What would a pilot use to verify altitude during a suspected pitot-static failure in flight?

• A. Standby instruments and outside references; cross-check with known ground features.
• B. GPS only.
• C. Engine instruments.
• D. Cabin pressure gauge.

Answer: (A)

When the pitot-static system is suspected to be faulty, you want readings that aren’t influenced by the same blocked ports. Standby instruments provide an independent source of information because they’re designed to operate on a separate or isolated feed, including a standby altimeter that can show your altitude even if the main instrument is unreliable. Using an alternate static source further reduces the chance that a blocked static port is skewing your altitude display.

Then, corroborate with outside references—visible ground features and known field elevations. By comparing the instrument readings with the actual terrain elevation you can confirm whether you’re higher or lower than shown, which helps you maintain safe clearance and proper procedural spacing.

GPS altitude could supplement your understanding, but it isn’t a guaranteed primary reference in a malfunction scenario because GPS integrity can vary and isn’t always reliable for precise altitude verification in all conditions. Engine instruments don’t indicate altitude, and a cabin pressure gauge measures interior pressure, not the aircraft’s true altitude.

So the best approach is to rely on the standby instruments and cross-check with known ground references to verify your altitude when pitot-static issues are suspected.