Which action is required if a FSSII reading is below the threshold of 0.03?

• A. Pilot must be notified
• B. Recalibrate the instrument
• C. Discard the sample
• D. Continue testing with a backup method

Answer: (A)

When a measurement falls below the designated threshold, the immediate step is to alert the person who makes flight decisions—the pilot. This threshold breach signals an abnormal condition that could affect safety or performance, so the pilot needs to know right away to decide on further action, such as flight plan adjustments or further inspection.

Calibrating the instrument on the fly isn’t appropriate because calibration procedures require controlled conditions and proper documentation, and attempting it during operation could mask or misrepresent the issue. Discarding the sample wastes potentially important data and isn’t the prescribed response to a low reading. Continuing with a backup method is only appropriate if there’s a documented procedure allowing it; otherwise, informing the pilot is the correct course to ensure timely and appropriate decision-making.