Ceiling (aeronautics)

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With respect to aircraft performance, a ceiling is the maximum density altitude an aircraft can reach under a set of conditions, as determined by its flight envelope.

Service ceiling is the density altitude at which the rate of climb drops below a prescribed value.

The service ceiling is the maximum altitude of an aircraft during normal operations. Specifically, it is the density altitude at which flying in a clean configuration, at the best rate of climb airspeed for that altitude and with all engines operating and producing maximum continuous power, will produce a given rate of climb. A typical value might be 100 ft/min (0.51 m/s) climb,^[1] or on the order of 500 ft/min (2.5 m/s) climb for jet aircraft.

The one-engine inoperative (OEI) service ceiling of a twin-engine, fixed-wing aircraft is the density altitude at which flying in a clean configuration, at the best rate of climb airspeed for that altitude with one engine producing maximum continuous power and the other engine shut down (and if it has a propeller, the propeller is feathered), will produce a given rate of climb, usually 50 ft/min (0.25 m/s).^[2]

However, some performance charts will define the service ceiling as the pressure altitude at which the aircraft will have the capability of climbing at 50 ft/min (0.25 m/s) with one

Most commercial

The absolute ceiling is the highest altitude at which an aircraft can sustain level flight. Due to the thin air at higher altitudes, a much higher true airspeed (TAS) is required to generate sufficient lift on the wings. The absolute ceiling is therefore the altitude at which the engines are operating at maximum thrust, yet can only generate enough lift to match the weight of the aircraft. Hence, the aircraft will not have any excess capacity to climb further. Stated technically, it is the altitude where the maximum sustained (with no decreasing airspeed) rate of climb is zero.

Compared to service ceiling, the absolute ceiling of commercial aircraft is much higher than for standard operational purposes. In the