Bill wrote:
I was told by a co-worker that a new Part 91-mandatory compliance reg
has come out, requiring all airplanes to meet a min. climb gradient of
2.5% for second stage climb gradient, unless published otherwise. In
other words, if no specific gradient is published for XYZ airport,
then the airplane must be able to climb out at 2.5% minimum.

I am unable to locate any regs or anything that address this, so if
anyone has further info and the reg, AC circular, etc, please let me
know

Thanks

I believe the 2.5% thing is called "second segment climb gradient" and
it is a requirement in Part 25 (Transport Category aircraft). If I
remember right, it refers to climb performance with the loss of one
engine on takeoff, after the gear has come up, but before the flaps.

The 200 ft/nm thing mentioned by others is a TERPS criteria for
designing the departure obstacle clearance route, and also for missed
approaches, I think. The obstacles can't penetrate a 152 ft/nm surface,
giving you a 48 ft/nm buffer if you just meet the minimum climb.

I'm not familiar with any NPRM, but if you fly IFR, the 200 ft/nm
requirement is fairly well regulated by physics--so you'd better be able
to meet the climb gradient regardless of the law!