Slide 1
BASIC AIRCRAFT STRUCTURES
The basic aircraft structure serves multiple purposes.
Such as aircraft aerodynamics; which indicates how smooth the aircraft flies thru the air
(The Skelton of the aircraft greatly affects these aerodynamics and consist of frames and stringers.)
The shape of the fuselage controls this aspect of the aircrafts aerodynamics.
The shape of the Frames control the shape of the fuselage.
Stringers keeps the Frames spaced correctly and gives strength to the Skeleton.
The Skelton is covered with aluminum or composite type materials made up of panels riveted to frames,
stringers, and some removable panels to allow maintenance technicians to work efficiently on the aircraft
.
The purpose of the this covering is to allow pressurization, aerodynamics and to provide protection for the
occupants.
The Wing box is attached to the fuselage.
Aft section structure is attached to a Horizontal stabilizer and Rudders
Slide 2
OBJECTIVES
• By the end of this lesson you will
be able to:
–State the Components names and
Location of Aircraft Structures
–Recall the location and function of
the components, related to Aircraft
Doors, and Nose Cone
–State the purpose of flight controls
By the end of this lesson you will be able to:
State the Components names and Location of Aircraft Structures
Recall the location and function of the components, related to Aircraft Doors, and Nose
Cone State the purpose of flight controls.
Slide 3
STRUCTURE TERMINOLOGY
Access panel
Are removable panels for inspection or
Maintenance
Forward
Is the direction the aircraft flies
Fuselage
is the main body of the aircraft, airframe without
the wings and the tail
Wngs and Under structure of the aircraft (belly are usually fuel tanks)
Frame
is a Loop-shaped fuselage member which gives
it its cross-sectional shape and strength
Aft
- the direction of the rear of the
aircraft
Aerodynamics
-is the study of how the moving body (aircraft)
interacts with air flowing around it, flies
Auxiliary spar
- an extra beam in the root in the wing for
extra strength
Center-line of aircraft
the line connecting geometric middle points of
cross sections of the aircraft structure
Center wing box
Is the central part of the wing which is located
inside, right under (Low Wing) or right above the fuselage (High Wing)
Empennage
- Is the rear section of the body of the airplane
with stabilizers
Fail safe
- principle of maintaining adequate performance
when some degree of damage or degradation
has happened
Rib
- part of the wing structure which provides the
wing-section’s shape and supports the skin and
Stringers
Stringer
- a stiffening member which supports a section
of the load carrying skin, to prevent buckling
under compression or shear loads
Sweep angle
- the angle between quart chord line of the
wing and center line of fuselage, swept-back
has a positive sweep angle
Tailplane
- the vertical or horizontal planes at the back of
the fuselage
Station line
-measuring line or plane giving frame position
-Usually from the tip of the nose measuring Aft in inches to each frame
Slide 4
Outboard
leading
edge
FLAPS
Listed are the basic flight control surfaces. larger aircraft flight control systems may include fly by wire
systems. While smaller aircraft may use hydraulics or more simplified systems. The flight control surfaces
listed here are the basics of a small aircraft.
AILERONS (ROLL)
The control wheel or yoke controls ailerons and turns the aircraft left or right. By turning left or right, the pilot
can change the position of the ailerons.
When the control wheel is turned to the right, the right aileron goes up and the left aileron goes down, rolling the
airplane to the right. Turned to the left, the right aileron goes down and the left aileron goes up, rolling the airplane to
the left.
ELEVATORS (PITCH)
By moving the yoke, the pilot can change the position of the elevators.
Pushing the control column forward, the elevators move down, pitching the tail of the airplane up and the nose down,
rolling the airplane down.
Pulling the control column back makes the elevators move up, pitching the tail of the airplane down an the nose up,
rolling the airplane upwards.
RUDDER (YAW)
The rudder is the vertical part of the tail that can move from side to side.
Pushing on the left rudder pedal moves the rudder to the left, causing the nose of the airplane to move to the left.
Pushing on the right rudder pedal moves the rudder to the right, causing the nose of the airplane to move to the right.
Outboard leading edges make the wing provide more lift at slower speeds with the Flaps it makes the wing take on
a gull wing look by curving it more on the bottom of the wing.
Lift is produced by air flowing over the curved upper wing surface at a velocity higher than airflow on the lower
surface. Increased airflow causes an increase in velocity and a subsequent drop in air pressure. There are four
variables involved in the production of lift; wing area, wing curve (camber), angle of attack, and airflow. Airflow is
achieved by maintaining forward movement. The larger the wing area the thicker the wing require lesser air flow or
lower forward velocity
Slide 5
FUSELAGE
main
main
frames
frames
The FUSELAGE is composed of the following:
main frames, usually pressurized bulkheads and engine attach points
secondary frames care th4e frames between Main frames,
Outer skins, stiffened by stringers, riveted to the structure, made of extrusions of variable thickness and
sections.
In some areas this assembly also includes mechanically-milled panels, frames in the openings in the
fuselage, and the protective elements Alodine, Primer, and Paint.
Most aircraft have crash skids underneath the fuselage to protect the fuel tanks in the event of a belly
landing with the landing gear retracted.
There are Thick protective shields that defend against the possible blow-out of parts from the engine fans
at multiple engine mount locations
The fuselage structure is of fully metallic monocoque construction and includes:
the cockpit,
the passenger cabin,
the center wing tanks,
The aft baggage compartments,
and aft service compartments.
The cockpit, passenger cabin and baggage compartment (accessible through an internal door) are
pressurized. The cockpit is soundproof and insulated against the effects of condensation resulting from
pressurization. Automatic drains are installed below the fuselage for the evacuation of water.
continuous tracks are fixed to the cabin floor structure for the installation of seats.
Slide 6
TYPICAL FUSELAGE
door
windows
The typical fuselage has windows, floors, and doors to enter the cabin
It also contains the seats, aircraft electrical systems, Hydraulic systems, flight control
system, toilet ,drinking water, storage cabinets and avionics systems.
Slide 7
NOSE CONE, COCKPIT AND
ENTRY
In this [articular visual representation of frame callouts and locations the
following is true….
Frame 0 is the First Pressurized Bulkhead- which holds the pressure in the aircraft All
aircraft that fly above 10,000 ft (Very little oxygen) usually have a pressurized cabin
typically 8 to 9 pressure per-square-inch or psi (which is what causes your ears to pop)
In this visualization Frame 0 thru 5 is the cockpit
Frame 5 thru 7 is the Entry Way
Slide 8
FRAMES DISTRIBUTION
Frames are distributed forward going aft. the circles in the visualization identify the
frames- example 7 frames aft of frame 0 is frame 7
The RED ID circles on the frames are pressurized bulkheads (walls) or extra strength
frames for added support.
Slide 9
FRAME LOCATION/SPACING
Frame locations are from 0 and go aft usually at 20 to 22 inch spacing. The location of
the frame is the dimension from Frame 0 or the nose depending on the manufacturer.
Slide 10
STRINGERS
Stringers
Stringers hold the frames in position as well as fill between them to give the structure
strength.
Materials range from 6061 T3 or T6 to 7076 type materials. very strong yet slightly
flexible so it does not break.
Slide 11
STRINGERS
BL
Stringers are placed like minutes on a clock about a 10 inch spacing
Right hand stringers are R1 R2 R3 ex and left hand stringers are L1,L2L3L going
clockwise. L
A given dimension from center line over straight up and down is called a butt line (BL),
this line is used to place items in the aircraft such has cabinets.
Stations are used for describing the location of frames as well as any spot on the
fuselage. The station is usually described as inches aft or forward of the datum. The
datum will be anywhere as called out by the manufacturer.
Slide 12
WING STRUCTURE
The structure of each wing is basically composed of aluminum alloy panels attached to
two spars and twenty two ribs.
Each wing is equipped with:
an outboard leading edge to give the wing more lift,
two trailing edge flaps to make the wing bigger for slower speeds such as landing
one aileron, on each wing, to make turns –Roll.
Slide 13
WING-TO-FUSELAGE
ATTACHMENT
The WING-TO-FUSELAGE ATTACHMENT structure constitutes the center box
structure and is designed to form the structural tank.
The attachment of the wings to the fuselage consist of:
a main attachment to the fuselage box structure,
a secondary attachment to the lower part of frame 21 of the fuselage.
The main attachment of the wings to the fuselage consists of a attachment fitting on the
lower and upper surface skins of the center wing box structure and at the foot of frames
on the forward and aft spars of the wings.
The secondary attachment attaches the wings to the fuselage through
An Auxiliary spar an extra beam or plate in the center line of the wing for extra
strength
Slide 14
EMPENNAGE
EMPENNAGE
The empennage includes:
a metal fin which sometime includes a two skin composite material leading edge,
an entirely metal horizontal stabilizer, composite material fin top fairings,
The aft structure supports the empennage, both engines and the APU.
The empennage is made of high resistance aluminum alloy.
Its life as a whole is therefore not limited to time.
Slide 15
EMPENNAGE
RIBS
stringers
stringers
Frames
The empennage is made up of Frames stringers and Ribs
This gives the tail section its strength.
Slide 16
Horizontal Stabilizer
RIBS
STRINGERS
RIB count
Rib 1
Horizontal Stabilizer
The Horizontal Stabilizer is made up of ribs and stringers just like the airplane its
covered with aluminum skin or composite type materials
Rib count usually is from the fuselage going to the wing tip starting at 1 this actually
depends on the manufacture.
Slide 17
PYLON
PYLON
PYLON STRUCTURE
The Pylon is the structure that hold the engines on.
Slide 18
PYLON STRUCTURE
FRAMES
RIBS
Pylon Structures are made of ribs and frames.
Slide 19
TYPICAL ENGINE MOUNT
Engine mount structures. Because of their purpose and location engine mount
structures are subject to extreme heat, vibration and torque. To withstand the demands
imposed on them, these structures may be constructed from welded tubular.
