Aviation & Aeronautics
Basic
MEL Rectification Interval
Latest date a deferred defect must be fixed: the discovery date plus the Minimum Equipment List category interval. The day of discovery is “day zero” and is not counted.
Formula
Variables
D_{due}Rectification due date
D_{disc}Defect discovery date
I_{cat}Category interval — A: per MEL, B: 3, C: 10, D: 120 calendar days
Example
Category C defect found on the 1st: due by end of the 11th (day of discovery excluded)
Did You Know?
MEL categories A/B/C/D come from the ATA/regulator standard: the calendar day a defect is recorded counts as day zero, so a Category B (3-day) item found Monday is due by end of Thursday.