RAF Aircraft Damage Categories
An explanation of the category of damage to Lightning aircraft as recorded in the main text is as follows:
Cat.1 – The damage sustained by an aircraft was capable of repair on site by established first-line personnel.
Cat.2 – The damage sustained by an aircraft was capable of repair on site by established second-line personnel.
Cat.3 – The damage sustained by an aircraft was repairable on site but was beyond the technical resources of the unit. Assistance from a repair and salvage unit or civilian contractor was required.
Cat.4 – The damage sustained by an aircraft was not repairable on site. The aircraft therefore had to be removed to an established repair depot or civilian repair organisation.
Cat.5 – The aircraft was damaged beyond repair or was missing, or, in accordance with Ministry of Defence policy that was current at the time, was not worth repairing.
These definitions of categories referred to the damage to the aircraft as a whole.
A major accident was considered to be an aircraft that had sustained Cat.3, Cat.4 or Cat.5 damage.