By :-

Tauseef khan

Vit university

Tauseefkhan529@gmail.com

FUNDAMENTALS OF AIRCRAFT DESIGN

The major structural component of a conventional aircraft includes the

fuselage, wings, empennage, control surfaces & landing gear. The empennage

comprises of tail plane & fin. The control surface comprises of ailerons, flaps,

elevators & rudder.

The fuselage is main body mounting the operating crew, passengers, payloads

& most of aircraft system. The wings & empennage are attached to the

fuselage. The ailerons & flaps are attached to the wings. The elevators are

attached to the tail plane & the rudder is attached to the fin. The leading gear

& power plant are accommodated in the wings & the fuselage depending on

the configuration.

The wings provide the lift. The control surfaces are the means to control the

movement of aircraft in flight about the longitudinal and vertical axis. The

landing gear supports the aircraft on the ground. The power plant provides the

thrust.

AIRCRAFT FORWARD PRINCIPLE OF FLIGHT

When aircraft is at rest, its weight is supported by landing gear. As the engine

are opened up to full power, the aircraft starts to move forward on its wheel

due to the ‘thrust’ created by the reaction on the aircraft forced rearwards by

propeller rotation. As the aircraft moves forward, the various part of the

aircraft offer resistance to the forward motion called ‘drag’. The drag is zero

at the commencement of the takeoff & builds up in proportion to the square of

the forward speed. The wings are specially shaped with an aero foil section.

There is an area of low pressure above the wings & area of high pressure

below the wings. The net effect causes a vertical component called ‘lift’. Lift

increases by increasing angle of attack and a stage is soon reached when lift

force is greater than the weight of the aircraft.

BLACK BOX

Often one of the first pieces of techno-speak that springs to mind when

we hear of an aviation disaster - and a catch-all phrase popular with the

media - is ‘Black Box,’ but how much do you really know about these

vital pieces of equipment?

Any commercial aero plane or corporate jet is required to be equipped

with a cockpit voice recorder and a flight data recorder. It is these two

items of separate equipment which we commonly refer to as a ‘Black

Box.’ While they do nothing to help the plane when it is in the air, both

these pieces of equipment are vitally important should the plane crash,

as they help crash investigators find out what happened just before the

crash.

(Black box external and internal)

Often, for example when a plane crashes into the sea, as happened with

the 1985 bombing of Air India flight 182 by Sikh terrorists over the

Atlantic Ocean just west of Ireland, investigators have very little to go

on – on this specific occasion the plane crashed before the pilot could

even issue a mayday signal and much of the debris sank into the sea,

leaving few clues.

Today, the Black Box is still just as vitally important in helping piece

together the causes of a plane crash, as seen by the discovery of the

Black Box in the Mexico plane crash that killed fourteen, including the

interior minister of Mexico on 4th November, 2008.

To help locate the cockpit voice recorder and a flight data recorder in the

aftermath of a plane crash that occurs at sea, each recorder has a device

fitted to it known as an Underwater Locator Beacon (ULB). The device

is activated as soon as the recorder comes into contact with water and it

can transmit from a depth as deep as 14,000 feet.

THE COCKPIT VOICE RECORDER

The main purpose of the Cockpit Voice Recorder is, unsurprisingly, to

record what the crew say and monitor any sounds that occur within the

cockpit. While investigators might be interested in any witty banter

between pilots that went on just before an explosion or plane

malfunction, trained investigators are keen to pick up on sounds such as

engine noise, stall warnings or emergency pings and pops. Investigators

are so skilled that they are then able to work out crucial flight

information such as the speed the plane was travelling and engine rpm

and can sometimes pinpoint the cause of a crash from the very sounds

the plane was making before it crashed. The Cockpit Voice Recorder is

also extremely important for determining the timing of events as it

contains information such as communication between the crew and

ground control and other aircraft. The Cockpit Voice Recorder is usually

located in the tail of a plane.

A cockpit voice recorder (CVR) is a flight recorder used to record the

audio environment in the flight recorder of an aircraft for the purpose of

investigation of accidents and incidents. This is typically achieved by

recording the signals of the microphones and earphones of the pilots'

headsets and of an area microphone in the roof of the cockpit. The

current applicable FAA TSO is C123b titled Cockpit Voice Recorder

Equipment. The details for a CVR are as follows-

Time recorded: 30 min continuous, 2 hours for solid state digital units

Number of channels: 4

Fire resistances: 1200 deg. C /30 min

Water pressure resistance: submerged 20,000 ft.

underwater locator beacon: 37.5 KHz

Battery: 6yr shelf life, 30 day operation