Instrument Pocedure Sheet(1)

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INDIAN AEROSPACE & ENGINEERING, NAVI MUMBAI

Note: Name of the students given overleaf.

ISSUE NO. 01 REVISION NO. 00

DATE: JULY 2012 DATE: JULY 2012 SIGNATURE OF CHIEF INSTRUCTOR:

REF: IAE/PS/INST./01

DEMONSTRATION/FAMILIARIZATION/FUNCTIONAL TESTING PROCEDURE SHEETS

SHOP: Instrument Shop CAR REF: 4.11.7

TASK: Familiarization with compass swing procedure and occasion on witch compass swing must be

performed

BATCH/SEM:

TIME STARTED: TIME COMPLETED:

S.No Description Sign of student Sign of Instructor

1 Occasions on which a compass swing must be

performed

1 2 3 4 5

1.1 When the Accuracy of the compass is suspected

1.2 After any cockpit modification or major replacement

involving ferrous metal

1.3 Whenever a compass has been subjected to a shock for

example after a hard landing or turbulence

1.4 After A/C has passed through a severe electrical storm

1.5 After lightning strike

1.6 Whenever a change is made to the electrical system

1.7 Whenever a change of cargo is likely to affect the

compass

1.8 When an A/C operation is changed to a different

geographic location with a major change in magnetic

deviation

1.9 After A/C has been parked on one heading for over a

year

1.10 When Flux valves are replaced

2 Compass swinging procedures

Magnetic compass must be checked for accuracy in a

location free of steel structures underground pipes of

cables of equipment that produces magnetic fields.

2.1 The Master compass is a Reverse reading compass with

a gun singe arrangement mounted on top of it

2.2 A/C facing north and the person in the cockpit running







the engine at 1000rpm, an AME standing approx 30 ftin front of the A/C facing south He will align master

compass with the A/C cent line, using Hand signals, the

AME signals the person in the cockpit to make

additional adjustment to align The A/C with the master

compass. Once aligned on The Reading, The person in

The cockpit runs the engine (S) to approx 1700 rpm to

duplicate the A/C s magnetic field and then the person

reads the compass.

2.3 If The A/C compass is not in alignment with the

magnetic North with the master compass, then AMEcan correct the error by making small adjustment to

the north south Brass adjustment screw with a non-

metallic screw Driver

2.4 A/C should be positioned facing south and aligned with

the master compass. Use the same procedure as given

above, correct any error

2.5 Similarly repeat above procedure for A/C facing west/

East direction

2.6 Check the compass Reading on all cardinal headings,

Record the last reading and prepare a compasscorrection card as per annexure I Note: The Maximum

deviation is 10 on any one Reading.

2.7 Prepare a Deviation card, as per format annexure II

compass










TASK: Familiarization with fuel quantity gauge (float type fuel quantity gauge).

BATCH/SEM:


S.

NoDescription Sign of student Sign of Instructor

1 Purpose: 1 2 3 4 5

1.1 It is to indicate quantity of fuel in a/c fuel tanks.

1.2 It is used in small and older designed a/c.

2 Construction.2.1 It consists of float of cork.

2.2 It floats on top level of fuel

2.3 It moves downwards as the fuel is consumed during

flight.

2.4 It’s movement is coupled to gears which rotates horse

shoe magnet.

2.5 Magnet is shield on a top of a ferrous material pointer.

2.6 Pointer rotates against the calibrated scale .

2.7 The magnet rotates the pointer to indicate the quantity

of fuel.3 Function

3.1 The float moves potentiometer wiper

3.2 The indicator is a electric meter which is calibrated in

terms of unit of quantity of fuel.

4. Disadvantage

2.4 Error due to altitude change in a/c .










TASK: Familiarization with cylinder head temperature indicator

BATCH/SEM:



1 Cylinder head temperature gauge consists of 1 2 3 4 5

1.1 Thermocouple

1.2 Connecting lead between thermocouple and gauge

(indicator)

1.3 CHT gauge or indicator

2. Thermocouple is attached to cylinder head by surface

contact type.

3. The connecting lead between the thermocouple probe

is copper – constantan.

4. Principle of working

4.1 Whenever dissimilar metals are joined there is

formation of hot junction and cold junction.

4.2 EMF exists between hot junction and cold junction.

4.3 Current flows from hot junction to cold junction, and

the amount of current flow is proportional to cylinder

head temperature.

4.4 A sensitive millivoltmeter calibrated in the unit of

temp. is used as an indicator.

5. Resistance of Thermocouple gauge

5.1 It’s resistance may be either 8 ohm or 25 ohm.










TASK: Familiarization with exhaust gas temperature indicator

BATCH/SEM:



1 Exhaust gas temperature gauge consists of 1 2 3 4 5

1.1 Thermocouple

1.2 Connecting lead between thermocouple and gauge

(indicator)

1.3 EGT gauge or indicator

2. Thermocouple is of immersion type and stagnation

type.

3. The connecting lead between the thermocouple probe

is chromel and alumel.

4. Principle of working

4.1 Whenever dissimilar metals are joined there is

formation of hot junction and cold junction.

4.2 EMF exists between hot junction and cold junction.

4.3 Current flows from hot junction to cold junction, and

the amount of current flow is proportional to cylinder

head temperature.

4.4 A sensitive millivoltmeter calibrated in the unit of

temp. is used as an indicator.

5. Resistance of Thermocouple gauge

5.1 It’s resistance may be either 8 ohm or 25 ohm.










TASK: Familiarization with hydraulic pressure gauge

BATCH/SEM:



1 Purpose. 1 2 3 4 5

1.1 It is used to measure the pressure of hydraulic fluid.

2. Construction. It consists of four basic elements

2.1 Detecting element. It detects the change in physical

quantity or state of hydraulic fluid. Bourdon tube is

used as a detector.

2.2 Measuring element: It measures the change in

physical quantity by linear displacement. Lever is used

as a measuring element

2.3 Coupling element: It is attached between measuring

element and indicating element. Gear and pinion are

used. It magnifies the measured quantity.

2.4 Indicating element: It indicates the change in physical

quantity by moving pointer over a calibrated scale in

the unit of pressure.

3. Operating Principle.

3.1 The hydraulic fluid enters the bourdon tube through

its fixed ends.

3.2 The bourdon tube is off C letter shape and one end of

it is free to move.

3.3 Hydraulic fluid exert pressure on the wall of it and the

tube tends to become straight.

3.4 The displacement of tube is transferred to measuring

element and amplified by coupling element and

deflect the indicating pointer against the calibrated

dial












TASK: Familiarization with tire pressure gauge

BATCH/SEM:



1 Purpose. 1 2 3 4 5

1.1 It is used to measure the tire pressure

2. Construction. It consists of four basic elements

2.1 Detecting element. It detects the change in physical

quantity or state of hydraulic fluid. Bourdon tube is

used as a detector.

2.2 Measuring element: It measures the change in

physical quantity by linear displacement. Lever is used

as a measuring element

2.3 Coupling element: It is attached between measuring

element and indicating element. Gear and pinion are

used. It magnifies the measured quantity.

2.4 Indicating element: It indicates the change in physical

quantity by moving pointer over a calibrated scale in

the unit of pressure.

3. Operating Principle.

3.1 The air enters the bourdon tube through its fixed ends.

3.2 The bourdon tube is off C letter shape and one end of

it is free to move.

3.3 Air exert pressure on the wall of it and the tube tends

to become straight.

3.4 The displacement of tube is transferred to measuring

element and amplified by coupling element and deflect

the indicating pointer against the calibrated dial.







4 Range. 1 2 3 4 5

4.1 This gauge is calibrated between 0 to 230 psi.

5 Precautions

5.1 Do not blow the gauge with mouth.

5.2 Do not use this gauge for measuring either oxygen or

nitrogen pressure.










TASK: Familiarization with capacitor type fuel quantity indicator.

BATCH/SEM:



1 Purpose. 1 2 3 4 5

1.1 It is used to indicate the quantity of fuel available in a/c

fuel tank.

2. Principle :

2.1 Its working principle is based on the variation in the

capacity of a capacitor caused due to the change in di-

electric value due to the depth of fuel quantity in the

tank.

3. Circuit details. The circuit consists of

3.1 Tank unit

3.2 Amplifier ckt.

3.3 Indicator.

4. Operation

4.1 The tank unit is a basically a capacitor connected in

sensing loop ckt. (Loop A) and the amount of current

flow through it is compared with the current flowing

through reference capacitor (Loop B).

4.2 This differential current is amplified by an amplifier

4.3 The amplified current is given to the control phase

winding of two phase motor.

4.4 The reference voltage is given to reference winding of a two

phase motor.

4.5 This difference in phase between control winding and

reference winding will move the pointer against calibrated

scale.










TASK: Familiarization/Demonstration of DR Compass.

BATCH/SEM:



The following check/test is to be done on DR

compass to confirm its serviceability.

1 2 3 4 5

1.1 Pivot friction test

1.2 Damping test

1.3 Over swing test

1.4 Card test

1.5 Heading test

2 Description of test

2.1 Pivot friction test

2.1.1 Set the compass to all cardinal points in level pos.

2.1.2 Deflect the magnet assembly through 10 degree either

side with the help of small magnet

2.1.3 Wait for 30 sec. in deflected position and move away

the external magnet

2.1.4 The magnet should come back to its original position

within following tolerance

P and O 2 degree, B – 16 1 degree, E2 2.5 degree.

2.1.5 Precaution Test to be carried in level position. External

magnet should be weak

2.2 Damping test

2.2.1 Set the compass to all cardinal points in level position

2.2.2 With the help of small magnet deflect the magnet

assembly through 90 degree either side

2.2.3 Wait for 1 min. so that liquid gate settled. Remove the

external magnet







2.2.4 Note time of travel from deflected position up to 85degrees and see that time is within the limits as given

here P and O 5 to 8 sec., B – 16 1.4 to 1.8 sec., E2 3

to 5 sec.

2.3 Over swing test



side wait for a min. in deflected position

2.3.3 Remove the external magnet and note the compass

card movement. The card should come to its original

position

2.3.4 If the card over swing note the over swing. Mean of

the over swing either side should be within 15 degree.

2.4 Card Test

2.4.1 Set the compass reading to 000 degree in level

position

2.4.2 Rotate the compass to 360 degree slowly and

smoothly in one minute. The difference of reading

should be within 2 degree after 360 degree

rotation.2.5 Heading Test

2.5.1 Tilt the compass to 20 degree

2.5.2 Rotate the compass through 360 degree and note that

magnet assembly is not touching the bowl.










TASK: Familiarization on DR Compass inspection and test .

BATCH/SEM:



Carry out the following inspection and test of DR

compass .

1 2 3 4 5

1. Document: Check the serial no. of compass and check

its certificate, check its self and service life. It should

not be expired.

2. Transit Damage: Check visually the compass and

ensure that there is no damage sign on the compass

3. As far as possible the compass should be stored in

manufacture packing .It should be position in store in

non magnetic rack.

4. Check the locate for discoloration due to ageing.

4.1. Check sediments

4.2 Check bezel glass is not loose, no crack /scratch

4.3 Compass card graduation marking condition is correct.

Check for luminous point.

4.4 For p type compass lock lever function correctly, is not

having cracks dents.

4.5 If the compass is fitted with integral lightning check

cable and bulb for it’s condition.










TASK: Familiarization on RPM Indicator (Tachometer) .

BATCH/SEM:



1. Purpose: It is to indicate rotation of crank shaft in

piston engine and turbine shaft in turbo jet engine per

minute.

1 2 3 4 5

2. Operation: Its working principle is centrifugal force

2.1 It consists of rectangular box which is off centre

hinged to a main shaft.

2.2 When the engine is running through flexible drive

main shaft is rotated.

2.3 Due to centrifugal force, light portion moves down,

pulley and rotor arm move down.

2.4. Pinion and pointer moves in clockwise direction to

indicate increase in RPM.

2.5 Flexible Drive is hardened steel core one end male

coupling nipple is brazed.

2.6 Twin wire is wound of fine layers in anti fashion. It is

protected by protective cover and fitted with end cap.










TASK: Familiarization with AC Tachometer.

BATCH/SEM:



1. Principle: It is working on the principle of measuring

frequency with variation in RPM.

1 2 3 4 5

2. Construction: It consists of

2.1 Transmitter

2.2 Indicator

3. Details of its parts

3.1 Transmitter : It is 3 phase alternator

3.2 It has stator 3 coils connected in star form 120 degree

apart.

3.3 A rotor is either 2 pole or 4 pole permanent magnet

3.4 Rotor is coupled to engine gear box

3.5 When the engine is running rotor rotates an emf is

generated in stator coil.

3.6 The frequency of emf generated is directly

proportional to rpm.

4. Indicator: It is basically 3 phase synchronous motor

with indicating element.4.2 Stator has 3 coils 120 degree apart.

4.3 When electrical supply is fed, a rotating magnetic

field is produced whose RPM is proportional to

engine RPM

4.4 To make itself starting the rotor is specially designed

4.5 Most of the rotor is 2 pole permanent magnet

another half is squirrel cage rotor both halves are

separated by aluminum disc squirrel cage rotor, starts

to rotate the rotor and permanent part make it to run







with synchronous RPM.4.6 Now the rotor is running proportional to engine RPM

on the extended portion of shaft

4.7 There is an indicating element which consists of 2

pole permanent magnet which is fixed on shaft and

copper cup closely encases it When rotor rotates

permanent magnetic field is cut by cup

4.8 EMF is generated in it whose current produces a field

which reacts with main field and tries to rotate. But it

only deflects due to tension of coil hair spring.

4.9 A pointer fitted over cup moves over the dial toindicate RPM of engine.










TASK: Familiarization with Ratio type temperature gauge.

BATCH/SEM:



1. Principle : Ratio of torque produced by 2 coils 1 2 3 4 5

2. construction :

2.1 It is a moving coil instrument having 2 coils and sensing

bulb

2.2 Coils are parallel connected to AC DC supply

2.3 One of the coil is deflection coil the other coil is

controlling coil

2.4 Sensing bulb is a thermistor

3 Function

3.3 A rotor is either 2 pole or 4 pole permanent magnet

3.4 Rotor is coupled to engine gear box

3.5 When the engine is running rotor rotates an emf is

generated in stator coil.

3.6 The frequency of emf generated is directly proportional

to rpm.

4. Indicator: It is basically 3 phase synchronous motor

with indicating element.

4.2 Stator has 3 coils 120 degree apart.

4.3 When electrical supply is fed, a rotating magnetic field

is produced whose RPM is proportional to engine RPM

4.4 To make it self starting the rotor is specially designed

4.5 Most of the rotor is 2 pole permanent magnet another

half is squirrel cage rotor both halves are separated by

aluminum disc squirrel cage rotor, starts to rotate the

rotor and permanent part make it to run with

synchronous RPM.







4.6 Now the rotor is running proportional to engine RPMon the extended portion of shaft

4.7 There is an indicating element which consists of 2 pole

permanent magnet which is fixed on shaft and copper

cup closely encases it When rotor rotates permanent

magnetic field is cut by cup

4.8 EMF is generated in it whose current produces a field

which reacts with main field and tries to rotate. But it

only deflects due to tension of coil hair spring.

4.9 A pointer fitted over cup moves over the dial to

indicate RPM of engine.










TASK: Familiarization with Wheatstone bridge temperature gauge.

BATCH/SEM:



1. Purpose : It is used to measure the temperature of the

system in the a/c

1 2 3 4 5

2. Principle: Resistance varies as per the temperature

variation this resistance is in the one arm of bridge ckt.

The voltage drop a cross the resistance varies the

equilibrium condition in the bridge ckt.

3 Construction: It consists of temperature sensor

resistance known as sensing bulb, bridge ckt,galvanometer, source of power.

4 Function:

4.1 Sensing resistance is mounted over the system whose

temp. is to be measured.

4.2 Sensing resistance is one arm of the bridge ckt.

4.3 Bridge ckt. is connected to 12 V supply.

4.4 Due to the change in resistance caused by the variation

in temp. will disturb the balance condition in bridge.

4.5 Current proportional to temp. change flows to the

galvanometer

4.6 A triangle is marked on dial which is known as null

point and bridge is balanced to the null point.

4.7 The galvanometer pointer is deflected against that

calibrated scales in the unit of temp.

5. Disadvantage

5.1 The variation in D.C supply produces errors in the

reading taken by this gauge










TASK: Familiarization with Manifold (Boost) pressure gauge.

BATCH/SEM:



1. Purpose: It is used to indicate induction manifold

pressure in terms of absolute pressure.

1 2 3 4 5

2. Application: It is fitted in super charge piston engine

and also in normally aspirated engine. In case of a/c

having constant speed propeller.

3 Construction: It consists of bellow type of sensor,coupling system and indicating system.

4 Function:

4.1 It maintains air pressure at a constant level.

4.2 When the engine is not running it indicates ambient

pressure.

4.3 The amount of pressure deflects the bellow in turn this

deflection is multiplied by coupling element and

ultimately deflects the pointer against the calibrated

scale.

4.4 To know the absolute pressure 15 PSI must be added ingauge reading.










TASK: Familiarization with Fuel flow indicator.

BATCH/SEM:



1. Purpose: It is to indicate the rate of fuel flow delivered

to the engine.

1 2 3 4 5

2. Application: It is used in Jet Engine .It is also used in

normally aspirated engine having more than one

engine.

3 Types of fuel flow indicator:

3.1 Direct type (Instantaneous type)

3.2 Integrated type.

4 Construction of direct type fuel flow indicator. It

consists of:

4.1 Transmitter: It is just like a piece of fuel pipe line fitted

in to the fuel line running up to the engine. Fuel enters

the metering chamber and spring controlled vane is

placed in the chamber, fuel strikes the vane and it

moves. A calibrated spring controlled the displacement

of vane .This deflection is transmitted to the indicator.

4.2 This displacement moves the wiper of a circular

potentiometer and it generates a signal which is

amplified by an amplifier ultimately given to

milliammeter calibrated in terms of rate of fuel flow.

4.3 A bypass line is provided and it comes in to action in

case there is any blockage/ restriction in main line.










TASK: Familiarization with Oil pressure gauge.

BATCH/SEM:



1. Purpose: It is to indicate oil pressure of engine 1 2 3 4 5

2. Application: It is used in all types of engine mounted

on the aircraft.

3 Construction: it consists of

3.1 Detecting element : It can be either bourdon tube or

diaphragm or capsule type depending on the amount of

pressure to be measured

3.2 Coupling element it is used to multiply the deflection of

detecting element

3.3 Indicating element the pointer moves against a

calibrated in the units of pressure

4 The range marking

4.1 Green arc marking it is marked between 30 to 60 psi

and indicates normal operating range.

4.2 Red radial line indicates the max. and min. allowable

range .

5. Note: It is one of the most important instruments of

power plant during starting of engine if oil pressure

does not develop with in 30 sec. the engine must be

stopped.










TASK: Familiarization with Oil temperature indicator.

BATCH/SEM:



1. Purpose: It is to indicate temperature of engine oil. 1 2 3 4 5

2. Application: It is used in all types of engine mounted

on the aircraft.

3 Construction: It may be of

3.1 Wheat stone bridge type or

3.2 Ratio meter

4 The range marking

4.1 Green arc marking indicates safe range of operation.

4.2 Red radial line indicates the max. and min. allowable

range .










TASK: Familiarization with Directional gyro, their function and maintenance check.

BATCH/SEM:



1. Purpose: It is to indicate direction of a/c when it is

encompassed with DR compass.

1 2 3 4 5

2. Principle: It make use of tied gyro and use the

property of rigidity.

3 Construction:

3.1 Rotor is pivoted to inner gimbal ring

3.2 Inner gimbal is pivoted to outer gimbal ring

3.3 Outer gimbal is pivoted to instrument case

3.4 A compass card graduated from 0 to 360 degree in step

of 5 degree is fitted to outer gimbal ring.

3.5 Instrument case consists of bezel assembly on which

there is a vertical line known as lubber line.

4 Operation :

4.1 when suction is created in instrument case ,

atmospheric air from rear enters through filter from

there it passes to the bottom bearing chamber of outer

ring through two tubes.

4.2 There are holes on the neck of bottom pivot of outer

gimbal ring through which it passes to vertical arm . Air

is divided into two air jets and strike the rotor buckets.

4.3 When rotor is running at sufficient RPM, due to rigidity

of gyro , rotor, inner gimbal ring, outer gimbal ring ,

compass card remains stationary .

4.4 Instrument case and lubber line are the integral part of

the a\c

4.5 When a\c turns, lubber line turns to indicate new







direction of a\c5 Caging device its purpose is to cage or uncage the gyro

during

5.1 Transit or storage

5.2 Starting

5.3 Resetting of card reading

5.4 Aerobatics

6 Operation of caging device

6.1 When caging knob is pushed in, on the same shaft

there is conical vertical, hollow bevel gear which

meshes with horizontal bevel gear fitted to the outer

gimbal ring

6.2 One arm is resting in the hollow portion of vertical

bevel gear

6.3 The arm moves downward causes to arms to move

opposite side

6.4 A sleeve is held in its position with the help of two

inwards pins

6.5 Sleeve move upward which raises horizontal arm and

the flat portion of this arm locks inner gimbal ring

7 Erection device two air jets striking the rotor buckets is

known as erection device

7.1 Purpose to maintain the rotor axis in horizontal

position

7.2 When rotor is in horizontal position air jets striking the

rotor buckets are at equal distance from the centre of

the rotor

7.3 Jet reactions are equal and opposite and no torque is

applied on outer gimbal ring and rotor remain in

horizontal position

7.4 In case rotor is deflected from its horizontal position jet

reaction will not be equal and opposite and resultant

torque is applied on the outer gimbal ring so that rotor

comes back to its horizontal position

Note 1 Ref: A\C instrument and integrated instruments by EHJ PALLET. A\C instruments by CA WILLAMS. CAIP2 and 15A










TASK: Familiarization with turn and slip indicator

BATCH/SEM:


S.No DescriptionSign of student Sign of Instructor

1. Purpose: is to 1 2 3 4 5

1.1 Indicate lateral attitude of a\c during level flight

1.2 Direction and rate of turn of a\c

1.3 Help pilot to take correctly bank turn, side slip or skid if any

2. Construction: it is a composite instrument which

consist of

2.1 Rate gyro

2.2 Bank indicator

3 Operation: rate gyro

3.1 Rotor of rate gyro is pivoted to gimbal ring in lateralaxis

3.2 Gimbal ring is pivoted to instrument case in

longitudinal axis

3.3 A restraining calibrated spring is fitted in between

gimbal ring and instrument frame

3.4 Rate of precession is directly proportional to gimbal ring

3.5 A pointer is attached to gimbal ring which indicate rate of

turn

3.6 The rate of turn is 1, 2, 3, and 4 which indicate 180 degree

per minute, 360 degree per minute, 540 degree per minuteand 720 degree per minute rate of turn respectively

3.7 No erection device is used because A restraining

calibrated spring is fitted and serve the purpose

3.8 Damping device is used to damp out pointer vibration

Note 1 Ref: A\C instrument and integrated instruments by EHJ PALLET.










TASK: Familiarization with turn coordinator

BATCH/SEM:



1. Purpose: it is to indicate coordinated turn of a\c 1 2 3 4 5

2. Operation:

2.1 It is similar to turn and bank indicator the difference

between the two is that the gimbal ring in place of

horizontal it is inclined to 30 degree

2.2 As the gimbal ring is inclined it is more sensitive to bank

as well as turn

2.3 Operation: rate gyro

3.1 Rotor of rate gyro is pivoted to gimbal ring in lateral

axis

3.2 gimbal ring is pivoted to instrument case in longitudinal

axis


gimbal ring and instrument frame

3.4 Rate of precession is directly proportional to gimbal

ring

3.5 A pointer is attached to gimbal ring which indicate rate

of turn

3.6 The rate of turn is 1, 2, 3, and 4 which indicate 180

degree per minute, 360 degree per minute, 540 degree

per minute and 720 degree per minute rate of turn

respectively

3.7 No erection device is used because A restraining

calibrated spring is fitted and serve the purpose

3.8 Damping device is used to damp out pointer vibration

Note 1 Ref: A\C instrument and integrated instruments by EHJ PALLET.







IAE/PS/INST./21



TASK: Mock-up for Tire pressure gauge

BATCH/SEM:



1. Purpose: it is used to demonstrate the working

principle of measurement of tire pressure

1 2 3 4 5

2. Construction

2.1 Pressure gauge ( 0 – 230 ) PSI

2.2 Pressure gauge ( 0 - 600 ) PSI

2.3 Source of pressure ( foot operated pump)

2.4 Pneumatic pipe lines

2.5 connector

2.6 Control valve

3. Operation

3.1 Press the pump handle , the piston moves inside the

chamber of pump and the air pressure flows through

the pipe lines

3.2 Pipe lines is connected to the pressure gauge

3.3 It will deflect the bourdon tube as the pressure

increases

3.4 The movement of bourdon tube is magnified and

transmitted to the indicator by the coupling element

gear and sector

3.5 The amount of pressure is indicated on the dial of the

pressure gauge

4. Precautions

4.1 Apply the force to the pump constantly

4.2 All the connection must be properly fitted and clamps

should be tight

4.3 Pipe lines should be straight to prevent pressure drop










TASK: Mock-up for Thermocouple principle

BATCH/SEM:



1. Purpose: 1 2 3 4 5

1.1 To demonstrate about the operation of thermocouple

1.2 To measure the temperature of cylinder head

temperature or exhaust gas temperature

2. Construction

2.1 220 V AC supply

2.2 Fuse

2.3 Power indicator

2.4 Switch

2.5 Heater

2.6 thermocouple

2.7 temperature indicator

2.8 Extension lead

3. Operation

3.1 Switch on to supply 220 V AC

3.2 Power is indicated on the power indicator

3.3 Wait for minute for heating up the heater

3.4 Place the one end of the thermocouple lead over the

heater to heat one end and other end to the room

temperature

3.5 As the heater heated up ( temperature increase ) the

indicator on the panel will indicate the temperature

change.

3.6 As the temperature different increases the voltage

generated and indicated by the moving coil meter

3.7 We use heater in place of cylinder head or exhaust gas







temperature4. Precautions

4.1 Be ensure that all the connections are appropriately

connected before switch on

4.2 Do not touch the heater

4.3 Thermocouple lead should maintain the appropriate

distance with heater to sense the temperature.

4.4 Extension lead should be of the same materials from

which the thermocouple made










TASK: Mock-up for Ratio meter principle

BATCH/SEM:



1. Purpose: 1 2 3 4 5

1.1 To demonstrate about the operating principle of Ratio

meter

1.2 To measure the temperature of oil and hydraulic fluid

etc

2. Construction

2.1 220 V AC supply

2.2 Fuse

2.3 Power indicator

2.4 Switch

2.5 Heater

2.6 Temperature sensor

2.7 temperature indicator ( Ratio meter )

2.8 Extension lead

3. Operation

3.1 Switch on to supply 220 V AC to heater

3.2 Power is indicated on the power indicator

3.3 Wait for 5 minute for heating up the heater

3.4 Place the temperature sensor over the heater and

maintain the distance.

3.5 As the temperature increases the resistance increases

and so the current varies on the one coil and so the

unbalance condition exist between the two coils.

3.6 This create a net torque to rotate the pointer over the

dial calibrated in units of temperature

3.7 We use heater in place of oil or hydraulic fluid.







4. Precautions4.1 Be ensure that all the connections are appropriately


4.2 Do not touch the heater

4.3 Temperature sensor should maintain the appropriate

distance with heater to sense the temperature.










TASK: Mock-up for Pitot-static heating system

BATCH/SEM:



1. Purpose: 1 2 3 4 5

1.1 It is used as an anti icing system in the pitot – static

tube

1.2 It prevent the formation of ice in the pitot tube

2. Construction

2.1 220 V AC supply

2.2 Transformer

2.3 Rectifier unit

2.4 Ammeter

2.5 Pitot tube mounted with heater

3. Operation

3.1 Switch on the power to supply 220 V AC

3.2 Transformer convert 220 V AC to 12 V AC

3.3 Rectifier unit convert 12 V AC to 12 V Dc

3.4 Ammeter indicate the current flow to the heater

3.5 If the heater is not functioning the ammeter will not

read

3.6 Wait for at least 5 min and then touch the pitot tube .

3.7 The tube will heated up as the time progress.

4. Precautions



4.2 Do not supply 220 V AC directly to the heater

4.3 Ammeter should be connected to appropriate polarity










TASK: Mock-up for Turn and slip indicator

BATCH/SEM:



1. Purpose: 1 2 3 4 5

1.1 To demonstrate about the working principle of TSI

indicator

1.2 To demonstrate about the precision

1.3 To demonstrate about the slip and skid

2. Construction

2.1 220 V AC supply

2.2 Transformer

2.3 Rectifier unit

2.4 Fuse and switch

2.5 DC motor to rotate the rotor

2.6 TSI

2.7 Stand connected with bearing in which the TSI is

mounted so that TSI will move freely

3. Operation



3.3 Rectifier unit convert 12 V AC to 12 V Dc

3.4 Fuse is used for circuit protection

3.5 Wait for few seconds so that the rotor rotates at the

full RPM and it become constant.

3.6 As the force applied on the input axis the precision will

take place at 90 degree away in the direction of

rotation.

3.7 And the pointer will move to show turning either the

left or right according to the force applied







3.8 The inclinometer will indicate the skid or slip dependingon the amount of force applied

4. Precautions



4.2 Do not supply 220 V AC directly to the rotor motor

4.3 Do not apply the heavy force

4.4 Move the TSI carefully









SHOP: Instrument Shop CAR REF: 4.11.2 TASK: Mock-up for ASI working principle and leak test

BATCH/SEM:



1. Purpose: 1 2 3 4 5

1.1 To demonstrate about the working principle of ASI

1.2 To demonstrate about the case leak

2. Construction

2.1 Power supply 220 V AC

2.2 Blower , pitot pressure source

2.3 Pipe lines and connectors

2.4 ASI indicator

2.5 Control valve

2.6 ASI in the sealed chamber

3. Operation

3.1 Switch on the power to supply 220 V AC to the blower

3.2 The output of blower is connected to the pitot line by

the pipe line and control valve control the pressure to

be fed inside the capsule

3.3 As we rotate the control valve , the amount of pressure

increases ,capsule expands and the ASI will indicate

according to the pressure increase

3.4 Switch off the blower

3.5 The reading of ASI mounted on sealed chamber does

not drop below the appropriate level.

3.6 If it drop there is a leakage in the ASI

4. Precautions

4.1 As the capsule is very sensitive so pressure should be

controlled

4.2 Valve should be opened constantly to avoid the

unbalance force

4.3 Connections should be tight and sealant is used in each

connection to prevent pressure leak

4.4 Never blow with mouth










TASK: Mock-up for Altimeter working principle and leak test

BATCH/SEM:



1. Purpose: 1 2 3 4 5

1.1 To demonstrate about the working principle of

Altimeter

1.2 To demonstrate about the case leak

2. Construction

2.1 Power supply 220 V AC

2.2 Suction pump , static pressure source

2.3 Pipe lines and connectors

2.4 Altimeter

2.5 Control valve

2.6 Altimeter in the sealed chamber

2.7 Suction gauge

3. Operation

3.1 Switch on the power to supply 220 V AC to the suction

gauge

3.2 The suction pump is connected to Altimeter static line

and the sealed chamber with the pipelines and

connectors

3.3 As we rotate the control valve , the amount of suction

increases and the pressure outside the capsule is

reduced

3.4 The altimeter will indicate the appropriate height

3.5 The created by the suction pump is indicated on the

suction gauge







3.6 Switch off the suction pump

3.7 The reading of altimeter mounted on sealed chamber

do not drop below the appropriate level

3.8 If it drop there is a leakage in the sealed chamber or

altimeter case

3.9 Check the sealing and repeat the procedure 2 or 3 time

4. Precautions

4.1 As the capsule is very sensitive so pressure should be

controlled

4.2 Valve should be opened constantly to avoid the

unbalance force

4.3 Connections should be tight and sealant is used in each

connection to prevent pressure leak

4.4 Never used high pressure source










TASK: Mock-up for RPM indicator

BATCH/SEM:



1. Purpose: 1 2 3 4 5

1.1 It is used to demonstrate the working principle of RPM

indicator

2. Construction

2.1 Three phase squirrel case synchronous motor

2.2 Cranking handle for rotating generator shaft

2.3 RPM indicator

2.4 Associated circuitry

3. Operation

3.1 Fit the cranking handle to shaft of the three phase

squirrel case synchronous motor

3.2 Rotate the handle by hand with minimum vibration

3.3 Three phase supply is connected to the RPM indicator

3.4 Current supplied to the indicator is indicated by the

pointer on the RPM indicator

4. Precautions


connected before start processing

4.2 Rotate the handle with minimum vibration and secure

properly by hand

4.3 Rotate the crank shaft in clockwise direction only










TASK: Mock-up for Float type fuel quantity indicator

BATCH/SEM:



1. Purpose: 1 2 3 4 5

1.1 It is used to demonstrate the working principle of Float

type fuel quantity indicator

2. Construction

2.1 220 V AC supply

2.2 Transformer

2.3 Rectifier unit

2.4 voltmeter

2.5 Potentiometer

2.6 Float type gauge

2.7 Associated circuitry

3. Operation



3.3 Rectifier unit convert 12 V AC to 12 V DC

3.4 The float move with hand upward that will move the

potentiometer wiper to the lower resistance end

3.5 So the maximum current will flow through the circuit

that will deflect the moving coil voltmeter to indicate

the high quantity of fuel

3.6 As the float will move downward by hand the

potentiometer wiper move to the higher resistance end

3.7 So the minimum current will flow through the circuit

that will deflect the moving coil voltmeter to indicate

the low quantity of fuel

4. Precautions







4.1 Be ensure that all the connections are appropriatelyconnected before start processing

4.2 Float should be moved constantly and in balanced

manner

4.3 Be ensure the voltmeter pointer rest at zero position

before switch on










TASK: Mock-up for Instrument panel

BATCH/SEM:



1. Purpose: 1 2 3 4 5

1.1 It is used to demonstrate the location of various

instruments on a instrument panel

2. Construction

2.1 Basic instruments ( flight instruments )

2.2 Instrument panel

2.3 Various navigational instrument

2.4 Engine instruments

2.5 Different screws

3. Position of instruments

3.1 Instruments are installed according to Basic six

arrangement

3.2 The color of panel is black

3.3 ASI is installed at the top left of the panel

3.4 Course deviation indicator is installed at the bottom

middle of the panel

3.5 Turn and slip indicator at the bottom right of panel

3.6 RMI and mach meter is installed at outside the Basic six

3.7 Inner, outer and middle marker beacon indicator is

installed at the top of the panel










2.1.5 Precaution Test to be carried in level position. External

magnet should be weak

2.2 Damping test


2.2.2 With the help of small magnet deflect the magnet

assembly through 90 degree either side

2.2.3 Wait for 1 min. so that liquid gate settled. Remove the

external magnet

2.2.4 Note time of travel from deflected position up to 85

degrees and see that time is within the limits as given

here

P and O 5 to 8 sec., B – 16 1.4 to 1.8 sec., E2 3 to 5

sec.

2.3 Over swing test



side wait for a min. in deflected position

2.3.3 Remove the external magnet and note the compass

card movement. The card should come to its original

position

2.3.4 If the card over swing note the over swing. Mean of the

over swing either side should be within 15 degree.

2.4 Card Test

2.4.1 Set the compass reading to 000 degree in level position

2.4.2 Rotate the compass to 360 degree slowly and smoothly

in one minute. The difference of reading should be

within 2 degree after 360 degree rotation.

2.5 Heading Test

2.5.1 Tilt the compass to 20 degree

2.5.2 Rotate the compass through 360 degree and note that

magnet assembly is not touching the bowl.










TASK: Demonstration/ familiarization of air speed indicator

BATCH/SEM:



1 Purpose 1 2 3 4 5

1.1 It is used to indicate the forward speed of aircraft with

respect to air typically in knot or miles per hour

2. Description

2.1 The air speed indicator is connected to the both pitot

and static air pressure source

2.2 The difference between pitot pressure and static

pressure is called dynamic pressure

2.3 As the dynamic pressure increase the indication of air

speed indicator increase

2.4 A traditional air speed indicator contains a pressure

diaphragm that is connected to pitot tube

2.5 The case around the diaphragm is air tight and is

vented to the static port

2.6 The higher the speed the higher the ram pressure the

more pressure exerted on the diaphragm and the

higher the needle movement through the mechanical

linkage

2.7 the reading of air speed indicator varies with square or

the speed of aircraft

3 Definition

3.1 Indicated air speed ( IAS) the direct instrument reading

obtained from the airspeed indicator ,uncorrected for

variation in atmosphere density , installation error or

instrument error .







3.2 Calibrated airspeed ( CAS) :- indicated air speedcorrected for installation error and instrument error

3.3 True air speed ( TAS ) calibrated airspeed corrected for

altitude and non standard temperature

3.4 Ground speed ( GS) the actual speed of the airplane

over the ground . it is true airspeed adjusted for wind

Ground speed decrease with a headwind and increase

with tailwind

4 Color marking

4.1 White arc :- this arc is commonly referred to as the flap

operating range since its lower limit represent the fullflap stall speed and its upper limit provides the

maximum flap speed

4.2 Lower limit of white arc (VSO) :- the stalling speed or

the minimum steady flight speed in the landing

configuration . in small airplanes, this is the power off

stall speed at the maximum landing weight in the

landing configuration ( gear and flap down )

4.3 Upper limit of white arc(VFE) :- the maximum speed

with the flap extended

4.4 Green arc: - this is the normal operating range of theairplane. most flying occurs within this range

4.5 Lower limit of the green arc : - the stalling speed or the

minimum steady flight speed obtained in a specified

configuration. for most airplanes , this is the power off

stall speed at the maximum takeoff weight in the clean

configuration ( gear up , if retractable , and flap up )

4.6 Upper limit of the green arc :- the maximum structural

cruising speed do not exceed this speed except in

smooth air

4.7 Yellow arc :- caution range . fly within this range only insmooth air , and then only with caution

4.8 Red line :- never exceed speed . operating above this

speed is prohibited since it may result in damage or

structural failure

5 Other airspeed limitations

5.1 Landing gear operating speed :-the maximum speed for

extending or retracting the landing gear if using an

airplane equipped with retractable landing gear







5.2 Landing gear extended speed :- the maximum speed atwhich an airplane can be safely flown with the landing

gear extended

5.3 Best angle of climb speed :- the airspeed at which an

airplane gains the greatest amount of altitude in a

given distance . it is used during a short field takeoff to

clear an obstacle

5.4 Best rate of climb speed :- this airspeed provides the

most altitude gain in a given period of time

5.5 Minimum control speed :- this is the minimum flight

speed at which a light , twin engine airplane can besatisfactorily controlled when an engine suddenly

becomes inoperative and the remaining engine is at

takeoff power

5.6 Best rate of climb with one engine inoperative :- this

airspeed provides the most altitude gain in a given

period of time in a light , twin engine airplane following

an engine failure










TASK: Demonstration/ familiarization of altimeter

BATCH/SEM:



1 Purpose 1 2 3 4 5

1.1 It is used to measure the height of aeroplane above a

given pressure level

It gives altitude information

2. Principle of operation

2.1 The pressure altimeter is an aneroid barometer that

measures the pressure of the atmosphere at the level

where the altimeter is located and presents an altitude

indication in feet

2.2 The altimeter uses static pressure as its source of

operation

2.3 The presentation of altitude varies considerably

between different types of altimeters . it may be one

pointer , two pointer or may be three pointer

2.4 Movement of aneroid element is transmitted through

gears to the three hand that indicates altitude

2.5 The shortest hand indicates altitude in tens of

thousands of feet, the intermediate hand in thousands

of feet and the longest hand in hundreds of feet

2.6 The change in temperature is compensated by bi-

metallic strip

2.7 The change in elasticity due to variation in ambient

temperature is compensated by U – shaped bracket

3 Definition

3.1 Indicated altitude := that altitude read directly from the

altimeter (uncorrected ) when it is set to the current












TASK: Demonstration/ familiarization of vertical speed indicator

BATCH/SEM:



1 Purpose 1 2 3 4 5

1.1 Vertical speed indicator (vertical velocity indicator) is

used to indicates the climbing , descending or level

flight

The rate of climb , descent is indicated in feet per

minute

It indicates zero at level flight if properly calibrated

2. Principle of operation

2.1 Vertical speed indicator operates solely from static

pressure

2.2 It is a differential pressure instrument

2.3 It contains a diaphragm with connecting linkage and

gearing to the indicator pointer inside an airtight case

2.4 The inside of the diaphragm is connected directly to

the static line of the pitot-static system

2.5 The area outside the diaphragm , which is inside the

instrument case ,is connected to the static line, but

through the restricted orifices (calibrated leak)

2.6 Both the diaphragm and the case receive air from the

static lines at existing atmospheric pressure .

2.7 When the airplane is on the ground or in level flight the

pressure inside the diaphragm and the instrument case

remains the same and the pointer is at the zero

indications

2.8 When the airplane climbs or descends, the pressure

inside the diaphragm changes immediately , but due to







metering action of the restricted passages , the casepressure remains higher or lower for a short time ,

causing the diaphragm to contract or expand ,

2.9 This causes a pressure difference that is indicated on

the instrument needle as a climb or descent.

2.10 The vertical speed indicator is capable of displaying two

different types of information

Trend information shows an immediate

indication of an increase or decrease in the

airplane”s rate of climb or descent

Rate information shows a stabilized rate ofchange in altitude

3. Instrument check :-

to verify proper operation , make sure the VSI is

indicating near zero prior take-off

After takeoff , it should indicates a positive rate

of climb










TASK: Demonstration/ familiarization of gyroscopic flight instrument

BATCH/SEM:



1 Gyroscope 1 2 3 4 5

1.1 A wheel or rotor designed and mounted to utilize these

properties is called gyroscope.

Two important design characteristics of an instrument

gyro are great weight for its size or high density and

rotation at high speed with low friction bearings

2. Properties of gyro

2.1 Rigidity in space :- rigidity in space refers to the

principle that a gyroscope remains in a fixed position in

the plane in which it is spinning .

2.2 It depends on three factors

1. the mass of the rotor

2. the speed of the rotation

3. the distance at which the mass acts from the centre

i.e. the radius of gyration

2.3 The change in direction takes place , not in line with

the force ,but always at a point 90* away in the

direction of rotation2.4 The rate of precession also depends on three factors

1. the strength and direction of the applied force

2. the moment of inertia of the rotor

3. the angular velocity of the rotor

2.5 The greater the force , the greater is the rate of

precession

2.6 The greater the moment of inertia and greater and the

greater the angular velocity the smaller is the rate of







precession2.7 The axis about which a force is applied is termed the

input axis and the axis about the precession takes place

is termed the output axis

2.8 Rigidity provides a stabilized reference unaffected by

the movement of the supporting body, and precession

controls the effects of apparent and real drift thus

maintaining stabilized datums.

3 Definitions

3.1 Apparent drift :- in horizontal axis gyroscope

Due to earth rotation earth rotates about its axis atthe rate of 15* / hour

3.2 Real drift :- real drift results from imperfections in a

gyroscope such as bearing and gimbal system

unbalance

Such imperfections cause unwanted precession which

can only be minimize by applying precession

engineering techniques to the design and construction.

3.3 Transport wander :- in vertical axis gyroscope

The control of transport wander is normally achieved

by using gravity sensing devices which automaticallydetect tilting of the gyroscopes spin axis and applying

the appropriate corrective torque

3.4 Gimbal lock :- this occurs when the gimbal orientation

is such that the spin axis becomes coincident with one

or other of the axes of freedom which serve as attitude

displacement references

3.5 Gimbal error :- this is the error which is also relates to

gimbal orientations and it occurs whenever the

gyroscope as a whole is displaced with its gimbal rings

not mutually at right angles to each other . the errors isparticularly relevant to horizontal axis gyroscope










TASK: Demonstration/ familiarization of gyro horizon

BATCH/SEM:



1 purpose 1 2 3 4 5

1.1 It is to indicate roll , pitch or level flight of A/C I relation

to natural horizon

Natural horizon :- a plane passing through virtual

meeting of the earth and the sky

2. Principle :-

2.1 It is an earth gyro and property of rigidity is used

3 Construction

3.1 Rotor is pivoted to rotor housing in vertical axis

3.2 Rotor housing is pivoted to outer gimbal ring in lateral

axis and outer gimbal ring is pivoted to the instrument

case in horizontal axis

3.3 There is an actuating pin on the rotor housing which

actuates horizon arm

3.4 Horizon arm is pivoted at the rear of the outer gimbal

ring and in front it carries a horizon bar which

represent natural horizon

3.5 In front of the outer gimbal ring a sky is fitted on which

a bank pointer is fitted either on top or at the bottom

4. Dial presentation :- miniature aircraft which represent

actual A/C is fitted at the centre . bank dial is fitted

either on top or at the bottom

5 Operation at level flight :- when the rotor is running

with sufficient RPM due to rigidity of gyro , rotor

housing and outer gimbal ring remain stationary .when

A/C is in level flight bank pointer is aligned with zero







and horizon bar is super imposed to the miniatureaircraft

6 Operation during bank:- when rotor is running with

sufficient RPM , due to rigidity of gyro , rotor housing

and outer gimbal ring remain stationary . bank pointer

fitted on outer gimbal ring , remain stationary . bank

dial which is integral part of aircraft , bank along with

the aircraft to indicate amount of bank

7 Operation during pitch :- when rotor is running with

sufficient RPM , due to rigidity of gyro , rotor housing

and outer gimbal ring remain stationary. The horizonbar is guided by rotor housing and remains stationary .

suppose the A/C is climbing , miniature aeroplane

which is integral part of A/C moves up to indicate

amount of climb

8 Bottom heaviness :- bottom of the rotor housing is

made heavier which minimize erection time at the time

of starting and at the same time it prevents the rotor to

deviate from vertical when power is off

9. Gimbal lock :- if freedom of rotor housing is 90 * on

either side and aircraft climbs and dive to 90 * there isloss of one degree of freedom . at this time if A/C turns

, complete gyro starts spinning . if A/C is coming

towards level flight , the rotor housing remains with

outer gimbal ring as if it is locked to outer gimbal ring .

it is known as gimbal lock










TASK: Demonstration/ familiarization of erection devices of vertical gyro

BATCH/SEM:



1 purpose 1 2 3 4 5

1.1 It is to maintain rotor in vertical position

2. Erection devices

2.1 Air which is coming out from rotor housing after rotor

rotation is coming through . the erection devices is

fitted at the bottom of rotor housing . it is a rectangular

block . it consists of air slot each side which is covered

with pendulous vane. Front and rear vanes are fitted on

one shaft . left and right vanes are fitted on another

shaft

3 Operation

3.1 When rotor is in true vertical position all the air slots

are covered partially and equally with their respective

vanes . jet reactions are equal and opposite and no

torque is applied on gyro. Rotor remains in vertical

position.

3.2 Due to any reason rotor is deflected from its vertical

position . a pair of vanes are coming into action . oneair slot is closed more and another air slot is opened

more . jet reactions are no more equal and opposite

and a resultant torque is applied to precess back the

rotor to its vertical position










TASK: Demonstration/ familiarization of attitude direction indicator(ADI)

BATCH/SEM:



1 purpose 1 2 3 4 5

1.1 It indicates roll, pitch attitude of A/C and also indicates

position of the A/C with respect to glide slope and

localizer radio wave , radio magnetic bearing from VOR

station

2. Function

2.1 Pitch and bank attitude signal is transmitted from

vertical gyro unit through computer . dial

representation also differ from gyro horizon .

2.2 In this a/c symbol is fixed at centre and pitch ribbon is

moving depending upon pitch attitude of a/c .

2.3 Drum is graduated from 0 to 90 * either side

2.4 When a/c is climbing sky blue color part is moving

downward . when a/c is diving brown color part is

moving upward to indicate amount of pitch in degree

.when a/c is in level flight dividing line match with a/c

symbol . command bars are incorporated to direct the

pilot to pitch or roll.

2.5 Bank:- ribbon is rotated by servomotor when a/c is

banking to indicate amount of bank in relation to bank

pointer

2.6 Glide slope and LOC indication := GS and LOC indication

are located left and bottom of ADI respectively . each

one consist of dial and pointer . the pointer is deflected

by micro ammeter . GS one dot represent 75 iA and

two dot represent 150 iA which represents 0.35* and







0.7 * deviation from beam . LOC has single dot left andright which represents 75 iA = 1* A/C deviation from

centre










TASK: Demonstration/ familiarization of horizontal situation indicator (HSI)

BATCH/SEM:



1 purpose 1 2 3 4 5

1.1 It is to indicate pictorial plan view of A/C in horizontal

plane in the form of heading VOR /LOC deviation

whether to & from to VOR , deviation from GS beam

and total distance covered by aircraft

2. Function

2.1 Heading indication is achieved by MHRS or INS . it

consists of compass card which is graduated from o* to

360 * . the direction of aircraft is read against lubber

line

2.2 It indicates lateral position of aircraft from VOR/LOC

radio beam

2.3 The deviation bar can be deflected left and right which

perform a directive command to be performed by the

pilot . each dot represent 1* deflection .

2.4 To or from is represented by a marker . if marker arrow

is towards heading of the aircraft , means aircraft is

heading towards the homing station . a warning redflag will appear on the meter to indicate that GS ,LOC

and VOR signal are unreliable or in operative .

2.5 The indicator receives signal from DME to indicate

distance flown in nautical miles .

2.6 In some of HSI is provided with indicator light which

glow when A/c has reached to decision altitude during

auto approach










TASK: Demonstration/ familiarization of mach meter

BATCH/SEM:



1 purpose 1 2 3 4 5

1.1 To indicate mach No of aircraft in step of decimal value

2. Principle

2.1 It is a composite instrument which comprises Air speed

unit for aircraft speed and altitude unit for sound

velocity

M = V/a = P-S/Ps

3. operation

3. 1 When aircraft speed increases differential capsule

expends which is transmitted to the rocking shaft via

input arm . output arm rotates the sector arm and

sector . the pinion and pointer rotate in clockwise

direction to indicate increase in mach number

3.2 Suppose speed is same but height increases . aneroid

capsule expands which moves the main rocking shaft

away from the aneroid capsule to decrease lever length

. therefore to increase mach number.










TASK: Demonstration/ familiarization of turn and bank indicator BATCH/SEM:



1 purpose 1 2 3 4 5

1.1 It indicates

a. lateral attitude of aircraft during level flight

b. direction and rate of turn of aircraft

c. correctly bank turn , side slip or skid if any

2. Principle

2.1 It is a composite instrument which comprises rate gyro

and bank indicator

3. operation

3. 1 Rotor is pivoted to gimbal ring in lateral axis . gimbal

ring is pivoted to instrument case in longitudinal axis .


gimbal ring and the instrument frame

3.3 Rate of precession is directly proportional to the rate of

turn of aircraft . it is also known as rate /rate principle

3.4 A pointer is attached to the gimbal ring which indicate

rate of turn either side rate 1,2,3,and 4 which indicates

180 */min , 360 * /min , 540*/min and 720 * /min rate

of turn respectively

3.5 When a/c turns a torque is applied and gimbal ring

precess against tension of spring to indicate rate of turn

of aircraft .

3.6 No erection devices is required because restraining

calibrated spring is fitted

3.7 Damping device is required to damp out pointer

vibration










TASK: Demonstration/ familiarization of types of gyro BATCH/SEM:



1 Space gyro :- it is mathematically calculated ideal gyro

having rotor , inner ring , outer ring mutually right

angle to each other . if it is kept in space , the rotor axis

will maintain its position with respect to space

2. Free gyro :- if we try to construct space gyro the out

come is a free gyro . its rotor axis is changing its

position continuously . this phenomenon is known as

gyro wander

3 Tied gyro:- it is same as free gyro but its rotor axis is

maintained constant with some external force

4 Earth’s gyro :- it is same as tied gyro but its rotor axis is

maintained vertical with the help of earth’s

gravitational force

5 Rate gyro :- it has only one degree of freedom other

than spinning freedom . rotor is pivoted to gimbal ring

in lateral axis . gimbal ring is pivoted to instrument case

in longitudinal axis a restraining calibrated spring is

fitted in between gimbal ring and instrument frame.

When aircraft turn a torque is applied to the rotor . the

gimbal ring process against the tension of spring . rate

of precession is directly proportional to the rate of turn

of torque applied . it is also known as rate /rate

principle










TASK: Demonstration/ familiarization of direction gyro BATCH/SEM:



1 purpose 1 2 3 4 5

1.1 It is to indicate direction of aircraft when it is

encompassed with DR compass

2. Principle

2.1 It is a tied gyro and property of rigidity is used

3. Construction

3.1 Rotor is pivoted to inner gimbal ring in horizontal .

3.2 Inner gimbal ring is pivoted to outer gimbal ring in

horizontal but 90* to rotor axis

3.3 Outer gimbal ring is pivoted to instrument case in

vertical axis

3.4 A compass card is graduated in from 0* to 360 * in step

of 5* is fitted to outer gimbal ring

3.5 Instrument case consists of bezel assembly on which

there is a vertical line is known as lubber line against

which reading of card is taken .

3.6 A caging knob is provided to cage or uncage the gyro

4. Air passage

4.1 When suction is created in instrument case ,atmosphere air from rear enters through filters , from

there it passes to the bottom bearing chamber of outer

ring through two tubes

4.2 There are holes on the neck of bottom pivot of outer

gimbal ring through which it passes to vertical arm . air

is divided into two air jets and strikes the rotor buckets

5 Operation during turn

5.1 When the rotor is running with sufficient RPM . due to







rigidity of gyro rotor,inner gimbal ring , outer gimbalring remains stationary .

5.2 Compass card which is fitted on outer gimbal ring

remains stationary

5.3 Instrument case and lubber line are integral part of

aircraft . when aircraft turns , lubber lines turns to

indicates new direction of aircraft










TASK: Demonstration/ familiarization of altitude alerting system BATCH/SEM:



1 purpose 1 2 3 4 5

1.1 To alert flight crew by aural and visual means when A/C

approach to or deviate from a preselected altitude

2. Function

2.1 The selected altitude is set by means of a knob on

controller which is indicated on digital counter which is

geared to synchro to provide signal . A/c pressure

altitude is provided to produce input signal .

2.2 Both the signal are compared when A/c approaches to

H1 (900 ‘) level from selected altitude , audio warning

for 2 seconds is on and warning light upto H2 (300) is

continuously illuminated from selected altitude.

2.3 When A/c approaches to selected altitude synchro

system becomes null . when A/c departed fro selected

altitude the sequence of operation is changed and

warning starts from H1 level








INSTITUTE OF AERONAUTICS AND ENGINEERING BHOPAL



TASK: Demonstration/ familiarization of pressure transducers BATCH/SEM:



1 purpose 1 2 3 4 5

1.1 It is used to convert one form of energy to another

form of energy .

2. Function

2.1 The transducers operates on the principle of force-

balance and comprises of two capsules

2.2 Pitot-static pressure transducers utilizing an “E” and “I”bars type of inductive pick-off unit

2.3 It consists of two capsules , the interior of one being

connected to the pitot pressure , while the other is

connected to the static pressure source

2.4 Both the capsules are connected to a pivoted beam

which in turn is connected to the “I “ bar of the pick-off

unit

2.5 When a change in airspeed takes place , the capsules

respond to the corresponding change in differential

pressure and the force they produce deflects thepivoted beam thereby displacing the “I” bar relative to

the limbs of the “E” bar

2.6 The air gap varies with the relative motion between E

and I bar and produce electrical signal that are

amplified and then applied to the control phase of the

servomotor which drives an output shaft and a lead

screw.










TASK: Demonstration/ familiarization of electrically operated fuel pressure gauge BATCH/SEM:



1 Purpose 1 2 3 4 5

1.1 To measure the pressure of fluid . diaphragm is used

2. Mechanism

2.1 The diaphragm has a flexible membrane with two sides

2.2 On one side is an enclosed capsule containing air or

some other fluid at a predetermined pressure

2.3 The other side can be left open to the air or screwed in

to whatever system the gauge is meant to measure.

2.4 The diaphragm is also attached to some sort of meter ,

which shows how much high pressure is .

3 Detecting element

3.1 A fluid in contact with a flexible membrane pushes on

that membrane , bending it .

3.2 The pressure is a measure of how hard it pushes .

3.3 When the outside preference is low, the reference

pressure bends the membrane out.

3.4 As the outside pressure increases , it pushes back on

the membrane , bending it back the other way .

3.5 By measuring how far the membrane bends , the gauge

can detect the outside pressure

4. Measuring the pressure

4.1 It consists of an electric resistance strain gauge

4.2 An electric resistance strain gauge uses a long strip of

an electric resistor – a device that resists the flow of

electricity .

4.3 The resistors is attached with the diaphragm

4.4 As the diaphragm bends , it stretches out the resistors ,




increasing the resistance .4.5 The more the diaphragm bends and increases the

resistance , the more the current drops.

By measuring the electric current , the gauge can

determine how far the diaphragm has bent, and thus ,

how much pressure the outside air is creating

Documents

Instrument Pocedure Sheet(1)