Why can I match certain CPCalc performance data when comparing it to paper AFM data?
There are cases where a direct CPCalc versus paper AFM comparison will not match. The reason for this is how performance data comparisons are done in the CPCalc. There are two specific conditions when CPCalc and AFM data may not match: Dry vs. Wet Runway Performance: When performing a Wet runway analysis, the CPCalc will calculate the wet and dry distance and display the longer of the two distances, but using the wet V speeds. The paper AFM data does not make the comparison, and will only display performance data pertinent to the condition listed in the table – comparing wet versus dry distance data is up to the pilot when looking up data with the paper AFM. Anti Ice ON Performance: When calculating Anti Ice ON performance data using the CPCalc, no comparison of the calculated data is made with Anti Ice OFF performance. The paper AFM has such a comparison included to minimize the confusion of Anti Ice ON performance being better than Anti Ice OFF in certain conditions. Sloped Runways:
