I apologize for my loose terminology in last message. Gliders are exempted within the FAR section 215 from transponder requirements, not by a separate 'exemption letter'. And I was not clear about why I distinguished the 'all airspace above 10,000 ft' from the 'more than 40 / 20 miles' regions.

First, transponders are GOOD TO HAVE.

Second, despite the continued misrepresentation, battery life is not nowadays a significant issue preventing installation and use of transponders.

The real issues are economics - a $3000 transponder installation in a $5000 glider ? - and safety and minimizing regulatory encroachment on airspace use. When safety is concerned, the FAA is not generally concerned about user economics. So our arguments should be based on the safety issues alone.

There are three groups of glider users; those with modern transponder installations, those with older installations, and the rest of us. Those with modern installations can in general operate just like powered aircraft, transponder on whenever FARs require it. Those with no transponder are not immediately affected by the petitioned change. So the petition addresses the hard cases - those with old battery-inhaling transponders plus the occasional 14-hr flight or the return trip on the day after without opportunity to recharge batteries. Hard cases make for poor law, better to have laws that accommodate everyone rather than just a few.

My objections to the wording, not the intent, of the SSA petition go like this. It sets up a whole new class of airspace affecting only SOME users; 10 mile wide doughnuts around the existing 10 mile or 30 mile transponder veils. Are our charts not complicated enpugh already ? By implication, allowing transponder switchoff outside these doughnuts also requires transponder switchon [for those affected] while inside. If this is good for safety, how long before there is some creep, like a requirement that ALL operators in the doughnuts install transponders ?

Who would then be affected ? Well, for starters there is Warner Springs, maybe Crystal, Torrey Pines... look at your own sectionals. All the surviving glider fields reasonably close to metropolitan areas are potentially at risk.

What I think is needed is a general policy statement from the FAA that transponders are GOOD TO HAVE AND USE and that anyone who voluntarily installs one when not required to will NOT be penalized if that installation and its operation does not meet all the requirements of the relevant FAR sections. That emphasises the voluntary nature of these installations and preserves the existing overall 'exemption'. It is permissive and flexible and should encourage widespread installation of transponders in cross-country gliders. It also gets away from the SSA 'liability letter' and the question of non-SSA pilots, and should keep us aligned with balloons and non-electric aircraft.

As a side issue, section 215b is hard to read, but appears to require either Modes A and C or Modes S and C. Section 217 then applies to both VFR and IFR and refers through section 413 [also both VFR and IFR] to Part 43 Appx E where altitude encoding accuracy tests are specified. The difference between VFR and IFR is only that IFR testing is 24-monthly, VFR is on installation and after any maintenance.

Ian