There are 40 Chinook Mk2/2a in the fleet.
‘Fully serviceable’ is interpreted as those aircraft in the Forward Fleet considered Fit for Purpose. Forward Fleet aircraft are those that are available to the Front Line Command for operational and training purposes, of which Fit for Purpose are those considered capable of carrying out their planned missions on a given date. In the latest month for which figures are available (October) an average of 19 were considered Fit for Purpose.
Aircraft which are not Fit for Purpose are considered to be Short Term Unserviceable and are able to be brought up to standard very quickly. During October only 11 aircraft were undergoing depth repair and not able to be bought up to standard quickly. Operational capability is measured in terms of flying hours rather than the number of airframes available.