Definition
A constant or calibration value used in aircraft fuel flow systems that represents the number of electrical pulses produced by a fuel flow transducer per unit volume of fuel passing through it. The K-factor allows the fuel flow indicator or flight management system to convert pulse counts into accurate fuel quantity and fuel flow readings.
Plain English
A calibration number that tells the fuel system how many electrical pulses equal one gallon (or one pound) of fuel moving through the sensor. Without the right number, the fuel readings on the instrument will be wrong.
Context Anchor
Seen in airframe maintenance when laying out, cutting, or forming sheet-metal parts and repairs.
Derivation
The letter 'K' has long been used in engineering to label a constant — a fixed value that doesn't change during normal operation. So 'K-factor' simply means 'the constant factor' for that system. Knowing this helps the term feel less mysterious: it's just the calibration number that makes the math work.
Why Pilots Care
If the K-factor is set incorrectly, fuel quantity and fuel flow readings will be wrong — sometimes by a lot. That can lead to misjudged range, inaccurate fuel planning, and in the worst case fuel exhaustion. Maintenance and avionics work that involves the fuel transducer almost always requires verifying the K-factor.
Grounding Statement
A flat strip of metal uses up some of its length when it is bent, and K-factor helps account for that used-up length.
Intuition Check
K-factor is not a material type or a guess. It is a calculation number used to make a sheet-metal bend come out to the correct final dimensions.
Example Sentence 1
After installing the new fuel flow transducer, the technician entered the K-factor stamped on its housing into the fuel computer.
Example Sentence 2
When forming the fuselage patch, the correct K-factor ensured the finished part matched the original contour without distortion.