How can you verify instrument readings if you suspect a pitot-static problem?

• A. Rely solely on the primary instruments.
• B. Ignore the issue and continue.
• C. Switch to manual fuel control.
• D. Use standby instruments, perform cross-checks, and reference outside air information; follow emergency procedures.

Answer: (D)

When you suspect a pitot-static problem, you don’t rely on a single source of data. The key idea is to use independent information from standby instruments and cross-check it against the primary readings, then confirm with outside air information and follow the emergency procedures.

Standby instruments are typically fed from independent sources, so their indications can serve as a reliable reference if the primary pitot-static data are suspect. By cross-checking, you compare, for example, the standby airspeed with the primary airspeed and the standby altitude/vertical speed with the primary altimeter/vertical speed. Any large discrepancy points to an error in one system, helping you determine which readings to trust and how to maintain safe flight.

Referencing outside air information means using data not tied to the suspect pitot-static system to verify your air data—such as alternate data sources if available or other available cues—so you can confirm a safe flight profile while you follow the established emergency procedures for unreliable air data. This approach is safer than continuing with potentially faulty readings or ignoring the issue.