Bob Kuykendall wrote:
Has anybody on this forum ever, ever looked at the OAT guage and said,
hey, it's too cold here, I'd better dump water or descend?

Yes.

Given how effective composite sandwich construction can be as an
insulator, it seems to me that what they _should_ be requiring is a
ballast temperature guage...

The main problem is the tail tank, which is a relatively small volume of
water, isn't all that well insulated, and will freeze in a matter of a
few hours if the outside temperature is low enough. In at least one
case, the expansion of the ice caused the vertical fin to split open...

Marc