where:

 

image\PERF0374_wmf.gif

is the increment in zero lift drag coefficient of the drag polar due to approach flaps.

 

image\PERF0375_wmf.gif

is the zero lift drag coefficient of the aircraft drag polar with landing flaps and landing gear extended.

 

image\PERF0376_wmf.gif

is the zero lift drag coefficient of the aircraft drag polar with take-off flaps and landing gear extended.