Air Tractor's new fire retardant delivery system

Photo courtesy of Air Tractor

Air Tractor, manufacturer of the AT-802F single engine air tanker, has been building agricultural aircraft, and later air tankers, at their facility in Olney, Texas since 1951. Air Tractor is the only manufacturer of purpose-built air tankers in the United States.

The Fire Retardant Delivery System (FRDS) controls the timing of the opening and closing of the doors on the retardant tanks. The pilot can select the coverage level, measured in gallons per 100 square feet, and the quantity of retardant or water to drop after dialing in the ground speed.

Air Tractor has just introduced their first redesign of the FRDS since 1993. According to Air Tractor:

Improved delivery accuracy, improved door speed and new advanced leakage compensation algorithms are among the second generation FRDS enhancements. The fire gate doors — which open and close with timing that’s measured in milliseconds — are even more responsive.


Numerous reliability enhancements have been designed-in throughout the new Air Tractor FRDS system. The components of the system have been “hardened” to protect against the effects of vibration and humidity; the system also has improved waterproofing throughout. Microprocessor and electro-mechanical back-up systems have been added. A three valve redundant auto salvo system assures reliable door opening for accurate drops.

Computer processing advances make the FRDS pilot interface more user friendly. An easy-to-read display allows pilots to assess system status at a glance.

Field service and maintenance has been simplified with a “black box” or cable swap-out program and self-diagnostic and alert message features that indicate possible malfunctions and help isolate problems in the system.

Our government could find worse things to spend the $800 billion economic stimulus dollars on than brand new United States-built air tankers, to replace or supplement our decades-old cobbled-together fleet we are now using.