Firefighting by air— challenge and triumph
Niche activity uses everything from helicopters, warbirds and airliners to purpose-built airtankers.
By Doug Wilson
Erickson S64E Aircrane in action. The Aircrane’s 2650-gal hold can be filled while hovering using a snorkel device or in forward flight using the ram scoop hydrofoil.
Aviation in itself is not inherently dangerous. But to an even greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity or neglect.” So begins one of the most recognized passages in aviation, reportedly spoken by Capt A G Lamplugh of the British Aviation Insurance Group in the early 1930s.
For the aerial firefighting industry, this well known quote was made tragically manifest one summer in 2002. On Jun 17 of that year, N130HP, a Lockheed C130A Hercules registered to Hawkins & Powers Aviation of Greybull WY, “experienced an inflight breakup that was initiated by separation of the right wing, followed by separation of the left wing, while executing a fire retardant drop over a forest fire near Walker CA.
Both wings detached from the fuselage at their respective center wing box-to-fuselage attachment locations.” The loss of Tanker 130 was captured on video, along with the subsequent crash that resulted in the deaths of the 3 flight crewmembers.
While aerial firefighting has always been regarded as a higher risk endeavor than other forms of aviation, the fate of Tanker 130 saddened both the pilot community and the public at large. To be sure, the inflight breakup of an airtanker was not a new phenomenon—in 1994 and 2000 other C130s experienced similar fates.
But before the industry could catch its collective breath, another tragedy would unfold—a mere 30 days after the loss of Tanker 130 and its crew. According to the testimony of Ellen Engleman-Conners, then chairman of NTSB, “On Jul 18, 2002, a Consolidated Vultee P4Y Privateer, N7620C, experienced an inflight separation of the left wing while maneuvering to deliver fire retardant over a forest fire near Estes Park CO.
The airplane was registered to Hawkins & Powers and was being operated by the Forest Service as a public firefighting flight. The left wing detached from the fuselage just inboard of the number 2 engine.
Both flight crewmembers were killed and the airplane was destroyed.” A WWII veteran, N7620C—Tanker 123—was 58 years old. On Apr 23, 2004, NTSB Safety Recommendation A-04-29 through A-04-33 was issued, largely as a result of the accidents of 2002.
In it, NTSB recommended development of “maintenance and inspection programs for aircraft that are used in firefighting operations that take into account and are based on:
- the airplane’s original design requirements and its intended mission and operational life
- the amount of operational life that has been used before entering firefighting service
- the magnitude of maneuver loading and the level of turbulence in the firefighting environment and the effect of these factors on remaining operational life
- the impact of all previous flight hours (both public and civil) on the airplane’s remaining operational life 5 a detailed engineering evaluation and analysis to predict and prevent fatigue separations.” Facing a compliance hurdle that was not economically feasible, the nation’s entire fleet of 33 large airtankers was grounded 2 weeks later in May 2004. Aerial firefighting was at a crossroads.
Four USAF airlift wings—the 145th (NC-ANG), 146th (CA-ANG), 153rd (WY-ANG) and 302nd (CO-ANG, pictured)—use the Lockheed C130 equipped with the modular airborne firefighting system (MAFFS).
With the exception of US Forest Service (USFS) survey flights, which began in 1919, the concept of actually extinguishing fires from the air with the use of aircraft wasn’t officially recognized until much later.
The industry’s beginning involved—somewhat predictably—small agricultural aircraft. John Ely, a USFS fire control officer for the Mendocino National Forest, is generally credited with creating the concept of the airtanker. In the spring of 1955, he brought local agricultural pilot Floyd Nolta into the discussion to bring his idea to fruition.
Nolta, who started Willows Flying Service in 1927, was operating cropdusters in the fertile farming grounds of the Mendocino Valley of California. Ely asked Nolta if he thought he could drop water on a fire accurately using an agricultural aircraft. Nolta asked Ely to return in a week.
By that time, Nolta had modified his Boeing N3N-3 Stearman by cutting a hole in the bottom of it and attaching a flapper valve that could be operated by a rope in the cockpit. Filling the hopper with 170 gallons of water, Floyd Nolta’s brother Vance, another well known pilot of the day, proceeded to extinguish a small demonstration fire set at the Willows airport.
Less than a month later, demonstration turned to real life when USFS contacted Willows about a fire that had broken out in the Mendenhall area of California. Vance Nolta responded in Stearman N75081, the very first airtanker, and made 6 drops over the fire, assisting in containing and eventually extinguishing it. That day, Aug 13, 1955, is universally considered the birthday of aerial firefighting.
Borate bombers and the development of large airtankers
Built in 1945, Hawaii Mars, one of 2 Martin Mars flying boats operated by Coulson Airtankers of Canada, continues to serve in the aerial firefighting role.
By the summer of 1956, the firefighting fleet had grown from a single Stearman with a 170-gal water tank to 7. By that time, it was already evident that water evaporated too quickly due to factors such as temperature, atmospheric conditions, altitude and drop speed.
Soon a mixture of water and natrium/calcium borate chemical salts was used to create a true fire retardant, which also solved the earlier problem of water evaporating during the drop. In addition to more of the load actually reaching the ground, the mixture gave rise to the term “borate bomber,” a name now synonymous with the corrosive properties of the mixture that hastened the demise of many a firefighting aircraft.
Over time, borate gave way to bentonite, a mineral which bonds with the water molecules to swell and form a gel-like substance. Through further experiments, USFS and the California Dept of Forestry (CDF)—known today as Cal Fire—settled on 2 retardants with the trade names of Firetrol (mainly phosphates, sulphates and iron oxide mixed with water) and PhosChek (a mixture of water, fertilizer-type salts, coloring agents and flow conditioners).
While these are the primary retardants in use today in the US, the term “borate bomber” still hasn’t slipped from the aviation lexicon, despite the inaccuracy. In the late 1960s and early 70s, while thousands of former WWII aircraft had already become victims of the scrapper’s torch, small numbers of the remaining fleets were being rescued for a return to duty by CDF itself, and by private firms like Hawkins & Powers and Aero Union, all of whom who were keen to find still larger aircraft with greater capacities and low acquisition costs.