ESDU 74018:1977

ESDU 74018 gives simple formulae, derived from an analysis of a wide range of aircraft operating data, that enable still-air estimates of range, fuel used, and time based on cruise performance to be adjusted for the net loss of energy during climb (including acceleration) and during descent (including deceleration). The method, suitable for project estimates of block distance, fuel and time, applies to stages in which climb and descent are not substantial portions of flight and where they are flown at small angles and at equivalent airspeeds similar to that in cruise.