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be practiced because these situations are hazardous and can damage the WSC and injure occupants. These examples are shown for informational purposes, in case similar situations arise in the future. 

The overall severity of a deceleration process is governed by speed (groundspeed) and stopping distance. The most critical of these is speed; doubling the groundspeed quadruples the total destructive energy and vice versa. Even a small change in groundspeed at touchdown, resulting from wind or pilot technique, affects the outcome of a controlled crash. It is important that the actual touchdown during an emergency landing be made at the lowest possible controllable airspeed using all available means. 

Most pilots instinctively—and correctly—look for the largest available flat and open field for an emergency landing. Actually, very little stopping distance is required if the speed can be dissipated uniformly; that is, if the deceleration forces can be spread evenly over the available distance. This concept is designed into the arresting gear on aircraft carriers, and provides a nearly constant stopping force from the moment of hookup. 

For example, assuming a uniform 2 G deceleration while landing into a headwind with a 25 mph groundspeed, the stopping distance is about 10.5 feet; in a downwind landing at 50 mph groundspeed, the required stopping distance is 42 feet—about four times as great. [Figure 13-3]  Although these figures are based on an ideal deceleration process, it is interesting to note what can be accomplished in an effectively used short stopping distance. Additionally, landing uphill reduces the stopping distance and landing downhill increases the stopping distance. Understanding the need for a firm but uniform deceleration process in very poor terrain enables the pilot to select touchdown conditions that spread the breakup of dispensable structure over a short distance, thereby reducing the peak deceleration of the fl ight deck area. A careful consideration must be made considering wind, slope, and terrain. 

##  Attitude and Sink Rate Control 

The most critical and often the most inexcusable error that can be made in the planning and execution of an emergency landing, even in ideal terrain, is the loss of initiative over the aircraft’s attitude and sink rate at touchdown. When the touchdown is made on flat, open terrain, an excessive nose- low pitch attitude brings the risk of “sticking” the nose in the ground. Steep bank angles just before touchdown should also be avoided, as they increase the stalling speed and the likelihood of a wingtip strike. 

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Since the aircraft’s vertical component of velocity is immediately reduced to zero upon ground contact, it must be kept well under control. A flat touchdown at a high sink rate (well in excess of 500 feet per minute (fpm)) on a hard surface can be injurious without destroying the fl ight deck structure depending on the design of the airframe and the shock absorbing system. On soft terrain, an excessive sink rate may cause digging in of the nose wheel with the wing and/or WSC aircraft rotating forward into the ground, stopping with severe forward deceleration or tumbling with higher speeds. 

