Wind and its Effect on Aircraft Performance

 

Wind velocity and direction can have a positive or negative effect on aircraft performance. For example, if you were taking off with a headwind at 20kts, your takeoff performance would be increased reducing your required runway length by approximately 40 percent. The opposite is true where if you have 20kts at your tail, you would have decreased performance and have to extend your required runway length by approximately 40 percent. This is because the relative wind flowing over the wing is greater with a headwind, and that increases your indicated airspeed without increasing your ground speed allowing you to reach your calculated takeoff speed in less time and distance. The same is true for landing. The increased airflow over the wings provides more lift at lower ground speed decreasing the landing distance required to come to a safe stop. So whenever possible, a pilot should take off and land into the wind. So, to mitigate the decreasing performance of a tailwind takeoff or landing, a pilot should elect to take off from a different runway with more favorable winds or ask for the opposite direction. If they are unable, they must calculate the takeoff or landing penalty and plan for the extended distance.

A tailwind can also increase performance at altitude. Once an aircraft has reached its cruising airspeed, a tailwind will increase the true airspeed allowing the aircraft to cover more distance in less time without exceeding aircraft speed limits. Because the true airspeed is relative to the air it is moving through, drag is decreased with a tailwind. It's not possible to control the weather, but you can plan for it. When planning for a flight with an extended period of cruise time, it's important to consider the winds at altitude and how they will positively or negatively affect your aircraft's performance.

Pilot’s Handbook of Aeronautical Knowledge. (n.d.). Retrieved July 7, 2022, from https://www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/phak/12_phak_ch5.pdf 

Pilot’s Handbook of Aeronautical Knowledge. (n.d.). Retrieved July 7, 2022, from https://www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/phak/12_phak_ch11.pdf