An aircraft is described as clean when it is configured for maximum aerodynamic efficiency. This means the landing gear is retracted, flaps and slats are up, and no external drop tanks or weapons are mounted on the pylons. Flying in a clean configuration minimizes parasite drag, allowing the aircraft to achieve its maximum cruise speed and optimal fuel efficiency.
Heard on the job
Gear up, flaps up, we're clean and accelerating to two hundred and fifty knots.
Do not mix it up with
- Dirty: Clean means all drag-inducing components are retracted; dirty means gear and flaps are extended for landing or takeoff.