11:3 AIRFRAME STRUCTURES Flashcards
What are the two main types of fuselage constructions
Monocoque or semi monocoque
What is the biggest problem with monocoque construction
Trying to maintain enough strength in the skin whilst keeping the overall weight within limits
How is the semi monocoque structure assembled
The skin shares the load with the stringers, the frames and with an additional clip
How is the monocoque structure assembled
Uses frame assemblies and bulkheads to give shape to the fuselage and the aircraft skin is riveted directly on to the frame
What components does the fuselage mainframe construction consist of
- Frames
- Bulkheads
- Stringers
- Floor beams
- Floor to skin shear ties
- Keel beam
What is the purpose of the aircraft stringers
They give shape to the fuselage shell, they are located on the inner side of the aircraft skin panel
What is a fillet seal
The application of a bead of sealant. The fillet should overlap the seam and be with out any bubbles and look even
What is the injection sealing process
The process where sealant is injected into (joggles or seams) which forces the air out and then is left with only the sealant in its place
When would pressure seals be used
When rods or cables move through pressure bulkheads
What type of seals are fitted to the main entry doors
- Flap type mechanical seals
- Diaphragm seals
What type of seal do most cargo doors use
The same as most of the main entry doors, a rubber tube spaced with pressurisation holes
What are the aircraft seat tracks known as
L-track or I-track
What is a ULD
A Unit Load Device
What is the purpose of a ULD
It is a container or pallet/bin which is designed to fit in a specific type of aircraft. It means that several items can be put into it and saves room. Each ULD requires its own manifest
Which regard to cargo loading, the conveyance components installed in the ball mat area are capable of moving ULDs in which directions
In nearly all directions
With regards to cargo loading the conveyance components installed beyond the ball mat area can move ULDs in which directions
Longitudinally only
What are main doors on the left hand side of the aircraft primarily used for
The loading of passengers quickly and efficiently
What are the main doors used for on the right hand side of the aircraft primarily used for
Used for service doors for galley servicing
What is the purpose of the service doors
To give access to the stabiliser, hydraulics or electronics compartments
What does the main door structure consist of
Frame, beams, formers and intercostals
What happens when the door mode selector is in the automatic position
It is in the armed and flight position and the emergency system is ready
At what angle does the door need to be open for the slide to deploy
60°
What are the overwing emergency exits called on smaller aircraft (example A320)
Plug doors
What are the requirements for an aircraft to have an approved secure cockpit
Aircraft in excess of 45500kg with a passenger seating capacity greater than 60
What is used in the fwd and aft cargo bays to ensure alignment of the latches
A centring roller
What connects the top of the cargo door to the fuselage on an Airbus
A piano hinge
How can you tell if an Airbus cargo door is fully open
A green door open light illuminates
The locking handle unlocks a safety mechanism on an Airbus. How many safety cams does it have
6
When does the pressure relief vent door open on a cargo door
When the differential pressure between outside and inside is greater than 1 pound per square inch
What is the purpose of the hook mechanism on a Boeing aircraft
The hook mechanism moves the door from the fully closed position to open to then allow the actuators to open the door
By what mechanical means are cargo doors operated
Hydraulically
What additional features do flight deck windows provide over observer/passenger windows
Protection against bird strike and ice build up
What type of glass is found on the outside of the flight deck windscreen
Thermally strengthened glass
What are the inner layers of the flight deck windscreen made from
Chemically strengthened glass
What are the layers of glass on the flight deck windscreen bonded together with
A specialised plastic called polyurethane
Where is the heating film on all flight deck windows located
The inner surface of the outer glass. It provides an anti ice and de fogging system
What is placed between the flight deck windscreen and the frame to seal it
A silicon seal
How are windscreens attached to the aircraft
They are attached to the frame of the fuselage structure, a second frame called a retainer is bolted on top
How many panes of glass to passenger windows consist of
An inner and an outer
What are 2 special features of the inner pane of glass on passenger windows
1 - there is a small vent hole which ensures the pressure between the 2 panes are the same
2 - the inner pane can carry the stress of both panes if the outer breaks
What is the main function of the wings
To produce lift
What 3 main areas are the wings made up from
- Left wing box
- Centre wing box
- Right wing box
Which part of the wing is used as the fuel tank walls
The front and rear spar
What type of load does the upper surface of the wing carry
Mainly compression loads
What type of load does the lower surface of the wing carry
Mainly tension loads
What would you find on the rear spar of a wing that you wouldn’t find on the front
The landing gear support arm which is sometimes referred to as the fake rear spar
What is the purpose of ribs in the wing
They are able to carry torsion, compression and shear loads and also give shape to the wing and provide walls for the fuel tank
What is the nose cap of the leading edge of the wing made from
Aluminium alloy
What is the purpose of the trailing edge of the wing
It supports the flight controls
What are the purpose of wing fences and winglets
They are both aerodynamic devices to improve the performance of the wing in terms of increasing the lift and reducing the drag
What does the emponage consist of
Unpressurised area consisting of vertical stab, dorsal fin and rudders, horizontal stab and tail section with tail cone
What does the tail cone consist of
A removable single unit which houses the APU compartment
How are the horizontal stabilisers normally constructed
Either 1 piece or 3 piece construction
What is the vertical stabiliser also known as
The fin
What joins the stabiliser smoothly to the ridge of the fuselage
The dorsal fin
What type of flight of hinges connect flight controls to the adjacent structures
A primary or master hinge and then normal hinges
What are the 3 main components of all surface hinges
- The ballbarings
- A fail safe bolt consisting of an inner and outer bolt
- sleeves
What is the purpose of ballbarings in flight control hinges
They compensate for misalignment
What is the purpose of the failsafe bolt in flight control hinges
Failsafe bolt consists of an outer and inner bolt. If the outer fails the inner can take the load
What is the purpose of the sleeves in the flight controls hinges
To prevent overstress of the fail safe bolt when tightened
What is different with the hinge sleeves on the primary/master hinge compared to the normal
Master has 1 sleeve, normal has 2. Master has a spacer instead
How is surface flutter prevented
If the surface is hydraulically powered or by static balancing if the control surface is mechanically operated
What is static balancing
Weights are placed on the flight control to balance out the potential flutter
When would static balancing need to be re done
If a repair to the flight control is required
What is the deflection angle
The angle of deflection compared to the 0 position
What are engine pylons also known as
Struts
What types of loads do the forward engine mount bolts take
Vertical loads. Thrust and side loads are transferred by shear pins
What loads does the support beam which is a part of the engine attachment system take
Axial loads from engine thrust
