Abnormal Systems: Partial Power and Pitot-Static Failures

A partial power loss or rough-running engine is a serious warning even when some power remains. The usual suspects are carburetor ice, a fouled spark plug, a failing magneto, or a fuel-system problem, and the pilot works through them methodically: carburetor heat for suspected ice, mixture and throttle adjustments, magneto checks, and switching fuel tanks — all while continuously planning for a possible forced landing in case the engine quits entirely. Pitot-static failures attack the instruments rather than the engine. A blocked pitot tube makes the airspeed indicator behave like an altimeter, reading higher as you climb and lower as you descend, while a blocked static port throws off the airspeed indicator, altimeter, and vertical speed indicator together. The fix is the alternate static source — or, in some airplanes, breaking the glass of an unused static instrument — and flying known pitch-and-power settings as a reliable backup while you sort out which instruments you can still trust.