The principle that takeoffs and landings should occur against the wind may be ignored if a permissible tailwind component exists. On the parallel runway system a tailwind component of 5 knots as a maximum (approx. 2.6 m/s) is permissible. This means that change of the operation direction on the parallel runway system is not mandatory in case the tailwind speed is 5 knots or less. The permissible tailwind component for Runway 18 West is a maximum of 15 knots (approx. 8 ms/s). This is due to the fact that the tailwind components for takeoffs are generally higher, unless aircraft performances are in conflict with such components. However, Frankfurt Airport hardly experiences wind with such a power. The final decision whether takeoff should occur from Runway 18 West or from the parallel runway system despite the tailwind present, rests with the pilot in command who is bound by security and safety considerations.