Simplex receives STC for Chinook internal tank

Simplex Chinook internal tank firefighting

Above: A Chinook with the Simplex Model 347 internal tank for firefighting. Simplex photo.

The following is a Simplex press release.


Simplex Aerospace was recently granted a Federal Aviation Administration (FAA) supplemental type certificate for a Fire Attack System (FAS) for the Columbia Helicopters CH-47D helicopter. The system is an internal/external system, comprised of a roll-on/roll-off internal tank system connected to an external plenum.

The Simplex Aerospace Model 347 FAS is the largest helicopter firefighting system in the world.

The Model 347 is comprised of a 3,050-gallon internal tank with a 2,800-gallon water reservoir, approximately 110 gallons of water through the hookwell and 140-gallon foam concentrate reservoir that can be loaded from the helicopter’s rear loading ramp. The system also includes a 12-foot-long, 10-inch diameter hover pump, capable of refilling the tank in less than one minute.

The system includes ground fill ports so the tank can be pre-filled and ready to go at a moment’s notice. The entire contents of the FAS can be dropped in less than four seconds.

The Simplex Model 347 has the capability for the pilot to select drop patterns ranging from a single drop to multiple drops depending on the demands of the mission. An automatic emergency water drop feature is included on all Simplex Fire Attack systems in the event of an aircraft power outage.

This new Simplex FAS can be installed on the helicopter using only four bolts. Only minor modifications are required to provision for FAS installation.

The gravity-fed Fire Attack tank is installed in the aircraft cabin; then connected to a sleeve, which extends through the aircraft hookwell, joining an external plenum in the belly. Vne (never exceed speed) for the Simplex 347 FAS is 140 knots, with or without the hover pump installed.

Water drops can be made at up to 100 knots. Newly developed pilot control and display allow for U.S. Forest Service Type-one compliance. The pilot controls can be configured to show water volume, and ground refilling volume displaying gallons (or weight) on both the flight deck and ground fill input location.

“This new and innovative CH-47D FAS for Columbia Helicopters is the largest helicopter FAS in the world today,” said Mark Zimmerman, Simplex president and CEO. “With total water evacuation in under four seconds, it is the most cost-effective FAS available to operators around the world.”

Zimmerman went on to say, “the system was developed for installation with very minimal aircraft provisioning required, making installation fast and cost effective.”

3 thoughts on “Simplex receives STC for Chinook internal tank”

  1. After working on the development of an internal tank for the Chinook (CH 47) for over a decade, producing three flying prototypes to be use in Guard aircraft (military, that is where the story ends) this is very exciting. “With total water evacuation in under four seconds……………..”, this will be the king of water dropping aircraft. No other aircraft in the world can deliver 2800 U.S. gallons in under four seconds! New records will be achieved for gallons delivered per hour if the water source is within five air miles of a wildfire. GO SIMPLEX.

  2. I saw a Colombia Ch-47 flying near my town today practicing with the internal tank for several hours. With binoculars I could watch them draft and do practice runs. Hope all the testing is going well, it looked awesome!

    1. Appropriate name for the 47 with an internal tank: “FireHog”. It should be an impressive addition to fire fighting.

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