KCSE Past Papers Aviation Technology 2011

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4.10 AVIATION TECHNOLOGY

4.10.1 Aviation Technology Paper 1 (450/1)

SECTION A (40 marks)

Answer all the questions in this section.

1 List four resources considered when planning to carry out a safe maintenance task on an aircraft(2 marks)

2 State three reasons for alloying metals.(3 marks)

3 (a) State the use of each of the following tools:

(i) oddleg calipers;

(ii) diamond chisel;

(iii) plug gauge;

(iv) dial test gauge.(2 marks)

(b) List four methods of joining metals in an aircraft.(2 marks)

4 (a) State the meaning of the term meteorology as applied to aviation industry.(1 mark)

(b) Explain two types of information provided by the meteorology department.(2 marks)

5 Sketch and state the use of each of the following aircraft hardware:

(a) stud;

(b) turnbuckle.(3 marks)

6 (a) Describe the behaviour of a totally stable aircraft. (1/2 marks)

(b) Give two reasons why aircrafts are not designed to enhance total stability.(2 marks)

(C) Explain two design features which promote lateral stability.(2 marks)

7 Describe the basic construction members of an aircraft Wing.(4 marks)

8 Sketch and name four types of aeropiston engine cylinder arrangements.(6 marks)

9 Explain five requirements of a basic electrical system.(5 marks)

10 (a) Draw the symbols for each of the following:

(i) transformer;

(ii) diameter;

(iii) internal threads. (1/2 marks)

(b) Figure 1 shows an isometric view of a truncated cone.

Fig.1 Draw the front and end elevation of the cone in:

(i) first angle orthographic projection;

(ii) third angle orthographic projection. (3 marks)

SECTION B (60 marks)

Answer question 11 and any other three questions from this section.

Candidates are advised to spend not more than 25 minutes on question 11

11 Figure 2 shows the three orthographic views of a bracket drawn in first angle projection.

Draw in good proportion, an isometric view of the bracket taking F as the lowest point. (15 marks)

12 With the aid of a sketch, explain the operation of a twin spool turbo jet engine. (15 marks)

13 (a) With the aid of sketches, explain how each of the following flaps functions:

(i) plain;

(ii) fowler;

(iii) slotted. (6 marks)

(b) With the aid of sketches, explain how each of the following flaps functions:

(i) plain;

(ii) fowler;

(iii) slotted. (6 marks)

14 (a) Explain four functions of hydraulic system accumulator. (4 marks)

(b) Explain four functions of hydraulic system accumulator. (4 marks)

(C) A hydraulic system has two pistons A and B with diameter 2 cm and 12 cm respectively.

(i) Sketch the arrangement and determine the distance moved by B when A moves 3 cm.

(ii) Explain why the system is used in an aircraft hydraulic system. (9 marks)

15 (a) Explain five properties that make aluminium based alloy most suited for the construction of an aircraft fuselage. (5 marks)

(b) Describe each of the following maintenance tasks:

(i) non-destructive testing;

(ii) on condition monitoring;

(iii) random testing;

(iv) destructive testing. (4 marks)

(c) Outline the procedure of carrying out the following methods of testing aircraft parts.

(i) X - Ray

(ii) Fluorescent (6 marks)

4.10.2 Aviation Technology Paper 2 (450/2)

STATION 1

The bracket provided represents an aircraft part.

(a) On the drawing paper provided, draw the isometric view of the bracket taking X as the lowest point.

(b) Measure and record the following dimensions:

(i) overall length;

(ii) Width;

(iii) height. (10 marks)

STATION 2

Using the tools, materials and equipment provided make the locking dowel as shown in the figure

STATION 3

(a) The parts labelled J, K and L are defective due to corrosion. Complete the table below by:

(i) naming each part;

(ii) stating the cause and remedy for each defect;

(iii) indicating where the defect is likely to occur in an aircraft. (4 1/2 marks)

(b) Study the cross-section of the aircraft tyre provided and:

(i) name the pans labelled M, N. P, Q and R;

(ii) state the function of each part;

(iii) state one rejection criteria on the part marked Mt (5 1/2 marks)

SECTION 4

(a) (i) Identify the instrument labelled X.

(ii) Take and record the readings on the instrument.

(b) Remove the cover of the instrument and complete the table below:

(2 1/2 marks)

(4 marks)

(c) State:

(i) its principle of operation; .........................

(ii) its limitations; ...................................

(iii) reason for its limitations. .......................(1 1/2 marks)

(d) (i) Identify two defects on the instrument

(ii) Give two requirements for its maintenance (2 marks)

(e) Replace the cover.

STATION 5

(a) Using the apparatus, materials and equipment provided, carry out the following tasks.

(i) Heat the metallic strip on one face and record your observations.

(ii) Quench the strip in the water and record what happens.

(iii) Heat the metallic strip on one face and record your observations.

(iv) Quench the strip in the water and record what happens.

(v) state reason for :

(i) and (iii)above

(i) and (iv) above

(vi) Relate your observation to two system in an aircraft

(6 marks) (b) (i) Name the aircraft components labelled X, Y and Z and state the function of each.

X ...........................

Y ............................

Z.............................

(ii) State the common maintenance requirement for X and Y.

(4 marks)

STATION 6

Using the tools and component B provided, perform the following tasks:

(a) (i) identify component B;

(ii) state the engine system Where it is used;

(iii) state the number of cylinders for the component.

(1 1/2 marks)

(b) Measure and record:

(i) the depth of the hole painted white;

(ii) the distance between lobe C and D;

(iii) the diameter of the journal labelled E;

(iv) the height of the cam lobe labelled F. (4 marks)

(c) (i) Count the number of teeth on the part labelled G.

(ii) Name the type of gears on the part labelled G

(ii) indicate the method of locking of part G to the shaft. (3 marks)

(iv) Give three causes of the defect on the part labelled E4(1 1/2 marks)

STATION 7

The set-up provided is an aircraft harness With terminals labelled A to H on one end and terminals labelled 1-8 on the other end.

(a) Using the tester provided, check the continuity between the terminals and match them accordingly and complete the following table. (8 marks)

(b) Comment on the condition of each of the following terminals: (2 marks)

B ........................

D ........................

G .......................

H .......................

STATION 8

(a) Identify and record two design features of the aircraft models labelled A and B. (2 marks)

(b) Using the models labelled A, B and C, demonstrate to the examiner the following ground operations:

(i) towing model A;

(ii) towing model B;

(iii) debogging model A;

(iv) debogging model B;

(v) turning left for A;

(vi) turning left for B;

(vii) turning right for A;

(viii) turning right for B;

(ix) take off for A;

(x) take off for B. (5 marks)

(c) (i) using the tools provided, measure and record the following in model A.

Span ...........................

Chord .........................

(ii) Determine the following:

wing area;

aspect ratio.(3 marks)

STATION 9

On the propeller blade provided, perform the following tasks.

(a) Measure and record the station of the lines marked 1 and 2. (2 marks)

1 .....................

2 .....................

(b) Identity:

(i) the side marked 3; .................

(ii) the side marked 4; .................

(iii) the part painted red; ..............

(iv) the part painted blue. ..............

(c) Study the defects marked 5 and 6 and complete the table below.

(d) Give two preventive maintenance required on the blade.

STATION 10

(a) Using the chain and the set-up provided, perform the following tasks

(i) Identify the type of chain

(ii) Mount the chain on the set-up with the pinion at the following positions and in each case record your observations.

A Observations ...........................

B Observations ...........................

C Observations ...........................

(iii) From the observations in (a) (ii) above, determine the appropriate position for the set-up and state two reasons for your choice.

Position: .................................

Reasons ....................................

(iv) Remove the chain from the set-up and count and record the number of teeth on: pinion gear; ...........................................

sprocket gear. ..........................................

(v) Determine the velocity ratio of the set-up. (9 marks)

(b) Relate the experiment to two aircraft systems. (1 mark)

27.0 AVIATION TECHNOLOGY (450)

27.1 Aviation Technology Paper 1 (450/1)

1. RESOURCES

Skilled personnel.

Tools, equipment and spares.

Documentation, information manuals.

Time.

Facilities like hangar.any (4 x 1/2)

2. REASONS FOR ALLOYING

Improve mechanical properties.

Improve chemical properties.

Improve physical properties.

Make them corrosive resistant.

Make them heat treatable.any (3 x 1)

3. (a) TOOLS

Oddleg calipers - determine centre of round bar and draw lines parallel to an edge.

Diamond chisel - cutting very sharp comers.

Plug gauge - checking hole limits.

Dial gauge - determining out-of-roundness.(4 x 1/2)

(b) JOINING METALS

Soft soldering

Brazing

Welding

Riveting

Bonding (4 x 1/2)

4. (a)

planning.(1 mark)

(b) TYPES OF INFORMATION

Wind velocity and direction.

Pressure for setting instruments.

Weather: clouds and visibility

Temperature of the aerodrome. (2 x 1)

5. (a) Stud

(Diagram missing)

METEOROLOGY is the science of predicting or forecasting weather for flight (1 mark)

any (2 x 1)

for assembling two thick parts e.g engine block and cylinder head. (b) Turnbuckle

(Diagram missing)

for tensioning cables. Sketches (2 x 1)

6. (a) TOTALLY STABLE AIRCRAFT

An aircraft which when disturbed will return to normal without the intervention of the pilot. (1 1/2 marks)

(b) REASONS FOR DESIGN

- If too stable it becomes difficult to control.

- tends to be sluggish when manoeuvring.

- can become unpleasant to fly in bumpy weather.

- incase of instability, the pilot has to continually watch the aircraft attitude and constantly normalize it. (Any 2 x 1 = 2 marks)

(c) DESIGN FEATURES

Placing the wings as high as possible above the centre of gravity to provide pendulum stability.

Placing dehedral on low wing rnonoplenes to prevent side slip.

Provide swept back wing format to level the aircraft.

Provide anhedral where wing are angled downward to prevent side slip.

(Any 2 x 1= 2 marks)

7. MEMBERS OF AIRCRAFT WING.

(i) Spars extend lengthwise of the wing and take the entire load carried by the wing.

(ii) Stringers/Stiffeners : Strengthen the spars and join the ribs together.

(m) Stress skin takes the force of the air acting against the flight and transmits it to the ribs and the spars.

(iv) Ribs support the skin and provides the aerofoil shape.

(4 x 1= 4 marks)

8. CYLINDER ARRANGEMENT.

INLINE

Horizontally opposed

V - inline space brick/block correct type (4 x 1/2)

Radial / correct sketch (4 x 1)

Use (2 X 1/2)

9. BASIC ELECTRICAL SYSTEM

Power source for supply of power e.g. generator or battery.

Power regulator/controls/switches

Power distribution - busbars.

Load

Power protection/feedback - waming system

Emergency. any (5 X 1)

10 (a) imagee (b)

11

12

EXPLANATION

Air is induced from the atmosphere by both ram effect and induction of the compressors.

INTAKE On reaching the intake the air is heated by either hot bleed air or heated elements for the purpose of anti-icing. The air passes inlet guide vanes where the angle of attack is corrected and also further heated for prevention of icing. (2 marks)

COMPRESSION

On leaving the intake the air is passed through stages of rotors and stators of the low pressure compressor to raise the pressure energy. The air is then passed through stages of rotors and stators of the low pressure compressor to raise the pressure energy. The air is then passed through stages of rotors and stator to raise the pressure energy to the required value. (2 marks)

COMBUSTION

On leaving the compressor the high pressure air is apportioned in the following manner. i 10% of the total air for mixing with air and ignited for combustion.

18% of the total air for completing combustion and shaping the flame.

72% of the total air for dilution/cooling. (2 marks)

EXPANSION

On leaving the combustion chambers the high pressure expanding gases pass through the Nozzle guide vanes which corrects the angle and also lowers the temperature.

The expanding gases impart torque on the turbine to rotate the compressors and the accessory gear box.

On leaving the turbines the expanding gases has some energy left to accelerate it through propelling nozzle to generate thrust. (2 marks)

13. (a) Plain Flap - This is the type of flat that increases the camber when lowered to increase the coefficient of lift at slow speeds during take off and landing. When lowered fully creates drag to decelerate the aircraft.

imageeeeeeee

Fowler Flap - This type of flap increases the wing surface area to increase the generated lift at slow speeds during take off and landing. When lowered fully it creates drags to decelerate the aircraft.

imageeeee

Slotted Flap — This type of fiat creates a slot when lowered to hold down the boundary layer to generate more lift during take off and landing. When lowered fully creates drag to decelerate the aircraft.

(b) imageeeeee

(3 x 2 = 6 marks)

When an aircraft wing is moving below the critical mach number there is no shock wave formed. (1 mark)

When the aircraft wing moves at critical mach number an uncipient shock wave forms at the maximum camber and starts the transonic.

(1 mark)

When the aircraft wings moves at a higher speed the top camber becomes more developed and moves 1 backwards. Also another uncipient shock wave forms at the bottom. (1 mark)

On increasing the speed of the aircraft further the two waves become developed and moves backwards and makes the end of the transonic range. (2 marks)

In power transmission in a closed container.

“ Pressure in an enclosed container 1/2 is transmitted equally and undiminished V2 to all parts of the container and acts at right angles 1/, to the enclosing walls according to Pascal’s Law V2 .

(4 x 1/2 = 2 marks) (c)

(ii) The distance moved by effort is bigger than the distance moved by load. The load (output) is far much bigger than the effort (input) depending on the piston diameters. (2 x 1)

15. (a) Corrosion resistance - when aluminium corrodes it forms an oxide known as alclad that prevents any further corrosion.

Light in weight - SG is about that of iron or steel.

Conductivity - Aluminium is a good conductor of heat and electric current /electricity

Maleability - Aluminium can be rolled into thin sheets without rupture for the construction of aircraft stressed skin.

Ductility - Aluminium can be drawn into thin wires without fracture for the construction of cables.

Strength to weight ratio - aluminium is very strong for the same cross sectional area of other metals.

Machineability - Aluminium is cheap to manufacture such as casting, drop forging, cutting etc. 523 (Any 5 x 1 marks)

It can be soldered, brazed and welded.

(b) Non - Destructive testing is a means of checking the serviceability of an aircraft or engine part Without causing any harm to the part. (1 mark)

On condition monitoring is a means of checking the serviceability of an aircraft component Insitu/without removing from aircraft to prevent inflight shut-down. (1 mark)

Batch/Random testing is a means of determining the performance of aircraft parts by peaking on item on line production and testing it to destruction on the assumption that the rest in the line production will behave in the same manner. (1 mark)

Destnictive testing is where a specimen is tested to failure on the assumption that the part to be used on the aircraft will behave in the same manner. (1 mark)

(c) X - RAY

Evacuate the personnel.

Encircle the area with red rotating beacons.

Position the tranducer and the sensitive film.

Wear protective clothing.

Use remote switch to operate.

Take the film to a dark room.

View with powerful light.

- Evaluate. Any (6 x 1/2= 3 marks)

FLUORESCENT

Clean the part to be inspected.

Apply the penetrant.

Clean the part.

Dry the part.

Put the component into a darkroom.

View with a fluorescent light.

Evaluate. Any (6 x 1/2 = 3 marks)

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