Thursday, January 1, 2004
Get The Most Out Of Winter Part 1
With cool temperatures and great visibilities, autumn-to-spring flying requires a different set of rules—and it all starts on the ground
Because aluminum structures shrink more than steel cables in the cold, you may need to have a mechanic re-tension those cables. If recommended by the manufacturer, install intake air baffles or oil cooler covers to help the engine retain its heat. Check all hoses, clamps, fuel lines and hydraulic fittings, and re-torque them to manufacturer’s specs if necessary.
Down below the wing, consider having the retractable-gear mechanism lubricated with graphite or another cold-weather lubricant rather than conventional grease. Some retractables don’t even have grease fittings for the gear legs, but on those that do, make certain any grease or oil is of an appropriate weight.
While you’re under the wings, be sure to air up the oleos and tires, since low temperatures cause pressure loss in those components. You can make your own decision as to whether to remove wheelpants. Some pilots up north suggest removing them to avoid buildups of snow and ice around the wheels and brakes with obvious consequences.
Your pre-winter maintenance should include inspection and service of any de-ice or anti-icing equipment that’s installed. Virtually every airplane is fitted with a heated pitot tube and you should assure that it’s working properly before charging off into the cold blue yonder, regardless of whether you plan to file IFR. If your airplane is fitted with wing, tail or prop de-ice boots, treat them with an appropriate dressing such as Agemaster 1 to minimize cracking and checking, and plan to carry some ICEX anti-ice fluid to help them shed ice.
Pilot And Passenger Preparation
While you’re preparing the airplane for winter, remember that pilot and passengers need a little preparation, as well. We could do a separate story in winter survival gear all by itself, but obvious considerations are for emergency blankets, appropriate clothing and passive combustible materials to help keep you warm on the ground. Also, remember that darkness comes early in winter. Proper emergency flashlights become more important.
Flight planning in winter can be a little more complicated than in summer, primarily because standard VFR pilotage can be difficult or downright impossible when snow covers the ground, obscuring the landscape. Many flat landmarks such as highways, railroads, frozen rivers and lakes, and even airports themselves may simply dissolve into the background in what seems an indistinguishable white slate.
I flight-plan for a higher cruise altitude in the cold season for two reasons. First, it may be tougher to spot emergency landing sites from lower altitude with snow obscuring ground detail. Second, most winter weather is low-lying, and a taller cruise height usually allows me to top it. Remember that seasonal temps up high may yield a density altitude well below standard. A pressure altitude of 10,500 feet may mean a density altitude of 8,500 feet, the reverse of summer conditions.
Your preflight weather briefing can be somewhat more critical in winter, because weather moves so quickly that a destination only 100 miles away may have dramatically different atmospherics than your point of departure. In addition to all the normal questions you ask the briefer about icing conditions aloft, freezing level and pilot reports on actual icing, you’ll want to inquire about landing conditions at your destination, any expected surface winds (especially crosswinds, since they may not be manageable on ice), and runway and ramp conditions.
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