## Pilot's Handbook of Aeronautical Knowledge Aircraft Performance Performance Charts

Pilot's Handbook of Aeronautical Knowledge

Preface

Acknowledgements

Appendix

Glossary

Index

 To find the takeoff distance for a pressure altitude of 2,500 feet at 20 °C, average the ground roll for 2,000 feet and 3,000 feet. 1,115 + 1,230 / 2 = 1,173 feet Figure 10-20. Interpolating charts.
 Density Altitude Charts Use a density altitude chart to figure the density altitude at the departing airport. Using Figure 10-21, determine the density altitude based on the given information. Sample Problem 1 Airport Elevation...............................................5,883 feet OAT........................................................................... 70 °F Altimeter........................................................... 30.10" Hg First, compute the pressure altitude conversion. Find 30.10 under the altimeter heading. Read across to the second column. It reads "–165." Therefore, it is necessary to subtract 165 from the airport elevation giving a pressure altitude of 5,718 feet. Next, locate the outside air temperature on the scale along the bottom of the graph. From 70°, draw a line up to the 5,718 feet pressure altitude line, which is about two thirds of the way up between the 5,000 and 6,000 foot lines. Draw a line straight across to the far left side of the graph and read the approximate density altitude. The approximate density altitude in thousands of feet is 7,700 feet. Takeoff Charts Takeoff charts are typically provided in several forms and allow a pilot to compute the takeoff distance of the aircraft with no flaps or with a specific flap configuration. A pilot can also compute distances for a no flap takeoff over a 50 foot obstacle scenario, as well as with flaps over a 50 foot obstacle. The takeoff distance chart provides for various aircraft weights, altitudes, temperatures, winds, and obstacle heights. Sample Problem 2 Pressure Altitude...............................................2,000 feet OAT..........................................................................22 °C Takeoff Weight.............................................2,600 pounds Headwind...............................................................6 knots Obstacle Height.......................................50 foot obstacle Refer to Figure 10-22. This chart is an example of a combined takeoff distance graph. It takes into consideration pressure altitude, temperature, weight, wind, and obstacles all on one chart. First, find the correct temperature on the bottom left- Figure 10-21. Density altitude chart.

10-19