[ summary: lots of plannig, heavily loaded plane. one good, clean
flight in the cool morning air, followed by a less admirable
return flight where density altitude and loading almost bit ]



KPAO - KBIH - KPAO Trip PIREP:

The goal here was to do a quick weekend trip to Bishop, California,
to so some rock climbing at Owen's River Gorge, the "Premier Sport
Climbing Area of the Eastern Sierras." There were several challenges
to this trip.

1. equipment was /A IFR Cherokee 180
2. pilot + 4 passenger ( 200#, 160#, 130#, 100# )
3. climbing gear ( 60# )
4. Crossing the Sierras
5. no O2.

As you know, I worked the Internet and the POH pretty hard to plan
this trip, and it kept working out on paper -- but just barely, at
least in my mind. Nothing ever said, "no!" but there were plenty of
potential gotchas, and though I thought I understood them, in hindsight
I think I did not fully respect how they were additive in nature.
(see, high, hot, and heavy at the end of this story. ;( )



Loading the A/C
---------------

With the passengers and gear, and fuel for Bishop, plus my traditional
add'l fuel: destination + alternate + 1 hr, the aircraft was within
five lbs of it's max gross. It was legal, but I'd never flown an
aircraft in that part of the envelope before. CG was not too bad,
however, about midway between fore and aft limits.

Outbound Leg ( KPAO - KBIH )
-----------------------------

Got up at a 4:45 am to get a briefing, shower and get to the airport.
The briefing, and my examination of the night sky outside my bedroom
window made it clear that we would have to depart IFR, but that the
central valley would be clear. I filed two flight plans, one IFR, one
VFR.

IFR: KPAO - SJC - V334 - SUNOL - V195 - ECA
VFR: ECA - KMMH - KBIH

At 6:30 my friends and I loaded up, and I picked up my clearance from
the tower just as they were opening for the day. We took off and were
soon climbing through about 750 feet of your basic summer marine layer.
This would be my 0.1 hrs of IMC for the weekend. (Exciting for me
nontheless, as I got to use my rather new IFR ticket!)

Oh, I should mention the takeoff. It was a little interesting. The
acceleration on the takeoff roll was underwhelming, and it took a good
chunk of the runway (2500' at PAO) to get to a rotate speed, this using
the short field takeoff technique. Nevertheless, the Cherokee departed
comfortably from the runway and climbed initially at a healthy 500 ft/min
in the cool morning air.

Before making it onto V195, I cancelled IFR and headed directly to
about the position where V230 (the 23 deg redial of FRA VOR) intersects
with the base of the sierras.

We climbed for a good long while. Though the initial climb rate out
of PAO was good, it soon tapered off considerably, and by the time we
were at 9000 or so, it was about 100 ft/min. what's always interesting
to me abou the high-altitude performance of these aircraft is how the
speed range at which the aircraft will climb is so limited. On Saturday
morning, it was between 80 and 90 mph. Go outside that range, and go down.

So, after I don't know how long, we were cruising allong at 11.5. When
we got close to the Mammoth Pass, I let the aircraft climb again, and there
was some lift to help us. But the time we were over the higher areas of
the pass, the aircraft was at nearly 13000.

The view was awesome. I didn't get to take pictures but the passengers
were happy.

Once past the high terrain, I let the plane descend under power, and
rolled well into the yellow arc (whee!) in the smooth mountain air as
we passed by KMMH (Mammoth) and turned towards Bishop.

The landing at Bishop was easy and pretty routine.

Odd experience after landing though. I had a mentally difficult time
getting the aircraft maneuvered to where I could push it into a tiedown
spot. Basically, there were a few other aircraft on the ramp, incluing
a couple of expensive ones with larger than average wing-spans, and for
some reason, my brain just "would not compute."

I suspect it was partly new airport confusion and potentially partly
hyopxia. Anyway, I think I'll invest in an O2 system if I do much more
mtn flying.



Return Leg ( KBIH - KPAO )
-----------------------------

Because of a passenger's constraint, we could not return on Monday morning
in similar cool air conditions that we had gone out in. I was not super-
happy with this, but I aquiesced to an early evening departure on Sunday,
around 7pm. I thought that this would be a good compromise between waiting
for the air to cool and not crossing the mountains in the dark.

As PIC, I think this was the biggest mistake of my trip, and I'll be
thinking about it for a good while to come.

I got a briefing, and a 15 minute-old PIREP from a Centurion at 12.5
said the ride through the Mammoth pass was smooth so I felt good about
the crossing.

We took off from BIH rwy 30 at about 7. The wind was light and variable,
and 30 seems to be the calm runway there, and it's the longest. The
density altitude was about 7500. The POH made it clear that I could
comfortably escape in those conditions, so I tried it, and regret doing
so.

It's not that there was an accident. There was none. I used the short-
field takeoff, leaning for best power before t/o, etc, and as in Palo
Alto, the aircraft accelerated at a meandering pace. However, we were
off and climbing in less than half the 7100 ft runway.

The first 100 feet or so, the plane climbed normally, and then... it
would not climb at all.

It was a frightening moment for me, though thankfully not for the
passengers who did not know something was amiss. (Except for the one
passenger up front, a pilot herself, though not current.)

Though there were no thunderstorms in the immediate area, there were
rain streaks visible under clouds that were perhaps 30 miles or more away
(and in the south, opposite of where we were going), and I think the
aircraft was caught in some drafts from them. I don't really know for
sure, though, whether they were related.

In any case, there was maybe a 30 second period when the plane wasn't
climbing, and was only 200 feet off the ground. Eventually, it started
to climb again, though with only about 100 ft/ min, and only in the
narrowest range of airspeeds. I told myself that if took more than
three more minutes to climb to 1000 ft agl, I would return to the airport.

The plane did start to behave a bit better, and, doing large circles
in the (thankfully flat) vicinity north of BIH, we slowly clawed our
way up to about 9000, then headed over to MMH, where we again circled
to about 12.5, and then we flew the pass. I was expecting downdrafts
on the eastern side of the sierras, and so I wanted to have altitude
to spare, and I also approached at a 45 degree angle, to allow for
an out if things went poorly. However, by now, the plane was out of
the hot air, and flying more like it's pitiful (but predictably)
performing regular self. Also, I unexpectedly found lift where I
expected sink -- and I took it to about 13000.

Once over the mountains, we flew direct palo alto. Over Livermore
it became obvious that the sunol pass was not going to work vfr,
so I asked NorCal approach (with whom I was getting vfr flight
following) if I could go off-frequency to air-file IFR to PAO. He
said I could stay with him and get the VOR-DME into PAO. While on
vectors for the approach, we were over San Jose airpot, from which I
could approach PAO VFR, so I cancelled and went in and landed
uneventfully.



what I Learned
--------------

I can cross the Sierras comfortably in an underpowered light
plane. It just takes time and patience to get up there, I want
room to spare, but it's possible. Nice to know.


But the more ominous lesson is to take density altitude, aircraft
performance, and aircraft loading seriously. I had made a classic
"high, hot and heavy mistake" -- and I paid for it. I didn't do so
with my life this time, but the pounding in my heart might have taken
some time off the end!

I flew the airplane at its limits. I flew according to the book
values, and they were actually more or less right, but I did not
leave myself safe latitude for them to be wrong. A random variable
-- some potential downdrafts or other strange winds, for example,
almost turned my barely acceptable climb rate into a descent.

Though the outcome was succesful, I think this flight is more of
the "Never Again" variety. If I had to do the whole thing over
again, I simply would have insisted on a lighter A/C (ie, one
fewer passener) and/or that we wait until morning and fly back
under similar smooth, cool, conditions we flew out in.

Thanks for reading!
Dave J