What is the maximum number of types of AIRMETs?

The maximum number of types of AIRMETs is four. AIRMETs, or Airmen's Meteorological Information, are designed to provide information about significant weather conditions that may affect the safety of aircraft operations. Each type of AIRMET addresses a different category of hazardous weather.

The four types of AIRMETs are as follows:

1. AIRMET Sierra – This type warns of widespread IFR conditions (visibility below 3 miles and/or ceilings below 1,000 feet) and/or mountain obscuration due to clouds or precipitation.

2. AIRMET Tango – This type indicates moderate turbulence and may also cover strong surface winds that could affect flying conditions.

3. AIRMET Zulu – This AIRMET warns of moderate icing conditions that may occur, providing pilots insight into potential hazards from ice accumulation.

4. AIRMET for non-convective weather phenomena – This category includes a general warning of significant weather conditions that do not fall under the other three specific types.

Each of these AIRMETs plays a crucial role in ensuring that pilots are aware of and can prepare for various weather-related hazards during flight.