content_image/613388.jpg content_image/613392.jpg content_image/613393.jpg
<img src='content_image/613388.jpg'>

<img src='content_image/613392.jpg'>

<img src='content_image/613393.jpg'>

particularly convenient thing to do while trying to fly. Figure 4-10 shows how steady, wings-level flight stall speed is affected by different altitudes. Figure 4-10  is only an example, and the figures used in it do not pertain to all gliders. For specific stall speeds, always refer to the POH of the glider that is being flown. 

A pilot can find TAS by two methods. The first method, which is more accurate, involves using a flight computer. In this method, the CAS is corrected for temperature and pressure variation by using the airspeed correction scale on the computer. A second method, which is a rule of thumb, can be used to compute the approximate TAS. This is done by adding to the IAS 2 percent of the IAS for each 1,000 feet of altitude. 

## Airspeed Indicator Markings 

Aircraft weighing 12,500 pounds or less, manufactured after 1945 and certificated by the Federal Aviation Administration (FAA), are required to have airspeed indicators that conform to a standard color-coded marking system. [Figure 4-4]  This system enables the pilot to determine, at a glance, certain airspeed limitations that are important to the safe operation of the aircraft. For example, if during the execution of a maneuver, the pilot notes that the airspeed needle is in the yellow arc and is rapidly approaching the red line, immediate corrective action to reduce the airspeed should be taken. It is essential that the pilot use smooth control pressure at high airspeeds to avoid severe stressors upon the glider structure. 

The following is a description of what the standard color- code markings are on an airspeed indicator and how they correspond to maneuvers and airspeeds. 

• The white arc—flap operating range 

• The lower limit of the white arc—stalling speed with the wing flaps and landing gear in the landing position. 

• The upper limit of the white arc—maximum flaps- extended speed. This is the highest airspeed at which the pilot should extend full flaps. If flaps are operated at higher airspeeds, severe strain or structural failure could result. 

• The lower limit of the green arc—stalling speed with the wing flaps and landing gear retracted. 

• The upper limit of the green arc—maximum structural cruising speed. This is the maximum speed for normal operations. 

