New Air Tanker System Passes Tests by Fires
CAPT. KERRY POPE
Langley AFB, Va.
Less than five minutes after takeoff from Stockton, Calif., the crew of Tanker 71, a Tactical Air Command C-130E from Dyess Air Force Base, could see columns of smoke boiling up out of the Sierra Nevada some 50 miles to the east. The source of that smoke was an infemo known as the Granite Fire, and the Granite Fire was Tanker 71’s destination.
Located 65 miles southwest of Lake Tahoe, the blaze was out of control and had already destroyed more than 5000 acres of timber. Giant redwood trees more than three centuries old had fallen victim as the fire spread destruction which would take nature hundreds of years to repair. On board Tanker 71, the crew quickly completed their checklists, each man in quiet anticipation of the mission he was about to perform.
As the Herkybird neared the target area, radio contact was made with 102 Zulu, an Aero Commander. The lead plane, 102 Zulu, was responsible for guiding the big tanker aircraft over its targets. The lead plane instructed the pilot of Tanker 71, Captain Greg Crum, to hold east of the fire at 7500 feet.
Notes escape route
While in his orbit, Crum surveyed the terrain, making mental notes on his planned drop run and escape route. It is sheer folly to make a run on a fire in mountainous terrain without first surveying the area to determine the best drop route and escape.
Tanker 71 was advised that he would be following a B-17 just starting its run down the mountain slope. Crum called slowdown, and the big transport was configured for the attack-flaps 50 percent, cargo ramp and door open, discharge tubes extended.
The lead plane directed Tanker 71 to descend to 5000 feet and position himself on a left downwind. The approach was to be made over a high ridge and down a 40-degree mountain slope. The drop itself would be made where the B-17 left off, about halfway down the slope.
Crum turned base leg and called the one-minute warning to his crew. The cargo door was closed, leaving two huge nozzles extending over the aircraft’s lowered ramp. The lead plane pulled into position to guide the tanker in on his run. The two aircraft turned final, descending to a scant 200 feet above the ridge. As he crested the ridge, Crum pulled his throttles to flight idle and began his roller coaster ride down the mountainside.
The crew sighted the bright red line of retardant left by the B-17’s drop and the five-second warning was given. Final adjustments for wind were made, and the crew awaited the signal for release. A few moments later, the C-130 surged forward as 3000 gallons for fire retardant spewed forth from its cargo compartment. In less than six seconds, the big bird had shed 27,000 pounds, and a raging forest fire was closer to being contained. Forty minutes later, Tanker 71 had reloaded its tanks and was en route back to the fire for another drop.
An Aero Commander, a B-17, and an Air Force C-130 working together? It happened last August as the Forestry Service battled dozens of major forest fires throughout the West and Northwest.
The story of TAC’s involvement, however, goes back to early 1971. The United States Forestry Service has been fighting forest fires for years with a fleet of World War II bombers: B-17s, B-26s, PB-4Ys (the Navy version of the old B-24 Liberator), and TEMs (single engine torpedo bombers). Recently, C-119s, DC-6s, DC-7s, and P2Vs have been added.
Too often, however, the heroics of the civilian tanker pilots and their ancient planes have not been enough to contain the biggest fires. A supplemental force was needed, and the Air Force seemed to be the answer. The secretary of the Air Force directed the Air Force chief of staff to develop a capability to support the forestry service in its airborne fire fighting operations. The Tactical Air Warfare Center (TAWC) at Eglin AFB was given the task of developing this capability.
In July 1971, a prototype system was flight-tested at Edwards AFB. The system was expanded and flown aboard an Air National Guard C-130A from Vau Nuys, Calif. An operational test indicated the concept was feasible, and a California corporation was contracted to develop an operational prototype to be designated the Modular Airborne Fire Fighting System (MAFFS).
In November 1972 my copilot, then Lieutenant Greg Crum, and I were sent to Marana, Ariz., to attend the Forestry Service’s first National Air Tanker Pilot School. At Marana, we were introduced to the modern science of forest fire fighting. We learned of the numerous factors that influence the nature of a forest fire: topography, fuel, wind, weather, command and control, ground fire fighting methods, use of aerial retardant, and tanker tactics.
The information was important and extremely interesting, but the most vital information came from the other pilots. These were the men who fly air tankers year-round and had been fighting forest fires for years.
We got advice that can come only from the lips of men who have been there: Never make a run before flying over the target to pick out an escape route. Unlike a C-130, a B-17 doesn’t have the power to make a steep climbout if its load can’t be jettisoned.
Never make your drop run uphill. Don’t fly below the rim of a canyon unless a lead plane precedes you, for there can be air currents which will render a loaded tanker uncontrollable. The smaller, faster lead plane can fly out of these currents, and it’s his job to warn the tanker of such dangers.
As we listened, Greg and I became infected with a fever common to all tanker pilots. Fighting forest fires from 150 feet above the ground is perhaps the most exhilarating, rewarding experience an airlifter may ever encounter. This was one job that could be done only by those who wanted to do it, and we both wanted to prove ourselves and our airplane.
From our discussions with Forestry Service officials and civilian tanker pilots, the advantages we would have with the C-130 and the MAFFS system became apparent. The C-130 gives us performance that our civilian counterparts could only dream of. The Hercules can descend at 2500 feet per minute at drop airspeed (140 knots). This makes a 40-degree slope easily negotiable. In contrast, a B-17 is limited to about a 900-foot-per-minute rate of descent at its drop airspeed of 110 knots. The great power available in the C-130 makes steep climbouts routine. For the old B-17, there is no power to spare.
The advantage of the MAFFS lies in the fact that the retardant (a chemical that weighs nine pounds per gallon and is also a growth-promoting fertilizer) is dispensed by compressed air instead of a gravity system, such as the civilian industry uses. Dropping at too low an altitude from a TBM, for example, allows the retardant to strike the ground before it has had a chance to break up into a mist. Such an impact can be devastating, and has been blamed for deaths on the fire line and destruction of equipment.
A MAFFS-equipped aircraft can spray a row of houses from 50 feet up with absolutely no damage. A gravity drop from such an altitude would smash the roofs of the buildings.
First look at system
In January of last year, we got our first look at the new MAFFS system. It consists of seven units: five holding tanks for the 3000 gallons of retardant, one control console pallet, and a discharge nozzle pallet. The entire system is palletized for use aboard any aircraft equipped with the 463L dual rail system. Loading time for the entire unit is less than 90 minutes.
The retardant is dispensed under compressed air pressure, which is variable from 5 to 40 psi. A low pressure is used on range or brush fires and a higher pressure on fires in heavy timber and other dense fuels. At 40 psi, the entire load of retardant is emptied in less than six seconds. Recycle time for onloading retardant and air is 15 minutes or less.
We flew the system back to Marana for extensive testing. A total of 24 drops were made at various altitudes and system pressures, artd we found that discharging the system had very little effect on the flight characteristics of the aircraft. Losing 27,000 pounds almost instantaneously has the effect of an afterburner kicking in and an elevator going up at the same time.
First drops on fires
The operational test of MAFFS came rather spectacularly last August when the rash of fires broke out in the West and Northwest. The MAFFS C-130, piloted by Capts. Greg Crum and Dick Henry from the 463 TAW at Dyess AFB, made more than two dozen drops on major fires in Idaho, Montana, and California.
MAFFS was given credit for saving a string of cabins and a restaurant in California by using its unique low altitude spraying capability. More importantly, MAFFS was proven to be an effective fire fighting system that can be safely employed by a TAC air crew. Spokesmen for the Forestry Service stated that the system and the aircraft give them performance and capability that never before existed.
If funds are approved for the equipment, the training programs will be set up at the tactical airlift wings designated to maintain MAFFS currency. Two would be required to maintain a certain number of MAFFS crews available during the fire season, May through October. In addition, the reserve forces could maintain a certain number of MAFFS-qualified crews.
Restricted to emergencies
Crews and aircraft would be used only on major fires threatening government property or inhabited areas and then only after all available civilian air tanker resources have been committed. This employment concept insures that tactical airlift will be used only in cases of genuine emergency while still providing the Forestry Service with a greatly increased capability to combat major fires.
The initial call for assistance will come from the International Fire Control Center in Boise, Idaho. The request will be authenticated, and the required number of C-130s will be launched. These aircraft will proceed to an onload station to install the MAFFS equipment. They will then proceed to a forward operating location to dispense their flame-smothering retardant. After the fire fighting operation is complete, the MAFFS will be returned to storage, and the aircraft and crews will return to their normal airlift duties.
The advent of MAFFS will provide the airlift forces of TAC and the reserve forces an opportunity to demonstrate another facet of their flexibility and versatility. It also demonstrates to the people of this country the ability of tactical airlift to employ its forces in peacetime roles which are beneficial to all—and absolutely vital to many.