PART Vi-OPERATING DATA

        (iii)  Descent

               The descent table gives the data for descending
               from one height to another.

    (b)  Use of the tables

          (i)  Pre-flight planning

               Enter the cruise data table in the sea level block at
               the fuel stage applying immediately after take-off.
               Select the height at which maximum range is avail-
               able at that fuel state. The distance available
               includes distance covered on the climb, but not on
               the descent. (Absolute maximum range is obtained
               by adding on the descent distance provided that the
               let-down is commenced at that distance from the
               destination). For short range flights inspect the sea
               level block and select the height at which the
               distance to be covered requires the least amount of
               fuel. This is the best altitude for the flight.

         (ii)  In-flight planning

               At any stage of a flight the available range may be
               ascertained by applying the fuel state to the level
               flight range in the particular block. If an increase
               in range is required, or if a climb has to be made,
               the new available range may be obtained by entering
               the existing block at the particular fuel state and
               moving vertically downwards within the block until
               the new altitude is reached. Figures in heavy type
               indicate the best altitude for the maximum increase
               in range. Above these heights no further range
               increase is possible. If a descent is necessitated the
               new range is shown by moving direct from the existing
               altitude level flight range for the particular fuel state
               to the new altitude level flight range.

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