KCSE 2018 Aviation Technology Paper 1 with Marking Scheme

QUESTIONS

SECTION A (44 marks)
Answer all questions in this section in the spaces provided

1. Outline three roles of the 1st officer or co-pilot.(3 marks)
2.                    
   1. Give the reasons why the following safety equipment must be carried on an aircraft. 
      1. Raft 
      2. Axe(2 marks)
   2. Outline two safety precautions to observe when using each of the following tools:
      1. Hand files
      2. Taps(2 marks)
3.                  
   1. List the type of clouds which
      1. can project up into the stratosphere 
      2. would cause moderate to severe aircraft icing(1 mark)
   2. Distinguish between the compass swing and the engine test areas.(2 marks)
4.                              
   1. Sketch the following types of locking devices.
      1. Spring washer
      2. Shake proof washer(2 marks)
   2. State four properties of aluminium alloy which makes it suitable for aircraft construction.
5.                      
   1. Explain the meaning of each of the following terms as applied in aviation:(2 marks)
      1. Indicated airspeed
      2. Mach number
      3. Viscosity(3 marks)
   2. With the aid of sketches, describe each of the following wing configurations:
      1. Mid-wing
      2. Dihedral(4 marks)
6.                        
   1. Outline three functions of the aircraft bulkhead.(3 marks)
   2. State the use of an inspection mirror in aircraft non-destructive testing (1 mark)
7.                                  
   1. Draw a cross-section of a cylinder piston assembly and show the following:
      1. Cylinder
      2. Piston
      3. Connecting rod
      4. Stroke(4 marks)
   2. Explain the application of Newton's third law of motion to a gas turbine engine.(2 marks)
8.                          
   1. Outline three methods of flight control systems.(3 marks)
   2. Name the type of instrument used to indicate each of the following:
      1. Aircraft pitching up and down (1 mark)
      2. The rate of altitude change (6 marks)
9. Outline the procedure of cutting internal threads.
10. Draw the symbol for each of the following as used in technical drawing.
    1. First angle projection (1 mark)
    2. Switch socket outlet (1 mark)
    3. External threads (1 mark)

SECTION B (56 marks)
Answer any four questions from this section in the spaces provided.

11.                                
    1. With the aid of a labelled sketch, show each of the following:
       1. Angle of attack
       2. Anhedral
       3. Angle of incidence(6 marks)
    2. State four factors that determine aircraft drag.(2 marks)
    3. With the aid of a labelled sketch, explain how the moments are balanced in flight.(6 marks)
12. With the aid of a labelled sketch, show the construction and airflow on a high bypass gas turbine engine.(14 marks)
13. Describe each of the following areas of the airport:
    1.                              
       1. Threshold
       2. Runway
       3. Touch down zone (3 marks)
    2.                        
       1. Outline five major causes of accidents in the aviation environment.
       2. Name four ways of communicating on the airside.(7 marks)
    3. Explain the following aircraft tasks:
       1. Parking
       2. Picketing
       3. Jacking
       4. Trestling (2 marks)
       5. Draw and label a cross section of unbalanced double acting actuator.(2 marks)
       6. With the aid of a labelled cross-sectional sketch, describe an airspeed indicator.(10 marks)
14.                              
15. Figure 1 shows an aircraft engine bracket drawn in isometric projection. In good proportion, draw in first angle projection the following views:
    1. Font elevation in the direction of arrow F.E.
    2. End elevation in the direction of arrow E.E.
    3. Plan
       

MARKING SCHEME

1.                              
   1. To assist in the safe and efficient conduct of the flight.
   2. Take charge of the aircraft if the captain is unable. 
   3. Assist in the safe navigation of the flight.
2.                    
   1.                        
      1. To help passengers and crew to float in case of a crash on water. 
      2. To assist in breaking out of the aircraft in case of a crash for quick evacuation.
   2.                    
      1.                  
         • Choose the right file for the material to be cut.
         • Ensure the handle is fixed firmly.
         • Keep the file clean by use of a file card or wire brush.
      2.                                  
         • Use the taps in their order, tapes, intermediate, plug or bottoming, 
         • The tap must be positioned vertically to the work piece. 
         • Avoid use of excessive force. 
         • Use cutting fluid.
3.              
   1.                                       
      1. Cumulonimbus
      2. Nimbo Stratus
   2.                      
      1. This is a designated area where aircraft compass is tested. 
      2. It is an area used to test run engine.
4.            
   1.                                  
      1.                          
         
         Spring washer
      2.                                        
         
         Shake proof washer
   2.                    
      1. Corrosion resistant
      2. Malleable and ductile
      3. Good conductor of electricity
      4. Strong and light
5.            
   1.                                               
      1. Indicated Speed: Airspeed of the aircraft indicated on the airspeed indicator. 
      2. Mach Number: Speed of the aircraft in relation to the speed of sound.
      3. Viscosity: The resistance to flow in fluids.
   2.                                
      
      MID WING 
      Straight wing fitted in the middle of fuselage 
      
      DIHEDRAL WING
      Wing fitted to the fuselage inclined at an upward angle
6.            
   1.                                
      1. Partition the fuselage
      2. Contain pressure (Pressure bulkheads)
      3. Fire wall (fire bulkhead) separate heat areas.
   2. Used to aid visual inspections particularly in hidden areas.
7.                                  
   1.                                        
      
      Sketch - 1 mark
      Correct labelling by 6 x 1/2 = 3 marks
   2.                        
      1. There must be an equal but opposite reaction.
      2. The mass of air is given an acceleration through the exhaust and this reaction pushes the aircraft in the opposite direction. (Thrust)
8.          
   1.                                
      1.  Manual - mechanical operated
      2. Powered - hydraulic operated 
      3. Fly by wire - Electrically operated
   2.                                  
      1.  Altitude indicator 
      2. Vertical Speed Indicator (VST)
9. Tapping procedure
   1. Drill hole to correct size. 
   2. Enter tap perpendicular to the work piece and turn in cutting direction
   3. Test the tap for squareness.
   4. Continue turning in cutting direction for half a turn then reverse for quarter a turn. 
   5. Change the second tap then plug tap (bottoming)
   6. Lubricate the work as you continue to cut.
10.                            
    1.                                              
       
       first angle projection
    2.                                             
       
       Switch socket outlet
    3.                                      
       
       External screw threads
11.                                             
    1.                                             
       
    2.                                               
       
    3.                                            
       
    4. Cd - co-efficient of drag
       e - density of air
       v² - velocity squared
       S.A - surface area
    5.                                              
       
       Explanation:
       - thrust is parallel to drag
       - lift is parallel to weight
       - lift in front of the centre of gravity
       - weight is behind the centre of pressure
12.                                                     
    
13.                              
    1.                                
       1. THRESHOLD
          It is the beginning of that portion of the run way usable for landing.
          (marking the start of Runway for landing)
       2. RUNWAY
          A defined rectangular area on an airport prepared for the landing and take off of aircrafts. 
       3. TOUCH DOWN ZONE
          The portion of the runway beyond the threshold intended for landing.
          (Aeroplanes first contact on the runway)
    2.                        
       1.                      
          • Complacency (over sure) 
          • Hurriedness (Hasty reaction Poor communication 
          • Ignorance (lack of training)
          • Failure to observe safety regulations
          • Indiscipline and attitude.
          • Poor judgement
          • Weather conditions
          • System malfunction
       2.                  
          • Use of hand signals (marshalling) 
          • Use of flares or lights 
          • By radio 
          • Use of painted signs
    3.                                      
       1. Putting an aircraft in designed safe area for static operations or storage. 
       2. Securing the aircraft if it is to stay parked for long periods. 
       3. Lifting the aircraft off ground for maintenance.
       4. Supporting the aircraft on trestles after it has been jacked to ensure safety during maintenance or if the aircraft has to stay on jacks for a long period.
14.                  
    1.                                                 
       1. Lighter in weight 
       2. Quick in response (dead beat) 
       3. It is reliable 
       4. Can be easily maintained 
       5. It's not a shock or fire hazard.
    2.                                                            
       
       sketch - 1 mark
       label 2  x 1/2 - 1 mark
       total - 2 marks
       
       A sealed case ported to static pressure
       A capsule (pressure sensitive) open to pitot pressure
       Capsule movement amplified by mechanical linkage which moves a pointer over a scale,
       Correct labelling (7 x ¹/₂)=3¹/₂ marks)
       Correct sketching (5 x ¹/₂) = 2¹/₂ marks)
       Description = 4 marks
15.