Using the Flaps

Flaps change the shape of the wing, creating more lift and adding drag. These two effects allow you to fly at low airspeed and descend at a steep angle without building up speed. Flaps are not primary control surfaces—you don't use them to steer the airplane.

How They Work

Flaps extend from the trailing edge of the wing. They increase the curvature, or camber, of the wing, which increases lift. They also hang down, increasing drag. Pilots extend flaps in increments, typically measured in degrees. On most airplanes, flaps move in five- or ten-degree increments through a range of 0 (fully retracted) to about 40 degrees (fully extended).

The first few increments add more lift than drag. On many aircraft, extending 5–15 degrees of flaps helps the airplane take off more quickly.

As the flaps extend beyond about 20 degrees, they add more drag than lift. Flap settings of 20 degrees or more are used for approach and landing.

On Flight Simulator, either click the flap lever with the mouse, or key F5 to completely raise the flaps, F6 to raise flaps one notch, F7 to lower flaps one notch, and F8 to lower flaps all the way.

Pitch Changes

As you extend or retract flaps, be prepared for changes in pitch. For example, as you extend flaps in the Cessna Skylane RG, the nose tends to rise. You need to add forward pressure on the yoke to hold the nose on the horizon, and then use the trim control to relieve the forward pressure. Likewise, as you retract flaps in the Cessna, the nose tends to drop, so be ready to add back pressure on the yoke and then use trim to relieve the back pressure as the airplane stabilizes.

Types of Flaps

Flaps come in several varieties:

1. Plain flaps are mounted on simple hinges. The trailing edge of the wing simply pivots downward. Plain flaps are common on small aircraft because they're simple and inexpensive.
2. Split flaps hang down from the trailing edge of the wing, but the top surface of the wing doesn't move.
3. Slotted flaps work much like plain flaps. But they leave a gap between the flap and the wing, allowing air to flow from the bottom of the wing over the top surface of the flap. This airflow dramatically increases lift at low airspeed.
4. Fowler flaps are the most complicated and efficient arrangement. They move backward and downward as they're deployed, increasing both the wing's area and its curvature. Large jet aircraft usually have Fowler flaps.

Operating the Flaps

Flaps increase drag, but they aren't speed brakes. You can extend the flaps only when the airplane is flying at or below the maximum flap operating speed (indicated by the top of the white arc on the airspeed indicator). Deploying the flaps at higher speeds may cause structural damage.

In general, extend 5–10 degrees of flaps before takeoff to help the airplane lift off the runway quickly. Remember, however, to follow the recommendations in each airplane flight manual. Retract the flaps after reaching a safe altitude and climb speed.

When preparing to land, extend the flaps in increments. A good rule of thumb is to extend about 10 degrees of flaps as you enter the traffic pattern or begin an approach. As you continue around the traffic pattern, add flaps in small increments. For example, in the Cessna Skylane RG, set 10 degrees of flaps on the downwind leg. Set 20 degrees of flaps as you turn from downwind to base. Add flaps as necessary as you turn to final and approach the runway.