Pitot static system failures can create confusing and misleading instrument indications. In this video, Jason Schappert walks through what happens when different parts of the pitot static system become blocked. The goal is to understand how each failure presents itself and how pilots should respond in real-world flying.
Understanding the Pitot Static System
The pitot static system provides airspeed, altitude, and vertical speed information. The pitot tube measures ram air pressure, while the static port senses outside air pressure. These pressures work together inside pressure-sensitive instruments to give accurate readings.
The pitot tube includes a ram air hole and a drain hole. The static port supplies pressure to the altimeter, vertical speed indicator, and airspeed indicator. When any part becomes blocked, the instruments react in specific and predictable ways.
More information on flight instruments and the pitot system can be found here.
What Happens When the Pitot Tube Is Blocked
When the pitot tube ram air hole becomes clogged but the static port remains open, airspeed drops to zero. Pulling an alternate static source will not help because the pitot pressure cannot enter the system. On glass panels, the indication may simply show zero without a warning flag.
If both the ram air hole and the drain hole become blocked, pressure becomes trapped inside the pitot line. In this case, the airspeed indicator behaves like an altimeter. As the aircraft climbs, indicated airspeed increases even though true airspeed does not. This can appear believable at first, which makes the failure especially dangerous.
When the pitot tube and static port both become blocked, all affected instruments freeze at their last readings. On glass panels, this failure may not immediately trigger alert messages. Pilots must recognize the abnormal behavior through cross-checking.
Using the Alternate Pitot Static System Source and Backups
Pulling the alternate static source introduces pressure from inside the aircraft. This causes the altimeter and vertical speed indicator to jump due to pressure differences. Pilots must expect this change and understand why it occurs.
The priority during pitot static system failures is restoring reliable pressure information. Older advice about breaking instruments does not apply to modern panels. Glass panel aircraft rely on standby instruments and independent systems. Redundancy and backups exist to give pilots usable information when primary systems fail.
Understanding how the pitot static system behaves builds confidence and prevents confusion. These failures may seem complex, but they follow consistent rules. Pilots who understand those rules can recognize failures quickly and make safer decisions.
Consistent learning and review prepare pilots for the unexpected. This knowledge turns confusing indications into manageable situations and supports safer, smarter flying in the real world.
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