Definition
A section of Title 14 of the Code of Federal Regulations (14 CFR Part 25) that prescribes the landing distance requirements used to certify transport category airplanes. It defines the conditions and procedures under which the airplane's landing distance must be determined, including approach speed, configuration, and the requirement that the landing be made without exceptional piloting skill and in a manner that can be consistently repeated in service.
Plain English
It is the rule the FAA uses to figure out, during certification, how much runway a transport category airplane needs to land. It sets the conditions the manufacturer must meet when measuring that landing distance.
Context Anchor
Seen in jet landing performance discussions, especially when comparing handbook landing-distance data with the rules used to certify the airplane.
Derivation
“Section” means a numbered part of a law or regulation. In “25.125,” the 25 points to Part 25, which covers transport-category airplanes, and .125 identifies the specific landing-distance rule within that part.
Why Pilots Care
It determines the published landing distances pilots must compare against available runway length to ensure safe operations.
Intuition Check
Do not read section 25.125 as a page number or a handbook chapter. It is a specific federal regulation used for airplane certification.
Example Sentence 1
The landing distances in the flight manual were established under the conditions specified in section 25.125.
Example Sentence 2
During preflight planning the crew confirmed the runway length met section 25.125 criteria for their landing weight.