Parts of an Aircraft:-
i)Body Construction.
ii)Aircraft Engine
iii) Fuel and fuel tank.
iv) Powered and pressurized system.
v) Seating
vi) Aircraft Access and Egress.
CLICK HERE👉Parts of an aircraft
Materials of construction:-
Aluminium Alloys:
This is the most common of the metals used I'm aircraft construction. Their composition varies depending upon where they are used i.e. skin surfaces, formers, stringers, spars etc.
Aluminium alloys can be readily cut with axes, hacksaws or powered cutting tools. Aluminium alloys are good conductors, quickly transmitting heat and equally rapidly cooled by water spray or form.
Magnesium and it's Alloys:
Magnesium alloys is light, strong metal that can be found in engine mounting brackets, crankcases in piston engines, compressor casings of turbined engines but various other area where strengthening may be required and where Bulkiness is no object. Magnesium and it's alloys once ignited, can prove difficult to extinguish as they react violently to most firefighting agents. Magnesium and alloys are unlikely to be found in areas where forcibly entry may be necessary.
Titanium alloys:
Titanium alloys is used where greater strength or resistance to heat is required. It's primary use in engine firewalls, tailpipe casings and turbine engine blades. In some high speed aircraft titanium is used to make major components such as the ledging edges of wings etc.
Titanium is difficult to ignite, but once ignited, it can be make major components such as the ledging edges of wings etc. Titanium is difficult to ignite, but once ignited, it can prove difficult to extinguish. Class "D" Dry chemical powders may be used, if available.
It is difficult to cut other than thin sections however, sparking may result from prolonged friction with the use of powered cutting tools.
Stainless steel:
Stainless steel is used where greater strength and rigidity is required such as in frames which act as attachments for the main plane, beams, supporting engines, parts of the undercarriage and for for reinforcement of skin surface.
An indication of the engineering complexity and meticulous attention to detail demanded in the construction of a modern aircraft.
Composite Material:
Although not a metal, the use of composite material in aircraft construction is common composite material are also known collectively as Man Made Mineral Fibres (MMMF) the term MMMF describes a wide range of materials which utilise the inherent strength and durability of woven fibres bonded together with resins. Carbon Fibres Reinforced Plastics (CFRP), Aramid Reinforced Plastic(ARP), Glass Fibres Reinforced plastic(CFRP) and Kevlar are all common name used to describe these materials.
CLICK HERE👉How do aeroplanes fly?
Types of Fuel tanks:-
A) Petrol (Gasoline, and Avgas) :
Petrol, also known as gasoline or avgas is used in piston aircraft the fuel having different grades. These grades are characteristic of the octane rating of fuel, which means that their composition differs depending on the engine compression ratio.
The grade (octane rating) of gasoline will have no bearing depending on the flammability of fuel.
CLICK HERE👉Fuels used in an aircraft
B) Kerosene:
These fuels are used in turbine engine aircraft and fall into two categories.
i) AVTUR (jet A1)
AVTUR or jet A1 is the most widely and commonly used kerosene and pressure but may do so if sprayed into a hot engine following a crash.
ii) AVTAG (jet B)
AVTAG is a wide cut fuel of approximately 60% gasoline and 40% kerosene. AVTAG will readily ignite at normal temperature and pressure having the characteristics of avgas.
Limit of Flammability:-
AVGAS 1.4% - 7.6%
AVTUR 0.7% - 5.8%
AVTAG 0.8% - 5.0%
Avgas and AVTAG will ignite at normal temperatures and ppressure. AVTUR will not ignite under these conditions, however if the fuel is sprayed onto a hot engine or hot aircraft components, it may ignite once ignited it will burns as readily and produce as much heat as a fire involving any of the other two fuels. The rate of flame spread is however greatly reduced.
It is important to remember that any fuel is MIST FORM will readily ignite and propagate the fire faster. All aviation fuels are corrosive, irritant, toxic and can contaminate other materials.
Various types of Aircraft fires:-
CLICK HERE👉What happens when an aircraft catches fire?
A) Engine Fire:
It is reasonable for ARFF personnel responding to aircraft engine fire to expect that all of the following actions have probably been accomplished by the flight deck crew, where appropriate:
1) Engine shutdown
2) Engine fire extinguishing system (if any) activated.
3) Electrical Power to the affected engine(s) de-energized
4) Fuel and hydraulic fluid supply to the affected engines shout down.
These actions should be verified as conditions permit. It should be emphasised that turbine engines. Following shout-off of power and fuel, can remain a potential hazard during "wind-down" with high heat retention continuing for as long as 30minutes. This heat constitutes a potential ignition source for flammable vapours. On propellers, or entry into their path of rotation, should be avoided during all stages of the emergency.
B) The overheating of wheel assemblies usually follows excessive braking.
This can happen on landing when a hydraulic failure reduces the ability of the pilot to utilize control surfaces and he feels the aircraft may over run the runway or more often, on an aborted take-off. Quite often tyres will burst or as the heat from the aircraft comes to a standstill, ignite by transference of heat from the brakes. To avoid metal failure, fire fighters attending overheated wheel assemblies should usually refrain from applying water and allow natural cooling. If there is fire however, a fine water fog applied from fore and after of the undercarriage assembly is generally used, personnel and appliances being kept away from the side of the wheel in case of rim failure, which may take place with explosive force. If there is any possibility of undercarriage failure, the officer in change should be available from the airline crew or ground engineers. Personnel working beneath an aircraft should always be kept to a minimum particularly when an undercarriage has sustained a form of damage.
C) Cabin Fire
There are seat of polyurethane foams, vinyl plastics for furnishings, electronic equipment a big number of carbon are present in the cabin so there is high fire & hazard while burning produces high concentrations of toxic gases.
D) Vapour cloud Explosion in fuel tanks.
There will be a variety of compressed gases present on an aircraft such as compressed air, nitrogen and oxygen. These have varying uses from lifesaving, to pressurization of fuel and hydraulic systems in an emergency.
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