C-12U1 US Army query

[SGS]

I logged a Beech C-12 on 10th September 2002 at Orlando marked 51-263 which on investigation at that time seemed to be
C-12T-1 serial 85-01263 c/n BP-54.
It is now reported as C-12U1 85-51263 operated by CAE Aviation from Sept 2016 to date.
My question -Has it always been 85-51263
Thanks

[falconfighting]

From what I can see it has always been 85-1263

[SGS]

It really depends on where you seek information. I have used Scramble, Planebase and United States Air Forces Directory 2021/22 all show as 85-51263 while other older publications suggest 85-01263.

[gull04]

A quick addendum, these and other C-12's seem to be outside the "expected" system/range for serial numbers. However they are referred to in official documentation using the additional digit;

T1
C-12T1 aircraft with serial numbers 85-51262 through 85-51268 and 85-51270 through 85-51272 modified with the cockpit and digital engine instrument upgrade.

T2
C-12T2 aircraft with serial numbers 86-60084 through 86-60089, 87-70160, and 87-70161 modified with the cockpit and digital engine instrument upgrade.

So it would seem that the seven digit system here is correct, but it does deviate from the standard.

Gull04