Analysis of the Flight Path by Robert Nicholson Assuming that the airliner remained on the centerline of V23 all the way from Seattle to the Red Bluff VORTAC in northern California, it would have covered a distance of 452 nautical miles in 2:32 hours for an average ground speed of 179 knots. After leveling off at 10,000 feet, the airliner's "bug speed" was 170 Knots Indicated Airspeed (KIAS) which is 195 Knots True Airspeed (KTAS). The 170 KIAS was the speed for best range in the aircraft configuration that Cooper had specified and that is the reading on the airspeed indicator that the crew attempted to maintain. The flight crew reported it was leveling off at 10,000 feet at 7:54 PM PST at a point about 13.5 nautical miles north of the Mayfield Intersection on V23. The winds aloft at 10,000 feet were estimated to be 26 Knots from the southwest (225 degrees true or with respect to the map grid lines). This winds estimate was based on information from FBI sources, iterations of the achieved ground speed, and other sources. From the point of leveling off at 10,000 feet, it is 13.5 nautical miles to the Mayfield Intersection, and using the above wind information, the ground speed would be 173 Knots and the aircraft would arrive at that intersection at about 7:59 PM PST. The distance from the Mayfield Intersection to the PDX VORTAC is 41 nautical miles, the airliner would have a ground speed of 177 Knots, and arrive at the PDX VORTAC at 8:13 PM PST. From the PDX VORTAC to the Point on V23 which was 23 DME (or nautical) miles to the south, the airliner would have a ground speed of 174 Knots, and would arrive at that point at 8:21 PM PST.