Glider Flying

The Atmosphere

The atmosphere is a mixture of gases surrounding the earth. Without it, there would be no weather (wind, clouds, precipitation) or protection from the sun’s rays. Though this protective envelope is essential to life, it is extraordinarily thin. When compared to the radius of the earth, 3,438 nautical miles (NM), the vertical limit of the atmosphere represents a very small distance. Although there is no specific upper limit to the atmosphere—it simply thins to a point where it fades away into space—the layers up to approximately 164,000 feet (about 27 NM) contain 99.9 percent of atmospheric mass. At that altitude, the atmospheric density is approximately one-thousandth the density of that at sea level. [Figure 9-1]

Figure 9-1. Atmospheric mass by altitude.

Composition

The earth’s atmosphere is composed of a mixture of gases, with small amounts of water, ice, and other particles. Two gases, nitrogen (N₂) and oxygen (O₂), comprise approximately 99 percent of the gaseous content of the atmosphere; the other one percent is composed of various trace gases. Nitrogen and oxygen are both considered permanent gases, meaning their proportions remain the same to approximately 260,000 feet. Water vapor (H₂O), on the other hand, is considered a variable gas. Therefore, the amount of water in the atmosphere depends on the location and the source of the air. For example, the water vapor content over tropical areas and oceans accounts for as much as 4 percent of the gases displacing nitrogen and oxygen. Conversely, the atmosphere over deserts and at high altitudes exhibits less than 1 percent of the water vapor content. [Figure 9-2]

Although water vapor exists in the atmosphere in small amounts as compared to nitrogen and oxygen, it has a significant impact on the production of weather. This is because it exists in two other physical states: liquid (water) and solid (ice). These two states of water contribute to the formation of clouds, precipitation, fog, and icing, all of which are important to aviation weather.

Properties

The state of the atmosphere is defined by fundamental variables, namely temperature, density, and pressure. These variables change over time and, combined with vertical and horizontal differences, lead to daily weather conditions.

Temperature

The temperature of a gas is the measure of the average kinetic energy of the molecules of that gas. Fast-moving molecules are indicative of high kinetic energy and warmer temperatures. Conversely, slow-moving molecules reflect lower kinetic energy and lower temperatures. Air temperature is commonly thought of in terms of whether it feels hot or cold. For quantitative measurements, the Celsius (°C) scale is used in aviation, although the Fahrenheit (°F) scale is still used in some applications.

Density

The density of any given gas is the total mass of molecules in a specified volume, expressed in units of mass per volume. Low air density means a smaller number of air molecules in a specified volume while high air density means a greater number of air molecules in the same volume. Air density affects aircraft performance, as noted in Chapter 5, Glider Performance.

Pressure

Molecules in a given volume of air not only possess a certain kinetic energy and density, but they also exert force. The force per unit area defines pressure. At the earth’s surface, the pressure exerted by the atmosphere is due to its weight. Therefore, pressure is measured in terms of weight per area. For example, atmospheric pressure is measured in pounds per square inch (lb/in²). From the outer atmosphere to sea level, a typical value of atmospheric pressure is 14.7 lb/in².

In aviation weather reports, the units of pressure are inches of mercury (“Hg) and millibars (mb) and 29.92 “Hg equals 1013.2 mb. This force or pressure is created by the moving molecules act equally in all directions when measured at a given point.

In the METAR report, see Figure 9-3, the local altimeter setting “A2955”, read as 29.55, is the pressure “Hg. In the remarks (RMK) section of this report, sea level pressure expressed as “SLP010”, the value expressed in millibars (hPa), is used in weather forecasting.

Figure 9-3. Example of how pressure is used in an aviation weather report.

Dry air behaves almost like an ideal gas, meaning it obeys the gas law given by P/DT = R, where P is pressure, D is density, T is temperature, and R is a constant. This law states that the ratio of pressure to the product of density and temperature must always be the same. For instance, at a given pressure if the temperature is much higher than standard, then the density must be much lower. Air pressure and temperature are usually measured, and using the gas law, density of the air can be calculated and used to determine aircraft performance under those conditions.

Standard Atmosphere

Using a representative vertical distribution of these variables, the standard atmosphere has been defined and is used for pressure altimeter calibrations. Since changes in the static pressure can affect pitot-static instrument operation, it is necessary to understand basic principles of the atmosphere. To provide a common reference for temperature and pressure, a definition for standard atmosphere, also called International Standard Atmosphere (ISA), has been established. In addition to affecting certain flight instruments, these standard conditions are the basis for most aircraft performance data.

At sea level, the standard atmosphere consists of a barometric pressure of 29.92 “Hg, or 1,013.2 mb, and a temperature of 15 °C or 59 °F. Under standard conditions (ISA), a column of air at sea level weighs 14.7 lb/in².

Since temperature normally decreases with altitude, a standard lapse rate can be used to calculate temperature at various altitudes. Below 36,000 feet, the standard temperature lapse rate is 2 °C (3.5 °F) per 1,000 feet of altitude change. Pressure does not decrease linearly with altitude, but for the first 10,000 feet, 1 “Hg for each 1,000 feet approximates the rate of pressure change. It is important to note that the standard lapse rates should be used only for flight planning purposes with the understanding that large variations from standard conditions can exist in the atmosphere. [Figure 9-4]

Layers of the Atmosphere

The earth’s atmosphere is divided into five strata, or layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere. [Figure 9-5] These layers are defined by the temperature change with increasing altitude. The lowest layer, called the troposphere, exhibits an average decrease in temperature from the earth’s surface to about 36,000 feet above mean sea level (MSL). The troposphere is deeper in the tropics and shallower in the polar regions. It also varies seasonally, being higher in the summer and lower in the winter months.

Almost all of the earth’s weather occurs in the troposphere as most of the water vapor and clouds are found in this layer. The lower part of the troposphere interacts with the land and sea surface, providing thermals, mountain waves, and seabreeze fronts. Although temperatures decrease as altitude increases in the troposphere, local areas of temperature increase (inversions) are common.

The top of the troposphere is called the tropopause. The pressure at this level is only about ten percent of MSL (0.1 atmosphere) and density is decreased to about 25 percent of its sea level value. Temperature reaches its minimum value at the tropopause, approximately –55 °C (–67 °F). For pilots, this is an important part of the atmosphere because it is associated with a variety of weather phenomena, such as thunderstorm tops, clear air turbulence, and jet streams. The vertical limit altitude of the tropopause varies with season and with latitude. The tropopause is lower in the winter and at the poles; it is higher in the summer and at the equator.

The tropopause separates the troposphere from the stratosphere. In the stratosphere, the temperature tends to first change very slowly with increasing height. However, as altitude increases the temperature increases to approximately 0 °C (32 °F) reaching its maximum value at about 160,000 feet MSL. Unlike the troposphere in which the air moves freely both vertically and horizontally, the air within the stratosphere moves mostly horizontally.

Gliders have reached into the lower stratosphere using mountain waves. At these altitudes, pressurization becomes an issue, as well as the more obvious breathing oxygen requirements. Layers above the stratosphere have some interesting features that are normally not of importance to glider pilots. However, interested pilots might refer to any general text on weather or meteorology.

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Pilot Emergency Equipment and Survival Gear

Filed Under: Abnormal and Emergency Procedures

Emergency equipment and survival gear is essential for safety of flight for all soaring flights.

Survival Gear Checklists

Checklists help the pilot to assemble the necessary equipment in an orderly manner. The essentials for survival include reliable and usable supplies of water, food, and air or oxygen. Maintenance of an acceptable body temperature, which is difficult to manage in extreme cold or extreme heat, is also important. Blankets and appropriate seasonal clothing help to ensure safe body temperatures.

Food and Water

An adequate supply of water and food (especially high-energy foods such as energy bars, granolas, and dried fruits) are of utmost importance during cross-country flight. Water from ballast tanks can be used in an emergency if free of contaminants, such as antifreeze. Water and food should be available and easily accessible during the entire flight.

Clothing

Pilots also need seasonal clothing that is appropriate to the local environment, including hat or cap, shirts, sweaters, pants, socks, walking shoes, space blanket, and gloves or mittens. Layered clothing provides flexibility to meet the demands of the environment. Desert areas may be very hot in the day and very cold at night. Prolonged exposure to either condition can be debilitating. Layered clothing traps air between layers, increasing heat retention. The parachute canopy can be used as an effective layered garment when wrapped around the body to conserve body heat or to provide relief from excessive sunlight. Eye protection, such as sunglasses, is more than welcome if conditions during the day are bright, as they often are on good soaring days.

Communication

Communication can be electronic, visual, or audible. Radios, telephones, and cell phones are electronic methods. Signal mirrors, flashlight or light beacons at night, signal fire flames at night, signal smoke during daylight hours, signal flares, and prominent parachute canopy displays are visual methods. Shouting and other noisemaking activities are audible methods but usually have very limited range. A whistle provides a good method for making sound.

Coin, cash, or credit cards are often necessary to operate pay phones. Charged batteries are required to operate cell phones, two-way radios, and emergency locator transmitters. Batteries are also necessary to operate flashlights or position lights on the glider for signal purposes. A list of useful telephone numbers aids rapid communication. The aviation transceiver can be tuned to broadcast and receive on the emergency frequency 121.5 MHz or any other useable frequency that elicits a response. The ELT can be used to provide a continuous signal on 121.5 MHz and/or the newer 406 MHz SAR system. A 406 MHz beacon on a downed aircraft activates either automatically or manually. The ELT transmits a digital identification code to the first satellite that comes into range. The satellites receive the signal and relay it to a ground station. If there is no ground station in view, the satellite records the digital signal in its onboard memory and downloads it to the next ground station. The ground station processor measures the Doppler shift of the signal and calculates its position; this calculation is usually accurate to within 1.5 nautical miles on the first satellite pass and is refined further with each pass. If the beacon has an integrated GPS or is connected into the onboard NAVCOM, the position is imbedded into the initial digital data stream.

After the ground station has completed processing, it transmits the identification and position to the United States Mission Control Center (USMCC). The USMCC attaches the information contained in the 406 MHz beacon registration database for that particular ELT and generates an alert message. If the location lies within the continental U.S., the alert is sent to the Air Force Rescue Coordination Center (AFRCC) at Langley Air Force Base, Virginia. The AFRCC then takes the registration data and attempts to ascertain the aircraft’s disposition. By calling the emergency contact numbers, or by calling flight service stations with the N-number, they can quickly determine whether or not the aircraft is safe on the ground.

Since most activations are false alarms, the ability to resolve them over the phone saves the AFRCC (i.e., U.S. taxpayers) millions of dollars. More importantly, it saves SAR assets for actual emergencies. If the AFRCC in unable to verify the aircraft is safe on the ground, they launch a Search and Rescue mission. This normally involves assigning the search to the USAF Auxiliary Civil Air Patrol and may include requesting assistance from the local SAR responders or law enforcement personnel.

The unique digital code of each 406 MHz beacon allows it to be associated with a particular aircraft. The registration contains information, such as tail number, home airport, type and color of aircraft, and several emergency points of contact. This provides rapid access to flight plans and other vital information. This can speed the search effort and can be the difference between life and death.

The parachute canopy and case can be employed to lay out a prominent marker to aid recognition from the air by other aircraft. Matches and a combustible material can provide flame for visibility by night and provide smoke that may be seen during daylight hours.

Navigation Equipment

Aviation charts help to navigate during flight and help pinpoint the location when an off-airport landing is made. Sectional charts have the most useful scale for cross-country soaring flights. Local road maps (with labeled roads) should be carried in the glider during all cross-country flights. Local road maps make it much easier to give directions to the ground crew, allowing them to arrive as promptly as possible. GPS coordinates also help the ground crew if they are equipped with a GPS receiver and appropriate charts and maps. Detailed GPS maps are commercially available and make GPS navigation by land easier for the ground crew.

Medical Equipment

Compact, commercially made medical or first aid kits are widely available. These kits routinely include bandages, medical tape, disinfectants, a tourniquet, matches, a knife or scissors, bug and snake repellent, and other useful items. Ensure that the kit contains medical items suitable to the environment in which the glider is operating. Stow the kit so it is secure from inflight turbulence but would be accessible to injured occupant(s)after an emergency landing, even if injured.

Stowage

Stowing equipment properly means securing all equipment to protect occupants and ensuring integrity of all flight controls and glider system controls. Items carried on board must be secured even in the event that severe inflight turbulence is encountered. Items must also remain secured in the event of a hard or off-field landing. No item carried in the glider should have any chance of becoming loose in flight to interfere with the flight controls. Stowed objects should be adequately secured to prevent movement during a hard landing.

Parachute

The parachute should be clean, dry, and stored in a cool place when not in use. It is imperative to keep the parachute free of contaminants to ensure the integrity the parachutes material. The parachute must have been inspected and repacked within the allowable time frame. The pilot is responsible for ensuring that the parachute meets with the required FAA inspection criteria.

Oxygen System Malfunctions

Oxygen is essential for flight safety at high altitude. If there is a suspected or detected failure in any component of the oxygen system, descend immediately to an altitude where supplemental oxygen is not essential for continued safe flight. Remember, the first sign of oxygen deprivation (hypoxia) is a sensation of apparent well-being. Problem-solving capability is diminished. If the pilot has been deprived of sufficient oxygen, even for a short interval, critical thinking capability has been compromised. Do not be lulled into thinking that the flight can safely continue at high altitude. Descend immediately and breathe normally at these lower altitudes for a time to restore critical oxygen to the bloodstream. Try to avoid hyperventilation, which prolongs diminished critical thinking capability. Give enough time to recover critical thinking capability before attempting an approach and landing.

For high altitude flights, such as a wave flight, the oxygen bailout bottle becomes a necessity. It should be in good condition and be within easy reach if a high altitude escape becomes necessary from the glider. Pilots need to be properly trained for an event requiring abandonment of a glider at a very high altitude, the use of oxygen, and proper use of a parachute at high altitudes.

Accident Prevention

The National Transportation Safety Board (NTSB) generates accident reports anytime a reportable soaring accident occurs. Any interested person can visit the website directly at www.ntsb.gov and look at the NTSB query database page to view summaries of both glider and towplane accidents. It is very important for all pilots to educate themselves on past accidents. In particular, they should look at the cause of the accident and how it could have been prevented. All too often accidents are caused from pilot error or equipment failure that, if trained and educated properly, the pilot could have reacted differently and saved a life, usually their own. The Soaring Safety Foundation is an excellent resource for pilots to educate themselves on glider safety and the website provides pilots with lessons learned information, as well as on-line safety learning. The Soaring Safety Foundation website is www.soaringsafety.org.

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Self-Launching Gliders (Part Two)

Filed Under: Abnormal and Emergency Procedures

Self-Launching Glider Propeller Malfunctions

Propeller failures include propeller damage and disintegration, propeller drive belt or drive gear failure, or failure of the variable blade pitch control system. To perform an air-driven engine restart, for example, many self-launching gliders require that the propeller blades be placed in a particular blade pitch position. If the propeller blades cannot be properly adjusted, then the propeller will not deliver enough torque to start the engine. The result is a failure to obtain an air-driven engine start.

Self-Launching Glider Electrical System Malfunctions

An electrical system failure in a self-launching glider may make it impossible to control the propeller pitch if the propeller is electrically controlled. It may also result in the inability to deploy a pod engine successfully for an air restart attempt. Self-launching gliders that require a functioning electric starter for an air restart are unable to resume flight under power. If an airport is within gliding range, an onairport precautionary landing can be made. If there is no airport within gliding range and the flight can be safely continued without electrical power, the pilot may be able to soar to the vicinity of an airport and land safely. If no airport is within gliding range and flight cannot be sustained without power, an emergency off-airport landing has to be made.

Some self-launching gliders are occasionally used for night flight, cruising under power. All night flights must be conducted in accordance with FAA regulation and the glider must have the appropriate aeronautical lighting required for night time operations (14 CFR part 91, section 91.209). If carrying a passenger(s), the pilot must be qualified to operate the glider at night in accordance with 14 CFR part 61, section 61.57(b).

If an electrical system failure occurs during night operations, pilots of nearby aircraft are not able to see the self-launching glider due to the extinguished position lights. Inside the cockpit, it is difficult or impossible to see the flight instruments or electrical circuit breakers. According to 14 CFR part 135, section 135.159(f), and part 121, section 121.549(b), the FAA requires that commercial and airline pilots have a flashlight “having at least two size D cells or equivalent” for such an emergency. It makes good practical sense for other pilots to follow the same rules.

If smoke or the smell of smoke is present, make no attempt to reset any circuit breakers. In accordance with CE-10- 11R, Special Airworthiness Information Bulletin, dated January 14, 2010, and available for download at http://rgl. faa.gov/Regulatory_and_Guidance_Library/rgSAIB.nsf/ (LookupSAIBs)/CE-10-11R1?OpenDocument, the best and safest practice is to not reset circuit breakers in the air unless absolutely necessary for safe flight. Resetting a circuit breaker may result in a greater overload and possible fire. [Figure 8-19] Head directly for the nearest airport and prepare for a precautionary landing there. Follow nighttime procedures and requirements. The aviation transceiver installed in the instrument panel may not function if electrical failure is total, so it is a good idea to have a portable batteryoperated aviation two-way radio onboard for use in such an emergency. It may be necessary to receive landing instruction by air traffic control (ATC) light-signal. Pilot should review 14 CFR part 91, section 125, and the Aeronautical Information Manual (AIM) section 4-2-13, Traffic Control Light Signals, for the proper response.

Figure 8-19. Self-launching glider circuit breakers.

In-flight Fire

An in-flight fire is the most serious emergency a pilot can encounter. If a fire has ignited, or if there is a smell of smoke or any similar smell, do everything possible to reduce the possibilities that the fire spreads and land as soon as possible. The self-launching glider GFM/POH is the authoritative source for emergency response to suspected in-flight fire. The necessary procedures are:

Reduce throttle to idle,
Shut off fuel valves,
Shut off engine ignition,
Land immediately and stop as quickly as possible, and
Evacuate the self-launching glider immediately.

After landing, distance yourself from the glider and try to stay upwind to avoid the harmful fumes. Keep onlookers away from the glider as well. The principal danger after evacuating the glider is fuel ignition and explosion, with the potential to injure personnel at a considerable distance from the glider.

CAUTION: Modern gliders are composed of composite materials and resins that can produce very poisonous fumes. The glider pilot should do whatever is necessary to avoid the fumes to include jettisoning of the canopy, which allows breathable air in and elimination of fumes from the cockpit. This same modern construction also means a fire can spread very quickly. A quick landing or abandoning the glider for a parachute landing may be the only option for the pilot. If the fire is spreading to the wings, bailout at a safe altitude may be the safest choice if the airframe will not last until the landing.

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Self-Launching Gliders (Part One)

Filed Under: Abnormal and Emergency Procedures

In addition to the standard flight control systems found on all gliders, self-launching gliders have multiple systems to support flight under power. These systems may include but are not limited to the following:

Fuel tanks, lines, and pumps
Engine and/or propeller extension and retraction systems
Electrical system including engine starter system
Lubricating oil system
Engine cooling system
Engine throttle controls
Propeller blade pitch controls
Engine monitoring instruments and systems

The complexity of these systems demands thorough familiarity with the GFM/POH for the self-launching glider being flown. Any malfunction of these systems can make it impossible to resume powered flight.

Self-Launching/Sustainer Glider Engine Failure During Takeoff or Climb

Engine failures are the most obvious source of equipment malfunction in self-launching gliders. Engine failures can be subtle (a very slight power loss at full throttle) or catastrophic and sudden (engine crankshaft failing during a full-power takeoff). High on the list of possible causes of power problems are fuel contamination and exhaustion.

To provide adequate power, the engine system must have fuel and ignition, as well as adequate cooling and lubrication. Full power operation is compromised if any of these requirements is not satisfied. Monitor the engine temperature, oil pressure, fuel pressure, and revolutions per minute (rpm) carefully to ensure engine performance is not compromised. Warning signs of impending difficulty include excessively high engine temperatures, abnormal engine oil temperatures, low oil pressure, low rpm despite high throttle settings, low fuel pressure, and erratic engine operation (surging, backfiring, and missing). Abnormal engine performance may be a precursor to complete engine failure. Even if total engine failure does not occur, operation with an engine that cannot produce full power translates into an inability to climb or perhaps an inability to hold altitude despite application of full throttle. The best course of action, if airborne, is to make a precautionary landing first and then discover the source of the trouble.

Regardless of the type of engine failure, the pilot’s first responsibility is to maintain flying airspeed and adequate control of the glider. If power failure occurs, lower the nose as necessary to maintain adequate airspeed. Pilots flying self-launching gliders with a pod-mounted external engine above the fuselage need to lower the nose much more aggressively in the event of total power loss than those with an engine mounted in the nose. In the former, the thrust of the engine during full power operations tends to provide a nose-down pitching moment. If power fails, the nose-down pitching moment disappears and is replaced by a nose-up pitching moment due to the substantial parasite drag of the engine pod high above the longitudinal axis of the fuselage. Considerable forward motion on the control stick may be required to maintain flying airspeed. If altitude is low, there is not enough time to stow the engine and reduce the drag that it creates. Land the glider with the engine extended. Glide ratio in this configuration is poor due to the drag of the extended engine and propeller. The authoritative source for information regarding the correct sequence of pilot actions in the event of power failure is contained in the GFM/POH. The pilot must be thoroughly familiar with its contents to operate a self-launching glider safely.

If the power failure occurs during launch or climb, time to maneuver may be limited. Concentrate on flying the glider and selecting a suitable landing area. Remember that the high drag configuration of the glider may limit the distance of the glide without power. Keep turns to a minimum and land the glider as safely as possible. Do not try to restart the engine while at very low altitude because it distracts from the primary task of maintaining flying airspeed and making a safe precautionary landing. Even if power in the engine system were restored, chances are that full power is not available. The problem that caused the power interruption in the first place is not likely to solve itself while trying to maneuver from low altitude and climb out under full power. If the problem recurs, as it is likely to do, the pilot may place the glider low over unlandable terrain with limited gliding range and little or no engine power to continue the flight. Even if the engine continues to provide limited power, flight with partial power may quickly put the glider in a position in which the pilot is unable to clear obstacles, such as wires, poles, hangars, or nearby terrain. If a full power takeoff or climb is interrupted by power loss, it is best to make a precautionary landing. The pilot can sort out the power system problems after returning safely to the ground.

Inability to Restart a Self-Launching/Sustainer Glider Engine While Airborne

Power loss during takeoff roll or climb are serious problems, but they are not the only types of problems that may confront the pilot of a self-launching glider. Other engine failures include an engine that refuses to start in response to airborne start attempts. This is a serious problem if the terrain below is unsuitable for a safe off-field landing.

One of the great advantages of the self-launching glider is having the option to terminate a soaring flight by starting the engine and flying to an airport/gliderport for landing. Nearly all self-launching gliders have a procedure designed to start the engine while airborne. This procedure would be most valuable during a soaring flight with engine off during which the soaring conditions have weakened. The prospect of starting the engine and flying home safely is ideal under such conditions.

As a precaution, an airborne engine start should be attempted at an altitude high enough that, if a malfunction occurs, there is sufficient time to take corrective action. If the engine fails to start promptly, or fails to start at all, there may be little time to plan for a safe landing. If there is no landable area below, then failure to start the engine results in an emergency off-field landing in unsuitable terrain. Glider damage and personal injury may result. To avoid these dangers, selflaunching glider pilots should never allow themselves to get into a situation that can only be resolved by starting the engine and flying up and away. It is best to keep a landable field always within easy gliding range.

There are many reasons that a self-launching glider engine may fail to start or fail to provide full power in response to efforts to resume full power operations while airborne. These include lack of fuel or ignition, low engine temperature due to cold soak, low battery output due to low temperatures or battery exhaustion, fuel vapor lock, lack of propeller response to blade pitch controls, and other factors. It is important for the pilot to have an emergency plan in the event that full engine power is not available during any phase of flight.

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Miscellaneous Flight System Malfunctions

Filed Under: Abnormal and Emergency Procedures

Towhook Malfunctions

Towhooks can malfunction as can any other mechanical device. Failure modes include uncommanded towline release and failure to release on command. Pilots must be prepared to abort any towed launch, whether ground or aerotow launch, at any time. Uncommanded towline release must be anticipated prior to every launch. Assess the wind and the airport environment, and then form an emergency plan prior to launch. If the towhook fails to release on command, try to release the towline again after removing tension from the line. Pull the release handle multiple times under varying conditions of towline tension. If the towline still cannot release, alert the towpilot and follow the emergency procedures described in Flight Maneuvers and Traffic Patterns.

Oxygen System Malfunctions

Oxygen is essential for flight safety at high altitude. If there is a suspected or detected failure in any component of the oxygen system, descend immediately to an altitude at which supplemental oxygen is not essential for continued safe flight. Remember, the first sign of oxygen deprivation is a sensation of apparent well-being. Problem-solving capability is diminished. If the pilot has been deprived of sufficient oxygen, even for a short interval, critical thinking capability has been compromised. Do not be lulled into thinking that the flight can safely continue at high altitude. Descend immediately and breathe normally at these lower altitudes for a time to restore critical oxygen to the bloodstream. Try to avoid hyperventilation, which prolongs the diminished critical thinking capability. Give enough time to recover critical thinking capability before attempting an approach and landing.

Drogue Chute Malfunctions

Some gliders are equipped with a drogue chute to add drag during the approach to land. This drag supplements the drag provided by the spoilers/dive brakes. The drogue chute is packed and stowed in the aft tip (tail cone) of the fuselage or in a special compartment in the base of the rudder. Drogue chutes are very effective when deployed properly and make steep approaches possible. The drogue chute is deployed and jettisoned on pilot command, such as would be necessary if the drag of the glider was so great that the glider would not otherwise have the range to make it to the spot of intended landing. There are several failure modes for drogue chutes. If it deploys accidentally or inadvertently during the launch, the rate of climb seriously degrades and it must be jettisoned. During the approach to land, an improperly packed or damp drogue chute may fail to deploy on command. If this happens, use the rudder to sideslip for a moment, or use the rudder to yaw the tail back and forth. Make certain to attain safe flying speed before attempting the slip or yawing motion. Either technique increases the drag force on the drogue chute compartment that pulls the parachute out of the compartment.

If neither technique deploys the drogue chute, the drogue canopy may deploy at a later time during the approach without further control input from the pilot. This results in a considerable increase in drag. If this happens, be prepared to jettison the drogue chute immediately if sufficient altitude to glide to the intended landing spot has not been reached.

Another possible malfunction is failure of the drogue chute to inflate fully. If this happens, the canopy “streams” like a twisting ribbon of nylon, providing only a fraction of the drag that would occur if the canopy had fully inflated. Full inflation is unlikely after streaming occurs, but if it does occur, drag increases substantially. It is much better to fly with a known drag configuration and adjust for it rather than be faced with a substantially increased drag coefficient at a place and time where a safe landing is no longer possible. If in doubt regarding the degree of deployment of the drogue chute, the safest option may be to jettison the drogue. Regardless of the malfunction type, the pilot should review approach and landing options for the drogue chute conditions.

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Glider System and Equipment Malfunctions (Part Three)

Filed Under: Abnormal and Emergency Procedures

Aileron Malfunctions

Aileron failures can cause serious control problems. Causes of aileron failure include:

Improper connection of the aileron control circuit during assembly.
Aileron control lock that was not removed before flight.
Separation of the aileron gap seal tape.
Interference of a foreign object with free and full travel of the control stick or aileron circuit.
Seat belt or shoulder harness in the back seat that was used to secure the control stick and not removed prior to flight.
Structural failure and/or aileron flutter.

These failures can sometimes be counteracted successfully, partly because there are two ailerons. If one aileron is disconnected or locked by an external control lock, the degree of motion still available in the other aileron may exert some influence on bank angle control. Use whatever degree of aileron is available to maintain control of the glider. The glider may be less difficult to control at medium to high airspeeds than at low airspeeds.

If the ailerons are not functioning adequately and roll control is compromised, the secondary effect of the rudder can be used to make gentle adjustments in the bank angle so long as a safe margin above stall speed is maintained. The primary effect of the rudder is to yaw the glider. The secondary effect of the rudder is subtler and takes longer to assert itself. In wings-level flight, if left rudder is applied, the nose yaws to the left. If the pressure is held, the wings begin a gentle bank to the left. If right rudder pressure is held and applied, the glider yaws to the right, then begins to bank to the right. This secondary banking effect by the rudder is useful if the pilot must resort to using the rudder to bank the glider wings. The secondary effect of the rudder works best when the wings are level or held in a very shallow bank, and is enhanced at medium to high airspeeds. Try to keep all banks very shallow. If the bank angle becomes excessive, it is difficult or impossible to recover to wings-level flight using the rudder alone. If the bank is becoming too steep, use any aileron influence available, as well as all available rudder to bring the wings back to level. If a parachute is available and the glider becomes uncontrollable at low airspeed, the best chance to escape serious injury may be to bail out of the glider from a safe altitude.

Rudder Malfunctions

Rudder failure is extremely rare because removing and installing the vertical fin/rudder combination is not part of the normal sequence of rigging and de-rigging the glider (as it is for the horizontal stabilizer/elevator and for the wing/aileron combinations). Poor directional control is so obvious to the pilot from the very beginning of the launch that, if rudder malfunction is suspected, the launch can be aborted early.

Rudder malfunctions are most likely to occur after failure to remove the rudder control lock prior to flight or when an unsecured object in the cockpit interferes with the free and full travel of the rudder pedals. Preflight preparation must include removal of all flight control locks and safe stowage of all items on board. The pretakeoff checklist includes checking all primary flight controls for correct, full travel prior to launch.

Although rudder failure is quite rare, the consequences are serious. If a control lock causes the problem, it is possible to control the glider airspeed and bank attitude, but directional control is compromised due to limited rudder movement. In the air, some degree of directional control can be obtained by using the adverse yaw effect of the ailerons to yaw the glider. During rollout from an aborted launch or during landing rollout, directional control can sometimes be obtained by deliberately grounding the wingtip toward the direction of desired yaw. Putting the wingtip on the ground for a fraction of a second causes a slight yaw in that direction; holding the wingtip firmly on the ground usually causes a vigorous yaw or ground loop in the direction of the grounded wingtip.

Careless stowage of cockpit equipment can result in rudder pedal interference at any time during a flight. During flight, if an object is interfering with or jamming the rudder pedals, attempt to remove it. If removal is not possible, attempt to deform, crush, or dislodge the object by applying force on the rudder pedals. It also may be possible to dislodge the object by varying the load factor, but ensure that dislodging the object does not result in its lodging in a worse place where it could jam the elevator or aileron controls. If the object cannot be retrieved and stowed, a precautionary landing may be required.

Commonly misplaced objects that can cause flight control interference include:

Water bottles,
Cameras,
Electronic computers,
Containers of food and similar items,
Clothing, and
Sunglasses.

Control these items by proper planning and good cockpit discipline.

Secondary Flight Controls Systems

Secondary flight control systems include the elevator trim system, wing flaps, and spoilers/dive brakes. Problems with any of these systems can be just as serious as problems with primary controls.

Elevator Trim Malfunctions

Compensating for a malfunctioning elevator trim system is usually as simple as applying pressure on the control stick to maintain the desired pitch attitude, then bringing the flight to safe conclusion. Inspect and repair the trim system prior to the next flight.

Spoiler/Dive Brake Malfunctions

Spoiler/dive brake system failures can arise from rigging errors or omissions, environmental factors, and mechanical failures. Interruptions or distractions during glider assembly can result in failure to properly connect control rods to one or both spoilers/dive brakes. Proper use of a comprehensive checklist reduces the likelihood of assembly errors. If neither of these spoilers/dive brakes is connected, then one or both of the spoilers/dive brakes may deploy at any time and retraction becomes impossible. This is a very hazardous situation for several reasons. One reason is that the spoilers/ dive brakes are likely to deploy during the launch or the climb, causing a launch emergency and a possible tow failure incident. Another reason is that the spoilers/dive brakes might deploy asymmetrically: one spoiler/dive brake retracted and the other spoiler/dive brake extended, resulting in yaw and roll tendencies that do not arise when the spoilers/dive brakes deploy symmetrically. A pilot expecting a smooth ,symmetrical deployment would be faced with a control issue that compromises flight safety. Finally, it is not possible to correct the situation by retracting the spoiler/dive brake(s) because the failure to connect the controls properly usually means that pilot control of the spoiler/dive brake has been lost.

If asymmetrical spoiler/dive brake extension occurs and the extended spoiler/dive brake cannot be retracted, several choices must be made. Roll and yaw tendencies due to asymmetry must be overcome or eliminated. One way to solve this problem is to deploy the other spoiler/dive brake to restore the symmetry. The advantages include immediate relief from yaw and roll tendencies and protection against stalling with one spoiler/dive brake extended and the other retracted, which could result in a spin. The disadvantage of deploying the other spoiler/dive brake is that the glide ratio is reduced. If the spoiler/dive brake asymmetry arises during launch or climb, the best choice is to abort the launch, extend the other spoiler/dive brakes to relieve the asymmetry, and make a precautionary or emergency landing.

Environmental factors include low temperature or icing during long, high altitude flights, which may occur during a mountain wave flight. Low temperature causes contraction of all glider components. If the contraction is uneven, the spoilers/dive brakes may bind and be difficult or impossible to deploy. Icing can also interfere with operation of the spoilers/ dive brakes. High temperature, on the other hand, causes all glider components to expand. If the expansion is uneven, the spoilers/dive brakes may bind in the closed position. This is most likely to occur while the glider is parked on the ground in direct summer sunlight. The heating can be very intense, particularly for a glider with wings painted a color other than reflective white.

Mechanical failures can cause asymmetrical spoiler/dive brake extension. For example, the spoiler/dive brake extend normally during the prelanding checklist but only one spoiler/dive brake retracts on command. The other spoiler/dive brake remains extended, due perhaps to a broken weld in the spoiler/dive brake actuator mechanism, a defective control connector, or other mechanical failure. The glider yaws and banks toward the wing with the extended spoiler/dive brake. Aileron and rudder are required to counteract these tendencies. To eliminate any possibility of entering a stall/spin, maintain a safe margin above stall airspeed. If the decision to deploy the other spoiler/ dive brake is made to relieve the asymmetry, controlling the glider becomes much easier but gliding range is reduced due to the additional drag of the second spoiler/dive brake. This may be a significant concern if the terrain is not ideal for landing the glider. Nevertheless, it is better to make a controlled landing, even in less than ideal terrain, than it is to stall or spin.

Flight Literacy Recommends

Glider System and Equipment Malfunctions (Part Two)

Filed Under: Abnormal and Emergency Procedures

Water Ballast Malfunctions

Water ballast systems are relatively simple and major failures are not very common. Nevertheless, ballast system failures can threaten the safety of flight. One example of ballast failure is asymmetrical tank draining (one wing tank drains properly but the other wing tank does not). The result is a wing-heavy glider that may be very difficult to control during slow flight and during the latter portion of the landing rollout. Another example is leakage. Some water ballast systems drain into a central pipe that empties through the landing gear wheel well. If the drain connections from either wing leak significantly, water from the tanks can collect in the fuselage. If the water flows far forward or far aft in the fuselage, pitch control of the glider may be severely degraded. Pitch control can be augmented by flying at mid to high airspeeds, giving the elevator more control authority to correct for the out-ofbalance situation, and affording time to determine whether the water can be evacuated from the fuselage. If pitch control is dangerously degraded, abandoning the glider may be the safest choice. The best prevention for water ballast problems is regular maintenance and inspection combined with periodic tests of the system and its components.

Retractable Landing Gear Malfunctions

Landing gear difficulties can arise from several causes. Landing gear failures arising from mechanical malfunction of the gear extension mechanism generally cannot be resolved during flight. Fly the approach at normal airspeed. If the landing gear is not extended, the total drag of the glider is less than it is normally during an approach with the landing gear extended. It may be necessary to use more spoiler/dive brake than normal during the approach. Try to land on the smoothest surface available, preferably an area that has good turf to help reduce the damage to the glider. The landing must be under control and as soft as possible. Slightly above stall speed soft touchdowns are preferable to full stall landings resulting in hard landings. This helps avoid a tailwheel first landing, and a hard touchdown of the glider onto the runway. Avoiding the hard touchdown helps to avoid injury and lessen damage to the glider components.

The glider makes considerable noise as it slides along the runway, and wingtip clearance above the ground is reduced. Keep the wings level for as long as possible. Try to keep the glider going as straight as possible using the rudder to guide the glider. The primary goal is to avoid collision with objects on the ground or along the runway border, including runway lighting and signage. Accept the fact that minor skin damage to the glider is inevitable if the gear cannot be extended and locked. Concentrate on personal safety during the approach and landing. Any damage to the glider can be repaired after an injury-free landing.

Primary Flight Control Systems

Failure of any primary flight control system presents a serious threat to safety. The most frequent cause of control system failure is incomplete assembly of the glider in preparation for flight. To avoid this, use a written checklist to guide each assembly operation and inspect every connection and safety pin thoroughly. Do not allow interruptions during assembly. If interruption is unavoidable, start the checklist again from the very beginning. Perform a positive control check with the help of a knowledgeable assistant. Do not assume that any flight surface and flight control is properly installed and connected during the post-assembly inspection. Instead, assume that every connection is suspect. Inspect and test until certain that every component is ready for flight.

Elevator Malfunctions

The most serious control system malfunction is a failure of the elevator flight control. Causes of elevator flight control failure include the following:

An improper connection of the elevator control circuit during assembly.
An elevator control lock that was not removed before flight.
Separation of the elevator gap seal tape.
Interference of a foreign object with free and full travel of the control stick or elevator circuit.
A lap belt or shoulder harness in the back seat that was used to secure the control stick and not removed prior to flight.
A structural failure of the glider due to overstressing or flutter.

To avoid a failure, ensure that control locks are removed prior to flight, that all flight control connections have been completed properly and inspected, and that all safety pins have been installed and latched properly. Ensure that a positive control check against applied resistance has been performed.

If the elevator irregularity or failure is detected early in the takeoff roll, release the towline (or reduce power to idle), maneuver the glider to avoid obstacles, and use the brakes firmly to stop the glider as soon as possible. If the elevator control irregularity or failure is not noticed until after takeoff, a series of complicated decisions must be made quickly. If the glider is close to the ground and has a flat or slightly nose-low pitch attitude, releasing the towline (or reducing power to zero) is the best choice. If this is an aerotow launch, consider the effect the glider has on the safety of the tow pilot. If there is sufficient elevator control during climb, then it is probably best to stay with the launch and achieve as high an altitude as possible. High altitude gives more time to abandon the glider and deploy a parachute, if worn.

If the decision is to stay with the glider and continue the climb, experiment with the effect of other flight controls on the pitch attitude of the glider. These include the effects of various wing flap settings, spoilers/dive brakes, elevator trim system, and raising or lowering the landing gear. If flying a self-launching glider, experiment with the effect of power settings on pitch attitude.

If aileron control is functioning, bank the glider and use the rudder to moderate the attitude of the nose relative to the horizon. When the desired pitch attitude is approached, adjust the bank angle to maintain the desired pitch attitude. Forward slips may have a predictable effect on pitch attitude and can be used to moderate it. Usually, a combination of these techniques is necessary to regain some control of pitch attitude. While these techniques may be a poor substitute for the glider elevator itself, they are better than nothing. If an altitude sufficient to permit bailing out and using a parachute is achieved, chances of survival are good because parachute failures are exceedingly rare.

Elevator gap seal tape, if in poor condition, can degrade elevator responsiveness. If the adhesive that bonds the gap seal leading edge to the horizontal stabilizer begins to fail, the leading edge of the gap seal may be lifted up by the relative wind. This provides, in effect, a small spoiler that disturbs the airflow over the elevator just aft of the lifted seal. Elevator blanking that occurs across a substantial portion of the span of the elevator seriously degrades pitch attitude control. In extreme cases, elevator authority may be compromised so drastically that the glider elevator is useless.

The pilot may be forced to resort to alternate methods to control pitch attitude as described above. Bailing out may be the safest alternative. Inspection of the gap seal bonds for all flight control surfaces prior to flight is the best prevention.

Flight Literacy Recommends

Glider System and Equipment Malfunctions (Part One)

Filed Under: Abnormal and Emergency Procedures

Flight Instrument Malfunctions

Instrument failures can result from careless maintenance practices and from internal or external causes. An example of careless maintenance is removal and replacement of the airspeed indicator but failure to connect the instrument correctly to pitot and static lines. A pitot tube clogged by insects or water ingress is an example of an external cause of instrument failure.

Pilots should always be aware of the glider’s normal attitudes for all flight regimes. Then, when presented with an instrument failure or erroneous indication, the pilot has a general sense of the glider’s normal attitude from outside flying cues to make a safe return and landing. Judging the altitude or airspeed of the glider without the guidance of instruments should not constitute a panic in the cockpit as many pilots can make precision approaches and landings without the use of an altimeter. In fact, many older and vintage gliders do not require an operational altimeter in the cockpit.

Airspeed Indicator Malfunctions If the airspeed indicator appears to be erratic or inaccurate, fly the glider by pitch attitude. Keep the nose of the glider at the proper pitch attitude for best glide or minimum sink airspeed. Additional cues to airspeed include control “feel” and wind noise. At very low airspeeds, control feel is very mushy and wind noise is generally low. At higher airspeeds, control feel is crisper and wind noise takes on a more insistent hissing quality. The sound of the relative wind can be amplified and made more useful in airspeed control by opening the sliding window installed in the canopy and by opening the air vent control. During the landing approach, maintain adequate airspeed using cues other than the airspeed indicator. Fly the approach with an adequate margin above stall airspeed. If conditions are turbulent or the wind is gusty, additional airspeed is necessary to penetrate the convection and to ensure adequate control authority. If in doubt, it is better to be flying 10 knots faster than optimum airspeed than it is to be 10 knots slower.

Altimeter Malfunctions

Altimeter failure may result from internal instrument failure or from external causes, such as water ingress in the static lines. Regardless of the cause, it is important to maintain sufficient altitude to allow a safe glide to a suitable landing area. During the approach to land without a functioning altimeter, it is necessary to rely on perception of maintaining a safe gliding angle to the target landing area. The primary risk to safety is entering the approach from an altitude that is lower than normal. It is better to enter the approach from a normal height, or even from a higher-than-normal height. During the approach, judge the angle to the target area frequently. If the angle is too steep, apply spoilers/ dive brakes to steepen the descent path. If necessary, apply a forward slip or turning slip to lose additional altitude. If the approach angle is beginning to appear shallow, close the spoilers/dive brakes and, if necessary, modify the approach path to shorten the distance necessary to glide to make it to the target landing area.

Static line contamination affects both the altimeter and the airspeed indicator. If it is suspected that either instrument is malfunctioning because of static line contamination, remember that the indications of the other instrument(s) connected to the static line may also be incorrect. Use the external cues described above to provide multiple crosschecks on the indications of all affected instruments. If in doubt about the accuracy of any instrument, it is best to believe the external cues and disregard the instrument indications. After landing and prior to the next flight, have an aviation maintenance professional evaluate the instrument system.

It is essential that a glider pilot be familiar with the procedures for making a safe approach without a functioning airspeed indicator or altimeter. Being accompanied by a glider flight instructor during the flight review provides an excellent opportunity to review these procedures.

Variometer Malfunctions

Variometer failure can make it difficult for the pilot to locate and exploit sources of lift. If an airport is nearby, a precautionary landing should be made so the source of the problem can be uncovered and repaired. If no airport is nearby, search for clues to sources of lift. Some clues may be external, such as a rising smoke column, a cumulus cloud, a dust devil, or a soaring bird. Other sources are internal, such as the altimeter. Use the altimeter to gauge rate of climb or descent in the absence of a functioning variometer. Tapping the altimeter with the forefinger often overcomes internal friction in the altimeter, allowing the hand to move upward or downward. The direction of the movement gives an idea of the rate of climb or descent over the last few seconds. When lift is encountered, stay with it and climb.

Compass Malfunctions

Compass failure is rare, but it does occur. If the compass performs poorly or not at all, cross-check current position with aeronautical charts and with electronic methods of navigation, such as GPS, if available. The position of the sun, combined with knowledge of the time of day, can help with orientation also. Being familiar with section lines and major roads often provides helpful cues to orientation and the direction of flight.

Glider Canopy Malfunctions

Glider Canopy Opens Unexpectedly

Canopy-related emergencies are often the result of pilot error. The most likely cause is failure to lock the canopy in the closed position prior to takeoff. Regardless of the cause, if the canopy opens unexpectedly during any phase of flight, the first duty is to fly the glider. It is important to maintain adequate airspeed while selecting a suitable landing area.

If the canopy opens while on aerotow, it is vital to maintain a normal flying attitude to avoid jeopardizing the safety of the glider occupants and the safety of the towplane pilot. Only when the glider pilot is certain that glider control can be maintained should any attention be devoted to trying to close the canopy. If flying a two-seat glider with a passenger on board, fly the glider while the other person attempts to close and lock the canopy. If the canopy cannot be closed, the glider may still be controllable. Drag is higher than normal; when flying the approach, plan a steeper-than-normal descent path. The best prevention against unexpected opening of the canopy is proper use of the pretakeoff checklist.

Broken Glider Canopy

If the canopy is damaged or breaks during flight, the best response is to land as soon as practicable. Drag increases if the canopy is shattered, so plan a steeper-than-normal descent path during the approach.

Frosted Glider Canopy

Extended flight at high altitude or in low ambient temperatures may result in obstructed vision as moisture condenses as frost on the inside of the canopy. Open the air vents and the side window to ventilate the cabin and to evacuate moist air before the moisture can condense on the canopy. Descend to lower altitudes or warmer air to reduce the frost on the canopy. Flight in direct sunlight helps diminish the frost on the canopy.

Flight Literacy Recommends

Off-Field Landing Procedures (Part One) – After Landing Off-Field

Filed Under: Abnormal and Emergency Procedures

Off-Field Landing Without Injury

If uninjured, tend to personal needs and then secure the glider. Make contact with the retrieval crew or emergency crew as promptly as possible. If the wait is likely to be long, use the daylight to remove all items necessary for darkness and cold. It is worth remembering that even a normal retrieval can take many hours if the landing was made in difficult terrain or in an area served by relatively few roads. If cellular service is available, use a cell phone to call 911 if you are concerned about personal safety. Glider pilots should always consider alternate means of communication to include satellite telephones and ham radios as cell phone service is not always available. To help identify position, relay the GPS coordinates, if available, to ease the job for the retrieval crew or rescue personnel. It is a good idea to write down the GPS coordinates if the GPS battery is exhausted or if the GPS receiver shuts down for any reason. Use the glider two-way radio to broadcast needs on the international distress frequency 121.5 MHz. Many aircraft, including civil airliners, routinely monitor this frequency. Their great height gives the line-of-sight aviation transceiver tremendous range when transmitting to, or receiving from, these high-altitude aircraft. Calling other glider pilots in the area on the glider-to-glider radio frequency can hasten retrieval or rescue. Another tool for pilots is the personal locator device offered by several companies as a rescue device. These devices use the 406 MHz satellite signal, and global positioning system (GPS) technology to accurately track and relay the pilot’s location in the event of an off-field landing requiring assistance.

Once contact has been made with outsiders to arrange for retrieval, attend to minor items, such as collecting any special tools that are needed for glider derigging or installing gust locks on the glider’s flight controls.

Off-Field Landing With Injury

If injured, tend to critical injuries first. At the first opportunity, make contact with emergency response personnel, with other aircraft, or any other source of identifiable assistance. Use the glider radio, if operable, to broadcast a Mayday distress call on emergency frequency 121.5 MHz. Also, try any other frequency likely to elicit a response. Some gliders have an Emergency Locator Transmitter (ELT) on board. If the glider is equipped with an ELT and assistance is needed, turn it on. The ELT broadcasts continuous emergency signals on 121.5 MHz. Search aircraft can hone in on this ELT signal using radio equipment designed for search and rescue (SAR). These SAR-equipped aircraft reduce the time spent searching for the pilot’s exact location. To transmit a voice message on an operable two-way radio at 121.5 MHz, turn the ELT switch to OFF for the voice message to be heard. The newer ELTs, like the 406 MHz Emergency Position Indicating Radio Beacons (EPIRBs), are becoming more popular because of their substantial benefits. Only ATC ground stations routinely monitor 121.5 MHz anymore and that is line-of-sight reception only. The newer EPIRBs have stronger signals, transmit longer, and are monitored by the satellite network. According to CFR part 91, gliders are not airplanes and therefore old very high frequency (VHF) ELTs are not required, which is why an EPIRB would make a much better choice when flying a glider. If mobile (cell) phone coverage is available, dial 911 to contact emergency personnel. If possible, include a clear description of the location. If the glider is in a precarious position, secure it, if possible, but do not risk further personal injury in doing so. If it is clearly unsafe to stay with the glider, move to a nearby location for shelter but leave clear written instructions in a prominent location in the glider detailing where to find you.

It is best to stay with the glider if at all possible. The glider bulk is likely to be much easier to locate from the air than is an individual person. The pilot might obtain a measure of protection from the elements by crawling into the fuselage or crawling under a wing, or using the parachute canopy to rig a makeshift tent around the glider structure. After attending to medical needs and contacting rescue personnel, attend to clothing, food, and water issues. The pilot should make every attempt to conserve energy.

Flight Literacy Recommends

Off-Field Landing Procedures (Part One)

Filed Under: Abnormal and Emergency Procedures

The possibility of an off-field landing is present on virtually every cross-country soaring flight, even when flying in a self-launching glider. If the engine or power system fails and there is no airport within gliding range, an off-field landing may be inevitable. It should be noted that many glider pilots not flying cross-country have faced the necessity of performing an off-field landing. Causes of off-field landings while soaring in the vicinity of the launching airport, include rapid weather deterioration, a significant change in wind direction, unanticipated amounts of sinking air, disorientation, lack of situational awareness, tow failures, and other emergencies requiring an off-field landing. In these situations, it usually is safer to make a precautionary off-field landing than it is to attempt a low, straight-in approach to the airport. If the glide back to the airport comes up short for any reason, the landing is likely to be poorly executed and may result in damage to the glider or injury to the pilot.

On cross-country soaring flights, off-field landings are not usually considered emergency landings. As a matter of fact, they are expected and are considered while preparing for flight. On the other hand, if equipment failure leads to the necessity of performing an off-field landing, then the landing can be characterized or described as an emergency landing. Whatever the reason for the off-field landing, each glider pilot must be prepared at all times to plan and execute the landing safely.

Unlike airport landings, no off-field landing is entirely routine. An extra measure of care must be undertaken to achieve a safe outcome. The basic ingredients for a successful off-field landing are awareness of wind direction, wind strength at the surface, and approach path obstacles. The glider pilot must be able to identify suitable landing areas, have the discipline to select a suitable landing area while height remains to allow sufficient time to perform a safe approach and landing, and the ability to make consistently accurate landings in the glider type being flown.

These basic ingredients for a successful off-field landing can be summarized as follows:

Recognizing the possibility of imminent off-field landing.
Selecting a suitable area, then a suitable landing field within that area.
Planning the approach with wind, obstacles, and local terrain in mind.
Executing the approach, land, and then stopping the glider as soon as possible.
Attempting to contact ground crew and notifying them of off-field landing location.

The most common off-field landing planning failure is denial. The pilot, understandably eager to continue the flight and return to an airport, is often reluctant to initiate planning for an off-field landing because, in the pilot’s mind, to do so probably results in such a landing. It would be better, the pilot thinks, to concentrate on continuing the flight and finding a way to climb back up and fly away. The danger of this false optimism is that there is little or no time to plan an off-field landing if the attempt to climb away does not succeed. It is much safer to thoroughly understand the techniques of planning an off-field landing and to be prepared for the occurrence at any time.

Wind awareness, knowing wind direction and intensity, is key when planning an off-field landing. Flying downwind offers a greater geographical area to search than flying upwind. The tailwind during downwind cruise results in a greater range; a headwind during upwind cruise reduces the range. Wind awareness is also essential to planning the orientation and direction of the landing approach. Visualize the wind flowing over and around the intended landing area. Remember that the area downwind of hills, buildings, and other obstructions will probably be turbulent at low altitude. Also, be aware that landing into wind shortens landing rolls.

Decision heights are altitudes at which pilots take critical steps in the off-field landing process. If the terrain below is suitable for landing, select a general area no lower than 2,000 feet above ground level (AGL). Select the intended landing field no lower than 1,500 feet AGL. At 1,000 feet AGL, commit to flying the approach and landing off field. If the terrain below is not acceptable for an off-field landing, the best course of action is to move immediately toward more suitable terrain.

For many pilots, there is a strong temptation during the off-field landing process to select a landing location based primarily on the ease of glider retrieval. The convenience of an easy retrieval is of little consequence if the landing site is unsuitable and results in damage to the glider or injury to the pilot. Select the landing site with safety as the highest priority. During an off-field landing approach, the precise elevation of the landing site is usually unavailable to the pilot. This renders the altimeter more or less useless. Fly the approach and assess the progress by recognizing and maintaining the angle that puts the glider at the intended landing spot safely. If landing into a strong headwind, the approach angle is steep. If headwind is light or nonexistent, the approach angle is shallower unless landing over an obstacle. When landing with a tailwind (due to slope or one-way entry into the selected field due to terrain or obstacles), the angle is shallower. Remember to clear each visible obstacle with safe altitude, clearing any poles and wires by a safe margin. Always keep in mind that from the air, wires are basically invisible until they are right in front of you, whereas towers are visible from a distance. Any time there are two supporting structures (telephone poles) it is safe to assume that there are wires connecting them.

Select a field of adequate length and, if possible, one with no visible slope. Any slope that is visible from the air is likely to be steep. Slope can often be assessed by the color of the land. High spots often are lighter in color than low spots because soil moisture tends to collect in low spots, darkening the color of the soil. If level landing areas are not available and the landing must be made on a slope, it is better to land uphill than downhill. Even a slight downhill grade during landing flare allows the glider to float prior to touchdown, which may result in collision with objects on the far end of the selected field.

Knowledge of local vegetation and crops is also very useful. Tall crops are generally more dangerous to land in than low crops. Know the colors of local seasonal vegetation to help identify crops and other vegetation from the air. Without exception, avoid discontinuities such as lines or crop changes. Discontinuities usually exist because a fence, ditch, irrigation pipe, or some other obstacle to machinery or cultivation is present. Other obstacles may be present in the vicinity of the chosen field. Trees and buildings are easy to spot, but power and telephone lines and poles are more difficult to see from pattern altitude. Take a careful look around to find them. Assume every pole is connected by wire to every other pole. Also assume that every pole is connected by wire to every building, and that every building is connected by wire to every other building. Plan the approach to overfly the wires that may be present, even if you cannot see them. The more visible the landing area is during the approach, the fewer unpleasant surprises there are likely to be.

The recommended approach procedure is to fly the following legs in the pattern:

Crosswind leg on the downwind side of the field
Upwind leg
Crosswind leg on the upwind side of the field
Downwind leg
Base leg
Final approach

This approach procedure provides the opportunity to see the intended landing area from all sides. Use every opportunity while flying this approach to inspect the landing area and look for obstacles or other hazards. [Figure 8-18]

Figure 8-18. Off-field landing approach.

Landing over an obstacle or a wire requires skill and vigilance. The first goal in landing over an obstacle is to clear the obstacle! Next, consider how the obstacle affects the length of landing area that is actually going to be available for touchdown, roll out, and stopping the glider. If an obstacle is 50 feet high, the first 500 feet or so of the landing area needs to be overflown during the descent to flare and land. If the field selected has obstacles on the final approach path, remember that the field must be long enough to accommodate the descent to flare altitude after clearing the obstacle.

Hold the glider off during the flare and touch down at the lowest safe speed manageable. After touchdown, use the wheel brake immediately and vigorously to stop the glider as soon as possible. Aggressive braking helps prevent collision with small stakes, ditches, rocks, or other obstacles that cannot easily be seen, especially if the vegetation in the field is tall.