of conversion from KC-135A to KC-135RE may be a detracting feature. Possibility, number three would be the purchase of some ex-airline Boeing 707 aircraft and to modify them to tanker layout.

During the recent Kangaroo ’81 exercise in October, an opportunity arose to examine the way an aerial refuelling mission takes place. Part of the aeronautical contingent for Kangaroo ’81 consisted of F-15 Eagle aircraft from Kadena, Okinawa. Also present were three KC-135A tanker aircraft to complement the F-15 operations. The KC-135As accompanied the Eagles on the flight to Australia refuelling them when required. They are part of the Pacific Tanker Task Force based at Guam.

On October 24 I was on board KC-135A serial number 62-3514 at Amberley for one of the regular missions it made during Kangaroo ’81. The crew, under the command of Lt-Col Lewis R. Sutherland, were from the 917 Air Refuelling Squadron based at Dyess Air Force Base, Abilene,· Texas.

Great emphasis is placed on safety during these flights. All personnel were briefed on the action to be taken in the case of an emergency should one arise. A compact portable oxygen supply in a pouch had to be carried at all times. As the refuelling zone was over the sea, an inflatable life preserver was also to be worn. The Boom Operator who detailed the safety aspects from a prepared checklist, also mentioned that if the life preserver was accidentally worn inside out and subsequently inflated, the pressure was sufficient to result in broken ribs. Thankfully, he ensured everyone wore it in the correct manner.

I was fortunate enough to be on the flight deck for both take-off and landing. The usual crew consists of three officers on the flight deck and the Boom Operator who controls the transfer of fuel from his position at the rear of the aircraft. At 10. 40 am engine start-up commenced. The plan for the flight was for two of the Eagles to accompany the KC-135A during the climb towards the refuelling area. As we taxied out towards the end of the runway two of the Eagles were already parked with engines running adjacent to the taxiway and ready to roll. All up weight of the KC-135A was 219,000 lb, of which 109,000 lb was JP-4 fuel. Endurance was 5 hours. Loads out of Amberley are generally restricted owing to the runway length.

At exactly 11. 00 am, Lt-Col Sutherland applied full power, released the brakes and 62-3514 leapt forward down the runway. With such a light load the take-off speed of 155 knots was rapidly reached. As we climbed out at 171 knots the two F-15s took off. The call sign of the tanker was rather appropriately Ampol 52 and that of the F-15 aircraft Foulplay One, Foulplay Two, etc. Within a matter of what seemed moments, a glance out of the cockpit window revealed two Eagles, one aircraft tucked in close just off each wing tip. This formation continued for quite some time. The initial heading after take-off was to Kilcoy on a course of 340 degrees, then to Maryborough and out to sea. Refuelling was to take place near Fraser Island at an altitude of 24,000 feet.

At 11. 25 am the first F-15 appeared below and to the rear of the KC-135A. It gently drifted upwards and the Boom Operator steering the refuelling boom ensured a speedy accurate contact. It was an impressive sight with the grey-coloured F-15 taking on fuel, superimposed against the deep blue of the ocean glistening nearly five miles below. In what seemed a very short space of time, the transfer was complete and the Eagle pilot gently eased his charge away. A small amount of fuel appeared to escape and immediately vaporise as detachment took place.

As soon as F-15 number one vacated his place, the second aircraft which had been sedately holding its position off the starboard wing tip drifted rearwards and just below the boom. Contact was promptly made and the operation commenced again. The transfer of fuel took about three minutes. As soon as the second Eagle had drifted apart and broke downwards towards the port side a third F-15 loomed into view. When he had obtained his quota and left us, phase one of the mission was complete.

Fuel is supplied to the F-15 at a maximum rate of 2000 lb per minute. In comparison, the F-16 takes on 1000 lb/min and the F-111 3000 lb/min. As the KC-135A is capable of delivery at a very fast rate the limiting factor is the size of the fuel inlet pipe on the receiving aircraft. During this flight, each F-15 took on 6000 lb of JP-4. On previous missions, some RAAF F-111s had also made practice refuelling sorties but had only taken on a token 2000 lb at each transfer of fuel.

Phase two of the flight then commenced with the arrival of another Eagle beneath the tail. The vantage point to witness the refuelling is provided in a bay on either side of the boom operator. The viewer lies in a prone position, as does the Boom Operator. From this vantage point, the Eagle makes a magnificent sight as it floats upwards to take up its position. As soon as its needs are satisfied, it breaks to the left and the final aircraft of this mission, F-15 number five, comes into view. At 12. 25 this last Eagle was rejoined by number four as they flew line astern before darting away to rejoin the other aircraft in the exercise area.

Although the main purpose of the flight is now complete, the KC-135A remains on station for some time before setting course for the return leg to Amberley. Now that all the activity has ceased there is time to have a look around the interior of the tanker. The noise level is certainly higher than its sister aircraft the Boeing 707. It is much darker with the only natural light coming from two windows on each side of the cabin. Apart from bench seating along the side, there are a few conventional seats bolted to the floor towards the front. The rest of the interior is rather empty except for various items of equipment lashed to the floor. No doubt that this is a very spartan aircraft inside compared to the 707. Equally beyond doubt is that this is a classic aircraft which fulfils its intended purpose with great efficiency.

Before long, power is cut back on the two outer engines and the height starts to wind back on the altimeter as we descend on the homeward leg towards Amberley. A practice missed approach has been planned to be flown by the co-pilot. A slight amount of turbulence is encountered as we pass through some innocent-looking cloud. A straight-in approach is made towards the runway. At a distance of two miles from the threshold with 180 kts on the airspeed indicator, the go-around is initiated. The power is applied and the lightly laden KC-135A climbs away with surprising agility. A fairly tight circuit is made of the airfield and this time a normal approach is made with a nice gentle landing to follow. The time is 1. 18 pm as we touch down and taxi towards the parking area, bringing a most interesting and enjoyable flight to an end.

All in all, it was a most informative flight and gave an insight into the type of operation that is carried out many times a day from USAF bases around the world. The variety of aircraft that are regularly and routinely refuelled by these aerial tankers runs to quite an impressive list. The strategic placing of these C-135 aircraft ensures that the maximum operational capabilities of fighters and bombers alike are achieved. It is pleasing to know that the RAAF is deriving some experience in the art of air-to-air refuelling during these exercises. Certainly, it will stand them in good stead when Australia eventually obtains an aerial tanker fleet of her own. It is hoped that we do not have to wait long until such an order is placed for an appropriate aircraft for the needs of the RAAF. Special thanks are due to Lt Carolyn Hodge and Lt-Col Lewis Sutherland for their cooperation and assistance with this flight.