After a relatively brief hiatus from the Private Pilot Practical Test Standards, the latest revision of the document includes the requirement to perform an emergency descent.
Emergency descents get the airplane from altitude down toward the ground at the fastest rate possible, without building up additional airspeed. They are best used when the situation requires immediate and controlled action, such as trying to extinguish an engine fire or landing at an airport directly below you for an unforeseen pit stop.
The difficulty in performing emergency descents comes primarily from having to divide attention between looking for traffic and staying within flap speed and an acceptable bank angle. Spend most of your time looking outside, but don't forget to verify by checking your instruments every few seconds.
Watch the ears
Don’t be alarmed if while practicing emergency descents you experience some discomfort in your ears. Rapid descents don’t give your ears enough time to acclimate to the higher pressure of lower altitude. It’s for this reason that you should try to keep any climbs or descents to around 500 feet per minute in an unpressurized airplane with passengers on board during normal operations.
Step by step
1. Slow down—Pull the throttle to idle. (See “Shock Cooling,” below.)
2. Add drag—When within the flap operating speed, add full flaps. If in a retractable-gear airplane, lower the gear.
3. Start down—Push the nose to VFE, or the maximum speed with full flaps extended.
4. Circle—In order to stay within a fairly confined area, to add further drag, and to look for traffic below, bank the airplane 30 degrees in either direction and stay in that position until you are ready to roll out.
Shock cooling
Airplane engines rely on rapidly flowing outside air to keep heat at bay. But transitioning from a hot environment of full power to a much cooler environment of low power and cold air can cause problems. This condition, called shock cooling, usually occurs when power is decreased considerably, followed by a long period of descent. Modern multicylinder engine monitors have shock-cooling warnings built in. But most trainers don’t have this, so it’s the pilot’s job to be smart and try to avoid shock cooling. One way to keep temperatures up is to keep the mixture lean. Since the power is already back in a descent, it’s usually not necessary to enrichen the mixture until ready for landing.
When you’re ready to recover from the maneuver
1. Straighten out—Stop the bank, then pull out of the dive methodically.2. Don’t stall—Make sure not to get too slow here and add power smoothly to the cruise setting.
3. Clean up—Retract the flaps (and gear, if applicable) one increment at a time, eventually resuming normal straight-and-level flight.
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