Page:CAB Accident Report, Pennsylvania Central Airlines Flight 19.pdf/41



The pilot reported himself over the Herndon fan marker at 2:31 P.M. at an altitude of 4,000 feet and continuing to climb. The intended cruising altitude, as shown by the flight plan, was 6,000 feet. The time from the take-off at Washington to passage over Herndon was therefore ten minutes. The distance from the airport to the Herndon fan marker is 19 miles. The average speed over the ground, assuming the correctness of the pilot's report, was therefore 114 m.p.h.; the average rate of climb, 400 ft. per minute; figures that are reasonably consistent with one another, assuming a light headwind as forecast, and assuming the engines to have been operated during the climb at the power output customary during that part of a flight. If the same airspeed and rate of climb had been continued past Herndon (making a small allowance for the time lost in the take-off before getting into steady climbing flight, and assuming the increase of airspeed with altitude to be offset by an equal increase in the strength of the headwind) an altitude of 6,000 ft. would have been reached just before 2:36 P.M., and at a distance from Washington of approximately 28 miles. Had the airplane then leveled off at an altitude of 6,000 ft. in accordance with the flight plan, and proceeded at its cruising speed of 180 m.p.h. against a 15-mile wind, it would have arrived over the scene of the accident, 44 miles from the Washington airport, at exactly 2:41 P.M. The reported time and altitude at Herndon, and continued adherence to flight plan thereafter, are therefore entirely consistent with the apparent time of the accident. The time of the accident is, of course, not known with such accuracy as to permit depending on calculations of this sort to fix the flight path or airspeed with a