CHAPTER 7—Skiplane Operations SKIPLANE OPERATIONS This chapter introduces pilots to the procedures required in the operation of skiplanes. Since most skiplane operations and training are conducted in single-engine airplanes with a conventional gear (tailwheel) configuration, this information is based on operating skiplanes of this type. [Figure 7-1] A skiplane configuration affects the overall operation and performance of an airplane in several different ways, including ground handling, takeoff, landing, and flight operations. Some manufacturers provide recommended procedures and performance data in the Airplane Flight Manual (AFM) and/or Pilot’s Operating Handbook (POH). Title 14 of the Code of Federal Regulations (14 CFR) part 61 does not require specific pilot training and authorization to operate skiplanes; however, it is important to train with a qualified skiplane flight instructor. Since most skiplanes operate in a wide variety of conditions, such as landing on frozen or snow-covered lakes and sloping glaciers, with varying qualities of snow, it is important to know how performance is affected. Use the performance data provided by the manufacturer. CONSTRUCTION AND MAINTENANCE Modern airplane ski designs are a compromise for the various forms and conditions of snow and ice. For example, a long, wide ski is best for new fallen, powdery, light snow, whereas a sharp, thin blade is best for hard-packed snow or smooth ice. Many ski designs feature a wide, flat ski with aluminum or steel runners on the bottom. Airplane skis may be made from composites, wood, or aluminum, and some have a polyethylene plastic sheathing bonded or riveted to the bottom surfaces. Ski designs fall into two main categories: plain and combination. Plain skis can only be used on snow and ice, while combination skis also allow the wheels to be used to land on runways. PLAIN SKI TYPES Wheel Replacement—Wheels are removed and ski boards are substituted. [Figure 7-2] Clamp-On—Skis that attach to the tires and benefit from the additional shock absorbing qualities of the tires. Roll-On or Full Board—Similar to the clamp-on type except the tires are bypassed and do not carry side or torque loads. Only the tire cushioning effect is retained with this installation. COMBINATION SKI TYPES Retractable Ski—Can be extended into place for snow operations or retracted for non-snow operations. This is accomplished by either a hydraulic pump or crank. Penetration Ski—The wheel extends down partially below the ski, allowing the skiplane to operate from both snow and non-snow surfaces. This type of ski gives poor ground clearance on non-snow surfaces and causes extra drag when on snow. [Figure 7-3] The plastic polyethylene sheathing on the bottoms of the skis may be punctured by sharp objects, including ice. It also may shatter from impacts in extremely cold temperatures. Replacing the bonded type sheathing is very difficult in the field. If the sheathing is riveted, machine screws may be used to secure loose sheathing, but the screw holes must provide for expansion and contraction. Follow the manufacturer’s recommendations for patching limited sheathing damage. If damage is extensive, the entire ski bottom may need new covering. Shock cord bungees used in ski rigging deteriorate rapidly when left under tension. When parking the skiplane overnight, detach the bungees at the lower fitting and allow them to hang free. Reattaching the bungees normally requires two or more people. Hydraulic ski retracting mechanisms usually function well in cold environments, but the small, abrupt change of ski attitude occurring at touchdown imposes a severe load on the external hydraulic lines leading to the skis. These lines are a more prevalent source of trouble than the internal parts. Use low temperature oils and greases to lubricate friction points. For lubrication requirements, see the AFM/POH or the ski manufacturer’s manual. The condition of the limiting cables and their fastenings is important to safety in flight. Be sure there is no fraying, kinking, rusting, or other defective condition before each flight.

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