Relay-Version: B 2.11 6/12/87; site scolex Path: uunet!uunet!zaphod.mps.ohio-state.edu!sdd.hp.com!hplabs!hpcc05!hpcc01!mtc From: mtc@hpcc01.HP.COM (Mark Cousins) Newsgroups: rec.aviation Subject: Mountain checkout Message-ID: <3400086@hpcc01.HP.COM> Date: Mon, 03 Jun 91 17:38:02 PDT Organization: HP General Systems Division Lines: 111 Last week I got a mountain checkout so I thought I'd write and share the experience with the net. As usual, comments are welcome. The only plane available was N21950, a 1975 172M. I had wanted to go in something a bit more capable but the other planes were booked, this being the Friday of Memorial Day weekend. I live in the San Francisco area, so "mountain checkout" usually means flying up to the Lake Tahoe vacinity. The instructor had me plan a flight to South Lake Tahoe airport (TVL) via (roughly) U.S. 50, at 9,500. I did so and dutifully filed two flight plans, one there and one back. I thought I'd also use the flight up to become reacquainted with my friend the instrument board so my flight plan used airways. I asked a friend if he'd like to come along as ballast and he agreed. This brought our takeoff weight up to about 2,200 (max is 2,300). It was a warm day. When we left Palo Alto (PAO), the density altitude at TVL was 8,000 feet. The flight up was uneventful. I stayed under the hood until Placerville and found that my instrument skills had not completely deteriorated, which was slightly reassuring. In fact, I found that I could divide my attention better than I remember I could previously. The climb to 9,500 sure does take a long time, and it takes a while to level off and accelerate to cruise. The attitude indicator showed about a 5-degree left bank when we were really straight-and-level. It took me a while to figure that out ("sure don't seem to be able to hold a heading very well here") but once done things were easier. I took off the hood at Placerville. I was greeted with that gorgeous Sierra scenery, complete with widely scattered clouds above, and crystal-clear air. Wow. There was some light turbulence in the form of occasional jolts, but nothing too terrible. As we got closer, we extended the flight plan so that we could spend some time maneuvering. I learned how to turn around quickly, and how look for ridge lift and that sort of thing. The wind was not blowing very hard so nothing was very dramatic, but still there was a lot for me to learn. Also, it would not have been pretty had we had engine problems. There are just not very many good forced landing spots up there. After twenty minutes or so of this he says, "Take me to Tahoe" so I climb to 8000 to cross the last ridge into the Tahoe Basin. (We had descended for the maneuvering.) It was spectacular! The clear mountain air that day made visibility seem unlimited -- they were reporting 50 miles. To see Lake Tahoe open up before you like that is thrilling indeed. And it's easier than easy to spot the airport, with its single 8,000+ foot runway. Traffic pattern altitude is 7,500; the airport is at 6,200 or so. But you are certainly not 1,300 AGL on downwind -- the terrain rises east of the field. On downwind, we go to full power with 30 degrees of flaps for the purpose of setting the mixture in anticipation of a go around. Mixture set, we reduce power and retract flaps to fly a normal pattern. Cleared-to-land, the instructor has me ask for *the option*, which I wasn't real happy about but I didn't say anything (yet). Maintaining normal sea-level indicated speeds, it's clear that groundspeed is much higher. And I find my depth perception to be way off -- I think I'm low but the VASI shows me high. On final about a half mile out, we rather suddenly lose 10 knots and start to sink. Wind shear. It takes close to full power to stop the sink. 10 to 15 knots of direct crosswind make things even more interesting but I get it down not totally out of control. Instructor calls for a touch-and-go so I add power and retract flaps. We roll, and roll, and roll. Finally, flying speed. Up we go, about 25 feet, and down we come again. Then up, down, and no climb. He calls, "abort!" so I do. Downdrafts. The guys in the tower say something like, "Welcome to Tahoe" and the instructor says that that experience is worth the whole lesson. 8,000 feet does not seem too long of a runway under these conditions! The experience spooked me enough that I said that we would do no more touch-and-goes but instead full stops with taxi backs. Under these conditions I don't want the workload of a touch-and-go, thank you. The instructor grudgingly agreed. Our next takeoff, using short-field technique of course, is more normal. The length of the ground roll is really amazing, as is the speed (or so it seems). And the acceleration is just about non-existent. Yes, of course I'd read of and heard of all this, but it's something else again to experience it personally. And 300 fpm is just about all you get in a 172 after takeoff up there. Boy is that a shallow climb! We did a half-dozen more circuits, each one different. Now updraft, now down. Everyone seemed to be having a time of it -- even a King Air made what could be described as a controlled crash. And this with only 15 knots of wind out of the west, at the surface. Finally, time to return to Palo Alto. We ask the tower to open our return flight plan, and away we go. Climb is no better but I'm more used to it now. We head for the ridges looking for a little help and find some. We can fly home at 8,500 without hitting anything. I'm glad for that because I'm beginning to feel the affects of the altitude and I would rather not be at 10,500 since we don't have any oxygen. At Placerville I go under the hood again and this time set up the LORAN for "direct present position --> PAO." This saves a little time and the route exactly avoids any part of the SF TCA and the San Jose ARSA. (I checked by actually drawing the course on the sectional.) Home at last, the instructor talks me through the pattern while I'm under the hood. At 300 feet he calls, "runway in sight" so I remove the hood, go to full flap (I had been holding 90 kts until then), and make a decent landing with a turn off at the first taxiway. A pleasant end to an exciting day. Hope to see/meet some of you at Minden. Mark -- Mark Cousins Hewlett-Packard Co. mtc@hpsemc.cup.hp.com HP-UX VAB programs 19055 Pruneridge Ave., MS 46T5 (408) 447-4659 Cupertino, CA 95014 FAX: (408) 447-4364 ---------------- Relay-Version: B 2.11 6/12/87; site scolex Path: uunet!uunet!elroy.jpl.nasa.gov!swrinde!mips!gate.ready.com!gate.ready.com!dhoward From: dhoward@ready.eng.ready.com (David Howard) Newsgroups: rec.aviation Subject: Re: Mountain checkout Summary: I thought 300 fpm was normal? Message-ID: <1991Jun4.154305.11018@ready.eng.ready.com> Date: Tue, 04 Jun 91 08:43:05 PDT References: <3400086@hpcc01.HP.COM> Organization: Ready Systems Lines: 25 Mark Cousins writes: >Our next takeoff, using short-field technique of course, is more normal. The >length of the ground roll is really amazing, as is the speed (or so it seems). >And the acceleration is just about non-existent. Yes, of course I'd read of >and heard of all this, but it's something else again to experience it >personally. And 300 fpm is just about all you get in a 172 after takeoff up >there. Boy is that a shallow climb! We who fly out of Reno (4400) and Truckee (5900) have the opposite experience when we go to the lowlands. A takeoff at sea level makes you feel you are in a Pilatus Porter or something. If you want the high altitude checkout and you don't want to commit to Tahoe first thing, (Many folks up here are leery up here about going into South Tahoe in a 172, the terrain is notorious for reaching up and grabbing any airplane with less than 180 hp) I recommend you go first to Stead in Reno, which has 8000 ft runways, is at 5000 feet, but is surrounded by a large flat area with no particular obstructions, so you can mush out a long way before running into anything. Besides, you are flying the runway the Unlimiteds race on at Reno. You can use the race pylons north of the airport as landmarks for traffic pattern entry. And watch out for the big flat clouds. We get the most beautiful Altocumulus Standing Lenticular cloud formations here in the winter.