Blockages in the pitot system or static ports primarily affect which instrument?

Blockages in the pitot system or static ports primarily affect which instrument?

• A. Airpeed indicator
• B. Altimeter
• C. Attitude indicator
• D. Vertical speed indicator

Answer: (A)

The key idea is that the airspeed indicator relies directly on pressures from the pitot-static system. The pitot tube provides dynamic pressure, while the static ports supply the reference ambient pressure used to translate that dynamic pressure into a displayed airspeed. If the pitot tube is blocked, there’s no dynamic pressure reaching the airspeed instrument, so it can read zero or otherwise become unreliable. If the static ports are blocked, the reference pressure is wrong, which also corrupts the airspeed reading. Although other instruments like the altimeter and vertical speed indicator depend on static pressure and can be affected by static-port blockages, the instrument most directly tied to both pitot and static pressures is the airspeed indicator, making it the one primarily affected.

The key idea is that the airspeed indicator relies directly on pressures from the pitot-static system. The pitot tube provides dynamic pressure, while the static ports supply the reference ambient pressure used to translate that dynamic pressure into a displayed airspeed. If the pitot tube is blocked, there’s no dynamic pressure reaching the airspeed instrument, so it can read zero or otherwise become unreliable. If the static ports are blocked, the reference pressure is wrong, which also corrupts the airspeed reading. Although other instruments like the altimeter and vertical speed indicator depend on static pressure and can be affected by static-port blockages, the instrument most directly tied to both pitot and static pressures is the airspeed indicator, making it the one primarily affected.