Definition
In a multiengine airplane, the maximum density altitude at which the airplane can maintain level flight with one engine inoperative and the operating engine(s) at maximum available power. At this altitude, the rate of climb on the remaining engine has fallen to zero.
Plain English
The highest altitude a multiengine airplane can hold steady with one engine failed. Above this altitude, it cannot stop descending no matter what the pilot does.
Context Anchor
Seen in multiengine performance planning, especially when considering engine failure after takeoff, over high terrain, or in hot weather.
Derivation
Absolute' here does not mean 'perfect' or 'final' in the everyday sense. It comes from Latin absolutus, meaning 'set free' or 'independent.' In aviation it signals a fixed performance limit, measured independently of other ceilings such as service ceiling.
Why Pilots Care
It tells the pilot whether the airplane can safely cross mountains or continue flight after an engine failure at altitude.
Grounding Statement
Picture a twin-engine airplane with one engine failed: at the single-engine absolute ceiling, it can hold level flight, but it cannot climb at all.
Intuition Check
Absolute does not mean perfect or safest here. It means the final performance limit: the point where level flight is still possible, but climb is not.
Example Sentence 1
Cruising at 12,000 feet over the mountains, the pilot noted they were already above the airplane's single-engine absolute ceiling, so an engine failure would mean a gradual descent to lower terrain.
Example Sentence 2
During the multi-engine checkout, the instructor noted that the single-engine absolute ceiling was well above the local terrain.