During this phase of your training we will be covering slow flight exercises and various descentsincluding
the jet penetration descent, the enroute/idle descent, the maximum range/idle descent, and the cruise
Factors affecting your descent include enroute or terminal weather, fuel, the presence of an emergency,
and the mission you are flying.
Use the jet penetration for quick descent to lower altitudes associated with instrument approaches, for
VFR entry to the landing pattern, when fuel is not a primary consideration, and when you do not want to
gain excessive airspeed or cover a large horizontal distance.
To perform this descent, reduce the power to IDLE (if above 30K-75% minimum) and extend the speed
brakes as required. Establish a descent rate of 4,000 to 6,000 fpm while adjusting the nose attitude to
maintain 250 KIAS. At 10% of the rate of descent (in feet) above the desired altitude, retract the speed
brakes and initiate level off. Adjust the power to maintain 250 KIAS.
NOTE: The rate of descent should not exceed your altitude above the ground in feet per minute when you
are below 5,000 ft AGL. This precaution is commonly referred to as the minute to live rule.
ENROUTE IDLE DESCENT
The enroute idle descent minimizes fuel consumption while descending at enroute airspeed.
To perform this descent, reduce the power to IDLE (if above 30K-75% minimum) and begin the descent
when the distance to your destination in nautical miles is approximately 2.5 times your altitude in thou-
sands of feet above the desired altitude. Maintain cruise airspeed throughout the descent. Begin level off
when you are at 10% of the rate of descent (in feet) above the desired altitude.
EXAMPLE: If you want to descend from FL350 to 15,000 ft MSL, calculate the beginning point of your
descent as follows:
2.5 x 20 (number of thousands) = 50 nm
Remember, this equation is simply a best guess as to when to start your descent. It does not account for
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