Aircraft systems and instrumentsQuestion 544 of 934

The pitot tube ram air opening is blocked, but the drain hole is clear. What does the ASI read?

  1. The correct airspeed
  2. Zero
  3. A higher airspeed than actual
  4. A lower airspeed than actual, but not zero
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Correct answer: Zero

The pressure in the system vents through the drain hole. The ASI then senses no difference between ram and static pressure.

Source: Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Chapter 8: Flight Instruments — Blockage of the Pitot-Static System — Blocked Pitot System, page 212

Practice aircraft systems and instruments

Questions last reviewed: 18 October 2026