Definition
The accumulation of ice on an aircraft's exterior surfaces while in flight, caused by supercooled water droplets striking the airframe and freezing on contact. It is reported by pilots in PIREPs using standard intensity categories: trace, light, moderate, and severe, and by type, typically rime, clear (glaze), or mixed.
Plain English
Ice building up on the airplane while you are flying through cloud or precipitation that contains very cold water droplets. When those droplets hit the aircraft, they freeze on the wings, propeller, windscreen, and other surfaces.
Context Anchor
You will see this term in pilot weather reports, weather briefings, and in decisions about whether a route, altitude, or cloud layer is safe to fly through.
Why Pilots Care
Ice accumulation reduces lift, increases drag, and can impair control surfaces, raising the risk of stall or loss of control.
Grounding Statement
Picture flying through a cold cloud and seeing ice begin to build on the windshield or wing edges; that is inflight icing.
Intuition Check
Inflight icing does not mean ordinary cold weather. It means ice is actually forming or building up on the aircraft during flight.
Example Sentence 1
The pilot filed a PIREP reporting moderate inflight icing between 6,000 and 8,000 feet over the ridge.
Example Sentence 2
The aircraft experienced reduced climb performance due to inflight icing on the wings.