Initially when planning this trip, I considered the more typical route of heading towards Lancaster, CA and crossing over the Tehachapi’s. Having been that route a couple of times though, I looked at the alternative of coming up the Eastern side of the Sierras and perhaps crossing over them at Yosemite. BIG rocks there, stuff in the 12,500 range so not something to consider lightly. I figured I could stop for gas at Furnace Creek in Death Valley then had the option of crossing the Sierras at Yosemite or the more familiar area around Lake Tahoe. Overall distance was very close between these two options.
I could file/fly IFR to Furnace creek but definitely not beyond that due to high MEAs. I filed essentially direct from Prescott to Furnace creek. Technically, via Kingman, AZ but it's on a straight line between the two. I could have requested a route on the airways to Las Vegas but figured I'd leverage /G capabilities and go direct (hence the straight line Eric). Requested 12000 and my clearance contained those wonderful words "as filed". The only change came when a LAS approach controller asked if I "was able higher". I figured I could possibly squeak out 14,000 but having never tried before, wasn't sure. The controller informs me that their MVA in that area is 14,000 so I reply with "I'll give it a try". Terrain avoidance wasn't much of an issue on my route at 12,000 so it must have to do with radar coverage. Much to my surprise, the Arrow made 400 fpm all the way up to 14,000. Nice...and boy am I glad I have oxygen. I'd planned on using it during the entire flight home anyway. Groundspeed at 12,000 was in the 130-135 range but when I got to 14,000, it dropped to 113 which sucked.
Prior to departure, the last check of my time enroute for the entire trip came out at 03:40 so I thought I'd see how things went to Furnace Creek and possibly not stop for gas but continue home (max I'll fly with full tanks is 4:30..but I don't like to). I'd already punched in the rest of my route and had been watching ETA times on the 430. About an hour into the flight, ETA at LHM was really going to result in more than a 4 hour trip so even before climbing to 14,000 and losing groundspeed, I'd decided to stop at Furnace Creek. Slowing to 113 kts GS more than sealed that deal.
About 35 minutes out of Furnace Creek, I start wondering when ATC will be able to have me descend. I have a lot more altitude to lose than normal. I ask for lower but am told they can't issue an IFR descent but I can cancel if I want...and I do. I start descending and in about four minutes, they lose me on radar and tell me to go away and squawk 1200. Now it’s just a matter of staying outside of the MOA until I’m under 3000 MSL. Landed at Furnace Creek and was lucky enough to catch the fuel guy at the pumps. It’s run by a gas station about a half mile away, cell service is non-existent, so it would have been a hike to get someone to come to the airport for fuel. Temp was a comfortable 78 degrees.
Depart, parallel the MOA for many miles (there was one in particular I wanted to avoid as it had a 300 AGL floor) climbing climbing climbing up to 12,500. Tried contacting flight service to open a VFR flight plan but couldn’t get in touch with them until I was almost over the top of Bishop, CA. By now, I’m staring at the wall of snow covered cumulo Granite, probably 35 nm away and I decide that 14,500 is a nicer altitude so up I go.
Now the fun/exciting/semi-uh-oh part. Having been in up/down drafts many times and this being my first time attempting to cross the Sierras near Yosemite, I’m watching very closely for up/down draft. As I’m maybe 4 nm away from the first set of snow covered pointy rocks near Mono Lake, the altimeter starts unwinding and the VSI goes from 0 to 500 fpm down in a heartbeat. Ok, we’re already at full power so prop to climb, pitch up...and...by the time it took to do just those two things, the VSI now reads 1000 fpm down. Without hesitation, I started a 180 degree turn to my right. I’m sinking all the way through the turn but as I roll out, the descent rate is back to 400-500 fpm. At about the 120 degree point of the turn, I glanced back over my left shoulder and despite the rocks being a good 4000-5000 ft. below me, I could sense the dramatic descent rate and it was pretty freaky. I knew I was going to be ok since *much* lower terrain was ahead and less than one minute prior, I was in an area of no downdraft...but still, it was a weird site picture and served to confirm that I’d just done the right thing. I also wondered how high above the terrain Steve Fossett had been before he encountered downdrafts (somewhere in the same general area from what I recall).
Time to execute Sierra crossing plan-B so I continue my present heading away from said big pointy snow covered rocks for maybe 10-12 nm then turn left and head direct to South Lake Tahoe. By now, I’ve recovered my lost altitude and am once again cruising at 14,500...then...going up! Hit a good updraft that took me up at 1000 fpm. I pushed forward a bit to keep the ascent rate lower but figured I’d take another 2000 ft. if mother nature wanted to give it to me. More altitude margin for attempting to cross the Sierras at Lake Tahoe would be just fine with me.
Approximately 30 nm South of Lake Tahoe, I decided to turn left and head direct to Lincoln, my home airport. I’m at 17K and change, watching the altimeter and VSI like a hawk. First ~20 nm or so go by and I’m still above 17K, no downdrafts, life is good. Then, a steady 200 fpm downdraft. Ok, pitch up, climb setting on the prop, and...*still*, 200 fpm descent. Ok, not good but not as immediate of a “fix it now” situation as near Yosemite. I was probably 3500-4000 ft. above a scattered to broken layer over the Sierras, I could see Lake Tahoe and the valley to the East where Minden NV lies (these were my Plan-C options, should my current Plan-B option not work. I’m passing through ~17,000 and figure I could keep up the 200 fpm descent for maybe 15-20 minutes before needing to execute Plan-C. Also, the second the descent rate increases beyond ~300 fpm, I’d do another 180 then head direct to Tahoe or Minden. My groundspeed absolutely sucked at 60-70 kts but the descent never went beyond 200 fpm. I experimented with the prop pitch, going from current 2500 RPM up to 2700, down to 2200 and spots in between to see if anything helped. Reason for trying the lower end of the RPM range is that I’d just read an FAA bulletin re: using a lower airspeed to maintain altitude during a prop over speed condition. I figured since my IAS was already way low (75-80 mph), I’d try the upper range, beyond normal 2500 climb setting. I also figured I’d try the lower end of the spectrum and places in the middle. There were short periods where ~2200 RPM and ~2700 RPM helped a bit...as in, stopped the descent but it didn’t last more than a minute so I went back to 2500 RPM climb setting. After 10-15 minutes of this nonsense, the downdraft stopped and I was able to climb so I eked my way back to 16,500 so I’d be at a recommended VFR cruising altitude. By now, I’m ~55 nm from home and it’s still looking like I’ll have to get a clearance for an ILS. Oh, forgot to mention that part. I’d been monitoring weather at Lincoln during the first leg and on the current leg. Conditions in the valley were broken at 6000 so I’d already been prepared to get a popup clearance into Lincoln.
I try for the second time to get in touch with Rancho Radio so I can close my VFR flight plan and this time they answer. I’ve already started my descent and it’s obvious that I’m going to arrive at Lincoln with several thousand feet to lose. Conditions went from broken to scattered so no cloud entry required today. By the time I’m 5 nm away and approximately on the 45 for left traffic to runway 15, I’m still at 9000 ft circling down through the scattered clouds. Lower the landing gear helps but I still do a BIG 360 descending at 1500 fpm (by now my ears are talking to me). Roll back out on the 45 at ~3000 and call it good. Land and make the first taxiway, skip refueling the plane, leave lots of stuff in it, and call it a day.
Lessons learned and things reinforced in my head:
1) It’s always good to have a plan-B and Plan-C when crossing pointy rocks (snow covered or not).
2) It’s always good to know exactly where/when you’d execute plan-B/C when crossing said pointy rocks. Do not pass Go, do not collect $200, fix it *now*!
3) Supplemental O2 rocks, especially when you’re trying (or not) to set altitude records in your airplane.
4) When the Arrow isn’t at max gross, it can indeed cruise at 14,000 and does so rather nicely. Refer to previous point re: supplemental O2.
5) Gas at -210 ft MSL is expensive but if you’re visiting Furnace Creek, do so this time of year when it’s ~78F vs. summertime when it’s 125F
6) Our Davtron chronometer does indeed register double digit negative temps in Celsius!