critical altitude


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critical altitude

[′krid·ə·kəl ′al·tə‚tüd]
(aerospace engineering)
The maximum altitude at which a supercharger can maintain a pressure in the intake manifold of an engine equal to that existing during normal operation at rated power and speed at sea level without the supercharger.
(ordnance)
The maximum altitude at which the propulsion system of a missile performs satisfactorily.

critical altitude

i. A specified altitude or height in the precision approach at which a missed approach must be initiated if the required visual reference to continue the approach has not been established. Decision altitude is with reference to mean sea level, while decision height is with reference to the threshold elevation. The visual reference means that section of the visual aids or of the approach area that should have been in view for a sufficient time for the pilot to have made an assessment of the aircraft's position and change of position in relation to the desired flight path.
ii. The altitude beyond which an aircraft reciprocating engine cannot maintain normal-rated power, or in some contexts, beyond which it cannot maintain military-rated power.
References in periodicals archive ?
However, at some point above critical altitude, the pilot must comply with a table that shows the maximum allowable manifold pressure and reduce power accordingly.
5) This altimeter operates in a CW mode at all altitudes that are equal or lower than a predetermined critical altitude [H.
The height at which sprites spark to life also roughly agrees with what theorists like Pasko estimate to be the critical altitude for breakdown.
Although it's a good, economical performer at low altitude, SMA originally spec'd a turbo that lacked sufficient pressure ratio, so the engines critical altitude was essentially sea level and its service ceiling was limited to 12,500 feet--anemic for a turbocharged engine.
An induction leak, while perhaps not an emergency situation, still affects the engine's efficiency as well as limits its critical altitude.
This term describes the relationship between manifold pressure, propeller speed and fuel flow at and above the engine's critical altitude, or where the turbo's wastegate is fully closed.
Light, pressurized aircraft tend to reach the critical altitude for cabin pressurization by 25,000 feet.
Once you know the critical altitude for yourself, you can use it as a rough gauge even if you don't have a pulse oximeter.
I use the autopilot on all my approaches and serve as its copilot, monitoring the quality of the approach, critical altitudes, and preparing for the missed.
This includes anticipating formation changes plus being ready to back the flight lead during an emergency - reading the checklist or calling out critical altitudes, for instance.
You can set the critical altitudes to any values you like, but the default is 4000, 8000 and 12,000 meters.