In aviation, what does the term "service ceiling" refer to?

The term "service ceiling" refers to the maximum altitude at which an aircraft can maintain a specified rate of climb, generally defined as 100 feet per minute. It indicates the operational limit for sustained flight where the aircraft’s performance decreases as altitude increases. This is pivotal information for pilots, as it helps them understand how the aircraft will perform as they ascend into thinner air.

While options like maximum altitude for sustained flight or the altitude for best climb performance may seem relevant, those terms describe different aspects of aircraft performance. The service ceiling specifically focuses on the altitude where the aircraft can barely maintain a minimum climb, which is crucial for safety and operational planning. Understanding this concept allows pilots to make informed decisions regarding ascent and flight operations at high altitudes.