FAA Regulations - Laserfiche WebLink

Home

6/24/75 AC 150/5300-48 CHAPTER 3. WIND ANALYSIS AND RUNWAY ORIENTATION 8. GENERAL. a. The configuration of the airport is determined by the number and orientation of the runways. One of the primary factors influencing runway orientation is wind. Ideally the runway should be aligned with the prevailing winds. Wind conditions affect all airplanes, the smallest to the largest, in varying degrees. Generally, the smaller the airplane, the more it is affected by wind, particularly crosswind components. Crosswinds are often a contributing factor in small airplane accidents. In some cases, construction of two runways may be necessary to give the desired wind coverage. b. Airport planners and designers should, therefore, make an accurate analysis of wind to determine the orientation and number of runways. The proper application of the results of this analysis will add substantially to the safety and usefulness of the airport. Appendix 3 provides information on wind data for the purpose of airport plan- ning and design, and the following paragraphs give procedures in its application to runway orientation concepts. 9. CROSSWINDS. a. A crosswind component of wind direction and velocity is the resultant vector which acts at a right angle to the runway. It is equal to the wind speed multiplied by the trigonometric sine of the angle between the wind direction and the runway direction. Normally, these wind vector triangles are solved graphically. An example is shown in Figure 3-1. From this diagram, one can also ascertain the headwind and tailwind component of combinations of wind velocities and direc- tions. b. Study and analysis of different combinations of velocities and directions, having an 11.4-mile-per-hour (mph) (9.9 knots) cross- wind component, have found that different combinations produce similar adverse effects on the control handling characteristics of airplanes. Considering this and the method of repotting wind data, the 12-mph or 10.5-knot speed was selected as a reasonable and convenient figure upon which to base runway orientation. 11). ORIENTATION AND COVERAGE. The most desirable runway orientation based on wind is the one which has the largest wind coverage and minimum crosswind components. Chap 3 Par 8 Page 7