Photos of Coulson’s 737-300 air tanker

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The company expects to have the conversion complete by the end of this year.

On May 21 we told you about Coulson Aviation branching out into a new line of air tankers to add to their three C-130s and a fourth C-130 that is being converted now. The company has purchased six 737-300’s from Southwest Airlines and intends to convert at least some of them into air tankers.

The first conversion has started, with a freshly painted 737 rolling out of the paint shop in Spokane today.

The next step is to add a gravity-based tank which will have the same technology used on their C-130’s.

Coulson 737 air tanker

The air tanker is being designed as a multi-use aircraft with the ability to haul passengers. Britt Coulson said, “With a full retardant load and 4.5 hours of fuel we are so far under max gross weight we are going to leave the full interior and galleys in even when just in airtanker mode.”

Coulson 737 air tanker


The photos were provided by Coulson Aviation.

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16 thoughts on “Photos of Coulson’s 737-300 air tanker”

  1. Will it retain the pressurization? Assuming the tank will be internal, there will need to be some engineering involved for some sort of seal in the exit area.

    1. Yes! That seems like a waste! If your going to a fire any way take as much as possible. But does this mean we can buy rides?

    2. Remember receiving a R 5 D (C 54, DC4) for conversion to an air tanker. It came from Arizona, Dross Metal Tucson. It was a Navy admirals flag ship. Beautiful wood interior, appointments very where. Instead of hauling around Navy royalty this “new” tanker helped protect lives and property for over two decades. GUT IT! Put on another grand. At 70 am I too radical?

      1. Johnny…
        You have always been radical. From your days in the B-17 to innovating with the CNG at Baseline! Keep on being radical! 🙂

    3. I’m guessing they don’t do that because it would mean designing, building and certifying a new, larger tank, which costs a lot of time, money and effort. Coulson bought the rights to an existing, previously-tested and approved RADS I tank and more or less wheeled it inside an airplane. I suspect they’ve considered adding more payload to the 737, crunched the numbers and aren’t satisfied with the ROI they came up with.

      1. That very well could be. I would still gut the interior and make the aircraft as light as possible anyway. The lighter the better in the mountains…the only time an aircraft can be too light is when you’re in an A-Star on top of Everest!

  2. By not challenging gross weight numbers, you are building in a safety factor. Bigger is not always better ( or in this case less may be better than more ).
    The bottom line is, at this point, the proposal is only a concept. Time will tell what we have when the first one flies.
    Maybe there are zero fuel weight considerations, or W&B issues.
    I am sure all the of this has been thought out, they do say that Boeing engineers are involved in the conversion.

  3. I’m glad to see the 737 converted. As the most produced Boeing jet aircraft I took my first ride on one of these in the 70s and have flown on countless ones over the years. A well proven, robust and reliable aircraft I hope it proves its self as a tanker and transport aircraft in the coming years. One might note the DC-3 was reborn several times in a variety of roles after modification and retrofit. I’m not sure if it every became a tanker.

  4. After seeing the discussion here and in the other article about the how much retardant the 737 could carry if the interior was gutted, Britt Coulson sent us this information:

    Basically, we could have packed more retardant and still left the interior in but we looked at the options and it just didn’t pan out.

    We chose to maximize aircraft safety and not tank volume, having the crew and airplane come home at the end of the day is more important to us than delivering an extra 1,000 USG per load. The interior is very light and only displaces around 100 gallons. The difference in 4,100 USG vs 4,000 USG was not enough for us to gut the airplane. The contract minimum is 3,000 USG which our competition marginally meets, we are already the largest LAT in the market now.

    1. Displaces around 100 gallons.

      The 737 interior (presumably 63 airline seats, interior walls, carpeting and overhead bins/lights/venting) weighs only approx 1000lbs?

    1. Last time I checked, there was no patent on a paint scheme, if they want to copy a design of another I see no problem as long as the thing is visible in the air and over a fire.

  5. I’m happy to see our old -300s put to good use (although I wouldn’t call them “low time”). I flew the military version of the C-130 (MAFFS) and always thought it was a shame that the civilian tanker operators couldn’t gain access to more retired military aircraft to modernize their fleet. I guess one unscrupulous operator used his “donated” aircraft in the off-season in parts of the world and doing things that the State Dept didn’t want former military planes visible. You would have thought the government would have got over that by now and can monitor that better now. My buddy is the USAF AMC Commander now and I have hopes I can influence him to relax the prohibition on letting civilian operators buy retired aircraft, just sitting in the Boneyard. Having all my hours in Hercs and 737’s, I’d rather use a Herc because of the engine spool-up time. 150′ is no time to be waiting for thrust if you need it!

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