What does the combination of primary, supporting, and cross-check provide in instrument scanning?

• A. Primary is the sole source of information during scanning.
• B. Primary provides main control reference, supporting provides secondary data, cross-check verifies consistency and detects errors.
• C. Primary, supporting, and cross-check are only used during panic.
• D. Cross-check is optional and used for navigation only.

Answer: (B)

In instrument scanning, you build a complete, reliable picture by using three roles together. The primary instrument gives the main reference for aircraft attitude and control—the primary source you rely on most. The supporting instruments provide secondary data to corroborate the primary and to supply additional information you need for safe flight, like altitude, airspeed, heading, and vertical speed. The cross-check is the ongoing comparison across all instruments to ensure readings are consistent; it helps you spot discrepancies and potential instrument failures early. This combination keeps you oriented, reduces dependence on a single instrument, and enhances safety by catching errors before they become problems.