are often pleasant on wave soaring days. Sunshine through the canopy keeps the upper body amazingly warm for a time, but shaded legs and feet quickly become cold. Frostbite is a very real threat. After an hour or two at such temperatures, even the upper body can become quite cold. Layered, loose-fitting clothing helps insulate body heat. Either wool gloves or light, fitted gloves with mittens over them work best for the hands. Mittens make tasks such as turning radio knobs difficult. For the feet, two or three pairs of socks (inner, silk; outer, wool) with an insulated boot are recommended. 

In addition, the low temperatures can cause two other symptoms: it frosts your exhaled breath on the inside of the canopy and it causes the kidneys to excrete liquid at an accelerated rate. 

A clean piece of cloth (that will not damage the canopy) can be used to wipe the condensation or frost from the canopy, if needed, but the best way to clear the canopy is a little fresh air through the side or front vent to help delay the buildup of frost. Unfortunately, this also quickly lowers the inside temperature, so it is best to wear clothing in layers so that you can easily take off or put on what is needed. There is little that can be done for the kidneys excreting liquid at an accelerated rate. The best course of action is to plan for it in advance by making a bathroom stop before you take off. Remember that the body is dehydrating more rapidly because of the cold and always be looking for signs of dehydration. 

## Cockpit Management 

Prior to launch, passengers should be briefed on the use of safety belts, shoulder harnesses, and emergency procedures. If ballast is used, it must be properly secured. Organize the cockpit so items needed in flight are accessible. All other items must be securely stowed. The necessary charts and cross- country aids should be stowed within easy reach of the pilot. 

## Personal Equipment 

If a parachute of the approved type is to be available for emergencies, Title 14 of the Code of Federal Regulations (14 CFR) part 91 requires that a certificated and appropriately- rated parachute rigger repack it within the preceding 180 days if it is made of nylon. The packing date information is usually found on a card contained in a small pocket on the body of the parachute. 

## Oxygen System 

14 CFR part 91 also requires that the pilot in command (PIC) use supplemental oxygen for flights more than 30 minutes in duration above 12,500 feet and at all times during a flight above 14,000 feet. If supplemental oxygen is used, the system should be checked for flow, availability, and the PRICE checklist should be used: 

• P = Pressure 

• R = Regulator 

• I = Indicator 

• C = Connections 

• E = Emergency bail-out bottle 

The importance of understanding the need for oxygen equipment in gliders has been heightened in recent years by a considerable increase in the number of high-altitude soaring flights. The exploration of mountain waves has led to numerous flights at altitudes in excess of 30,000 feet with several record flights in excess of 40,000 feet. In some parts of the country, it is frequently possible to soar to a 16,000- to 18,000-foot cloud base in thermals. In almost all parts of the United States such altitudes are attainable in cumulonimbus clouds. 

At 18,000 feet, air density is only one-half that at sea level. The purpose of breathing is to supply oxygen to the blood and remove carbon dioxide. In each breath at 18,000 feet, the pilot breathes in only half as much oxygen as at sea level. This is not enough to deliver an adequate supply of oxygen to the blood, and the situation worsens as altitude increases. The automatic reaction is to breathe twice as fast. This hyperventilation, or overbreathing, is almost worse than going up without oxygen in the first place because it results in eliminating too much carbon dioxide from the blood. The immediate effects of hyperventilation are: 

• Spots before the eyes 

• Dizzy feeling 

• Numbing of fingers and toes, followed by possible unconsciousness 

The dangers of oxygen deprivation should not be taken lightly. At around 20,000 feet MSL, pilots might have only 10 minutes of “useful consciousness.” By 30,000 feet MSL, the time frame for “useful consciousness” decreases to 1 minute or less. For planned flights above 25,000 feet MSL, an emergency oxygen backup or bailout bottle should be carried. 

The U.S. Air Force in cooperation with the Federal Aviation Administration (FAA) provides a 1-day, high- altitude orientation and chamber ride for civilian pilots. The experience is invaluable for any pilot contemplating high-altitude soaring and is even required by many clubs and operations as a prerequisite. 

## Aviation Oxygen Systems 

Aviation oxygen systems are designed for airborne aviation applications. Unlike a medical-type oxygen system, an aviation system is generally much lighter, compact, and 

