Pitot heat indication systems

This regulation requires transport category airplanes operating under Part 135 to have a pitot heat indication system if the aircraft has pitot heat. The indication system alerts pilots when pitot heat is functioning, which is critical because pitot tubes can ice over and cause unreliable airspeed indications—a serious safety hazard.

The requirement took effect April 12, 1981, and the indication system must meet the standards specified in § 25.1326 as it existed on April 12, 1978. Certificate holders could request extensions up to April 12, 1983, if they could demonstrate circumstances beyond their control prevented compliance and provided an acceptable compliance schedule.

In practical terms, this means Part 135 operators flying transport category aircraft must have a working indicator (typically a light or annunciator) showing when pitot heat is active, ensuring pilots can verify this critical anti-icing system is operating during flight in icing conditions.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*