What are the dangers of instrument error due to failures or out-of-calibration conditions?

• A. Inaccurate readings can cause actions outside operating parameters; instruments must be calibrated per regulations and manufacturers’ recommendations.
• B. Inaccurate readings have no effect if pilots ignore them.
• C. Inaccurate readings automatically correct themselves during flight.
• D. Instrument faults are only a maintenance issue and do not affect operations.

Answer: (B)

Instrument indications guide how you control and monitor the engine and airplane systems, so any failure or out-of-calibration condition means the readings may not reflect reality. When readings are off, acting on them can push engine parameters, pressures, or temperatures outside safe operating limits, creating a real safety risk. That’s why keeping instruments calibrated and within specified tolerances is essential—the indications must be trustworthy so the crew or mechanic can rely on them to prevent unsafe conditions.

The other statements miss the point: ignoring inaccurate readings doesn’t make them accurate and can still lead to unsafe actions; readings don’t automatically correct themselves in flight; and instrument faults aren’t just a maintenance issue—they can directly affect how the aircraft operates.