Your challenge. All I can think of is American? Something is written on the fuselage..."DEADEND"...?
Graeme, I don't envy you that!!! And the writing? Well, I don't know!!! The mag cutting that it is from is small and so not clear. It doesn't have any bearing on the type, as far as I'm aware.
RR
PS: Yes... American!
PPS: I re-checked and it says "Pat Pend"!