一次搞清楚Ceiling

Ref FAA-H-8083-25C version 2023 5-24, 7-12, 11-8,12-17

Ceiling related to metrology?

Ceiling is the lowest layer of clouds reported as being broken (5/8) or overcast (8/8) OR the vertical visibility into an obscuration like fog or haze

Ceiling related aircraft performance?

absolute ceiling : the altitude at which the aircraft has no excess thrust for climb, and so no longer able to climb – produce zero rate of climb (ROC)

service ceiling : the altitude at which the the aircraft has no sufficient capability for a normal climb – no sufficient MAP (no sufficient power), rate of climb

The thrust required for a stabilized climb equals drag plus a percentage of weight dependent on the angle of climb. For example, a 10° climb would require thrust to equal drag plus
17 percent of weight. To climb straight up would require thrust to equal all of weight and drag. Therefore, the angle of climb for climb performance is dependent on the amount
of excess thrust available to overcome a portion of weight. Note that aircraft are able to sustain a climb due to excess thrust. When the excess thrust is gone, the aircraft is no
longer able to climb. At this point, the aircraft has reached its “absolute ceiling.”

The service ceiling is the altitude at which the aircraft is unable to climb at a rate greater than 100 feet per minute (fpm).

Rear More-

About Superchargers and Turbosuperchargers

Ref page 7-12

Both superchargers and turbosuperchargers are used to pressurized the induction air of the engine so as to “boot” the engine climbing performance, and increase the service ceiling~

Critical altitude is the maximum altitude at which a turbocharged engine can produce its rated horsepower. Above the critical altitude, power output begins to decrease like it does for a normally aspirated engine.

About aircraft performance

Ref page 11-8

Climb performance is directly dependent upon the ability to produce either excess thrust or excess power.

Weight has a very pronounced effect on aircraft performance – increases the induced drag of the wings, as well as the parasite drag of the aircraft.

Increased drag means that additional thrust is needed to overcome it, which in turn means that less reserve thrust is available for climbing;