11.3 AEROPLANE STRUCTURES Flashcards
What are the 3 aircraft fuselage constructions?
Truss type (Pratt or Warren)
Monocoque type
Semi-monocoque type
Pratt truss ?
→ wooden longerons (main longitudinal structural members)
→ Longerons supported by wooden struts
Warren Truss ?
→ Longerons connected with diagonal members
→ carry both tension and compression
How is a fuselage pressurised ?
- Air pumped into cabin after take off
- Results in difference outside/inside cabin pressure
- Differential pressure is regulated/maintained throughout flight
- Causes significant stresses leading to metal fatigue
- Semi-Monocoque construction
2 sealant application methods on aircraft fuselage ?
- Faying seal (2 metals overlap)
- Fillet seal (corner)
Why must electrical and flying control cable must be sealed ?
- prevent excessive pressure leaks as they pass through pressure bulkheads
- rubber, silicon seals or sealant plates
Common fuselage on modern day aircraft ?
- Semi-monocoque construction
What is a stressed skin fuselage
All loads carried in the exterior skin
How are electrical cables and flying control cables sealed to prevent excessive pressure leaks
Special designed rubber or silicon seals used
What is the pylons structural purpose
Transfers thrust generated by engines to airframe
Passengers and flight crew seats are secured to longitudinal tracks using what type of fasteners
Quick release fasteners
What are the seat tracked bolted/riveted to
Floor beam
Cargo loading system components include
-transport components
- guidance components
- locking components
What type of door is the ‘main entry doors’
Plug type
What type of door is a ‘service door’ e.g. potable water system
Non plug type
What type of door are cargo doors
Non Plug type
Explain plug type door
- Seal itself by utilising differential pressure
- One side has higher pressure so it wedges it in
Explain non-plug type door
Open outwards and use locking mechanisms such as latches
What are the left doors of the aircraft usually used for
Passenger entry
What are the right doors of the aircraft usually used for
Galley servicing
If a door is incorrectly latched/open is a warning given to a flight crew
Yes
What do the door frame house
Pressure stop fittings
What is the function of the pressure stop fittings and how is it achieved
Holds the door closed when cabin is pressurised
By a ‘stop pin’
How are door seals held in place
Adhesive compounds, screws
> than 45,500 kg/> than 60 passenger seating capacity shall be equipped with what
-compartment door between cabin and flight deck
Should the aircraft door be opened if the cabin pressure ‘indicator’ is lit
No, risk of door violently opening and injuring outside personnel
What are safety gags used for
Prevent hydraulic actuation of cargo doors
What do witness points indicate on cargo door
If latches have been fully engaged
What device are doors usually fitted with to ensure they are securely locked for flight
Proximity devices
What are doors usually fitted with to ensure they are securely locked for flight
Proximity devices
Explain passenger windows
- plug type
- made of acrylic plastic
- 2 layers of acrylic plastic for failsafe reasons
Explain flight deck windows
- usually 6 flight deck windows
- constructed from laminations of tempered glass and plastic
- electrically heated
- silicon seal in between windows and frame to bond
What do you inspect for window damage
- Delamination and bubbles
- chips, cracking, scratches
What does the keel beam support
- wheel well area
