Hailstones, Hitches, and Hauling Wind

Oh, and How to Keep Your Aircraft Right-Side Up

By Tom Hoffman
Reprinted with permission from FAA Safety Briefing

Predicting weather can be as difficult as that classic challenge: Nailing Jell-O to the wall. And, no time of the year seems to be as unpredictable as summer. Clear blue skies and a calm breeze can morph into gale-force winds with pelting rain in mere minutes.

As airmen, we have the choice of grounding ourselves during these spurts of inclement weather, perhaps to embrace a good book (or a copy of FAA Safety Briefing) until the offending weather passes over. Yet, as we admire the forces of Mother Nature from a dry and safe place, we must consider the fate of our trusty winged steeds out there in the elements, exposed to everything from powerful gusts to golf ball-sized hail. Ask yourself: Have you done everything possible to protect your aircraft?

Batten Down the Hatches

Much like the midshipmen of days past protecting their ships from the brutal high seas, there are numerous ways to protect your aeronautical vessel from the harmful effects of severe weather. While no part of the United States is immune to inclement weather, it’s important to be aware of the unique climate conditions common in your area. Whether it’s hurricanes in the Gulf and up the East Coast, or hail- and tornado-producing thunderstorms across parts of the Midwest, knowing your area and the weather phenomena associated with it is key to understanding how best to protect your aviation assets.

Of course, the best way to keep your aircraft safe from something like an oncoming hurricane is to move it away from the affected area. The second obvious choice is to store the aircraft in a hangar built to withstand storm forces. If neither of these is an option, making sure your aircraft is tied down properly and securely is the next best thing. Here are some tips to help you “batten down the hatches” when weather threatens to rattle your aircraft.

As the Wind Blows, the Airplane Will Rock

The damage from winds produced by thunderstorms, hurricanes, and tornados is of particular interest to aircraft owners, as it is among the leading factors in aircraft damage insurance claims. With this in mind, owners should heed all possible mitigation techniques.

For starters, when securing your aircraft, make sure all windows and doors are closed and locked. Wind can easily jar open an unlocked door or window. Cover any engine openings, as well as pitot-static tubes to help prevent foreign object damage. Also, clear the ramp area of any debris that can easily become a dangerous projectile.

Whenever possible, an aircraft should be “hauling wind,” or pointed into the prevailing wind when parked to minimize weathervaning. Make sure there is also adequate clearance between adjacent aircraft; planes have a tendency to twist around and change direction, even when tied down securely.

Using control locks will prevent flight controls from banging against the stops and causing damage to hinges or cables. (Remember, though, that if you use external control surface locks, make sure they have streamers or flags to remind pilots to remove them before flight.) Ailerons, rudders, and elevators should all be secured in a neutral position, except for tail-wheel aircraft, which should have elevators secured in the “up” position when facing into the wind. If equipped, set and lock the parking brake and use wheel chocks fore and aft each wheel, preferably after securing tie down ropes or chains.

Tying It All Together

Among the most critical components of keeping your aircraft on terra firma are the ropes used to secure to tie down anchors. FAA recommends tie down ropes capable of resisting a pull of 3,000 pounds. Nylon or Dacron rope is preferred because of its tensile strength and rot resistance. Always inspect the ropes to check for signs of chafing or fraying. Rope has a limited life span, so ask if you are in doubt of its integrity. Other tie down options includes chains and nylon straps.

Before you start tying down your aircraft, check the condition of the tie down anchors, an item we often take for granted. Like the rope, the anchor should provide a minimum holding power of 3,000 pounds. The type of anchor will vary according to the type of parking area, whether a concrete-paved surface, a bituminous-paved surface, or an unpaved grass area. Most importantly, don’t depend on single stake-driven tie downs, as they are likely to loosen once the ground becomes wet. A multi-pin anchor using stakes at different angles will provide more holding power.

Finally, when tying the rope, try not to leave any slack. Any slack in the rope may allow for movement or rocking and can loosen even the best of knots. And, speaking of the best knots, a modified double half-hitch or a bowline are both tried and true. A good practice is to tie down the wings first followed by the tail and/or nose wheel, which should keep the lines taut.

Fight Water with Water

Like wind, rain can also be harmful to an aircraft. Some airports are located in a river valley or have local low spots that flood quickly. If significant rain or flooding is expected, try to move your aircraft to a higher tie down point. Also, check all windows, doors, and seals for any cracks or separations, which, if uncorrected, may lead to a soggy instrument panel. A good way to check for a proper seal is to wash your aircraft. Look for signs of interior leaking immediately after a good dousing with a hose.

Although a distant cousin of rain, hail is altogether a different entity. Beyond seeking shelter for your aircraft, there’s not much you can do to prevent hail damage. Some aircraft can be outfitted with custom wing or cockpit covers, which may offer some protection in light hail. Keep in mind that wind speed can enhance the damaging power of hail, so even pebble-size hail can have destructive consequences.

After the Storm Has Passed

You’ve done all you can do to ward off storm damage. Now, it’s time to inspect. Follow your aircraft’s preflight checklist to make sure you cover all areas, including draining samples from the fuel sumps. Look for structural damage around control hinges, and inspect the aircraft skin for signs of dimpling or tearing. Also, inspect the landing gear in case the aircraft was lifted and dropped. Consult with a mechanic if you’re unsure of anything that you suspect may affect airworthiness.

Don’t wait until a bad storm is bearing down on your airport to learn the proper way to secure your aircraft. Take time to read through your pilot operating handbook (POH) or consult with the manufacturer for specifics on tie down procedures. Getting into a routine of properly securing your aircraft will not only protect you on those “dark and stormy” nights in the forecast, but also when a gale-force wind or storm cell comes along without warning.

Tom Hoffmann is associate editor of FAA Safety Briefing. He is a commercial pilot and holds an A&P certificate.

For More Information

Aviation Maintenance Technician Handbook, FAA-H-8083-31A