TMG or not TMG?

[Genghis the Engineer]

I'll let you into a secret old chap, the Vigilant T1 was the first full aircraft type I certified - obviously for the RAF / HQAC for whom I sort of worked at the time. So, I have a bit of a soft spot for it (even if it is totally the wrong aeroplane for what the AC use it for).

The civil definiiton of a TMG/SLMG includes certain performance / weight issues. One of those is that the MTOW mustn't exceed 850kg. The MTOW for the Vigilant T1 is 908kg, it also has a different instrument fit, a few subtle mods here and there and it's own military operators manual. We certified it against a combination of JAR-22 (the civil motorglider rules) and Def.Stan 00-970 (the military fixed wing rules). Because it was of no interest to us, we never investigated to find out whether it met the civil SLMG/TMG definition, we just wanted to know whether it was safe for use by Air Cadets.

So, in my opinion at-least and I'd be more than happy to backup this statement to the CAA, the Vigilant T1 is an aeroplane and should be logged as such in a CIVIL logbook, and not a motorglider. This isn't all that odd, civil aviation is full of these subtly destinctions - there are other aircraft that are patently SLMG to the untrained eye, which on the paperwork are either light aircraft or microlights.

So, you should (again in my opinion) be logging in your civil logbook all flying as being in a Vigilant T1 NOT A G109b and listing it under SEP (or whatever your particular column heading is).

To give you another instance of this sort of thing, there are a few other types out there - obvious examples are the Minimax, Rans S6, Shadow, Jabiru which with subtle variations of powerplant, wingtip and fuel tank can be either a light aircraft or a microlight - and there are many pilots happily and safely flying one of these who don't have the license or rating to fly a near identical aircraft that happens to have a slightly different wingloading or stall speed.

Finally, GG said "A motor glider having a certificate of
airworthiness issued or accepted by a JAA Member State having an integrally mounted, nonretractable engine and a non-retractable propeller". The Vigilant doesn't have a CofA as defined in the Chicago Convention, it is flying under military regulations called something similar, but actually quite different.

G