Definition
The minimum runway length a transport-category jet must have available at the destination airport under Federal Aviation Regulations. It is calculated by taking the actual demonstrated landing distance from 50 feet above the threshold to a full stop on a dry runway, then dividing that distance by 0.6 (i.e., multiplying by 1.67) to provide a 40 percent safety margin. For wet runways, the result is increased by an additional 15 percent.
Plain English
The shortest runway the rules will let a jet land on. Engineers measure how much runway the airplane actually needs to stop, then add a big safety cushion on top so the pilot has room to spare if things don't go perfectly.
Context Anchor
Seen in jet landing performance charts when checking whether a runway is long enough for the airplane’s weight, configuration, and landing conditions.
Derivation
FAR stands for Federal Aviation Regulations, the body of rules issued by the FAA that govern civil aviation in the United States. 'Landing field length required' simply means the runway length the regulations require for a legal landing.
Why Pilots Care
Determines whether a runway is long enough for a safe landing and directly influences go/no-go decisions on every jet approach.
Intuition Check
Do not read “required” as “the exact distance the airplane will use.” Here it means the runway length that must be available after the required safety margin is included.
Example Sentence 1
Before dispatch, the crew confirmed the destination runway was longer than the FAR landing field length required for their landing weight.
Example Sentence 2
High density altitude increased the FAR landing field length required, so the captain chose a longer runway.