FAA Airline Transport Pilot (ATM)Meteorology and Weather ServicesMedium
A pilot files a PIREP stating that occasional use of the deicing boots removes ice accumulation, but the encounter could become a problem if the flight in icing conditions were extended beyond one hour. Which icing intensity should be reported?
- ASevere
- BTrace
- CLight
- DModerate
Show answer & explanationAnswer & explanation
Correct answer: C. Light
Light icing is defined as an accumulation rate that could create a problem if the flight is extended in icing conditions for more than one hour, with occasional use of deicing/anti-icing equipment removing or preventing accumulation. Trace icing is barely perceptible and rarely requires equipment use; moderate and severe require more urgent action or diversion.
Why the other options are wrong
- A. Severe icing overwhelms deicing equipment and demands immediate diversion.
- B. Trace icing barely requires any deicing action, even over an hour.
- D. Moderate icing makes even short encounters potentially hazardous and requires diversion consideration.
Icing Intensity PIREP Scale
A 4-level scale (Trace, Light, Moderate, Severe) used in PIREPs to describe the rate and hazard of airframe ice accumulation.
- Light: problem if extended beyond 1 hour, occasional deice use
- Moderate: even short encounters hazardous, equipment or diversion needed
- Severe: deicing equipment fails to control hazard, immediate diversion required
Memory trick: Trace tickles, Light lingers an hour, Moderate matters immediately, Severe demands escape