Maintenance. The upkeep of equipment, including preservation, repair, overhaul, and the replacement of parts.
Maintenance Manual. A set of detailed instructions issued by the manufacturer of an aircraft, engine, or component that
describes the way maintenance should be performed.
Maintenance Release. A release, signed by an authorized inspector, repairman, mechanic, or pilot after work has been
performed, stating that an aircraft or aircraft part has been approved for return to service. The person releasing the aircraft
must have the authority appropriate to the work being signed off.
Master tank. The propane tank, usually tank number one, that offers all appropriate services, such as liquid, vapor, and
backup system.
Maximum allowable gross lift. The maximum amount of weight that a balloon may lift under standard conditions. Usually
a part of the balloon’s design criteria, and may be found on the type Certificate Data Sheet for that particular balloon.
METAR. In weather, an acronym for Aviation Routine Weather Report, which is an observation of current surface reported
in the standard international format. Routine METARs are transmitted hourly; there is a special report (as indicated by the
acronym “SPECI”) that may be issued at any time for rapidly changing weather conditions.
Metering valve. A valve on a balloon heater that can be set to allow propane to pass through at a specific rate.
Methanol. A type of alcohol, usually fermented from wood, required by most balloon manufacturers to be introduced into
propane tanks annually to adsorb, and thus eliminate, small quantities of water from the fuel.
Mildew. A gray or white parasite fungus which, under warm, moist conditions, can live on organic dirt found on balloon
envelopes. The fungus waste materials attack the coating on the fabric.
Mooring. Operation of an unmanned balloon secured to the ground by lines or controlled by anything touching the ground.
See Title 14 of the Code of Federal Regulations, part 101.
Mouth. The bottom, open end of a hot air balloon envelope. Also called the “throat.”
MSL. Mean sea level.
Neutral buoyancy. A condition wherein a balloon is weightless and is neither ascending nor descending.
Nitrogen charging. A technique of adding nitrogen gas to propane tanks to increase fuel pressure. Used in place of temperature
to control propane pressure in hot air balloons during cold weather.
Nomogram. Technically, a calculating chart with scales that contain values of three or more mathematical variables, widely
used in engineering. In ballooning, a balloon’s performance chart is a nomogram.
Nonporous. The state of having no pores or openings which will not allow gas to pass through. New hot air balloon fabric
is nearly nonporous.
Notice to Air Missions (NOTAM). A notice containing information concerning facilities, services, or procedures, the timely
knowledge of which is essential to personnel concerned with flight operations.
Nylon. The registered name for a polymeric fabric. Most balloon envelopes are made of nylon.
OODA Loop. An aeronautical decision-making model particularly suited to ballooning. Originally devised by Col. John
Boyd for use by Air Force combat pilots, it has come to be widely utilized in the business community. See the discussion
in chapter 1 of this handbook.
O-Ring. A doughnut-shaped packing, usually rubber, used between two moving parts to act as a seal. Balloon heater and
tank valves usually have O-rings between the valve stem and valve bonnet.
Orographic. A term pertaining to mountains or anything caused by mountains, as in orographic wind (wind formed by
mountains) and orographic cloud (a cloud whose existence is caused by disturbed flow of air over and around a mountain
barrier).
Overtemp ( or over temperature). The act of heating the air inside a hot air balloon envelope beyond the manufacturer’s
maximum temperature.
Oxygen starvation. The condition inside a balloon envelope where all available oxygen has been consumed by the heater
flame and additional burning is impossible since propane must have oxygen to burn. In extreme cases, the blast flame and
pilot light flame will extinguish after a long burn or series of burns and may not relight until the envelope has “breathed”
additional air.
Parachute top. A deflation system wherein the deflation port is sealed with a disc of balloon fabric shaped like a parachute.
Lines attached to the edge of the parachute disc gather into a single line that may be pulled down by the pilot in the basket.
Pibal. Pilot balloon; a small helium-filled balloon sent aloft to help determine wind direction, velocity, and stability.
Pilot in Command (PIC). The pilot responsible for the operation and safety of an aircraft during flight.
Piezo. (Pronounced pee-ate' zo). A piezoelectric spark generator that is built into many modern balloon heaters to ignite
the pilot light.
Pilot light. A small, continuously burning flame used to ignite the main “blast” flame of a balloon heater.
Pilotage. Navigation by visual reference to landmarks.
Pinhole. Any small hole in a balloon envelope smaller than the maximum dimensions allowed for airworthiness.
Porosity. A condition of the envelope fabric that allows hot air to escape. Excessive porosity requires increased fuel use
and results in higher envelope temperatures.
Positive control. According to Title 14 of the Code of Federal Regulations, control of all air traffic, within designated
airspace, by air traffic control.
Preflight. All preparations, including gathering information, assembly, and inspection performed by the pilot before flight.
Pressure gradient. In weather, the difference between high and low pressure areas. Wind speed is directly proportional to
the pressure gradient.
Pressure relief valve. A device in a propane tank designed to release excess pressure—which may be caused by overfilling,
overheating, or excessive nitrogen pressurization—to prevent tank rupture.
Preventive maintenance. Simple or minor preservation operations and the replacement of small standard parts not involving
complex assembly operations.
Prohibited area. According to Title 14 of the Code of Federal Regulations, designated airspace within which the flight of
aircraft is prohibited.
Propane. A colorless and odorless gas. Ethyl mercaptan is added to propane to give it a detectable odor. Propane weighs
4.2 pounds per gallon at 60 °Fahrenheit.
Practical Test Standard (PTS). Book containing areas of knowledge and skill that a person must demonstrate competency
in for the issuance of pilot certificates or ratings.
Pull test. A strength test in which a section of envelope fabric is pulled to a definite pound measurement to determine if it
meets the certification requirements for airworthiness.
Pyrometer. An instrument used to measure air temperature inside the top of a balloon envelope.
Rapid descent. A relatively fast loss of altitude. A subjective term, but usually meant to describe a descent of more than
500 fpm.
Rating. According to Title 14 of the Code of Federal Regulations, a statement that, as part of a pilot certificate, sets forth
special conditions, privileges, or limitations.
Red line. Refers to a line which activates the deflation panel of a balloon, or the maximum envelope temperature allowed,
or the maximum on a gauge.
Repair station. A facility where specified aircraft and their parts may be inspected, repaired, altered, modified, or maintained.
FAA approval is issued to a facility upon qualifications specified by the local FSDO.
Repairman certificate. An FAA certificate issued to a person who is employed by a repair station or air carrier as a specialist
in some form of aircraft maintenance. A repairman certificate is also issued to an eligible person who is the primary builder
of an experimental aircraft, to which the privileges of the certificate are applicable.
Required equipment. Equipment that must be aboard an aircraft, as required either by the FAA or balloon manufacturer,
to maintain airworthiness.
Restricted area. Airspace of defined dimensions within which the flight of aircraft is restricted in accordance with certain
conditions.
Return to service. A certificated mechanic or authorized inspector must approve an aircraft for return to service after it has
been inspected, repaired, or altered. In addition, an aircraft that has been modified must be test flown by an appropriately
certificated pilot before return to service.
Ridge. In weather, an elongated area of high pressure with no rotative motion.
Rip panel. A deflation panel, usually circular or triangular, at the top of a balloon envelope, which may be opened by pulling
a line in the basket to allow hot air or gas to escape, and the envelope to deflate.
Rotator vent. See Turning Vent.
Rotor. May be found embedded in mountain waves. Formation usually occurs where wind speeds change in a wave, or
where friction slows the wind near the ground. See Figure 4-22 of this handbook for a graphical representation of rotors.
Sectional chart. Published on a routine basis, these charts are similar to automobile road maps, and provide useful information
regarding airspace, reference points, tower frequencies, etc., to a balloon pilot. They are generally not very helpful for
navigation, as the scale, 1:500,000, is too small to be of use to the balloon pilot.
SIGMET. Significant Meteorological Information.
Single Pilot Resource Management. A variant of the crew resource management model that is or more practical application
to the balloon pilot. Defined as the “art and science of managing all resources available to the single pilot to ensure the
successful outcome of the flight.”
Skew-T plot. In weather, a graphic depiction of the data received from a radiosonde.
Small aircraft. Aircraft having a maximum certificated takeoff weight of 12,500 pounds or less. All currently type-certificated
balloons are small aircraft.
Serial number (S/N). A number, usually one of a series, assigned for identification.
Step descent. A method of allowing a balloon to lower toward the ground by reducing the altitude, leveling off, and repeating
the step, to lower the balloon in increments rather than one continuous motion.
Superheat. A gas balloon term, superheat occurs when the sun heats the gas inside the envelope to a temperature exceeding
that of the ambient air, resulting in expansion of the gas.
Superpressure balloon. (1) A type of hot air balloon which has no openings to the atmosphere—the mouth is sealed with
a special skirt—and is kept pumped full of air (at a higher pressure than the atmosphere) by an on-board fan. Used on
moored balloons to allow operations in relatively strong wind. (2) In gas ballooning, a sealed envelope in which the internal
envelope pressure exceeds that of a non-sealed envelope.
Suspension lines. Lines descending from the mouth of a balloon envelope from which the basket and heater are suspended.
Syllabus. An abstract or digest of training. It is intended to be a summary of a course of training, and should be brief, yet
comprehensive enough to cover essential information.
Telling and Doing Technique. A four-step process teaching process particularly well suited to teaching physical skills.
Terminal Aerodrome Forecast (TAF). TAFs are valid for a 24-hour time period, and are updated four times daily. The
TAF reporting system uses the same abbreviations as used in METAR reports.
Temperature gauge. The thermometer system, required in all type-certificated hot air balloons, that gives a constant reading
of the inside air temperature at the top of the envelope. May be direct reading or remote, using a thermocouple or thermistor
connected to a gauge in the basket or reading signals sent by a transmitter.
Temperature recorder. A small plastic laminate with temperature-sensitive paint dots that turn from white or silver to
black, to record permanently the maximum temperature reached.
Tensile strength. The strength of a material that resists the stresses of trying to stretch or lengthen it.
Terminal velocity descent. A term used by balloonists for the speed obtained when the balloon is allowed to fall until it
apparently stops accelerating, at which point the envelope acts as a parachute and its vertical speed is no longer affected by
its lifting gas, but only by its shape (which is caused by design), load, and other factors.
Tethering. Operation of a manned balloon secured to the ground by a series of lines.
Thermal. A column of rising air associated with adjacent areas of differing temperature. Thermal activity caused by the
sun’s heating usually starts 2 to 3 hours after sunrise.
Time in service. According to Title 14 of the Code of Federal Regulations, with respect to maintenance time records, means
the time from the moment an aircraft leaves the surface of the earth until it touches it at the next point of landing.
Touch-and-go landing. An operation by an aircraft that lands and takes off without stopping.
Topographic map. A map depicting area information on a smaller scale that an aviation sectional chart, and of much
more value to the balloon pilot. Most topographic charts show areas of vegetation, roads, built-up areas, and the general
topography (or terrain) of a given area.
Trough. In weather, an elongated area of low pressure with no rotative motion.
Turning vent. A vent on the side of a hot air balloon envelope which, when opened, allows escaping air to exit in a manner
causing the balloon to rotate on its axis.
Type certification. Official recognition that the design and operating limitations of an aircraft, engine, or propeller meet
the airworthiness standards prescribed by the Code of Federal Regulations for that particular category or type of aircraft,
engine, or propeller.
Uncontrolled lift. Lift that occurs without specific action by the pilot. Often referred to as false lift.
Useful lift (load). The potential weight of the pilot, passengers, equipment and fuel. It is the basic empty weight of the
aircraft subtracted from the maximum allowable gross weight.
V AD winds. In weather; velocity azimuth display winds are derived from the output of the 160 or more WRS-88 radar sites
located throughout the United States. The WRS-88 is configured to produce radar returns off of dust and other particulate
matter in the air, and in turn, those returns can be used to indicate wind direction and speed at different altitudes. Generally
reported in 1000 foot increments.
Variometer. See Vertical Speed Indicator.
Vent. (1) The action of opening the vent to cool the air in the envelope. (2) An envelope opening that will automatically close.
Vertical Speed Indicator (VSI). An instrument that continuously records the rate at which an aircraft climbs or descends.
Usually measured in FPM. A required instrument in a balloon.
Vent line. The line that activates the cooling vent.
Visual Flight Rules (VFR). Flight rules governing aircraft flight when the pilot has visual reference to the ground at all times.
Virga. Precipitation that falls from a cloud and evaporates before reaching the ground.
Volume. The total amount of air or gas (expressed in cubic feet) contained in a balloon envelope.
Warm front. In weather, the leading edge of a warm air mass displacing a colder air mass.
Warp. The threads in a piece of fabric that run the length of the fabric.
Weigh-off. Determine neutral buoyancy of a gas balloon or airship by taking weight off at launch.
Wind direction. The direction the wind is coming from.
Wind shear. A strong and sudden shift in wind speed or direction, which may be either vertical or horizontal. Wind shear
should not be confused with normal wind change, which is gentler. Wind shear is often associated with the passage of a
weather front, or a strong temperature inversion.
WINGS Program. A program that encourages general aviation pilots to continue training and provides an opportunity to
practice selected maneuvers in a minimum of instruction time. Participation in the WINGS program relieves a pilot from
compliance with flight review requirements, provided all WINGS requirements are met. Previously governed by Advisory
Circular 61-91, the WINGS program is available as an online education program at www.faasafety.gov, effective mid-2007.