AIR TANKERS GO BIG TIME

Turning from base to final approach, Boeing 747-200 captain/pilot Cliff Hale calls for full flaps and adjusts engine power to keep the aircraft on a controlled flight path, aimed at a San Bernardino, Calif., airport taxiway. First Officer Bob Roshak calls altitudes as the huge aircraft descends. Several hundred feet above the ground, Hale gently pulls the 747's nose up, leveling at about 180 ft., then holds a 3-4-deg. nose-up attitude and 150-kt. airspeed.

"Stand by . . . ," he calls. Behind and to Hale's right, Steve Goddard, the flight engineer, double-checks a small display and control panel, confirming its settings are correct.

A few seconds later, I hear a loud, extended "whoosh" behind me, signaling that Hale has punched a "pickle button" on his control yoke. He slowly pulls four throttles back, maintaining the 747's slight nose-up attitude as 20,500 gal. of water blast through four 12-in. ports on the aircraft's belly. Driven by eight tanks of air pressurized to 165 psi., the 10-sec. deluge drenches several hundred yards of the targeted taxiway. The intense manmade rainstorm terminates as we fly past a crowd gathered near the airport terminal.

Monitoring the flat-panel display, Goddard calls, "That's it." Hale pushes the throttles forward, calls for flaps up, starts a climb, then banks left to downwind. A few minutes later, we're on the ground, taxiing slowly toward that waiting crowd. With its San Bernardino water drop, Evergreen Aviation's 747 Supertanker completes a five-state demonstration tour aimed at introducing this new tool to the aerial firefighting community. And this Aviation Week & Space Technology editor is a step closer to fully understanding what a U.S. Forest Service (USFS) executive suggested: High-capacity, next-generation air tankers could radically alter the aerial firefighting business.

Armed with 10,000-20,000 gal. of water/fire retardant, these aircraft might be able to extinguish relatively small fires, protect valuable structures single-handedly, and even alter the humidity over a fire at night, forcing the blaze to "lay down," so ground crews can contain them sooner.

A few wide-body air transports have been modified as air tankers in recent years, but their operators have yet to sign long-term contracts in the U.S. A Russian Ilyushin Il-76 has seen service overseas, yet a variety of political factors, resistance among veteran firefighters and severe cost constraints have kept the approximately 11,000-gal. tanker offshore. Evergreen Aviation's new 20,500-gal. 747 Supertanker and "10 Tanker STC's" 12,000-gal. DC-10 Supertanker are angling to get on U.S. fire lines, hampered primarily by scant USFS budgets and lingering questions about the suitability of high-capacity firefighting tankers. But that may change during this fire season.

Evergreen is negotiating for a USFS demonstration contract, but has a number of FAA and USFS hurdles and procedures to clear first. As of last week, the company had not secured FAA-certification of its firefighting system, nor Interagency Air Tanker Board (IATB) approvals to fight fire.

The "10 Tanker STC" DC-10--a joint venture that includes Omni Air International--has its FAA Supplemental Type Certificate covering tanker-related modifications, and recently received IATB approval of its external, gravity-drop tank system. In mid-July, though, the DC-10 Supertanker dropped two loads of retardant on a fire under a "call-when-needed" contract issued by the State of California.

The DC-10 has not completed a USFS Supertanker Operational Assessment Project (SOAP), which could preclude getting a federal demonstration contract this year. The Evergreen 747 completed its SOAP flights last spring, erasing a number of critics' concerns about the feasibility of supertankers.