Aerial Fire Fighting: Flying a SEAT

A Single-Engine Air Tanker Pilot tells what it's like to fight forest fires from the air.

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(Editor’s note: In the last 20 years the development, deployment and proliferation of Single-Engine Air Tankers (SEAT), nimble fire fighting airplanes converted from the biggest turbine crop dusters, has caused significant changes in the way forest fires are fought. While not able to carry as much fire retardant as the multi-engine tankers, they are faster to dispatch and often are the best way to keep smaller fires from becoming big ones. The following is taken from the blog of Dr. Stan Musick, a SEAT pilot flying 1600-horsepower Air Tractor AT-802s by summer and physician and warbird airshow pilot the rest of the year.)

Oregon is on fire. Fires have names. “Kitten” (innocent sounding, for such a nasty fire). “Black Butte” (sounds more like the fire it was…off a butte, down in a canyon, burning in between lava rocks). I never knew lava would burn (of course, the lava isn’t burning, but the vegetation that is in between the rocks does. Brogan (I always think of my Grandad’s shoes), Juniper (now there’s a fire name that sounds like an “out west” fire name should sound).

In the past two days we have flown almost constantly. All of the above fires have had repetitive visits from SEATs (Single Engine Air Tankers). The daily battle has become, well, routine. “Show time” (the time to arrive at the base) here is usually 0800, other bases usually are at 0900. The plane has to be preflighted, oil checked, and if I’m in a new-to-me plane, I have to set up the cockpit. Rudder pedals are critical—too much travel, and you can’t put that jab of rudder in at the right moment to keep the big taildragger straight, too little travel and your feet are cramped up and you are miserable. I’ve learned to check the radios. Even though our company planes are well standardized, a couple of them have “secret switches” on the radios, and it’s mandatory to make sure they’ll work. I had the “learning experience” of getting dispatched on a fire, got in a new-to-me plane, and loaded, ready to take off—and couldn’t make the radios work. Finally found the switch, all went well, but there were a few minutes of embarrassing silence.

Morning brief is highly variable. Sometimes it’s really brief -“Today, same as yesterday. Any questions?” Sometimes, it’s excruciating, sort of death by PowerPoint. The briefer will read sheet after sheet of paper printed out from the USFS, BLM, BIA, NOAA, and they’ll have much of the same information. Here the briefing is done by one of the Fire Incident Commanders, and it’s highly professional, with enough detail to know what to expect for the day, know where the new TFR (Temporary Flight Restrictions) are, and any other issues.

The past two days, we almost immediately got a dispatch, put on our flight suits, headed to the planes, and started. Lining up for our loads, we get clearance in and out of the “pit”, and then taxi for takeoff. Once in the air, get “cleaned up”, and then call dispatch. “Burns dispatch, Tanker 892 on Direct, off Burns, enroute to Black Butte. 3 hours and 30 minutes of fuel, 18 minutes enroute, one SOB”. Those of us who trained “back in the old days”, still say “SOB” for “souls on board”. There are days when we really mean it.

Dispatch calls back with confirmation of AFF (automated flight following), an we’re off to the fire. AFF eliminates the requirement for 15 minute check-ins, and reduces the amount of radio traffic on the frequency.

The mighty 802 pulls along, soon we’re into cooler air, and the scenery rolls by at a stately pace. Those are the minutes that soothe those of us that have a pilot soul. Then it is time to check in with the “Air Attack”. Air Attack (officially known as ATGS), orbits over the fire, communicates with the ground forces, coordinates the helicopters, the SEATs, and the heavy air tankers. He (it’s almost always a “he”), coordinates with dispatch, and sometimes “sells us” to another fire that has a greater need. More than once this summer I’ve been enroute to one fire, and suddenly I get diverted to another one. “Black Butte Air Attack, Tanker 892, 15 miles out”.

“Hi 892. Altimeter 30.02, come in at 6000, we’re at 7500, helicopter at 4500, another SEAT at 5000.”

“892 copies 6000, 3002.” I motor on towards the fire. The column of smoke has been visible for some time, and now I can see the flames. The butte is quite pretty, the fire has burned along the drainage (the common descriptor for terrain that falls away—where water would drain), and is among the lava rocks. I watch the prior SEAT make a drop, a nice line of retardant “tying in” with my prior drop.I still see no ground forces.

“Tanker 892, Air Attack. No one is here on the ground yet. Do you see where the prior SEAT just dropped?”

“Affirmative.”

“Above his end point, on the top of the butte, I want to paint a line along the edge. Coverage level 1, taper it along the edge of the butte”

This is going to be cool. The butte edge is flat (always making life easier—the day prior I had dropped on the fire dropping over the edge of the butte at about 10 feet, pushing over and going straight downhill toward the fire). I set the computer for a coverage level 1, and put it on “pilot control”. Much of the time we set the computer for a known amount to drop, and just push the switch, and the computer controls the rate and the gallonage.

I drop in along the edge of the butte, and fly along dropping retardant. I call off the fire, and look as I turn out to head for the “load and return”. Nice! One of my best drops. I’m still learning how to adjust for wind drift, and I was hoping that I hadn’t let my load drift off the edge of the cliff, it wouldn’t do much good there. I was rewarded with a nice pretty line along the edge.

I call in to dispatch, let them know my estimated time back to base, and settle in for the flight back. The 802, carrying nothing but me, fuel, and itself, feels happy and light. I relax, take in the scenery, look over all the instruments, and then do a quick estimate on my next load calculation. Prior to each load, we have to know the pressure altitude, the temperature, our fuel load, and the gallons of retardant. We plug all that in, and make sure our performance, weight, and allowable takeoff weight are all acceptable. I’ve learned to do as much of that as possible prior to landing, because the turnarounds can be quick.

Arriving back at base, a quick call to dispatch to let them know “landing assured,” call base, tell them “load and return,” then announce position on Unicom. I land, taxi in, and pull up to the loading hose. My driver/loader, David, offers me water each time. I’ve learned—don’t drink too much water. We get another 750 gallons loaded, and the process repeats. Yesterday we flew 4.1 hours, the day before flew 6.4 hours.

The worst part of the day is when we have to quit.

The Mighty 802

Our SEAT is the Air Tractor AT-802. Genealogists would have a great time tracing the family lineage, from Leland Snow’s first creation of a crop duster in South Texas back in the 50s, to his move to Olney, and his Snow, Thrush and Air Tractor planes. Throughout much of the agricultural land of the nation, Thrushes and Air Tractors race back and forth across fields, stopping insects, fungus, and weeds; putting out seed and fertilizer.

Flying the 802 is intimidating at first. It’s a big airplane. You don’t walk up and get in. You climb up steps, stand on the wing, and carefully placing a foot on the (tiny) footrest you lift yourself up to check the oil. You then climb into the window of the plane, holding onto an impossibly small piece of welding rod attached to the roof of the cabin, and lower yourself into the seat. Caution is advised, because it’s a long way down to the ground. Leland made it crashworthy, not safe to climb into.

The Fire Gate system, which dispenses the load of water or fire retardant, is an excellent piece of engineering. Different coverage levels can be selected, the gate is computer-controlled to allow dropping of fairly precise amounts of retardant, and it allows everything from a quick “bump” of the gate to drop off 50 or so gallons, to a “double bump” which releases the whole load, all at once. Pilots have been known to accidentally “double bump,” or even hold the button when working down a particularly exciting run. The designer quite correctly assumed that if a pilot was so involved with things that he gripped the handle too tightly, he might be in a spot requiring a quick reduction in load, so that too will “auto-salvo” the entire load.

I can verify that procedure works.

After spending years starting the old radials, the turbine start seems strangely simple. Starter on, observe enough engine rpm (engine speed), and add fuel. Keep an eye on the temperatures, and if they start to get too high, turn the fuel off, and keep the starter running to keep an expensive flame from burning too hot. You would correctly assume that it’s not exactly that simple, or they would start student pilots on turbines, and only after lots of experience would they get to learn to start piston engines. The reality is that most of us start on pistons, where the mistakes usually aren’t expensive, and the worst thing that typically happens is that you drain the battery or burn out a starter. On a turbine, even a brief mistake in the procedure can completely destroy the engine in seconds. Accidentally let off the start switch at a critical point in the light-off? Expensive. Move the “condition lever” (us piston guys would think of it as the mixture) too far too fast? Expensive. Introduce fuel prior to a high enough rpm in the gas generator? Expensive. Attempted restart too soon, or downwind? Expensive.

Once the engine is started, “in feather” (prop blades turned sideways, so the prop turns much slower than when the blades are ready to take a “bite” of air), all is confirmed ready, the avionics (radios) are turned on, and the air conditioner is fired up. Ah, the bliss of the air conditioner. Taxi is similar to the T6, with a tail wheel that is either “locked” or “unlocked”. No steering. You use the rudder to full travel, then a tap of brake to move the monster in the desired direction.

Action

It had been ten long days. Ten days of getting up, showing up at briefing, pre-flighting the plane…..and sitting. Ten days of walking the ramp, watching the jack rabbits chase the cottontails. Ten days of counting quail. Ten days of taking naps, watching the gradual edginess sneaking up on everyone. In the “fire business”, we have a strange relationship with fire. We hate it—the phrase “fighting fire” indicates the passion with which we try to put it out; we love it—every fire fighter, from the newest ground guy to the oldest semi-retired experienced chief lights up when dispatched, and we miss it when we don’t see any fire.

A day or two without a dispatch is okay. Three or four days starts to make you a bit cranky. More than that….and the irritability seems to rule. Habits of other men that ordinarily amuse you seem to indicate need for urgent mental evaluation to see if they need to be committed.

This morning dawned bright. A small storm moved through during the night, with lightning. Up on the hill above the town, a smoke was sighted. A dispatch is received. I have my loader start mixing a load of retardant mud and go through my “dress up drill.” It involves shedding tennis shoes, moving stuff from shirt and pants pockets and putting on the “monkey suit,” the mandated Nomex flight suit.

If you’ve never had the pleasure of Nomex, it’s a fabric that is—ostensibly—designed to never burn. If it gets hot enough, it simply fades into dust. The idea is that if you are in a fire, it gives you some protection, and importantly, doesn’t add to your burns. Nylon will melt and stick to your remaining skin. Cotton merely burns faster and adds to the fire. That’s the good part of Nomex. The bad side of Nomex is it takes an outside air temperature that’s merely tolerable and transforms it into unbearable. It retains sweat, odor and moisture and, I think, is designed to smell like a dirty tennis shoe.

Monkey suit is on, pockets suitably charged—have to have the reading glasses handy, the cell phone has a calculator for doing the mandated load calculations, keep a knife in a lower leg pocket just in case—and try to make sure that nothing is poking me in an uncomfortable or embarrassing way. Remember, we’re going flying in the mountains, in hot weather, with significant winds and gusts. That translates into a Disney E-ticket ride. Put your shoulder harness and seat belt on tightly, boys and girls, as the ride may cause you to shift in your seat. Something that ordinarily is merely slightly uncomfortable in a car seat can give you misery in a bouncing plane, when you are tightly bound to said plane.

Today, the flight suit went on easily. I love the rhythm. The “mudders” working off hand signals connect the loading hose. As I’m putting on the belts, I give the signal to load. The meter showing gallons (of retardant) climbs rapidly. I spin the big PT-6 over, watching the ITT (temperature) and the gallons simultaneously.

Nice smooth start. My baby is running right. Gallons climbing through 350—headed to 700. I’ve got to climb 4000 feet in six miles, so don’t want too much, and I’m full of fuel. Quickly I page the GPS over to “user waypoint,” enter the name (“Ridgetop”), the latitude/longitude, then punch “direct/enter.” Gallons now at 585; stay focused on the meter. Don’t want too much, don’t want too little.

Arm out the window at 675, ease down starting at 685—nailed it. (The flow meter later revealed it to be 704 gallons…I’ll take it!) The view through the hopper window confirms that the load is close to the 700 gallon line on the window. As far as I’m concerned, it’s the most fool-proof gauge we have. It’s 700 gallons.

Call into base…”T-8XX is on the roll.” Time is received; written down on the log. We keep a current weight and balance on our knee board, including times…to the minute. The knee board log is crucial. We are to do a W&B calculation on each load. The numbers come quickly—empty weight 7144; plus my weight; plus fuel, 302 gallons at 6.6 lbs/gallon; plus 700 gallons of retardant at 9.3 lbs/gallon—15,887 pounds. That’s 13 pounds below gross weight. Outside temperature is 85 degrees. Not quite hot enough to trigger a temperature limitation on the engine.

I make the call on Unicom, “T-8XX taxiing from base to runway 32”. In an odd sort of way, once the window is closed and the radio call made, I’m “in the cocoon.” A feeling of peace comes over me. We’re going.

Pre-takeoff checks are done on the roll. “T-8XX departing runway 32.” Power up to the torque limit, quick engine gauge check done, emergency dump armed. The 1600-horsepower PT6 surges with power, and the heavy air tractor sluggishly moves forward. Slowly the airspeed climbs, and the controls come alive.

The tail comes up, and I “feel” the control stick aft. A classic move in the 802 is to ease one wheel off, then the other, and hold the plane in ground effect as it accelerates. At this weight, simply getting the drag of the tires and wheels off the ground allows more acceleration. The end of the runway is approaching at about 100 MPH, and I ease the left wheel off, then the right, and feel the 802 leave the ground. The stall warning chirps, and I stay in ground effect as the Air Tractor—yeah, it flies like a tractor—accelerates. The flaps are bumped up just a tiny bit, to that magic point at which the extra lift is more than offsets the drag.

The approaching farm house goes by about 50 feet below and several hundred feet off to the right. A gentle turn puts me on course towards the fire. Slowly accelerating, the 802 becomes more lively, and I gently and intermittently tweak off the flaps.

The fire is high on the nearby mountain. It’s only about 6.9 miles from the end of the runway, but the airport elevation is 4300 feet above sea level. The fire is about 8000 feet above sea level, so it means a steady climb. I head towards the nearest hill. Approaching at a 45-degree angle, I get as close as I can and ride the air upwards. On the windward side of the hill, the air rises, just as water climbs to get over a rock. I position the tanker in that rising air, and climb along the edge of the mountain, slowing each time I find rising air. Better to stay longer in the air that is upward bound.

Checking in with Dispatch (we contact them on the way to and from the fire, as they are watching on the Automated Flight Following—AFF), which gives them our number, speed, and direction, “Air Attack, Tanker 8XX 5 miles, climbing.”

“Roger, 8XX, cleared in at 8500 feet, just me and you out here right now.”

Working up and down the ridge, I get to the altitude specified, give Air Attack a call and let him know I’m inbound.

“8XX, you see the ridge with the prior retardant drop?”

Yes, I do, it went a bit long, but the terrain’s steep—very steep, and judging by the smoke the wind is moving pretty good up here. I set up for the drop he wants, a split load, indirect. I’m anticipating a strong tailwind. I put it right where I want it to go, but it’s not exactly what he had in mind. One of the difficulties of the job is the ever-present need to understand, by verbal description only, what Air Attack wants. He wanted it “more direct,” more on top of the fire. Okay, I can do that.

I come around, set up over the ridge again, and on short final I see the flames. Okay, brother, there you go. I give the second half of my retardant load to the fire, get a firm “Attaboy” from Air Attack, and head out for another load. Tony is one of the good Air Attacks. Lets you know when it’s not what he wants, but when it is, it’s affirmed.

Back to Dispatch on the radio, call base, then make the pattern radio calls. This feels good. The drill, the rhythm, all somehow speak to that internal part of me that matches this job. Loaders are ready, rapidly attaching the hose, loading, releasing, and off we go again. The drill is repeated.

This time the fire is boxed in on all sides but one. Air Attack wants the load across the head of the fire, where it has backed across the ridge into a bowl. The best approach to it is to come out of a right turn, make a sharp turn across a spur ridge, drop over the spur ridge and make a turning drop “slinging” the load into the line across the upper edge of the bowl.

“Exactly what I wanted, 8XX.”

Seeing that retardant line laid in along the edge of the flame made the day great.

I love this job.

Stan Musick is an antesthologist with a flying problem. He practices medicine nine months of the year; in summers he flies a SEAT fighting forest fires in the western U.S.; on weekends he can be found flying airshows in a T-6, P-51 or Corsair. Material in this article is pulled from his blog at www.cafmustang.com.

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