Approach Timing

"Howard Nelson" wrote in message . com...

I really, really, really would recommend flying an airspeed under all
circumstances.

Ditto. Planes fly airspeed, not groundspeed. I was taught to fly
standard configurations of pitch, power, and trim. These should
produce known airspeeds which set the plane up well for the specific
phase of flight.

Do you use the distance to the airport to determine/verify the MAP, even
though the time may not have expired?

Legally your IFR approved clock for timed approaches and NDB for NDB
approaches are what you WILL use. Rationally if my clock or NDB disagreed
with my GPS and I had to make a choice I would trust the GPS.

The conservative choice would be to listen to the first box that cries
"miss." Let's say the wind shifts and your groundspeed changes, the
handheld says you're there. Might be good to miss it. If OTOH the
clock says you're there and the GPS doesn't, you're not going to
increase your risks by missing on that basis.

I can understand the FAA wanting to avoid a free for all by regulating GPS
usage so carefully. But each pilot, if faced with conflicting data, needs to
decide which technology they trust their life to. The best way to do that is
lots of practice under VFR checking clock vs. GPS, NDB vs. GPS, VOR vs. GPS,
Localizer vs. GPS and make up your own mind.

I use handheld GPS and panel Loran to cross-check everything else in
my non GPS-equipped C-172.

Like you say, there's no way the FAA will ever allow handheld GPS as
an official navigational device for IFR, but they've also made a wise
decision to not prevent it from being used anyway. A Decent handheld
GPS and COM radio give a pilot a fighting chance to get down through
the clouds in a total electrical failure, which is one of the
emergencies I worry about most in a middle-aged plane like mine. (NB-
I have a Precise Flight standby vacuum already)

Also if you are not a renter you might consider spending 15-20K for an IFR
certified GPS linked to your autopilot.

You could probably put a good used box in for a lot less, though
perhaps not linked to the A/P. 6K range for a used King/Apollo unit +
install/certification is the estimate I've seen from multiple sources
for a 172.