This glossary is written for virtual airline and flight simulation use within Virtual Air Canada Airline. It is not intended as a real-world aviation reference.
CDL
Configuration Deviation List
The Configuration Deviation List (CDL) is an approved document, specific to each aircraft type and operator, that lists external components of the airframe that may be missing at dispatch without compromising airworthiness, subject to defined operational limitations or performance adjustments. CDL items are typically aerodynamic fairings, access panel covers, small external fittings, or non-structural components whose absence affects aerodynamic performance in a predictable and quantifiable way. The CDL is part of the aircraft’s approved Flight Manual or Operations Manual and must be authorized by the aircraft manufacturer and the certifying authority.
The CDL differs from the MEL (Minimum Equipment List), which addresses inoperative aircraft systems and avionics. Where the MEL covers systems that fail to operate, the CDL covers physical external parts that are physically absent. For each CDL item, the document specifies the permitted configuration, any associated performance penalties (such as a drag increment affecting climb or cruise performance), any operational limitations (such as speed restrictions or flight envelope adjustments), and any required maintenance actions before the next scheduled check. Dispatch under a CDL item requires a determination that the performance penalties are accounted for in the preflight weight and performance calculations.