What must occur any time a TH-73 enters visible moisture regarding pitot heat?

• A. Should be turned on
• B. Shall be turned on
• C. May be turned on
• D. Can be turned on

Answer: (B)

When operating a TH-73, regulation specifies that the pitot heat must be engaged whenever the helicopter enters visible moisture. This requirement is rooted in the need to prevent ice formation and ensure the accuracy of the airspeed indicator. Ice buildup in the pitot tube can lead to erroneous readings, which are critical for safe flight operations.

The phrasing "shall be turned on" indicates a mandatory action, establishing a strict protocol that pilots must follow to maintain safety when encountering conditions like rain, fog, or clouds where visible moisture is present. This requirement is part of the aircraft's operating procedures and reflects the importance of mitigating any risks associated with moisture in the air that could impact instrument performance. The use of mandatory language emphasizes the necessity of pilot compliance to uphold safety standards during flight operations.