Induction system ice prevention

This regulation requires that Part 121 air carrier airplanes must have equipment to prevent engine failures caused by ice building up in the engine's air intake system. When ice forms in the induction system, it can block airflow or break loose and damage engine components, potentially causing power loss or engine failure.

The "means" of prevention varies by aircraft type and might include:

• Heated air intake systems that melt ice before it accumulates
• Anti-ice systems that prevent ice formation
• Alternate air sources that bypass iced-over intakes

This is a design and certification requirement that manufacturers must meet before an aircraft can be approved for Part 121 operations. As a pilot, you'll use these systems according to your aircraft's procedures, but the regulation itself ensures the protective equipment exists on your airplane in the first place. It's part of the safety infrastructure that allows commercial operations 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.*