Originally Posted by
Art Smass
The CAA registration summary (see G-INFO) used the term Constructor's Number - I had a look at DH.51 G-EBIR which was registered in Jan 1924 - the pdf quotes C/n (though I guess these early sheets may have been filled out later)
Yes - as alluded to earlier, what you are looking at is the 1938 version of CA Form 113 (Aircraft Register card) retrospectively raised for aircraft that were first registered prior to that year:
