Glossary
100-HOUR INSPECTION—An inspection required
by 14 CFR 91.409 for FAA-certificated aircraft
that are operated for hire, or are used for flight in-
struction for hire. A 100-hour inspection is similar
in content to an annual inspection, but it can be
conducted by an aircraft mechanic who holds an
Airframe and Powerplant rating, but does not have
an Inspection Authorization. A list of the items
that must be included in an annual or 100-hour
inspection is included in 14 CFR part 43, Appen-
dix D.
14 CFR (TITLE 14 OF THE CODE OF FEDERAL
REGULATIONS)—Federal regulations pertaining
to aviation activity. Previously known as Federal
Aviation Regulations.
800-WX-BRIEF—Phone number for reaching an
FAA Flight Service Station 24 hours a day almost
anywhere in the United States.
ABORTED TAKEOFF—To terminate a replaned
takeoff when it is determined that some condi-
tion exists which makes takeoff or further flight
dangerous.
ACCELERATION—Force involved in overcoming
inertia, and which may be defined as a change in
velocity per unit of time.
ADM—See AERONAUTICAL DECISION
MAKING.
AERONAUTICAL DECISION MAKING (ADM)—
A systematic approach to the mental process used
by pilots to consistently determine the best course
of action in response to a given set of circum-
stances.
A/FD—See AIRPORT/FACILITY DIRECTORY .
AFM—See AIRCRAFT FLIGHT MANUAL.
AIRCRAFT—A device that is used or intended to be
used for flight in the air.
AIRCRAFT ACCIDENT—An occurrence associ-
ated with the operation of an aircraft which takes
place between the time any person boards the
aircraft with the intention of flight and all such
persons have disembarked, and in which any
person suffers death or serious injury, or in which
the aircraft receives substantial damage. (NTSB
830.2)
AIRCRAFT CATEGORIES—(1) As used with
respect to the certification, ratings, privileges, and
limitations of airmen, means a broad classification
of aircraft. Examples include: powered parachute,
airplane, rotorcraft, glider, lighter-than-air, and
weight-shift control. (2) As used with respect to
the certification of aircraft, means a grouping of
aircraft based upon intended use or operating limi-
tations. Examples include: transport, normal, util-
ity, acrobatic, limited, restricted, and provisional.
AIRCRAFT OPERATING INSTRUCTIONS—A
document developed by the aircraft manufacturer
and accepted by the Federal Aviation Administra-
tion (FAA). It is specific to a particular make and
model powered parachute by serial number and it
contains operating procedures and limitations.
AIRFOIL—An airfoil is any surface, such as a wing
or propeller, which provides aerodynamic force
when it interacts with a moving stream of air.
AIRPORT—An area of land or water that is used or
intended to be used for the landing and takeoff of
aircraft, and includes its buildings and facilities, if
any.
AIRPORT/FACILITY DIRECTORY (A/FD) —A
publication of the Federal Aviation Administration
containing information on all airports, seaplane
bases, and heliports open to the public. The A/FD
contains communications data, navigational facili-
ties, and certain special notices and procedures.
AIRSPACE—See CLASS A, CLASS B, CLASS C,
CLASS D, CLASS E, or CLASS G AIRSPACE.
AIRWORTHINESS—A state in which an aircraft or
component meets the conditions of its type design
and is in a condition for safe operation.
AIRWORTHINESS CERTIFICATE—A certifi-
cate issued by the FAA to aircraft that have been
proven to meet the minimum standards set down
by the Code of Federal Regulations.
ALTIMETER—A flight instrument that indicates
altitude by sensing pressure changes.
AME—See A VIATION MEDICAL EXAMINER.
ANGLE OF ATTACK (AOA)—The acute angle be-
tween the chord line of the airfoil and the direction
of the relative wind.
ANGLE OF INCIDENCE—The angle formed by
the chord line of the wing and a line parallel to the
longitudinal axis of the PPC cart.
ANNUAL INSPECTION—A complete inspection
of an aircraft and engine, required by the Code of
Federal Regulations, to be accomplished every 12
calendar months on all certificated aircraft. Only
an A&P technician holding an Inspection Authori-
zation can conduct an annual inspection.
AOA—See ANGLE OF ATTACK.
ARM—The horizontal distance in inches from the
reference datum line to the center of gravity of an
item. Used in weight and loading calculations.
AROW— The mnemonic aid to remember the
certificates and documents required to be onboard
an aircraft to determine airworthiness: Airworthi-
ness certificate, Registration certificate, Operating
limitations, Weight and balance data.
ASOS—See AUTOMATED SURFACE OBSERV-
ING SYSTEM.
ASPECT RATIO—Span of a wing divided by its
average chord.
ASYMMETRICAL AIRFOIL—An airfoil section
that is not the same on both sides of the chord line.
ATIS—See AUTOMATIC TERMINAL INFORMA-
TION SERVICE.
AUTOMATED SURFACE OBSERVING SYS-
TEM (ASOS)—Weather reporting system which
provides surface observations every minute via
digitized voice broadcasts and printed reports.
AUTOMATED WEATHER OBSERVING SYSTEM
(AWOS)—Automated weather reporting system
consisting of various sensors, a processor, a com-
puter-generated voice subsystem, and a transmitter
to broadcast weather data.
AUTOMATIC TERMINAL INFORMATION SER-
VICE (ATIS)—The continuous broadcast (by ra-
dio or telephone) of recorded noncontrol, essential
but routine, information in selected terminal areas.
A VIATION MEDICAL EXAMINER (AME)—A
medical doctor authorized to perform aviation
medical exams for aviators.
BANK ATTITUDE—The angle of the lateral axis
relative to the horizon.
BASE LEG—A flight path at right angles to the
landing runway off its approach end. The base leg
normally extends from the downwind leg to the
intersection of the extended runway centerline.
CAMBER—The curvature of a wing when look-
ing at a cross section. A wing has upper camber
on its top surface and lower camber on its bottom
surface.
CANOPY—The fabric body of a parachute.
CARBURETOR ICE—Ice that forms inside the car-
buretor due to the temperature drop caused by the
vaporization of the fuel. Induction system icing
is an operational hazard because it can cut off the
flow of the fuel/air charge or vary the fuel/air ratio.
CART—The engine and seats, attached by a struc-
ture to wheels; sometimes referred to as the fuse-
lage, cockpit, chaise, or airframe.
CA VITATION—A condition that exists in a fluid
pump when there is not enough pressure in the
reservoir to force fluid to the inlet of the pump.
The pump picks up air instead of fluid.
CENTER OF GRA VITY (CG)—The point at which
an aircraft would balance if it were possible to
suspend it at that point. It is the mass center of the
aircraft, or the theoretical point at which the entire
weight of the PPC is assumed to be concentrated.
It may be expressed in inches from the reference
datum, or in percent of mean aerodynamic chord
(MAC). The location depends on the distribution
of weight in the aircraft.
CENTER OF LIFT—The location along the chord
line of an airfoil at which all the lift forces pro-
duced by the airfoil are considered to be concen-
trated.
CENTER OF PRESSURE (CP)—The point along
the wing chord line where lift is considered to be
concentrated.
CENTRIFUGAL FORCE—The apparent force
occurring in curvilinear motion acting to deflect
objects outward from the axis of rotation. For
instance, when pulling out of a dive, it is the force
pushing you down in your seat.
CENTRIPETAL FORCE—The force in curvilinear
motion acting toward the axis of rotation. For
instance, when pulling out of a dive, it is the force
that the seat exerts on the pilot to offset the cen-
trifugal force.
CERTIFICATED FLIGHT INSTRUCTOR (CFI)—
A flight instructor authorized by the FAA to
provide flight instruction in designated category of
aircraft.
CFI—See CERTIFIED FLIGHT INSTRUCTOR.
CFR—See CODE OF FEDERAL REGULATIONS.
CG—See CENTER OF GRA VITY .
CHECKLIST—A list of procedures that provides
a logical and standardized method to operate a
particular make and model aircraft.
CHECKRIDE—A practical test administered by
an FAA examiner or designated examiner for the
purpose of issuing an FAA certificate or rating.
CHORD LINE—An imaginary straight line drawn
through an airfoil from the leading edge to the
trailing edge.
CLASS A AIRSPACE—Airspace from 18,000 feet
MSL up to and including FL600, including the
airspace overlying the waters within 12 NM of the
coast of the 48 contiguous states and Alaska; and
designated international airspace beyond 12 NM
of the coast of the 48 contiguous states and Alaska
within areas of domestic radio navigational signal
or ATC radar coverage, and within which domestic
procedures are applied.
CLASS B AIRSPACE—Airspace from the surface
to 10,000 feet MSL surrounding the nation’s
busiest airports in terms of IFR operations or pas-
senger numbers. The configuration of each Class
B airspace is individually tailored and consists
of a surface area and two or more layers, and is
designed to contain all published instrument pro-
cedures once an aircraft enters the airspace. For all
aircraft, an ATC clearance is required to operate in
the area, and aircraft so cleared receive separation
services within the airspace.
CLASS C AIRSPACE—Airspace from the surface
to 4,000 feet above the airport elevation (charted
in MSL) surrounding those airports having an
operational control tower, serviced by radar ap-
proach control, and having a certain number of
IFR operations or passenger numbers. Although
the configuration of each Class C airspace area is
individually tailored, the airspace usually consists
of a 5 NM radius core surface area that extends
from the surface up to 4,000 feet above the airport
elevation, and a 10 NM radius shelf area that
extends from 1,200 feet to 4,000 feet above the
airport elevation.
CLASS D AIRSPACE—Airspace from the surface
to 2,500 feet above the airport elevation (charted
in MSL) surrounding those airports that have an
operational control tower. The configuration of
each Class D airspace area is individually tailored,
and when instrument procedures are published, the
airspace will normally be designed to contain the
procedures.
CLASS E AIRSPACE—Airspace that is not Class A,
Class B, Class C, or Class D, and it is controlled
airspace.
CLASS G AIRSPACE—Airspace that is uncon-
trolled, except when associated with a temporary
control tower, and has not been designated as
Class A, Class B, Class C, Class D, or Class E
airspace.
CODE OF FEDERAL REGULATIONS (CFRs)—
Regulations issued by the U.S. Federal Govern-
ment as published in the Federal Register.
COMBUSTION—Process of burning the fuel/air
mixture in the engine in a controlled and predict-
able manner.
COMMON TRAFFIC ADVISORY FREQUENCY
(CTAF)—A frequency designed for the purpose
of carrying out airport advisory practices while
operating to or from an airport without an operat-
ing control tower. The CTAF may be a UNICOM,
Multicom, FSS or tower frequency and is identi-
fied in appropriate aeronautical publications.
CONTROLLED AIRSPACE—An airspace of de-
fined dimensions within which air traffic control
service is provided to IFR flights and to VFR
flights in accordance with the airspace classifica-
tion. Note: “controlled airspace” is a generic term
that covers Class A, Class B, Class C, Class D and
Class E airspace.
CONTROL TOWER—A terminal facility that uses
air/ground communications, visual signaling, and
other devices to provide ATC services to aircraft
operating in the vicinity of an airport or on the
movement area. Authorizes aircraft to land or
takeoff at the airport controlled by the tower or to
transit the Class D airspace area regardless of the
flight plan or weather conditions. May also pro-
vide approach control services (radar or nonradar).
COORDINATED TURN—Turn made by an aircraft
where the horizontal component of lift is equal to
the centrifugal force of the turn.
CRAB ANGLE—The angle formed between the
direction an aircraft is pointed and the direction it
is tracking over the ground resulting from a cross-
wind component.
CREWMEMBER—A person assigned to perform
duty in an aircraft during flight time.
CREW RESOURCE MANAGEMENT (CRM)—
The application of team management concepts in
the flight deck environment. This includes single
pilots of general aviation aircraft. Pilots of small
aircraft, as well as crews of larger aircraft, must
make effective use of all available resources; hu-
man resources, hardware, and information. Human
resource groups include but are not limited to:
pilots, dispatchers, cabin crewmembers, mainte-
nance personnel, and air traffic controllers.
CRM—See CREW RESOURCE MANAGEMENT.
CROSSWIND—Wind blowing across rather than
parallel to the direction of flight. In a traffic pat-
tern, the crosswind leg is a flight path at right
angles to the landing runway off its upwind end.
CROSSWIND CORRECTION—Correction applied
in order to maintain a straight ground track during
flight when a crosswind is present.
CROSSWIND LANDING—Landing made with a
wind that is blowing across rather than parallel to
the landing direction.
CROSSWIND TAKEOFFS—Takeoffs made during
crosswind conditions.
CTAF—See COMMON TRAFFIC ADVISORY
FREQUENCY .
DATUM—An imaginary vertical plane or line from
which all measurements of moment arm are taken.
The datum is established by the manufacturer.
DECIDE MODEL—Model developed to help pilots
remember the six-step decision-making process:
Detect, Estimate, Choose, Identify, Do, Evaluate.
DECK ANGLE—The angle of the cart’s lower
frame (from the front wheel to the rear wheels), to
the landing surface.
DENSITY ALTITUDE—Pressure altitude corrected
for variations from standard temperature. When
conditions are standard, pressure altitude and
density altitude are the same. If the temperature is
above standard, the density altitude is higher than
pressure altitude. If the temperature is below stan-
dard, the density altitude is lower than pressure
altitude. This is an important altitude because it is
directly related to the PPC’s performance.
DEPARTURE LEG—The leg of the rectangular
traffic pattern that is a straight course aligned with,
and leading from, the takeoff runway.
DESIGNATED PILOT EXAMINER (DPE)—An
individual designated by the FAA to administer
practical tests to pilot applicants.
DIRECTIONAL STABILITY—Stability about the
vertical axis of an aircraft, whereby an aircraft
tends to return, on its own, to flight aligned with
the relative wind when disturbed from that equi-
librium state. The pendulum design is the primary
contributor to directional stability, causing a PPC
in flight to align with the relative wind.
DOWNWIND LEG—Leg of the traffic pattern flown
parallel to the landing runway, but in a direction
opposite to the intended landing direction.
DPE—See DESIGNATED PILOT EXAMINER.
DRAG—An aerodynamic force on a body acting
parallel and opposite to the relative wind. The
resistance of the atmosphere to the relative motion
of an aircraft. Drag opposes thrust and limits the
speed of the aircraft.
DRAG COEFFICIENT (Cd)—A dimensionless
number used to define the amount of total drag
produced by an aircraft.
DRIFT CORRECTION—Correction that is applied
to counter the affects of wind on an aircraft’s flight
and ground track.
DUAL FLIGHT—Flight time that is received and
logged as training time. Dual flight time must be
endorsed by a Certificated Flight Instructor.
DYNAMIC PRESSURE (q)—The pressure a mov-
ing fluid would have if it were stopped. Reference
14 CFR 61.51(h).
EIS—See ENGINE INFORMATION SYSTEM.
E-LSA (EXPERIMENTAL LIGHT-SPORT AIR-
CRAFT)—An aircraft issued an experimental
certificate under Title 14 of the Code of Federal
Regulations (14 CFR) part 21.
EMERGENCY FREQUENCY—Frequency that
is used by aircraft in distress to gain ATC assis-
tance. 121.5 MHz is an international emergency
frequency guarded by Flight Service Stations and
some military and civil aircraft. Reference AIM
paragraph 6-3-1.
ERROR CHAIN—A series of mistakes that may
lead to an accident or incident. Two basic prin-
ciples generally associated with the creation of an
error chain are: (1) one bad decision often leads to
another; and (2) as a string of bad decisions grows,
it reduces the number of subsequent alternatives
for continued safe flight. Aeronautical decision
making is intended to break the error chain before
it can cause an accident or incident.
FAA—See FEDERAL A VIATION ADMINISTRA-
TION.
FAA INSPECTOR—FAA personnel who can
administer practical and proficiency tests and can
issue pilot certificates.
FAA KNOWLEDGE EXAM—Written exam ad-
ministered by the FAA as a prerequisite for pilot
certification. Passing the knowledge and practical
exams are required for pilot applicants to be issued
FAA certificates or ratings.
FAR—See FEDERAL A VIATION REGULATIONS.
FDC NOTICE TO AIRMAN (NOTAM)—Notice to
Airman that is regulatory in nature.
FEDERAL A VIATION ADMINISTRATION
(FAA)—The federal agency responsible to pro-
mote aviation safety through regulation and educa-
tion.
FEDERAL A VIATION REGULATIONS (FARs)—
The division within the Department of Transporta-
tion of the United States government that has the
responsibility of promoting safety in the air, by
both regulation and education.
FIELD ELEV ATION—The highest point of an
airport’s usable runways measured in feet from
mean sea level.
FINAL—Leg of the traffic pattern that is a descend-
ing flightpath starting from the completion of the
base-to-final turn and extending to the point of
touchdown.
FIXED-PITCH PROPELLERS—Propellers with
fixed blade angles. Fixed-pitch propellers are
designed as climb propellers, cruise propellers, or
standard propellers.
FIXED-WING AIRCRAFT—An aircraft whose
wing is rigidly attached to the structure. The term
fixed-wing is used to distinguish these aircraft
from rotary-wing aircraft, such as helicopters and
autogiros.
FLARE—The slow, smooth transition from a normal
approach attitude to a landing attitude. This ma-
neuver is accomplished in a PPC by pulling down
on the steering lines to increase drag, reducing the
forward speed and decreasing the rate of descent.
FLIGHT PLAN—Specified information relating to
the intended flight of an aircraft that is filed orally
or in writing with an FSS or an ATC facility.
FOUR FORCES—The four fundamental forces of
flight: lift, weight, drag and thrust.
FOUR-STROKE ENGINE—The principle of opera-
tion for some reciprocating engines involving the
conversion of fuel energy into mechanical energy.
The strokes are called intake, compression, power,
and exhaust.
FSS—FAA Flight Service Station.
GLIDEPATH—The path of an aircraft relative to the
ground while approaching a landing.
GLIDE RATIO—The ratio of the forward distance
traveled to the vertical distance an aircraft de-
scends when it is operating without power. For
example, an aircraft with a glide ratio of 10:1 will
descend about 1,000 feet for every 2 miles (10,560
feet) it moves forward.
G LOADS—Loads imposed on an airframe due to
inertia (centrifugal force). 1G of load factor repre-
sents the weight of the actual aircraft. 2G repre-
sents effectively twice the aircraft’s actual weight.
GLOBAL POSITION SYSTEM (GPS)—A satellite-
based radio positioning, navigation, and time-
transfer system.
GO-AROUND—The termination of a landing
approach. Reference the AIM Pilot/Controller
Glossary.
GO OR NO-GO DECISION—Decision of whether
or not to make a flight based on environmental,
personal or mechanical factors. A focus area for
human factors study.
GPS—See GLOBAL POSITION SYSTEM.
GROUND-ADJUSTABLE PROPELLER—A type
of aircraft propeller whose blade pitch angle can
be adjusted when the engine is not running. The
adjustment requires loosening the blades in the
hub.
GROUND EFFECT—A condition of improved per-
formance encountered when an airfoil is operating
very close to the ground. When an airfoil is under
the influence of ground effect, there is a reduction
in upwash, downwash, and wingtip vortices. As
a result of the reduced wingtip vortices, induced
drag is reduced.
GROUNDSPEED (GS)—The actual speed of an air-
craft over the ground. It is true airspeed adjusted
for wind. Groundspeed decreases with a head-
wind, and increases with a tailwind.
GROUND TRACK—The aircraft’s path over the
ground when in flight.
HAZARDOUS INFLIGHT WEATHER ADVISORY
SERVICE (HIW AS)—Recorded weather forecasts
broadcast to airborne pilots over selected VORs.
HEADWIND—A wind which blows from the direc-
tion the aircraft is flying. The ground speed of an
aircraft (the speed the aircraft is moving over the
ground) is less than the speed through the air by
the velocity of the headwind.
HIW AS—See HAZARDOUS INFLIGHT WEATH-
ER ADVISORY SERVICE.
HOUR METER—An instrument installed in many
aircraft to show the actual number of hours the
engine has operated. The hour meter is an electri-
cal clock that starts when the engine oil pressure
builds up, and runs until the engine is shut down
and the oil pressure drops to zero.
HYPERVENTILATION—Occurs when an indi-
vidual is experiencing emotional stress, fright, or
pain, and the breathing rate and depth increase,
although the carbon dioxide level in the blood is
already at a reduced level. The result is an exces-
sive loss of carbon dioxide from the body, which
can lead to unconsciousness due to the respiratory
system’s overriding mechanism to regain control
of breathing.
HYPOXIA—State of oxygen deficiency in the body
sufficient to impair functions of the brain and
other organs.
IFR—See INSTRUMENT FLIGHT RULES.
INCIDENT—An occurrence other than an accident,
associated with the operation of an aircraft, which
affects or could affect the safety of operations.
INDUCED DRAG—That part of total drag which
is created by the production of lift. Induced drag
increases with a decrease in airspeed.
INSTRUMENT FLIGHT RULES (IFR)—Rules
governing the procedures for conducting instru-
ment flight. Also a term used by pilots and con-
trollers to indicate type of flight plan.
INTERFERENCE DRAG—Type of drag produced
by placing two objects adjacent to one another.
Combines the effects of form drag and skin
friction.
INVERSION—An increase in temperature with
altitude.
JUDGMENT—The mental process of recognizing
and analyzing all pertinent information in a par-
ticular situation, a rational evaluation of alternative
actions in response to it, and a timely decision on
which action to take.
KINESTHESIA—The sensing of movements by
feel.
KITE—To pressurize and raise the wing overhead
the PPC cart.
KITING—Taxiing the PPC on the ground with the
wing inflated and overhead.
KNOWLEDGE EXAM—See FAA KNOWLEDGE
EXAM.
LATERAL AXIS—An imaginary line passing
through the center of gravity of a PPC and extend-
ing across the PPC from one side of the aircraft to
the other side.
LEADING EDGE—The part of an airfoil that meets
the airflow first.
LIFT—One of the four main forces acting on an
aircraft. On a powered parachute, an upward force
created by the effect of airflow as it passes over
and under the wing.
LIGHT-SPORT AIRCRAFT (LSA)—An aircraft
that meets the requirements defined in 14 CFR
1.1, regardless of airworthiness certification.
LINE-OVERS —A dangerous situation when the
suspension line goes over the top of the wing
instead of going straight from the wing to the riser
system. This condition will prevent proper infla-
tion of the wing.
LINE TWISTS—When the PPC suspension lines on
both sides of the wing are spiraled together. Flying
with a line twist is unsafe; the wing is unairworthy
until it is corrected.
LOC—A preflight check: L – Lines Free, O – Cells
Open, C – Wing Centered.
LOGBOOK—A record of activities: flight, instruc-
tion, inspection and maintenance. Reference 14
CFR 43, 14 CFR 61.51, and 14 CFR 91.417.
LONGITUDINAL AXIS—An imaginary line
through an aircraft from nose to tail, passing
through its center of gravity. The longitudinal axis
is also called the roll axis of the aircraft.
LSA—See LIGHT-SPORT AIRCRAFT.
MAC—See MEAN AERODYNAMIC CHORD.
MAGNETO—A self-contained engine-driven unit
that supplies electrical current to the spark plugs.
MAKE/MODEL—Refers to the manufacturer and
model of a specific aircraft.
MANEUVERING ALTITUDE—An altitude above
the ground that allows a sufficient margin of
height to permit safe maneuvering.
MAXIMUM GROSS WEIGHT—The maximum au-
thorized weight of the aircraft and all of its equip-
ment as specified in the TCDS for the aircraft.
MEAN AERODYNAMIC CHORD (MAC)—The
average distance from the leading edge to the trail-
ing edge of the wing.
MECHANICAL TURBULENCE—Type of tur-
bulence caused by obstructions on the ground
interfering with smooth flow of the wind. Trees,
buildings and terrain can all cause mechanical
turbulence.
MEDICAL CERTIFICATE—Acceptable evidence
of physical fitness on a form prescribed by the
Administrator.
MEDIUM-BANKED TURN—Turn resulting from
a degree of bank (approximately 20 to 45 degrees)
at which the PPC remains at a constant bank.
MILITARY TRAINING ROUTES (MTR)—Special
routes developed to allow the military to conduct
low-altitude, high speed training.
MILITARY OPERATIONS AREA (MOA)—Air-
space of defined vertical and lateral limits es-
tablished for the purpose of separating certain
military training activity from IFR traffic.
MINDSET—A factor in aeronautical decision
making where decision making is influenced by
preconceived ideas about the outcome of events.
For example, an expectation of improving weather
conditions can lead to increased risk during a
flight.
MOA—See MILITARY OPERATIONS AREA.
MODE C TRANSPONDER—A receiver/transmit-
ter which will generate a radar reply signal upon
proper interrogation; the interrogation and reply
being on different frequencies. Mode C means the
reply signal includes altitude information.
MOMENT— A force that causes or tries to cause
an object to rotate. The product of the weight
of an item multiplied by its arm. Moments are
expressed in pound-inches (lb-in). Total moment
is the weight of the PPC multiplied by the distance
between the datum and the CG.
NEWTON’S THIRD LAW OF MOTION—When-
ever one body exerts a force on another, the sec-