DGCA Module 06
4th Session of 2025
1. How should wires be identified.
A) A wire 3 to 7 inches in length should be identified approximately at the centre
B) A wire 7 inches in length should not be marked
C) Wires less than 3 inches should always be marked at both ends
Answer
2. Which type of spring is used in a valve when one spring is used in conjunction with another spring.
A) Helical compression spring
B) Helical torsion spring
C) Torsion bar
Answer
3. Fuselage tubing, turbine engine mounts and landing gear are made of.
A) Chromium steel B) Nickel-chromium steel C) Chrome-molybdenum steel
Answer
4. The Barcol tester is used to.
A) Test the hardness of steel
B) Test the hardness of copper, brass and other relatively soft non-ferrous alloys
C) Test the hardness of ferrous materials
Answer
5. The hardness of steel can be tested by.
A) Hardness test
B) Spark test
C) File test – the piece of material is cut into with the corner or edge of a file
Answer
6. To carry the same amount of current.
A) Aluminium wire should be 2 gauges larger than copper wire B) Aluminium wire should be the same gauge as copper wire C) Aluminium wire should be 2 gauges smaller than copper wire
Answer
7. A lock plate should provide.
A) Positive retention of the nut
B) Prevention of corrosion only
C) Reduction of vibration only
Answer
8. The tooth that projects above or outside the pitch circle is called the.
A) Dedendum
B) Addendum
C) Pitch diameter
Answer
9. What is the composition of chrome-molybdenum steel.
A) 0.25–0.55% Carbon, 0.15–0.25% Molybdenum, 0.50–1.10% Chromium
B) High nickel content steel
C) Low carbon plain steel
Answer
10. Normalizing is a heat-treatment process applied to.
A) Iron-base alloys
B) Aluminium alloys
C) Magnesium alloys
Answer
11. Which of the following is a nickel steel designation.
A) SAE 2330
B) SAE 1045
C) SAE 1095
Answer
12. A castellated shear nut is used with a.
A) Clevis
B) Vibration fitting
C) Radial-load fitting
Answer
13. In a four-digit aluminium alloy designation, the second digit indicates.
A) Alloy modification
B) Carbon percentage
C) Heat treatment
Answer
14. In die-casting, if low weight is of primary importance, which material is used.
A) Magnesium
B) Aluminium
C) Zinc
Answer
15. Which fitting is used where routine disconnection is not required.
A) Gyrofit fitting
B) Swaged fitting
C) Flared fitting
Answer
16. Aramid fibre has approximately.
A) Four times greater strength than aluminium
B) The same strength as aluminium
C) Less strength than aluminium
Answer
17. Parkeron-2 type screws are.
A) AN 530 and AN 531
B) AN 3 bolts
C) NAS screws
Answer
18. Where is a light drive fit permissible.
A) General-purpose bolt
B) Structural bolt
C) High-tensile bolt
Answer
19. The 2XXX series aluminium alloy is alloyed primarily with.
A) Copper
B) Magnesium
C) Silicon
Answer
20. Lockwashers should never be used.
A) With fasteners in primary/secondary structure, where the screw is subject to frequent removal, or where the washer is subjected to airflow
B) In non-structural locations
C) For temporary fastening
Answer
21. Which fibre has high tensile strength.
A) Nextel 480
B) Glass fibre
C) Carbon black
Answer
22. Corrosion repair in accordance with the SRM may be carried out by.
A) Damage repair by patching
B) Repair by insertion
C) Replacing the complete structure
Answer
23. A quick-disconnect coupling is designed to.
A) Permit connection and disconnection without loss of fluid or entry of air into the system
B) Provide a permanent connection
C) Be used only for fuel tanks
Answer
24. A surface composite repaired by blind rivets and sheet patching is considered a.
A) Temporary attachment
B) Structural repair
C) Workshop repair
Answer
25. The letter “A” in front of A214 indicates.
A) Addition of zinc to improve pouring quality
B) Addition of copper for increased strength
C) Addition of magnesium for increased hardness
Answer
26. MTCS – Which of the following statements about pins is correct.
A) Taper pin is used to carry shear load
B) Flat head pin is used with rod terminals and secondary controls
C) Roll pin is tubular in shape and slotted along the full length of the tube D) All of the above
Answer
27. Which forms of corrosion are commonly found in aircraft structures.
A) Surface corrosion and stress corrosion
B) Filiform corrosion and intergranular corrosion
C) Dissimilar metal corrosion and intergranular corrosion
D) All of the above
Answer
28. In an ultrasonic test, what is recorded by the transducer.
A) The frequency of the material
B) The temperature of the material
C) The time taken for the wave to return to the transducer
Answer
29. Which type of nut has a full load-carrying section with the thread strength of a standard bolt while locking the bolt firmly in position.
A) Castle nut B) Plain nut C) Check nut D) Boot self-locking nut
Answer
30. Which of the following defects is permitted in aircraft wood.
A) Pin knot clusters, as small clusters are acceptable because they produce only a small effect on grain direction
B) Large knot clusters
C) Severe cross grain
Answer
31. Which statement about the Barcol tester is correct.
A) The unit can be used in any position and in any space that allows the operator’s hand
B) It can be used only in the vertical position
C) It is used only for testing steel
Answer
32. About electric wire AWG, which statement is correct.
A) AWG wire diameter becomes smaller as the gauge number becomes larger
B) AWG wire diameter becomes larger as the gauge number becomes larger
C) AWG is based on the length of the wire
Answer
33. MTCS – Which statement about aircraft bearings is correct.
A) Roller bearings take radial loads
B) Ball bearings take both radial and axial loads
C) Roller bearings can carry more load than ball bearings
D) All of the above
34. Thermosetting resin is cured by.
A) Chemical reaction
B) Heat only
C) Adhesive action
Answer
35. Which statement about the Rockwell tester is correct.
A) Hardness of curved surfaces with a radius of 3/8 inch or greater can be obtained by the Rockwell tester
B) A 1/16-inch ball uses a 100 kg load and a red-colour scale
C) A 120° diamond cone-shaped penetrator is used for hard steel, while a 1/16-inch diameter ball is used for soft material
D) All of the above
Answer
36. NAS-type bolts are available with which of the following head types.
A) Hex head
B) Internal wrenching
C) Countersunk
D) All of the above
Answer
37. During inspection of glue on an aircraft, how should the paint be removed.
A) With the help of a scraper
B) With the help of proper solvents
C) By performing a kick-break test
Answer
38. Which statement is associated with carbon steel identification.
A) It is magnetically strong and can be identified by a nitric acid test
B) It is non-magnetic and has a rapid chemical reaction with nitric acid
C) It has a high chromium content
Answer
39. What is the maximum resistance specified for a bonding jumper.
A) 0.003 ohm (Ω)
B) 0.03 ohm (Ω)
C) 0.3 ohm (Ω)
Answer
40. What does a high diametral pitch indicate.
A) Larger tooth size
B) Smaller tooth size
C) Larger gear diameter
Answer
41. Filiform corrosion is associated with.
A) Humidity of air between 78–90% and a slightly acidic surface
B) Completely dry conditions
C) Steel surfaces only
Answer
42. Which plating is commonly used on aircraft parts for corrosion protection.
A) Cadmium plating
B) Chromium plating
C) Zinc plating only
Answer
43. MTCS – Which rivets are used in aluminium alloy structures where greater strength is required.
A) 2017-T and 2024-T rivets
B) Soft aluminium rivets only
C) Magnesium alloy rivets
Answer
44. Flexible hoses are used for.
A) Connecting a stationary part to a movable part
B) Connecting only stationary parts
C) Connecting only movable parts
Answer
45. An ideal gear is considered to be one that.
A) Has no losses
B) Has maximum friction losses
C) Converts all motion into heat
Answer
46. A Dzus fastener consists of.
A) Stud, grommet and receptacle
B) Head and shank only
C) A blind-type rivet only
Answer
47. What should be done with an icebox rivet after two weeks without use.
A) Discard it
B) Reheat it
C) It cannot be reheated
Answer
48. A brazier head rivet has a.
A) Large diameter head
B) Small diameter head
C) Flush head
Answer
49. Which statement about diametral pitch is correct.
A) Diametral pitch is the number of teeth per inch of pitch diameter
B) Diametral pitch does not depend on tooth size
C) Diametral pitch depends only on the material of the gear
Answer
50. Stainless steel springs have.
A) Low creep at high temperature
B) High creep at high temperature
C) No creep at any temperature
Answer
51. A turnbuckle is used for.
A) Minor adjustment in cable length
B) Major adjustment in cable length
C) Adjustment of rigid linkages only
Answer
52. MTCS – Which statements about spring materials are correct.
A) Flat springs are made from high-carbon steel
B) Small coil springs are made from high-carbon steel (1090) in sheet form
C) Large coil springs, such as engine valve springs and landing gear springs, are made from chrome-vanadium steel (6140)
D) Both 6140 and 1090 are interchangeable
Answer
53. 1100 rivets are used for.
A) Riveting softer aluminium alloys
B) Riveting high-strength steel
C) Riveting magnesium alloys only
Answer
54. Which statement regarding the suitability of metals for aircraft is correct.
A) In aircraft, electrical conductivity must also be considered in conjunction with bonding to eliminate radio interference
B) Only mechanical strength is important
C) Only corrosion resistance is important
Answer
55. MTCS – Which statement about a bolt fit is correct.
A) A 1-foot bolt can easily be turned with the fingers
B) As in (A), and the bolt is manufactured to a Class 2 fit
C) As in (A), and a Class 3 fit is a close fit
Answer
56. About aluminium wire.
A) Aluminium wire should not be used where there is frequent disconnection
B) Use of aluminium wire is discouraged for run of less than 3 feet.
C) Aluminium wire is preferred for very short run
57. Stainless-steel springs have.
A) Low strength at high temperature
B) Good resistance to corrosion and retain useful properties at elevated temperatures
C) No resistance to corrosion
Answer
58. A Cryofit fitting sleeve is made from.
A) Corrosion-resistant steel (CRS)
B) Shape-memory alloy (Tinel)
C) Aluminium alloy
Answer
59. Which statement about bearing groups is correct.
A) Group 2 bearings have large radial clearance
B) Group 4 bearings have small radial clearance
C) Normal-group bearings are used for most general applications
Answer
60. A turnbuckle is used for.
A) Making minor adjustments in a cable system
B) Joining two hydraulic pipes
C) Locking aircraft wheels in position
Answer
61. Which statement about aircraft springs is correct.
A) Flat springs are made from high-carbon steel, small coil springs are made from high-carbon steel such as 1090, and large coil springs are made from chrome-vanadium steel such as 6140
B) All aircraft springs are made only from aluminium alloy
C) High-carbon steel and chrome-vanadium steel springs are completely interchangeable
Answer
62. 1100-series rivets are generally used for riveting.
A) High-strength steel structures
B) Titanium structures only
C) Aluminium alloy structures where high strength is not required
Answer
63. In an aircraft, electrical conductivity must be considered along with bonding primarily to.
A) Eliminate radio interference
B) Increase engine thrust
C) Reduce hydraulic pressure
Answer
64. Which statement about aluminium wire is correct.
A) Aluminium wire should always be used where frequent disconnection is required
B) The use of aluminium wire is discouraged for runs of less than 3 feet
C) Aluminium wire is preferred for all short wire runs
Answer
65. If leakage still occurs after tightening the nut a total of 1/3 turn, the assembly should be removed and inspected for.
A) Scores
B) Cracks
C) Damage from overheating
D) All of the above
Answer
66. The four-numeral series is used to designate.
A) Aluminium alloys
B) Plain carbon and alloy steels
C) Titanium alloys
Answer
67. In an AN standard fitting, the letter “D” indicates.
A) Brass
B) Steel
C) Aluminium alloy
Answer
68. Miter gears are.
A) Mating bevel gears
B) Mating worm gears
C) Mating bevel gears with a conical angle of 75°
D) Mating worm gears with a pitch cone angle of 45°
Answer
69. Which type of gear, when meshed with another gear, is used to change rotary motion into reciprocating motion.
A) Gear pinion
B) Gear rack
C) Internal gear
Answer
70. MTCS – Which statement about a bolt fit is correct.
A) A 1-foot bolt can easily be turned with the fingers
B) As in (A), and the bolt is manufactured to a Class 2 fit
C) As in (A), and a Class 3 fit is a close fit
Answer
71. The most common rotating-beam or rotating-cantilever test used for testing materials is the.
A) Impact test
B) Torsion test
C) Fatigue test
Answer
72. Which series of wrought aluminium alloys, when alloyed with magnesium, results in heat-treatable alloys of very high strength.
A) 1200 series
B) 5000 series
C) 6000 series
D) 8000 series
Answer
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