Retardant at Ryan AAB and S-2's

In today’s post I am going to be writing about retardant mixing at Ryan Air Attack Base (AAB). This is possible because I have learned about retardant mixing operations at Ryan AAB from TL Stein. Moreover, Ryan has an S-2 air tanker. This provides me with a unique opportunity to link mixing retardant with a specific type of air tanker. In addition, unlike Ramona AAB which uses a mobile mixing system, Ryan AAB has a permanent mixing system. Ramona, the oldest AAB, uses a (mobile) mixing trailer because they have little room for expansion. Ryan like many other larger AAB’s use permanent mixing facilities.

Ryan Air Attack was first used as an air attack base by the USDA Forest Service in 1957 and the California Dept. of Forestry (CDF) started air attack operations at Ryan in 1959, making Ryan the first joint air attack base in the U.S. In the 1960s a permanent retardant mixing system was installed and shared by both the USDA Forest Service and the CDF (now known as CAL FIRE). In 1998 the USDA Forest Service moved their air attack base to the San Bernardino International Airport.

Thanks to TL Stein -- who made a short video on retardant mixing operations, took some photographs and gave me an excellent write up of retardant mixing at Ryan -- I am in a position to make this blog entry. The video is included in this post. After you watch this short video, I hope that you will have a good idea of how retardant mixing at Ryan works.



In addition to the video, I am including a couple of TL Stein’s photos. One is a photo of an eductor assembly at Ryan where the water and retardant pipes are labeled. As you will learn in the video, as water flows through the eductor, it creates suction in the retardant pipe. Retardant is therefore drawn into the eductor. The powdered retardant mixes with water at the point (see the photo) where the water and retardant pipes come together. From there it goes into a storage tank. The second picture is of the retardant mix control panel where the mixing operation and flow of mixed retardant to the various storage tanks on the base.

In my next post, I will write a little more about the process of loading the retardant mixture onto the S-2 and share some of TL Stein’s up close and personal photos of the S-2.