Originally Posted by
gantshill
Ah good one G! So it is indeed a microlight owing to the calibrated and not indicated stall speed.
Yes according to the manual, the max weight seems to vary depending on some kind of registration? I don't really understand though.
Just a final quick one as I can't remember the rules - can such a microlight legally enter controlled airspace (excluding class A) in VFR so long as it has a radio and transponder (and clearance!)?
Thanks guys, just the discussion/clarification I was after!
Now I'm on a keyboard not my phone, I can answer a bit more fully.
Firstly, the CTSW is a super little aeroplane, with sparkling performance, and don't let me talk you out of flying one. If you've not flown anything that slippery, do get a checkout from an instructor familiar with the type, as it has a few interesting characteristics, mainly to do with energy management, that can catch the unwary.
The current microlight definition is 300kt / 450kg, allowing another 5% for a ballistic parachute system and another 10% for floats (both have to be fitted for that to count). So the CTSW actually has an MTOW of 472.5kg so long as the optional BRS is fitted, which it usually is in my experience. The old 25kg/m^2 wing loading limit was based upon the very early very crude aeroplanes, and hasn't been in routine use since about 1999. Pretty much anything since then, when the UK converged with the European norm for microlight definition, has used the Vso<=35kCAS definition, and it's worked well enough - but there was no reason to remove the old version, since there are still a fair number of old aeroplanes flying safely, and nobody's life is going to be improved by flight testing them to find out what the calibrated stall speed really is.
Some other countries may have different numbers for their microlight definition, and for example the Germans apply lower structural safety factors than the British so the same aeroplane can be certified there to a higher MTOW than in the UK. Is that wise? Well, I'll just say that it's the British who are copying the international norms for larger aeroplanes, and the Germans who are reducing the safety margins.
In the UK, use the BMAA TADS or HADS - they're all on the BMAA website to download, and those are definitive information (along with the approved POH - something downloaded from the net may not be the approved version of course).
A microlight can potentially enter any airspace, with permission and the right equipment on board. What it can't do of course is fly IFR, so trying to enter class A airspace on any terms than SVFR is probably going to end in tears and I really wouldn't recommend trying. Entering class D on the other hand, microlight pilots do all the time, and even the transponder is just "nice to have", just 2-way VHF.
Certified part 23 aeroplanes have a requirement that the ASI must be within 3 knots or 5% of CAS. Microlights have no such requirement, so the ASI can be quite a long way off. This really isn't a safety issue, as the manual and placards will be written in IAS, not in CAS and you just fly it to the numbers in the POH.
G