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Tiedown Sense
Part I
Each year numerous aircraft are needlessly damaged by windstorms because of inattention to weather forecasts, negligence, or improper tiedown procedures. Windstorms may be broadly classified as cyclonic storms or low pressure systems, regional or localized terrain induced winds, thunderstorms or tornado induced winds and hurricanes. The best protection against windstorm damage is, of course, to fly the aircraft out of the impending storm area provided you have sufficient warning time. The next best protective measure is to secure the aircraft in a stormproof hangar or other suitable shelter. The remaining alternative is to assure that the aircraft is tied down securely. When securing your aircraft, it is considered good practice to fasten all doors and windows properly, thereby minimizing damage inside the aircraft. Engine openings (intake and exhaust) for both reciprocating and gas turbines should be covered to prevent entry of foreign matter. Pitot-static tubes should also be covered to prevent damage or entry of foreign matter. Make sure your neighbor's aircraft is also tied down. |
It is the mission of the NWS to help mitigate the threat to life and property from natural hazards through the issuance of tornado and severe thunderstorm watches and warnings. NWS meteorologists at the National Severe Storms Forecast Center (NSSFC) monitor atmospheric conditions utilizing information from many sources and locations. When hazardous conditions are anticipated or detected, watches or warnings are issued.
Watches are issued by the NSSFC to indicate when and where severe thunderstorms and/or tornadoes are mast likely to occur. Watches are usually issued for areas about 140 miles wide, 200 miles long and generally 2 to 4 hours in advance of severe weather. Listen to the National Oceanic and Atmospheric Administration (NOAA) weather radios continuous broadcasts for the latest weather information directly from NWS offices, and use commercial radio or television for further information.
Warnings are issued by local NWS offices when severe thunderstorms or tornadoes are indicated by weather radar, weather observers or trained spotters. A warning describes an imminent risk from a tornado or severe thunderstorm in a relatively small area such as one or several counties. The key to damage avoidance or reduction is to be routinely weather conscious.
Be prepared for the worst conceivable windstorm conditions: pouring rain, gusty winds ranging from 30 MPH and up, for example intermittent sheets of water blowing across the runways, ramps, and parking areas, and lack of hangar facilities. With such conditions in mind, aircraft owners and operators should plan in advance by learning their aircraft manufacturer's instructions for tiedown; location and/or installation of tiedown rings for attachment of tiedown ropes; any special instructions for securing nosewheel type aircraft vs. tailwheel type aircraft; and manufacturer's charts and graphs denoting aircraft weights and relative wind velocities that would make varied tiedown procedures necessary for pending weather emergencies.
Any aircraft parking area should be equipped for three-point tiedowns. Aircraft should be tied down at the end of each flight to preclude damage from sudden storms. The direction in which the aircraft are to be parked and tied dawn will be determined by prevailing or forecast wind direction.
Aircraft should be headed into the wind, or as nearly as possible, depending upon the 1ocations of the fixed parking area mooring points. Spacing of tiedowns should allow for ample wingtip clearance. Spacing should be equal to the major axis (wingspan or fuselage length) of the largest aircraft usually operated plus 10 feet. After the aircraft is properly located, lock the nosewheel or the tailwheel in the fore-and -aft position.
Tiedown anchors for single engine aircraft should provide a minimum holding power (strength) of approximately 3,000 pounds each. The type of anchors in use varies depending upon the type of parking area--- whether for a concrete paved surface, a bituminous paved surface, or an unpaved turf area. Location of tiedowns are usually indicated by some suitable means, either white or yellow paint, or a painted tire which has been fastened into the ground, or surrounding the tiedown anchor with crushed stone. The tiedown anchor eye should not protrude more than 1 inch above ground.
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