With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements : I. All types of UAVs can do vertical landing. II. All types of UAVs can do automated hovering. III. All types of UAVs can use battery only as a source of power supply. How many of the statements given above are correct?
- (a) Only one
- (b) Only two
- (c) All the three
- (d) None ✓ UPSC's answer
Why the answer is (d)
• UAVs come in several classes: multirotor (quadcopters), fixed-wing, hybrid VTOL and single-rotor; the statements generalise features that belong to only some classes.
• Statement I is wrong: fixed-wing UAVs take off and land like aeroplanes on a runway, by catapult or by belly-landing; only rotorcraft and VTOL types land vertically.
• Statement II is wrong: fixed-wing drones cannot hover at all — they must keep moving to generate lift; hovering is a rotorcraft capability.
• Statement III is wrong: many UAVs, especially long-endurance military ones such as the MQ-9 or Heron, use petrol or turbine engines, and some use hydrogen fuel cells or solar power.
• None of the statements is correct, option (d).
Why the other options are wrong
- (a) Only one
- No statement is correct; each falsely generalises to all UAV types.
- (b) Only two
- None of the three holds for all UAVs.
- (c) All the three
- Fixed-wing UAVs disprove statements I and II, and engine-powered UAVs disprove III.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2025, held on 25 May 2025. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.