The construction number ('c/n') column contains references to both genuine c/n's and also the numbers allotted to Supermarine built aircraft in the 'Production Ledger' held by the RAF museum.
C/n's commencing 'CBAF', 'S6/' 'WASP' and 'SMAF' are genuine construction numbers.
The source of the RAF museum 'Production Ledger' is uncertain. It covers production up to December 1943 only.
The document contains a number of errors, the obvious ones having been corrected on this site.
The nature of the errors suggests that the document was not contemporaneous. The most likely explanation seems to be that document was created either late in the war or post-war from works order cards, possibly for the purpose of reconciling production to the RAF contracts, as a number of summaries of production, analysed by type, were created at this time for that purpose.
The construction number is recorded on the firewall (frame 5). Other components also carry plates carrying part numbers.
Many Spitfire components were built by subcontractors. Often when the firewall was built by a subcontractor an additional number similar to the Supermarine c/n (i.e. HAI/6S.370240) was also attached to the component. This is not the official c/n.
Refer to abbreviations for a list of abbreviations.