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| CHAPTER 11. Approaches and Landings
Short and Soft Field Landing Techniques Many WSC aircraft land routinely on short and soft fi elds. The type of WSC and appropriate systems for short and soft fi eld was discussed in the Components and Systems chapter. Here, some techniques for these landing areas are discussed. Short-Field Approaches and Landings Short-field approaches and landings require the use of procedures for approaches and landings at fields with a relatively short landing area or where an approach is made over obstacles that limit the available landing area. [Figure 11-22] As in short-fi eld takeoffs, it is one of the most critical of the maximum performance operations. It requires that the pilot fl y the aircraft at one of its crucial performance capabilities while close to the ground in order to land safely within confi ned areas.
To land within a short fi eld or confi ned area, the pilot must have precise, positive control of the rate of descent and airspeed to produce an approach that clears any obstacles, results in little or no fl oating during the roundout, and permits the aircraft to be stopped in the shortest possible distance. As with the short takeoff maneuver, this should only be done for unusual situations or emergency operations and is not recommended. There are numerous airports, fi elds, and other areas to land, so prefl ight planning should avoid short-fi eld landings. However, short-fi eld procedures are provided for information. A stabilized approach is essential. These procedures generally involve the starting to fi nal approach from an altitude of at least 500 feet higher than the touchdown area. In the absence of a manufacturer’s recommended approach speed and in calm winds, example approach speeds are 1.3 times the stall speed or 8 knots above the stall speed. For example, in an aircraft that stalls at 30 knots with power off, the approach speed should be 38 to 40 knots. This maneuver should not be performed in gusty air because of the slow speeds and close proximity to the ground. If it is necessary to accomplish in gusty air, no more than one-half the gust factor should be added. An excessive amount of airspeed could result in a touchdown with an after-landing roll that exceeds the available landing area. For the steepest glide angle to clear obstacles such as trees or buildings, the maneuver should be performed at idle power; if the landing surface does not have obstacles that must be fl own over, power on approach may be used to reach the landing surface. The pilot should simultaneously adjust the power and the speed to establish and maintain the proper descent angle. A coordinated combination of both speed and power (if used) adjustments is required to set up a stabilized approach. The short-fi eld approach and landing is in reality an accuracy approach to a spot landing. The procedures previously outlined in the section on the stabilized approach concept should be used. If it appears that the obstacle clearance is excessive and touchdown will occur well beyond the desired spot leaving insuffi cient room to stop, lowering the pitch attitude and reducing power (if used) steepen the descent path and increase the rate of descent. If it appears that the descent angle will not ensure safe clearance of obstacles, power should be increased to shallow the descent path and decrease the rate of descent. Care must be taken to avoid an excessively low airspeed. If the speed is allowed to become too low, an increase in pitch and application of full power may result in a further rate of descent. This occurs when the AOA is too great and creating so much drag that the maximum available power is insuffi cient to overcome it. This is generally referred to as operating in the region of reversed command or operating on the back side of the power curve. Because the final approach over obstacles is made at a relatively steep approach angle and at the minimum manufacturer’s recommended approach speed, the initiation of the roundout must be judged accurately to avoid fl ying into the ground or stalling prematurely and sinking rapidly. A lack of fl oating during the roundout with suffi cient control to touch down properly is one verifi cation that the approach speed was correct. Upon touchdown, the nose should be brought down completely for aerodynamic braking and providing maximum pressure on the wheels for using the braking system. Immediately upon touchdown, appropriate braking should be applied to minimize the after-landing roll. The aircraft should be stopped within the shortest possible distance consistent with safety and controllability. If the situation arises and the minimum landing distance is required, the WSC can be landed above the normal speed, the nose brought down for aerodynamic braking while the brakes are applied for the shortest distance possible |
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