Saturday, May 1, 2004
Worst-Case Weather Scenarios
If you find yourself in hazardous situations, nothing helps you more than having a plan
How To Survive A Thunderstorm
Powerful and imposing, thunderstorms form as individual cells, often in a single line. Hence, although they may be the longest moments of your life, if you pass through the line nearly perpendicularly, the actual time that you spend inside a storm cell will be relatively short. If you find yourself about to enter a thunderstorm, follow these steps:
• Tighten all safety belts and secure loose objects.
• Aim for the narrowest part of the cell, as close to the edge of the upwind side of the cloud as possible.
• If flying a retractable-gear plane, increase the stability by lowering the landing gear.
• Establish turbulent air penetration speed (Va) and trim.
• Keep flaps up; lowered flaps reduce the maximum G load that the airplane can withstand.
• Turn off an autopilot’s altitude hold (“attitude hold” and heading/nav modes are beneficial to keep on).
• Fully turn up the cockpit lights and keep your eyes in the cockpit to avoid being blinded by lightning.
• Maintain the power setting and attitude; accept altitude and airspeed deviations (tell, don’t ask, air traffic control that you need a “block altitude”).
• Keep the wings level and hold the heading to minimize your time in the storm and to keep the G loading to a minimum.
• Land as soon as it’s practical after exiting the storm. Have a mechanic thoroughly check the airplane for damage before anyone flies it again.
How To Survive Hail
Hail forms in towering cumulus clouds and can be ejected as much as 20 miles from a severe thunderstorm (that’s where the admonition to avoid flying between storm cells that are less than 40 miles apart comes from—stay at least 20 miles from any one cell). Should the skies go green and you fly into a shaft of hail, make sure to do the following:
• Slow the airplane to reduce impact forces; also, you’ll likely encounter wind shear and strong downdrafts.
• Protect your face and eyes, just in case hail comes through the windshield (here’s a use for Foggles™ that you’ve probably never thought about).
• Hold the heading to minimize the time spent in the hail.
• After entering clear air, carefully test the airplane control at progressively lower air speeds (we suggest doing tests at five-knot increments).
• Establish a minimum landing speed using the zero-flaps landing speed or 1.2 times the speed at which you get the very first indication of control difficulty or impending stall, whichever is higher.
• Land as soon as it’s safe by using your established landing speed. Do not use flaps—extending flaps increases the angle of attack of the horizontal stabilizer, which may also be damaged. Also, the flaps themselves may be damaged.
• Call your insurance agent—you’re not flying that airplane for a while.
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Labels: Accident Statistics, Decision Making, Flight Hazards, Learning Center, Pilot Guide, Safety, Weather Skills