point of no alternate

point of no alternate

point of no alternateclick for a larger image
A point on a track or the time from where it is not possible to reach the declared alternate with the available fuel. The distance to the point of no alternate from destination = DO/2A Cosine θ. D is the distance of the diversion from the destination, A is the ground speed to the destination, A is the TAS (true air speed), and θ is the angle between the track to the destination and the track to the diversion from the destination.