Update on next-gen air tankers

Tanker 160 retardant grid test December 13, 2013
Aero-Flite’s Tanker 160 at the retardant grid test, December 13, 2013. Photo by Jeff Zimmerman.

Five companies received contracts on May 6, 2013 for seven “next-generation” air tankers. Of those seven, only two have met all of the specifications in the contracts and received the required certifications from the FAA and the Interagency AirTanker Board (IATB) for a supplemental type certificate, a static drop test on the ground, and an airborne test of dropping retardant into a grid of hundreds of cups. The two that have passed and have flown on fires are 10 Tanker Air Carrier’s 11,600-gallon DC-10, and Coulson Group’s 3,500-gallon C-130Q.

Here is what we learned this week while talking with aviation professionals at Cheyenne.

Minden Air Corp, who received a contract for one BAe-146, has passed the static test. They have not attempted a formal monitored grid test. The retardant system they are building has some impressive capabilities, including a high flow rate and a great amount of flexibility in the flow rate. It has the ability to select two different flow rates on one drop, for example, going from coverage level 5 to coverage level 8. (The numbers refer to the number of gallons of retardant that lands on 100 square feet of flat terrain.) That feature could be used when there is a change in vegetation or topography, moving, for example from grass to timber, or flat terrain to a steep slope. In each case it would be helpful to increase the coverage level.

Erickson Aero Tanker, received contracts for two MD-87s. One of the aircraft participated in a grid test in January, and the Interagency Air Tanker Board is still reviewing the results. Even though they added a fairing to modify how the air flow affected the performance of the aircraft and the retardant flow near the fuselage, the aircraft experienced some problems in qualifying at the higher coverage levels. The engineers may need to enlarge the retardant door openings to increase the flow rates.

Aero-Flite has two RJ-85s, an aircraft similar to the BAe-146. It has passed the grid test and the company is working on obtaining dual “citizenship”, supplemental type certificates for the retardant system from Transport Canada and the United States FAA . It is likely that the aircraft will be certified very soon by the IATB for an 18-month interim approval, which will be the new standard operating procedure for air tankers that receive an initial blessing from the IATB. The interim approval provides an opportunity for field trials, to determine if anything surfaces that was not apparent during the static, STC, and grid tests.

Bonus coverage:

Evergreen’s 747 “Supertanker” was not part of the next-gen contract, but the company did have a couple of call when needed contracts (CWN), with the last one being issued June 14, 2013. After receiving the contract Evergreen scheduled a needed C check which would have started August 2, and depending on what was found during the process would have been ready to fly in mid- to late September — about the time the western wildfire season begins to wind down. The cost of the C check is over a million dollars. But a few weeks after receiving the contract, Bob Soelberg, the Vice President of Evergreen Supertanker Services, told Fire Aviation they reconsidered and decided to postpone the C check since there was “insufficient fire season remaining to justify the expense of an expedited C check as well as several system or component upgrades.”

A matter of weeks after Mr. Soelberg gave us that update the company filed for bankruptcy. The change in ownership made the CWN contract void. As of now, the 20,000-gallon 747 Supertanker is not covered by an air tanker contract.

Neptune has one BAe-146 working on the “legacy” air tanker contract, even though it now meets the criteria for a next-gen, including the required air speed and a 3,000-gallon retardant capacity. Before they modified the tanking system for the third time last fall, the tank held about 2,900 gallons and there was a problem in coverage level of the last 400 gallons exiting the tank, so the Forest Service restricted it to only carrying 2,500 gallons. The modifications increased the tank size to 3,000 gallons and made other changes in the system. At another grid test last fall it showed improved consistency for all 3,000 gallons, and in the flow rate at all coverage levels. As a result the Forest Service has now certified the tank system to carry 3,000 gallon of retardant. Their new design is innovative in that it uses GPS to measure the aircraft speed and then can automatically modulate the retardant flow rate to maintain the desired coverage level. They also have a sensor on the drop tubes which measures the actual flow rate. They system can then direct the valves or doors to change the size of the opening in order to maintain the coverage level as other factors change, such as the head pressure in the tank or if the aircraft encounters turbulence. Neptune expects to have a total of five BAe-146 air tankers available by later this summer.

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