Ch 07.qxd 8/25/04 11:20 AM Page 7-4 ¥ Hardware— Inspect the condition and security of the clamping bolts, cotter keys, diaper pins, limiting cables, and bungees. Be sure cables and bungees are adjusted properly. ¥ Retracting Mechanism— (if equipped)—Check the hydraulic fluid level and examine the hydraulic lines for leaks. Inspect all cables for fraying and check cable ends for security. Do not cycle the retracting mechanism while on the ground.  ¥ Ski Freedom— Be sure the skis are free to move and are not frozen to the surface. If the ambient temperature approaches the melting point, the skis can be freed easily. Gentle swinging of the tail at the rear fuselage, or rocking the airplane at the struts may free the skis. If this does not work, dig the skis out.  ¥T ire Pressure— Check the tire pressure when using skis that depend on the tires for shock absorption, as well as for combination skis. This is especially important if moving a skiplane from a warm hangar to cold temperatures outdoors, as tires typically lose one pound of pressure for every ten-degree drop in ambient temperature. ¥T ailwheel— Check the tailwheel spring and tail ski for security, cracks, and signs of failure. Without a tail ski, the entire tailwheel and rudder assembly can be easily damaged. ¥ Fuel Sump— During fuel sump checks, some- times moisture can freeze a drain valve open, allowing fuel to continue to drain. Ice inside the fuel tank could break loose in flight and block fuel lines causing fuel starvation. If the manufac- turer recommends the use of anti-icing additives for the fuel system during cold weather opera- tions, follow the ratio and mixing instructions exactly. ¥ Survival Equipment— Check that all required survival equipment is on board and in good con- dition. STARTING  proper level. Conversely, the electrolyte in a weak or discharged battery may freeze at temperatures near 32 F. If a fully charged battery is depleted by an unsuccess- ful start, it may freeze as it cools to ambient temperature. Later, when the engine is started and the battery is receiving a charge, it could explode. After start, a proper warmup should be completed prior to a runup and high power settings. Perform the warmup according to the engine manufac- turer’s recommendations. Some manufacturers recommend a minimum of 1,000 r.p.m. to ensure adequate lubrication. If the skiplane is parked on heavily crusted snow or glaze ice with the skis frozen to the surface, it may be possible to start the engine and perform the runup in the parking area. Be sure the area behind the skiplane is clear, so as not to cause damage with the propeller wash. If a ski should become unstuck during the runup, reduce power immediately. Then use one of the following procedures to secure the airplane. Tie down or chock the skiplane prior to engine start, warmup, and runup. Keep all ropes, bags, etc., clear of the propeller. After warmup is complete, and if no assistance is available, shut down the engine to untie and unchock the skiplane, then restart as quickly as possible. If a post, tree, boulder, or other suitable object is available, tie a rope to an accessible structural component in the cockpit, take the end around the anchor object, bring it back to the cockpit, and tie it off with a quick-release knot. When the warmup and runup are complete, release the knot and pull the rope into the cockpit as the skiplane begins to taxi. If tiedowns or chocks are not available, build small mounds of snow in front of each ski. The mounds must be large enough to prevent the skiplane from taxiing over them during engine start and warmup, but small enough to allow taxiing when power is applied after the warmup is complete. If tiedowns or means to block the skis are not available, the runup can be accom- plished while taxiing when clear of obstacles or other hazards. [Figure 7-4] Adequately preheat the engine, battery, and the cockpit instruments before startup and departure. Sometimes engine oil may require heating separately. Check the manufacturer’s recommendation for starting the engine when ambient temperatures are below freezing.  Batteries require special consideration. In cold climates a strong, fully charged battery is needed. With just a lit- tle cold-soaking, the engine may require three times the usual amperage to crank the engine. Another consideration is the electrolyte freezing point. A fully charged battery can withstand temperatures of -60 to -90 F since the electrolyte’s specific gravity is at a Figure 7-4. Engine warmup. 7-4