What is instrument cross-check?

• A. The continuous cross-verification of primary flight instruments to maintain accuracy.
• B. A periodic preflight inspection of navigation radios.
• C. A procedure to align the inertial reference system after engine start.
• D. An emergency procedure to reset the attitude indicator.

Answer: (A)

Instrument cross-check is the ongoing process of comparing readings from multiple flight instruments to ensure they agree and reflect the aircraft’s actual state. By continually scanning the attitude indicator, altitude, airspeed, heading, and turn indicators (often including the standby instruments), a pilot can spot discrepancies that signal instrument errors or failures and take appropriate action to maintain accurate flight attitude and performance. This isn’t something done only before flight or after engine start; it’s a continuous verification during all phases of flight so you can rely on the instruments rather than chasing false readings. If a mismatch appears, you isolate the potentially faulty instrument using the other sources of information, and you can rely on the remaining instruments or the standby system to fly safely. The other choices describe specific procedures that aren’t about this ongoing cross-checking process.