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Smokejumper Aircraft Evaluation Process

by Jack Demmons (MSO 1950) |

The criteria for an "approved" smokejumper aircraft were developed and are maintained by the Smokejumper Aircraft Screening and Evaluation Board (SASEB). Membership within the SASEB includes smokejumping and aviation
representatives from the FS, BIM, and OAS.

A smokejumper aircraft evaluation is structured to identify flight performance characteristics, safe deployment of standard smokejumping parachutes, special accessories that will be needed, and procedures to provide for safe smokejumping.

The smokejumper aircraft evaluation process was first used in the mid-1970's, with the responsibility of overseeing evaluations assigned to the Missoula Technology & Development Center, located at Fort Missoula. Responsibility for conducting flight performance evaluations is assigned to pilots from the FS, BIM. or OAS.

The sponsor of a candidate smokejumper aircraft is usually a smokejumper unit. The smokejumper base manager's liason person is appointed by the manager of the base chosen to support the evaluation.

The first step in the process is for the sponsoring unit (unit that is interested in contracting for a currently unapproved aircraft) to prepare a paper evaluation on the aircraft.

This evaluation must address an established set of SASEB requirements. The aircraft must be FAA certified as a normal or transport category aircraft; must be FAA approved to fly with the jumper exit door removed; must not exceed an airspeed of 115 knots when dropping smokejumpers; and the jumper door must be at least 25 inches wide and 36 inches high.

The SASEB reviews the sponsor's preliminary report and recommends technical acceptance or rejection. Then the FS, BLM, and OAS management groups review the SASEB recommendation and decide if they want to provide funding to evaluate the aircraft. Pending the availability of funding needed to accomplish the evaluation, an Evaluation Director is appointed and the Flight Performance and Functional Evaluations are accomplished. If the flight performance and functional evaluations are successful, needed accessories are designed and fabricated. A smokejumper base then contracts for the aircraft for a field evaluation. If the field evaluation is successful, the Evaluation Director then submits a package of complete documentation, showing that the candidate aircraft has met all of the requirements for an "approved" smokejumper aircraft.

SASEB then reviews the package. If it is complete and acceptable, SASEB recommends to management that the aircraft be added to the list of "approved" smokejumper aircraft.

While time requirements vary, the complete process of evaluating and approving an aircraft for use by smokejumpers cart take two years or more. Costs for such an evaluation, including flight time, design, fabrication, and FAA Supplemental Type Certificates (STC's) for accessories can easily total $50,000 to $100,000 (1997 dollars).

There are many considerations to be taken into account when evaluating an aircraft smokejumpers might use. Contract economics are a key consideration. Performance and physical characteristics are critical. For example, how close is the horizontal stabilizer to the jump exit and cargo door locations? Is there a chance of a tail strike by jumpers or paracargo? Is there the possibility of parachutes deploying over the top of a stabilizer or in the area of the elevator hinge? Is the distance from the anticipated primary static line anchor location to the horizontal stabilizer compatible with the use of standard 15-foot static lines? Is the aircraft "clean" around the exit door and back along the fuselage, so that static lines will not be damaged or cut? How is the aircraft affected when the cabin door is removed-are flight characteristics affected and is there the possibility of exhaust fumes entering the cabin? Are the pilot's and spotter's visibility adequate for smokejumper and paracargo operations? And does the aircraft have suitable seats and restraint systems for smokejumpers and paracargo, or can it be equipped with the special bench seats designed for use in smokejumper aircraft?

For evaluation, MTDC designs accessories needed to configure an aircraft for smokejumping. Such accessories might include static line anchors for both jumpers and cargo parachutes, spotter tether anchors, jump door handles, jump steps, and door boots to provide smooth, nonabrasive surfaces for static lines.

It is critical that the BLM Ram-Air drogue static lines be attached to anchors located appropriate distances from the jump doors to insure proper drogue deployment. This is tyically accomplished by using "extenders" of proper length attached to the static lines of the drogue chutes. (The drogue chutes stabilize BLM jumpers in an upright position after exiting an aircraft. The jumpers then pull rip cords to deploy their main chutes.)

Jump steps must be attached to aircraft doors if they are not large enough to allow jumpers to make standing exits. The steps have to be designed so dangling boot laces or jump suit pocket ties cannot get hooked on them.

A number of factors have to be considered when testing the aircraft, such as performance with one engine out at different altitudes, and when making turns; center of gravity; use of flaps; stall warnings for different situations and attitudes; and airspeed requirements for varying conditions and loads.

Before live drops are conducted, "torso dummies" are used. Generally, no more than two torso dummies are dropped during one pass. All types of cargo chutes are dropped with varying types of loads attached. Video and high-speed film is taken of the drops from cameras mounted at appropriate locations on the aircraft.

Live drops then take place. Spotters and jumpers are thoroughly briefed before each flight, as to objectives of the test flight, specific procedures to be followed and special safety concerns. Cargo drops follow behind the live jumps during at least one test flight.

Finally, a field evaluation consisting of a full season of operational use is needed to validate smokejumping procedures and the configuration of smokejumping accessories developed for the aircraft. Modifications are made where needed and supplemental type certificates (STC's) are obtained from the FAA for special accessories.

Using this process, the aircraft in use today by smokejumpers at the seven U.S. Forest Service and two Bureau of Land Management jumper bases are among the safest for this unique mission.

Aircraft currently approved for the smokejumper mission are: The Sherpa, Casa, DC- 3 C, Twin Otter, Bandeirante, Dornier 228, Beech 90, Beech 99, Cessna 208 Caravan and the Shorts Sky Van.

Editor Note: Special thanks are due Eldon Askelson, Chairman of the Screening and Evaluation Board, for his help. He is currently stationed in Missoula and is the U.S.F.S. Region 1 Airplane Manager. Eldon is a qualified pilot for both heavy and light Forest Service aircraft He is a fonn er McCall smokejumper-'66.

Special thanks also go to Art Jukkala, MSO '56 , retired, who once worked full-time with MTDC. He was very helpful by providing details for this article.