Justin Anderson takes off in the late afternoon in Tri-Rotor’s AT-402. Justin also flies the AT-602. Tri-Rotor’s pilots must be proficient in all the rotor-wing or fixed-wing aircraft.

Taking pictures at night is next to impossible. The digital camera barely captures the Hiller as it makes a low pass with Danny Lyle at the controls.

Lou Dinnon (right seat) pilots the OH58 for a systems check by Danny Lyle (left seat).

by Bill Lavender
What has eyes as bright as the sun, is nocturnal and flies in the desert? There are seven of them and they came from Kansas to prey in Arizona. You give up too easily. The answer is Tri-Rotor Ag Service’s four fixed-wing and three rotary-wing ag-aircraft outfitted for night ops!

Tri-Rotor Ag Services is the Yuma branch of Larry Smiths’ Ulysses, Kansas-based Tri-Rotor Spray and Chemical, Inc. Forming the parent company in 1980 with a Hughes 269, Larry decided on the name Tri-Rotor simply because the Hughes had three rotor blades. Today, Tri-Rotor is a major ag-operation with a fleet consisting of an Air Tractor AT-602 and three AT-402s, Thrush 660, Cessna Ag Truck, Bell OH58 helicopter (converted military version of a Bell Jet Ranger 206), and one each of a Hiller Soloy turbine and a Hiller piston-powered helicopter; quite a diversified fleet by anybody’s standards.

In 2000, Larry was approached by Morris Ag Air to buy their Yuma operation. Larry traveled to Yuma for the first time and fell in love with the desert area. Yuma is uniquely positioned between Mexico on its southern and western borders, California to the north and Arizona to the east. San Luis, Mexico is only 15 miles away, with its city lights easily seen in the distance during night ops. California is a mere 25-30 miles away with its stringent regulations, in some ways more so than Arizona. In the case of this writer’s visit, the mission was to spray organic produce. That’s right, an organic crop. Many people have the misconception organic crops are not sprayed. Not true, as this application contained a dose of copper sulfate for insects and fungi control.

In the last three years, Larry has taken a two-plane operation and turned it into one that uses up to seven aircraft. Tri-Rotor is the only ag-operation in Arizona that uses helicopters. From two bases, one a few miles south of Yuma and the other 30 miles east in Wellton, Arizona, during the busy months of October and November all seven aircraft are working with a majority of the work flown at night.
Mainly due to urbanization and field workers in the Yuma, Gila and Dome Valleys, Tri-Rotor elects to fly at night. Ag-aircraft are not permitted to come within a 1/4 mile of field workers. Whether it is a crew or one single irrigation inspector crossing the field in the dark, Tri-Rotor must spot and remove anyone from the field before spraying it, or go somewhere else to spray. This is why on-site ground personnel monitor applications. Although Tri-Rotor aircraft are outfitted with Satloc GPS units, a truck meets the aircraft at the field with its flashing roof light and maintains radio contact with the aircraft and the home base.

As an added benefit to night flying, typically the air is very stable and cooler than in the daytime. However, summer nights air temperatures can be over 100°F, especially after a 120°F day. These conditions require relatively high application rates, typically from seven to fifteen gallons per acre.

Tri-Rotor’s season in Yuma is the busiest in October and November. There is a slow down during December and January, but the work picks back up in February and March. Although, of the seven aircraft, one could keep up with the work in spring and summer, one of the Hillers and two AT-402s, one set up for wet and the other dry applications, remain in Arizona. The other four aircraft fly back to Kansas for its spraying season. The split operations compliment each other for efficiency, even though there is some overlap in the spring months.

Larry likes to assign the aircraft best suited for the job. The helicopters work in close, loading from the top of a nurse truck. The Thrush 660 is the designated herbicide plane with its special drop booms, in flight 0° CP nozzle orientation and 55-foot swath. Larry realized during spraying operations that the nozzles weren’t truly straight back. On the ground, he used a protractor to determine that the booms needed a 9° rotation up to get a true 0° angle on the nozzle while in flight.

Sometimes the Soloy Hiller (425 shp Allison turbine engine conversion) is used for herbicide work. It uses CP’s helicopter nozzles, the CP-71s, tilted 45° aft mounted on a round boom system. If a high degree of precision in an application is required, where a single boom (left or right) is needed, Larry will opt for the OH58 because it has the Auto-Cal controller with the Ag-Air Systems hydraulic system. This is a very smooth variable rate system that will adjust the boom pressure to interface with the Satloc GPS, regardless whether left or right side booms are spraying.

The OH58 (a Garlick Helicopters conversion) is new to the Tri-Rotor fleet. It appears to be a more efficient helicopter for Tri-Rotor’s needs than the Hillers. The aircraft has the same payload as the Soloy Hiller, with basically the same engine, (the OH58’s Allison is the military version). The OH58 has a longer tail and larger tail rotor than the Jet Ranger 206. It costs the same as the turbine-powered Hiller, but has a faster ferry speed, as well as is more comfortable for the pilot. However, the Hiller will turn around quicker at the end of the field.

According to Larry, the AT-402s are excellent fixed-wing aircraft for Tri-Rotor’s Arizona operations. Most of the fields are slightly less than 40 acres, including the waterways in the field. The AT-402’s 400-gallon hopper fits most applications perfectly. The aircraft is quick, easy to fly and economical to operate.

At Tri-Rotor there are several commonalities. All of the aircraft are similarly outfitted for night work. The fixed-wing aircraft have four 450,000 and two 600,000 candlepower halogen lights, plus two 450,000 candlepower turn lights. The helicopters have two 600,000 candlepower units and one 450,000 candlepower unit.

All seven aircraft are outfitted with Satloc GPS units. The OH58 is different in that it has the ACE system and the Auto-Cal unit with Ag-Air Systems hydraulics. Larry has elected to designate the OH58 for special application contracts that may require the variable rate technology of the ACE and Auto-Cal combination.

The fixed-wing aircraft cockpits have been inlaid with a special soundproofing and have active noise reduction that makes them much quieter for the pilots. All aircraft have CP Products nozzles. Tri-Rotor is in the process of outfitting the fleet with AeroFlow Systems check valves. Of course, all of the aircraft have mobile-to-mobile radios.

Not too long ago, the Yuma, Gila and Dome Valleys supported seven or eight flying services. Today, there are only two, albeit they are two large companies. The three valleys grow a variety of crops, but the Big 3 are lettuce, broccoli, and cauliflower. Other crops grown in the valleys include produce of all sorts, onions, alfalfa, potatoes and cotton, as well as some citrus. Cotton used to be king, but with the introduction of BT cotton, it has become a minor crop for aerial applications.

The three valleys are moving more and more to utilizing the helicopter. Ultimately, the Pest Control Advisor (PCA) determines the parameters of the application, dictating the chemical and application rate, and in many cases the aircraft used. PCAs have requested an increase in the use of the helicopter, even though applications cost considerably more than fix-wing applications.

Matt Fieldgrove is Tri-Rotor’s operations manager and also flies the AT-402 year round in Yuma. When asked how he managed the operation during the busiest of times and still found time to fly, Matt replied, “Flying gives me time to think.”

Night operations begin when the chemicals arrive, usually at dusk. Matt begins his scheduling based on data from the Arizona Department of Agriculture’s 1080 forms. A 1080 form is a work order filled out by the PCA giving Tri-Rotor all the information it needs to make an application, including chemical and rate.

When the pilots are handed their 1080 forms and intended schedules for the night, the field spotters are given field locations and they disperse for the first field in the schedule. Helicopter nurse trucks load up their materials and head for the first application job, with the helicopter pilot coordinating his and the nurse truck’s arrival at the field.

Joe Whardle, Tri-Rotor’s AI mechanic reports for work at dusk and begins taking care of maintenance during the early part of the night. The AT-602 and Thrush 660 launch for Wellton to work, often staying there for several days. The flying at both strips can continue into the early hours of the morning, even up to daylight in the hectic part of the season.

Tri-Rotor becomes a very active place, 24/7 during the busy part of the season. The work is hard on the pilots, catching naps at odd hours. Some pilots can handle the stress of flying in the dark, others can’t. There’s no extra “night pay” for the pilots. They can either do the job or not. There are the pluses of stable and cooler air, but then, there is the possibility of disorientation and the ever presence of the dark. Night ops are special and Tri-Rotor Ag Services has them down to a science.