What is the typical rate of climb at an aircraft's service ceiling?

At an aircraft's service ceiling, the performance is characterized by extremely reduced power available, which limits the rate of climb significantly compared to lower altitudes. The service ceiling is defined as the maximum altitude at which the aircraft can maintain a minimum required rate of climb, usually about 100 feet per minute. A rate of climb of around 500 feet per minute is generally considered a good representation for many conventional fixed-wing aircraft at or near their service ceiling. This rate reflects the diminishing power available and the increasing air density issues that affect lift and thrust. As altitude increases, despite still being able to climb, the climb performance wanes considerably due to these aerodynamic and power limitations, making 500 feet per minute a realistic figure at the service ceiling.