"Steven P. McNicoll" wrote in message
ink.net...

"Journeyman" wrote in message
. ..

On the way to Pinckneyville last weekend, I stopped at Jimmy Stewart
Field, Indiana, PA. KIDI. I had to shoot the GPS 28 approach with
a cirle to land 10. There's a nice transition off the Revloc VOR.

Since we had a late start, we had planned to stop there for the night,
but by the time we left for the hotel, the overcast had broken up and
it was clear. Next morning, we left VFR.

Looking at the plates, 10/28 has minima 300-1 and 600-1 respectively.
The procedure for runwya 10 is to climb runway heading to 2300 before
proceeding on course. The MSA for the area is 4200. How do you get
from the DP to the nearest Victor airway safely when it's 300 and 1?


Departing runway 28 I'd make sure I crossed the departure end of the
runway at least 35 feet above the departure end of runway elevation, that
should be easy as the runway slopes downward to the west some 45 feet.
I'd climb to 400 feet above the departure end of runway elevation before
making my initial turn and I'd maintain a minimum climb gradient of 200
feet per nautical mile until above the minimum IFR altitude.


If there are no specific instructions on the DP it is considered a "diverse
departure". Like Steven says, you only have to cross the departure end of
the runway at 35' (or greater) and climb 200'/nm to 400' at which point you
can turn any direction and continue to climb 200'/nm to a published altitude
(MEA, MOCA, OROCA). The actual obstacle plane is 152'/nm so you are gaining
48' of additional clearance each mile if you are climbing the minimium
(200'/nm).

In the IDI case there are obstacles that penatrate the obstacle plane, that
is the reason for listing TO minimiums. Once you are above the 300' or 600'
you won't hit anything if you climb 200'/nm. Below those altitudes you must
avoid obstacles visually

The "gotyas" on a departure of this kind are cross winds and tail winds.
Crosswinds can put you off centerline and into the obstacles, You really
should be flying a runway track as opposed to a heading. A tail wind will
reduce your climb gradient because of your increased groundspeed. In really
strong winds you might want to climb higher than 400' before turning and
make your turns into the wind even if it means turing 300 deg instead of 60
deg.

There was an article in IFR about diverse departures recently.

Mike
MU-2