Description

The Despatch Deviation Guide (DDG) is a guide to operators and their maintenance organisations to assist in understanding how to operate an aircraft in the various nonstandard configurations permitted by the MEL and the CDL.

The DDG is the umbrella document covering all issues with aircraft airworthiness. The MEL and CDL are 'sub' documents:

• The MEL covers equipment failures (e.g. Pack inop, FMC, Rad Alt etc) and specifies the Minimum Equipments an aircraft can depart with.
• The CDL is applicable to physical parts of the airframe - service panels, flap seals etc - and will inform the crew how far they can deviate from a complete airframe in order to depart. If the CDL contains no reference to the 'missing part' then the deviation is not allowed and despatch is not possible until rectification has been completed.