5. You must complete a turnaround run to record an official time.
An official speed is only recorded after completing a turnaround run within two hours (turnaround rules vary according to sanctioning bodies—FIM allows two hours). This accounts for any tail winds that might assist you in one direction. The current record held by the Ack Attack is 376.363 mph, a combined score of their first run at 394 mph and a turnaround run of 358.8 mph.