More about CAL FIRE's S2-T tankers - January 10th edition

I am returning to writing a little more about CAL FIRE’s S2-T Tankers. This article serves as a follow-up to two articles I wrote before Christmas, Reflections on CAL FIRE’s S2-T Tankers, Part 1 (December 16, 2019) and Part 2 (December 23, 2019)

This article is possible because of recent e-mails with an experienced CAL FIRE pilot.

First, he made a couple of corrections to part 1 that are reflected in the article. The most important correction is clarification on the number of S2-T’s in California. Twenty-two are assigned to twelve air attack bases with one or two S2-T’s assigned to each base. One, T-100 is a spare and is at McClellan Air Attack Base until needed. See the CAL FIRE pilot’s Association website for more information on CAL FIRE’s tanker bases, aircraft and other news.

He had a few things that he wants me to share with you using part 2 as a starting along with one of the earlier articles that I referenced in part 2, Reflections, S2-T's, SEATs and initial attack (May 24, 2009). So perhaps you will want to take a few minutes to review these two articles before going any further.

My friend started with initial attack,”97% of fires are stopped before 10 acres thanks to the rapid intervention and coordination of ground and air resources. Air (tankers and copters) are here to support the ground fire fighters and can't replace them. When retardant is dropped to stop the spread, buy time and contain the fire, it needs to be backed up by fire fighters.”

I asked him about dropping retardant on fires, he said “the perfect drop is a difficult equation and an eternal quest: perfect speed, height, timing, drift, line, quantity, and coverage level (note 1). Very humbling most of the time and very gratifying once in a while when it's achieved.”

Finally he talks about the airplane: “You need a good airplane, well maintained, a good tank system, good retardant (well mixed) and an experienced pilot to start, then you might have a chance to make a decent, safe, efficient, effective drop.”

Note 1. coverage level is the density of retardant in drop. Normally ranges from 1 to 7 and represents the number of gallons in a 100 square foot area (see  terminology on the Associatied Aerial Firefighters website.)

Reflections on CAL FIRE's S2-T tanker (part 2)

Long-time readers of this my blog know that I cut my teeth following wildland fires in California, partly because I knew a former CAL Fire pilot and a some current CAL Fire pilots who answered my questions and guided me in the early days of this blog. They showed me around various places on the web, nationally as well as CAL Fire sites where I could find more information. Much of my conversations with these friends were what I called background research and learning. I am forever grateful to these pilots, who are know friends. Some are still flying and when I see a video, photograph, or live stream I may sometimes get a glance at their tanker number.

So, because of those early days when I spent hours following wildfires in California through various live streams from California news stations, I will always have an affinity for CAL Fire pilots. But there is more. That is, I have some family and close friends who live in southern California. I know that the S2-T tanker pilots, CAL Fire helicopters, and other local helicopters are flying these wildfires to support the wildland firefighters on the ground. If the fire is large enough, other aerial resources either from the national fleet of tanker and helicopters, MAFFs tankers, National Guard helicopters, and other assets from California will help. The same hold for wildfires elsewhere in California. Anyway, I know that the aerial firefighters and firefighters on the ground do what they do to keep residents and businesses safe from wildfires. In regards to southern California, it is personal because of my loved ones.

I had hoped to do a little more background research to answer some questions I have about CAL Fire's S2-T tankers. But with the holiday season upon us, I decided to wait until next year. Perhaps there will be nothing new to add, but it is worth the effort. In the meantime, some of you may want to check out some of these older posts that I wrote on the S2-T tanker:

S2-T tanker (part 1) (December 16, 2019)
A closer look at CAL Fire's aviation program (September 18, 2019)
A peak inside a CAL Fire S2-T (October 15, 2010)
Reflections, S-2_T's, SEATs and initial attack (May 24, 2009)
S2-T's end of season tank maintenance (May 9, 2009)

Reflections on CAL FIRE's S2-T tanker (part 1)

I would be remiss to write reflection pieces on air tankers and not include the Grumman S2-T Tracker flown by CAL FIRE. I am not quite sure how many S2-T's are currently flown by CAL FIRE. According to CAL FIRE's fact sheet (2005) on the S2-T there are 23 S2-T tankers in service. Twenty-two are assigned to twelve air attack bases with one or two S2-T’s assigned to each base. One, T-100 is a spare and is at McClellan Air Attack Base until needed.

I first learned of the S2-T in the spring of 2009 shortly after I decided to devote this blog to aerial wildland firefighting and related concerns. I have grown to love the S2-T and her pilots. S2-T's are based at air attack bases around California so they can easily and quickly be deployed to fly wildfires in support of the wildland firefighters on the ground. They do a lot of initial attack work and many times their quick response coupled with the wildland firefighters on the ground wildland fires can be put out while they are still small. And when that is not possible, they will continue to fly the fire with, the support of other air tankers and helicopters.

I do not live on the west coast, but I have visited southern California a couple times and stopped by Ramona Air Attack Base for a visit. The morning I visited, it was a quiet day and one of the S2-T's, T-71, was sitting on the ramp along with the OV-10 air attack plane. I was delighted to be able to take a tour of the base with some photos which I shared in my July 13 2012 post.

I found a very cool video, almost six minutes long, of footage shot from inside a S2-T tanker. According to a knowledgeable friend, the pilot is Bob Forbes, now retired, and the video was probably shot near Hemet California where his home base (Hemet-Ryan in Riverside County California) was located. I love videos that take me inside the cockpit of a tanker flying a fire. There is no audio, but I found the sound of the engines to be comforting. Enjoy.



Direct link to video

A closer look at Cal Fire's aviation program

I am a non-pilot member of the AOPA. Actually the AOPA makes no distinction between pilots and non-pilot's in their fee structure but for purposes of this blog it is important that I be clear that I am a non-pilot aviation enthusiast. The AOPA puts out a weekly video called AOPA Live, an interesting video about 25 to 30 minutes long with weekly aviation news. They do not only focus on general aviation as is evident by The AOPA Live episode on May 23, 2019. In that week's episode that had a report on CAL Fire's aviation program. Because the video was about 27 minutes long, I did not share it here. I recently found the clip devoted to Cal Fire's aviation program so I am sharing it here, a direct link to the clip from AOPA Live may be found here. AOPA Live has a youtube channel where I also found the video, and I am embedding that video below.

I like this video because you will hear from a S2-T pilot, Jimmy Ferreira about what is like to fly fires in an S2T. You will also learn about the Cal Fire program. While there are going to be differences between Cal Fire's S2T's and other tankers, Jimmy does give me an idea of what it is like to fly fires. Enjoy!

Thank-you Jimmy and stay safe.



Other links:
Cal Fire home page
Cal Fire Air Program
S2-T Air Tanker (pdf)
California Pilot's Association
California Pilot's Association Newsletters

Reflections on learning about aerial firefighting almost 10 years ago

After  i wrote about P-2 Neptune tankers the other day, I spent some time reflecting on first learning about the business of aerial firefighting nine and ten years ago. I am eternally grateful to some now good friends who helped me learn about the business. I spent a lot of time watching live stream coverage of some of the larger wildfires that were burning in southern California in mid to late 2009. A couple of times, I was watching the live stream as I was exchanging e-mails with one of my former tanker pilot friends. He would share a little about what was going on. I enjoyed seeing the tankers and helos in action, working to help the wildland firefighters on the ground. As they say, one picture is worth a thousand words. The video that I am sharing below is from Alan Simmons of Firestorm HD Production. He uploaded the video to Youtube in April 2010. I believe that at least some of the fire footage is from 2009, perhaps there is footage of some of the wildfires that I was following in 2009. Alan’s footage is a highlight video from a longer DVD that he put out, go here for more information on the video that is available for purchase only. 

I love watching videos like Alan’s of tankers working a wildfire. Elegance in action. What they do is very dangerous. Please remember that if it is very windy or the smoke is very bad tankers and helicopters may not be flying the fire because it is not safe to do so.

The video from Alan Simmons that I have embedded below has about eight minutes of highlights from his 80 minute video. In the first half, you will see footage of the S-2T, P-2 Neptunes, P-3 Orion, Canadair 215/415, and the DC-10. The final three or four minutes includes footage from 1999 of now historic tankers including some footage of T-123 which crashed in 2002.

Direct link to video from Alan Simmons on Youtube

Historic Airtankers - CAL FIRE S2A Airtankers (1973)

Enjoying a little downtime today, Presidents Day in America. Enjoy this video from 1973 about the Grumman S2-A tankers that began to serve what was then the California Division of Forestry (CDF) in 1973. It is entirely possible that I have embedded this video at some point. And if so, it is worth sharing again. In the later half of this footage you will see some footage of TBM single engine tankers that flew for the CDF before the CDF acquired the Grumman S3A tankers and some Lynch B26 tankers.

I wrote about the Grumman S2-A (and the S2-T's), the last of which flew in 2005 here, they were replaced by the S2-T tankers which are still flying. I have several posts on the TBM Avenger that I you may read here, with the latest post at the top (sorry).

Direct link to video

A peek inside a CAL Fire S2-T

While I am working out the final details on the article that I hope to post later today, I want to offer this video showing you the inside of one of CAL Fire's S-2T tankers. Enjoy! And stay tuned!

Reflections, S-2T's, SEATs and initial attack

I love the light tankers (S-2T’s and single-engine air tankers) in a special way. Perhaps it is because I live in NJ, and I have grown to appreciate and the role that single-engine air tankers (SEATs) have in initial attack (and extended attack). And it is not only NJ that uses SEATs, many states contract for SEATs. In the case of NJ, I am aware that the majority of our wildland fires are small in size. I also know that during our spring season that the NJ Forest Fire service deployed SEATs and helicopters to fires that were only a couple of acres in size. I am aware of this because of a couple of websites that I have followed, not because of the media.

Some of you know that I got interested in wildland fire fighting last July because I have a couple of friends who lived in or near the area burned by the Basin Complex Fires. And I have written about a couple of other larger California fires. I have written about CAL FIRE’s S-2T’s. Up until now, I have neglected to write about the very important role the S-2T’s, a light tanker, play in initial attack. Until now when I want to focus on initial attack.

California has an impressive number of large fires that make national news. I don’t know the numbers, but most of California’s fires are small in size, being 2, 5, or 10 acres. I have recently engaged in an e-mail exchange with an experienced air tanker pilot who will be flying S-2T’s this year. He was telling me about the importance of initial attack in keeping fires small and manageable until ground crews can get in:

Regarding the use of tankers, the best tactic is initial attack. In initial attack, S-2T tankers and helicopters are deployed to the wildfire as soon as possible in order to stop the spread and hold until ground troops have access and put it out. The goal is to keep the fire small: 2, 5, 10 acres maximum so it is ‘easy’ to manage. Roughly ninety-seven percent of fires in California are put out this way. The public may not hear about it. But...if you're not aggressive enough you get behind the power curve and then get complicated fast (wind, fuel, terrain...).

I understand that things can get complicated, especially with the drought, sundowners and the Santa Ana winds. And the terrain. I get that. Sometimes initial attack is not going to keep the fire small. But most of the times it does. How many houses have been saved, lives saved? You light tanker pilots -- the workhorses of CAL FIRE, other State fire fighting agencies, and the national fleet -- what you do is special. I want you to know that.

S-2T: end of season retardant tank maintenance

At the end of the season, or when maintenance on the retardant drop system is required during the season, the retardant tank is washed out. When this happens, the flapper valve and the tank doors at the bottom of the aircraft are in the open position. In addition the hotload cap is off. This allows any standing water to be vented from the system.

Here is a video of what this operation looks like:

S-2T: in action (2 of 2)

If you have nine minutes and want to see a good video of a few S-2T's in action along at a helicopter with a bucket working fires in California, take a look at this video. SCU refers to Santa Clara Unit.

S-2T: in action (1 of 2)

Here are a couple of very short videos of S-2T's in action. In the first video, the S-2T is working with a lead plane in the 2007 Zaca Fire in Los Padres National Forest. The first plane you see is the lead plane showing the S-2T where to make the drop. A few seconds later, the S-2T tanker flies through to make the drop.



In the second video, the S-2T tanker seems to be working with out a lead plane. At least a lead plane is not shown in the video. The last few letters in the name of this video is cut off, it is "CDF Air Tanker 78 Drops on Felter Fire/Santa Clara Unit"

S-2T: making the retardant drop

When an air tanker such as an S-2T is deployed to a wildland fire, the air tanker pilot will be in touch with either the incident commander on the ground or some one known as the air tactical group supervisor (ATGS). The ATGS oversees aerial support for the fire, including retardant drops from a tactical aircraft, sometimes known as an air attack plane flying over the fire. The ATGS will be in touch with the incident commander (IC) on the ground. CAL FIRE’s tactical aircraft are known as OV-10’s and there is one OV-10 at each air attack base. The ATGS, after consulting with the IC, will give the S-2T tanker the information that s/he needs to make the drop, including but not limited to the location. In initial attack the S-2T pilot may make his own determination about the necessary settings and where to make the drop.

The settings that S-2T air tanker pilot (and other air tanker pilot’s) use for the retardant drops are on a panel on the cockpit. This is the same one pictured in the preceding post, so I will be using that picture as a reference. Perhaps you will want to open up a new window in your browser so you can look at TL Stein’s photograph and follow along.

The pilot adjusts the dial on the left to set the amount of retardant to be dropped while the dial on the right is set to determine the coverage level (also known as gpc). The coverage level is gallons of retardant per 100 square feet. Coverage levels are somewhat technical, depending on the type of vegetation on fire (fuels) and the fire behavior. The coverage settings dial is scaled from .5 to a maximum of 8 (gallons per 100 square feet). A switch known as the arm-disarm switch is set in the disarm position until it is near time to make the actual retardant drop. This prevents accidental drops. The button that the pilot pushes to make the drop, drop control switch (not pictured), is on the pilot’s control panel for ease of access. The door control (switch in the middle), is set to automatic.

Once the settings on the two dials are made, and the pilot is at or near the location and correct altitude for the drop -- 150 feet above ground level for the S2-T -- the pilot flips the arm-disarm switch to arm the system. The pilot has only to push the drop control switch at the appropriate time, the tank doors open and the drop is made. It is not merely the cockpit controls that make the retardant drop possible, there are various avionics (aviation electronics) and hydraulics that make the retardant drop possible.

If there is an emergency situation, the pilot can make an emergency retardant drop by pulling an emergency handle (not pictured).

S-2T: Retardant loading at Ryan AAB

Loading retardant onto the S-2 is a reasonably simple process. The yellow hoses in the photo are called pit supply lines, running from the storage tank to a high capacity, high volume pump. Each storage tank has it’s own pump. TL Stein tells me that “as the pump pulls the retardant from the storage tank it sends it into the pit supply line.” Once the pit supply is fully charged, the black loadout hose (see picture) is connected to the hot load at the tail end of the aircraft (see photo). The gate valve at the end of the load-out hose is gradually opened allowing the retardant to flow into the tank on the aircraft.

He explains how they know when the tank is full:

On some of the S-2T’s, there are a series of loading lights on the right side of the aircraft that light up to indicate how full the tank is getting. On others a mass flow meter is watched to indicate how much retardant has been pumped into the aircraft. As the aircraft fills, it will tend to settle due to the addition of weight and the tail will drop about six to eight inches. This settling action is not slow, but a rapid drop and signals the loader that the aircraft is getting close to full. When this happens, the loader will close the gate valve about halfway until either the full light lights up or the mass flow meter reads the desired amount of retardant has been pumped into the aircraft.

After the aircraft has been filled, the gate valve on the loadout is closed and the hose is disconnected from the aircraft. The ground crew leaves the area, and the plane is ready for take off.

Take a look at the annotated close-up of one of the panels in the cockpit. I will be talking more about the controls on this panel in my next post. On the top right, is a switch labeled “open - closed control for tank backflow valve.” This valve, also known as a flapper valve sits between the retardant tank and the hot load. To put it simply, the flapper valve seals the system. It serves three important purposes: (1) the valve is open when retardant is being loaded into the tank (2) when closed, prevents retardant in the tank from flowing back to the rear of the plane to the fill point, and (3) is left open when the retardant tank is washed out at the end of the season or when maintenance is necessary (more on this in a later post).

Recall from the post on S-2T specifications that the S-2T holds 1,200 gallons of retardant. There are times when the retardant tank will not be filled to capacity. One of these times is when it is very, very hot outside. TL Stein tells me that Ryan sits in a large basin, and when it is hot, it is very, very hot at Ryan. During times like this, the air density is lower. And when the air density is low, heavy airplanes do not fly very well. So, on a really hot day, the weight of the air tanker needs to be lightened. So, less retardant will be put in the tank on the S-2T. Retardant weighs about 8.5 pounds a gallon. Filling the tank with 1,000 gallons of retardant instead of 1,200 gallons saves 1,700 pounds. Lowering the weight of the air tanker by 1,700 pounds on a really hot day, according to TL Stein, makes a huge difference!

Still to come in this series of posts on the S-2T are (1) the retardant drop; (2) videos of the S-2T making retardant drops, and (3) cleaning out the retardant tank at the end of the season.

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.

CDF S-2A

The photo is a picture that TL Stein’s Dad (TW Stein) took of the first S-2 that CDF (predecessor agency to CAL FIRE) took delivery of in February 1972. He says:

My father took this photo within an hour of it arriving from the AMARC facility. As pictured, the original fleet of S-2’s served with VT-27 “Boomers” training squadron out of Corpus Christi, Texas. One thing I remember vividly, is that one of the aircraft ferried in that morning still had a practice torpedo in the bomb bay.

I love knowing something about the history of the aircrafts that I am writing about, that there was a life before it was upgraded and retrofitted to work as an air tanker. History makes things come alive, again and again.

There are two short YouTube videos of a CAL FIRE S-2A here and here.

S-2T: history and specs

In the mid 1970’s CAL Fire’s fleet of air tankers were growing old and needed to be retired. These aging air tankers were replaced by newer Grumman S-2A aircraft (sometimes referred to as the S2-F1) beginning in 1975. These aircraft were used from the from the mid-1950s to the mid to late 1970s by the U.S. Navy for surveillance. The S-2A’s used by CAL FIRE were modified for use as civilian air tankers. The last of CAL FIRE’s S-2A air tankers was retired in 2005.

For a short history of the military service of the aircraft that is also known as the Grumman S2-F, the S-2 Tracker Museum has a webpage on it’s history. When you get to the home page, click on the “history” link at the top of the page.

By the mid-1990’s the fleet of S-2A’s had been in service for about 20 years, CAL FIRE began to prepare to retire the S-2A fleet. A decision was made to replace the S-2A’s with what CAL FIRE calls model S-2E/G series aircraft. Without getting into the complexities of changing model numbers over time, let’s just say that these were later variations of the Grumman S2-F aircraft. CAL FIRE acquired at least 23 S-2E/G aircraft from the Department of Defense. Marsh Aviation made extensive modifications to the S-2E/G aircraft including: adding a 1,200 gallon constant flow retardant tank, new turboprop engines, new avionics, and new electronics. CAL FIRE has 23 of these air tankers that they call S-2T’s. By 2005 the last three S-2T air tankers were delivered. Twenty-two are stationed around the state at CAL FIRE air attack bases and one is used for maintenance relief. CAL FIRE has a fact sheet on the S-2T air tanker that may be found here. The CAL FIRE Pilots Association has a nice map of CAL FIRE’s air attack bases that includes links for more information on each base, it may be found at this location.

Specifications of the S-2T:

length (ft): 65
wing span (ft): 73
turn radius (ft): 45
cruise speed (knots): 250
gross weight (lbs): 29,200
range loaded (st. miles): 1,500
contract operating weight (lbs): 29,200
retardant load (gallons): 1,200