From: barney@sol.usc.edu (Barney Lum)
Newsgroups: rec.aviation
Subject: Flying/Camping the Sierras: Grass Valley / Tahoe
Date: 11 Sep 1992 20:41:39 -0700
Organization: USC University Computing Services, Los Angeles
Distribution: world
NNTP-Posting-Host: sol.usc.edu
Summary: "You are my density."

O22-O17: Columbia to Grass Valley, Day 4 (and Tahoe-Carson, day 5)

Done with breakfast (and trying to shoo off LOTS of killer-wasps that kept 
attacking our food!), we got the plane loaded... once more :).  We're all set 
to go except that the mic was stuck on again.  I couldn't figure out the 
source - if it's the push-to-talk mounted in the plane or my intercom.  
(In afterthought, I probably didn't WANT the problem to be the intercom, 
so I didn't try isolating it... I chose to find a work-around instead).  

The other two PTT's - one on the right yoke, the other on the handmike -
were disconnected.  Position 3 on the transmit selector knob prevents audio 
from coming in through comms 1 & 2.  The only way I was able to make things  
"work"  was to turn off comm 2 and leave the selector there when listening 
to 1.  The problem with that was it also turned off Nav 2.  Made it a bit 
inconvenient in that I won't be (easily) able to cross-check radials for 
the next hour (or possibly the rest of the return trip).

Departure was uneventful.  We climbed only to about 6,500'.... not really
high enough over the mountains to get good coverage from the TRACONS below 
(Sacramento or whoever).  Below us is the highway that the ground-folk are 
driving along.... Knowing them, they were probably moving faster than us. 

There were no clouds over our route, but some pretty "interesting" cumulus 
build-ups were starting to the east over the Sierras.  While not quite yet 
towering, they did stretch along the range with some pretty wide girths.  
The sunlight off their tops accentuated the billows, casting some rather 
dark shadows below.  That warm, moist airmass is still following us (or us 
them).  However, the air along the route was a lot smoother than just the 
day before.

No turbulence to speak of on this leg... just the usual bumps-n-nudges one 
expects over the hills.  The landscape was covered with trees laid out
green carpet that was full of gorges and streams.  There were also numerous
"bald" spots with cumlulo-granite of the worst kind exposed.

Alta Sierra Airport, a private field, was originally our planned destination.
It turned out that they no longer allow "guests" of its residents to use
it unless they've paid some fee.  Having spoken to my Aunt earlier in the
day, we continued northward to Grass Valley.

By the time we landed, the clouds over the Sierras towards Truckee (over I-80) 
were REALLY huge, rising to at least 25,000'... definite UDDF stuff! I'll 
just tie the plane down and spend the afternoon/evening enjoying dinner, 
thanks :).   Our greeting party arrived shortly after we did...got our 
"stuff" out of the plane and into the camper for the festivities!  Meanwhile, 
an S-2 Tanker returns to this firefighting base followed by a Skymaster 
observer.  Fires were keeping those tankers busy ALL OVER the place.

It was about 2 hours after our arrival that Gus and Robert et al made it to 
the house.  The steep grade and high temps had caused their cars some 
overheating problems, forcing them to make a couple stops on the way up.  
Dunno.... it was a nice 55 degs at our altitude :).

[Dinner/Luau/Festivities/etc... was lotsa fun with yet more wasps! 
 Most of of the guests were from out of town (in Alta Sierra, who isn't?), 
 so many of us all pitched our tents in the large back yard for the night ]

*********
017-TVL-O04: Grass Valley-South Tahoe-Carson City, Day 5

Clouds had formed again in the late morning, but were mostly of the 
scattered-broken type.  Flight Precautions/Airmets for MDT-SVR TB over the
Sierras with widely scattered  TRW's was in the briefing.  Looking east over 
the mtns, there were many "little white puffy clouds" with some moderate
cumulus north.  One PIREP included moderate turbulence over Truckee at 
9500', about 3500' AGL.  

It was one of those times where the briefing says one thing, but a good look 
towards the route says "it doesn't look too bad out there."  The cloud bases 
appeared to be high enough (lots of space between the cumulo-whitestuff and 
cumulo-hardstuff), as well as between the clouds themselves (didn't look like 
heavy convective/orgraphic activity up there).  The decision was made to 
"go", but  I passed on the precautions and emphasized keeping the seatbelts 
snug in case things got exciting up thar.  

The fuel dipstick read ~8 gallons in each side, just about right for the 
50 minute trip to Carson + ~45 minute reserves.  95 degrees at the 3100' 
elevation made for a density altitude of about 6000'... enough to cause 
bringing out the book and re-check the numbers.  Having unloaded a lot of 
"stuff"  at 017, we were now about 200 lbs lighter than waaaaay back at EMT.

A check of the radios goes fine... no stuck mic.  Maybe it was caused by the
warm temperatures?  Shrug.   Comm/Nav2 is recommissioned and we're ready to 
go.  A downhill takeoff into a light breeze helped get airborne  in about 
1000' with climbout a lively 500-600 fpm.  The plan was to circle over my 
Aunt's house 8 miles south for a few minutes, then depart to the east.

After waving bye-bye with our wings, we picked up I-80 and followed it up to 
the lake area.  We cruise-climbed at about 80 indicated to avoid the pointy 
rocks, encountering only a few interesting bumps...mostly of the "occasional
chop" variety.  Sacramento Approach had handed us off to Oakland Center soon 
after radar-identifying us, so I gave them a quicky pirep of the light 
turbulence before switching over.  

Lake Tahoe came into view as we peered over the ridge line.  Clouds bases 
over the "hill" were still SCT-BKN with bases at about 12,000', quickly 
clearing and smoothening out as we got over the Lake.  At this point, ZOA 
terminated flight following and suggested Reno.  Truckee airport passed
under our left (north) wing 3 miles away, nestled in a large flat basin 
surrounded by the mountains.

We're still at 11,000 and about 5 miles south of the northern shoreline. 
The water below shimmers... it looks *very* refreshing! Brian and Linda 
(and myself) suggest flying  south along the western shoreline to take in 
the sights,  but that meant dipping into the fuel reserves.  No problem...
we'll just stop at South Tahoe to get some.

From someone on the ground (water), we musta looked like we were lost.
Having almost reached the eastern side, we turned back to the west, 
zig-zagging along the NV/CA boarder over the lake (still at 11,000' ...
about 5000' ALL (above lake level).  A glance at the outside temp. gauge 
showed 70 degs.. quite warm for that altitude.  TVL has no ATIS, so I'd  
ask them on callup what the ground temperature is.  

There's a lot of traffic departing, some going north, some west.  It's
almost a zoo... I'm barely outside of Emerald Bay (~6 miles NW) before
I get my call in.  I'm instructed for "straight-in runway 18 (which turned
out to be a half-rightbase entry), departing traffic should be over the lake 
and no factor."  In the chatter, I forgot to ask the temperature.

TVL's runway is 8,400' x 150', lots of asphalt for the landing.  Winds are
out of the south and slightly from the right, no problem.  The shoreline
passed below and Brian pointed out the low water level: the sand/beach
extends about 100 yards from where it should be.  I'm still a little
high... got three-and-a-half whites on the PAPIs, but airspeed is nailed
at 65.  The twice-as-wide-that-I'm-used-to runway makes the approach appear 
to be at "normal"; stall warning honking as we roll onto the runway.
Temperature on the ground is about 80 degrees.

Made a quick call to Flight Service to close the flightplan and give
another PIREP of the clouds and  relatively light turbulence enroute.
Having flown for about 50 minutes, there should be about 10 gallons total 
left.  I place an order for 20 gallons - 10 on each side.  That would
bring our weight up to about 2300 lbs.  After emptying our own tanks
and getting a drink (funny how that works), we headed back to the plane
for the next leg.

A quick check of the oil and fuel level reveals, HORRORS, that we're 
practically TOPPED OFF.  We weren't over-fueled in the sense that the guy 
put in too much... I got what I asked for (i think).  The problem was that 
I didn't  think to check the level *before* fueling.  Apparently there was 
more fuel in the plane than the dipstick indicated.  I suspect that the 
loaded plane (somewhat tail-low) swayed the indication a bit (lot).  I 
basically subtracted 8 gallons from the 16 I *thought* we had, and wanted a 
total of ~30.  It might not seem like much, but 10 gallons (60 lbs) extra
was something I didn't expect.

So what to do... plane is now at ~2350 lbs.  It climbed quite well earlier 
in the day up to 11,000' without problem.  I've flown similar density 
altitudes, but probably a couple hundred pounds less.  Those other planes 
weren't exactly perky, so this 172 should be able to take on the extra weight.

Tower reports 83 degrees, altimeter 30.something, "check density altitude." 
That worked out to be 8500'.  Welllll.... it's kinda high, but comparing 
previous similiarly high D.A. experiences in our Cherokee with its sea-level
performance against the C172 at about the same weight says that we should be 
okay.. figure on about 300-400 FPM climb.  Again,  setting an abort point 
allowing for stopping is in order.  The wind is at 10 knots, still from the
south but now from the left.

Well, I decide to make a go for it.  If things don't look good the first
2000' of runway, then it's time for the brakes.  If climb doesn't look good,
there's ample runway.. provided an abort is made early.  I had familiarized
myself somewhat with the surrounding terrain and studied the "Golf Course
Procedure" (that's not what it's called, but essentially one can circle
over it to the south to gain altitude if needed... No turn to x-wind 
before reaching 7500' due to .. terrain).

Engine runup goes fine... near-full power and leaned to 50 degs rich of peak 
EGT.  Static full RPM reads about 2400; no constant-speed prop on this bird 
to push forward.  We're cleared for takeoff; engine power comes up smoothly
and acceleration is... well, there. We're now at 40 knots and  I've got 10 
degs of flaps hanging out.  The plan is to climb at about 65.. somewhere 
between Vx and Vy.

50 knots. Engine still humming smoothly, 1000' of runway has gone by.
Acceleration is fine, it "feels" like we're ready to fly.

55 knots. We're at about rotate speed.

The nose starts to come up a bit, so I hold the yoke and let the plane fly 
itself off.  Still plenty of runway to go back down if need be, but it looks 
like we're free as we lift off the asphalt and readily climb out at 60 knots.
2000' of runway has gone by, 6000' left.

The stall horn honks a bit as we're buffeted by the wind.  We're about 100
feet up, but we're not climbing as well now that we're out of ground effect.  
Although we're not sinking, there's that sensation that we are we move 
towards  the tree-covered hills ahead.  

We're now 300' up with about 2000' of runway left.  I don't think I'll be 
able to land ahead safely.  There's a strong urge to hold the nose back to 
keep the nose up and maintain (or gain) altitude, but the stall horn reminds 
me not to.  Despite that knowledge, it is VERY DIFFICULT to relax on the 
yoke with "rising terrain" ahead.

It's a little breezy outside and we've been pushed off to the right a bit.  
Trying to keep the wings level, I let the drift continue... this would put 
me in a better position to do a 180 and make a downwind landing.  However, I 
don't want to sacrifice *any* lift in order to make that turn just yet.

65 knots.  Stall horn chirps.  We're to the right of the departure end of 
the runwayto the right but still over the airport, but I'm not really sure 
if we're climbing.  There is this strong urge to hold back on the yoke a bit 
and get the nose up.  

60 knots.  Stall horn honks again... not quite climbing; we're not sinking.
We're now about 500' to the right of the runway and I'm contemplating turning 
around to land back on 36.  But that *terrain* looks *very* inhospitable.
Any turn now would have to be very wide but risk running into terrain,
or sharper and lose altitude at the same time towards the rising ground
below.

Pushing (actually relaxing) the nose a bit forward got us back up to 65 
knots and  our "climb" improves to about 300 FPM.  But terra-firma below
is rising at about the same, if not higher, rate.

"Cessna 53E, the golf course ahead and to your right is available for
 circling", the tower advises.

A terse "53E" was all I could respond with.  

The hill and trees pass ~300' below us with seemingly little clearance, the 
altimeter showing 6800'.  The golf course is just ahead to the southwest,
sheltered between three or four ridges.  It's about three miles in diameter 
(including surrounding area)... two miles "usable".  I found myself making 
shallow left turns even though the procedure calls for right... but I wasn't 
going to change now as I wanted to keep the low wing on my side (not sure 
why).  I also remember the caution that downdrafts might exist in the 
western portion of the area.

Climb rate is now a bit better at 400 FPM.  One lap into it and we're at 
7500'.  Looks like we've picked up an updraft (or possibly we had downdrafts
earlier that now ceased) as we're now climbing at 600 (!) FPM.  I advise the 
tower of our progress and that we'll continue with one more circle.

------------------
   At this point I remember to bring the flaps back up.  Thinking back to
   all the discussions about density altitude,  I don't recall any wisdom
   on the use of flaps and ideal airspeed.  Any general (or particular to 
   cessna/piper) advice out there in that respect?

   Should I not have used flaps at all?  Should one fly at Vx or Vy?
   I found that flying Vy might really be better, but it doesn't *seem*
   that way with respect to climb angle (ie Vx).  Flying close to Vx
   also could put one uncomfortably close to stalling... and as I saw
   above, it's VERY counter-intuitive to nose-forward with terrain ahead.

   Our climb was there, but so was the rising terrain.  If we had (stronger?) 
   downdrafts or any loss of power,  well, I probably wouldn't be typing this.
   I coulda/SHOULDA  waited (or perhaps made the decision to abort earlier) 
   but a combination of confidence in the aircraft,  wanting to avoid the 
   dark, and get-there-itis bit me.  If I had waited a couple hours, the sun 
   would have gone down but there'd still be light.  Temps probably would've
   dropped at least 10  degrees.

   Destiny altitude let me get away with it.  This time.  

   Specs again: C172XP, 2350 lbs, elev 6200, temp. 83F, altimeter ~30.20
   10 Degs flaps, 65 knots. 
   Initial climb: 300 FPM;  Out-of-ground-effect: 200 FPM
   With those numbers to work with, I think I have a *much* better idea
   of what I can.. and what I *won't* do again.
------------------
That was the "horror" of the trip.  We left the golf course at 8000' and
continued to climb to 10,000', zipped through Spooners Pass before dropping 
into Carson City.  Brian sat up front so that he could keep us from getting
lost ;)  and point out its highlight(s) as we went in.  

As it were, 10,000' was a bit high as were now only 10 miles out and still 
~6000' AGL from the airport.  I think those mountains around Tahoe scared 
me too much so I wanted as mucah altitude as I could get.   Flaps and shallow 
S-turns at 80 knots got down without shocking our ears... or the engine.

Carson City airport is non-towered at about 4400' MSL, thus sits below the 
water level of Lake Tahoe contained in the bowl of mountains to the west.  
Kinda interesting to realize that we're below this huuuge reservoir of
water just a few miles over.

As we turned final, a Malibu that had called in earlier now reports being 
downwind, but I don't see him (I wasn't really looking that hard).  If he is 
where he says he is, I'll accept that.  None of us saw him until we were on
the ground and ready to cross back the runway to get to the other side (the
parallel taxiway is only along the south; I needed to get to the northwest
corner).  Kinda unnerving not to see other traffic even though we knew it 
should have been.

Needless to say, I was glad we were now on the ground.  

[ We spent the next day in Virginia City, passing brothals and cat houses on 
  the way up.  Drove to Lake Tahoe for some sand castle-building and swimming 
  (brrr!), then the buffet dinner at Caesar's ... more gross weight!]

Next: Flying back home to El Monte via Yosemite, Fresno, and Porterville
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              >|      barney@usc.edu  Barney@USCVM
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