Welcome back to PART 3 & 4 on the Journey to Yellowstone by guest contributor, Jamie Fitzel. Missed the first one? Get caught up here.
Great Falls (elev 3,680ft) to West Yellowstone (elev 6,649ft) via Helena, Three Forks / Bozeman, Ennis-Big Sky.
Flight #2: The Mountain Valleys of West MontanaDepart: KGTF Great Falls Int’l
Arrive: KWYS West Yellowstonevia// HLN, 8U9, 9S5, EKSDistance: 199nm /// AirTime: 1h55 (planned), 1h54 (actual)FuelOn Board: 40gal (4.0 hrs) // Fuel Burn: 16.3gal (actual)
KGTF Wx//Wind: 310 @ 10kts / Vis >10m / Sky: Clear / Temp:17C / DewPt: 2C / Press: 29.88” / DensAlt: 4,793ft
Looking up showed nothing but pure blue but never let a clear sky fool you: mountain flying can be very tricky, mostly due to complications of unpredictable weather, combined with the risks associated with ever-rising, unrelenting terrain. Then, account for the limitations of a low-performance non-turbocharged airplane, which is seriously reduced in it’s ability to pop ‘up and over’ mountain ranges. It’s then you start to realize your flight planned route leaves you locked in a very narrow altitude window to operate, with even tighter navigational demands, requiring purely visual meteorological conditions to execute safely, especially when you’ve never flown here before.
A short glance at the VFR chart surrounding my route through the valleys shows ‘minimum safe altitudes’ being 7,400 ft. above sea level and continue escalating upwards to 11,700 ft., at the southern end of the route at Yellowstone. And, these MSA’s mean exactly what you think: below this altitude, terrain is unsafe … in absolutely every direction of the entire route. There’s no ‘bail-out’ direction for virtually 95% of the flight, which is always something I study for every flight plan. If weather deteriorates here, divert south, safe to descend to remain visual. Not, in the mountains. If weather went sour, ‘Plan B’ would always and only be: turn around, maintain altitude or climb to MSA if safely if practical. Luckily, the valleys of West Montana are dotted with many airfields, so the options to divert and safely land are plentiful, should the need arise.
But, terrain complications certainly add to the complexities and flying below the safe altitudes is exactly where I would be conducting the flight. The obvious plan here is to navigate following the shallowest points of the valley contours, with considerations to wind directions and flows. Even the valley floors themselves are high, beginning at around 4,000 feet above sea level and slowly rising to over 6,600 feet at it’s highest point upon entering the rolling ‘bowl’ of terrain that surrounds West Yellowstone Airport. Being in an airplane relatively incapable of flying above 12,000 ft., the surrounding peaks locked me into tight altitude corridors that required a snaking route to navigate.
Visually, the morning brought me a clear blue sky above Great Falls. Kind-of …
I use the term ‘clear’ very loosely. Why? One word: Smoke. It was all over the horizon. The sky conditions were still reported and forecast to remain over 10 miles, well within my comfort zone, but smoke is tricky. It’s not like fog which hangs heavy in the sky. Nor is it like mist or haze, which usually scatters evenly. Smoke is really dense, colorful, and it layers itself in the sky in weird ways, with the heaviest particles down near ground level, and the lightest ashes lingering many thousand feet above ground; It virtually completely obscures the horizon. But worse, the varying densities of smoke layers stirred in the air currents, are left layered in varying contours & definition, giving you a false-horizon sensation. Even false-terrain illusions can be apparent on the horizon; something that can play tricks on even the most focused of minds. You’ll really want to be comfortable flying and navigating with your instruments when any amount of smoke is dancing aloft in the atmosphere.
Perfect, let’s go flying!
The fuel truck meets me at the airplane and bring the main tanks up to almost full, leaving the auxiliary tank nearly empty. Planned flight time was 2.0 hours, safely within the 3.8 hour usable capacity on board, and many alternates were in close proximity to the route. There was no requirement to drag along any extra fuel in the back. After the fuel was loaded, we pack the airplane back up with all of our gear, all while paying special note to the loading arrangements to ensure proper balance; I revised my initial packing scheme to better optimize the loading. Pre-flight inspection complete, we climb in, buckle-up, and proceed with engine start-up and run-up.
All instruments in the green. All systems behaving normal. Request taxi for a VFR departure southwest to 6,500. Let’s go!
That morning I got cleared for take-off from runway 21, with a light but steady 90-degree crosswind, perhaps even a slight tailwind on the take-off run. Regardless of the shifty winds on the runway, this afforded me a straight-out departure en route. After the wheels lifted up, I proceeded into a climb to my initial cruise altitude of 6,500 feet.
Then, visually tracking the Missouri River southwest out of Great Falls, the sheer magnificence of the Rockies revealed themselves in a ghostly manner through the smokey horizon, as I’m lead across a martian landscape of buttes, ridges, canyons and mesas, all leading the way into the first mountain valleys of West Montana…
An interesting flight problem had unveiled itself at this point in the flight, something I’ve never experienced before; a terrain-intermittent radio signal. For a pilot, this is a huge inconvenience, especially for a flatland flyer like myself. It’s a phenomena I’ve never really had to deal with before. But here, flying below the peaks of the surrounding mountain ranges, poor radio reception is daily life for the pilots and air traffic controllers that call these skies home. VHF radio reception is heavily obscured by terrain; the low-powered radio equipment on-board the airplane certainly will not pass through rock or earth, and the high-powered land transmissions surely aren’t well-received, either. Reception is limited to line-of-sight, and as such, near Helena I was only able to receive Helena Approach at a mere 25-miles north, and subsequently lost them less than 15-miles south east of the airport.
Thankfully, the seasoned controllers of both Helena, and later Bozeman Terminal Area Control are certainly aware of this, and their ability to handle a busy corridor of mixed low-level VFR and IFR traffic weaving through radio dead zones seemed very well executed. They offered spot-on messages of: “I’m going to lose you in about 2 miles, switch to Helena Approach on 119.5 in 8 minutes, note opposite-direction Beech at 8.5, 1-o’clock, 10 miles”. Even though most of my route had me in uncontrolled airspace, the extra services of “Flight Following” from en-route (and terminal) ATC centers can offer to be a wealth of information to a VFR flight through unfamiliar airspace; you get the services of many flight aids, from communication and traffic awareness, to important navigation and terrain information. Very, very handy.
In the flatter terrain back home, I would expect normal VHF reception distance to be 80-miles, or more, depending on the flight altitude (remember when I had to climb to over 10,500 feet to establish 130-nautical mile communication at the border?). But here, below the peaks, the phenomena of poor radio reception continued for virtually the entire flight beyond Great Falls. Though I had the added assistance of ‘flight following’, I paid the penalty with a tedious effort of continually having a controller to establish radio contact with, and being handed-off to, many different controllers en route.
Ultimately, not a single transmission was missed, and the trusty feature of ‘filter-bypass mode’ on the comm radio came to good use to enhance the VHF reception sensitivity, even if it only helped out a little.
Density & Terrain
As remarkably beautiful as these West Montana mountain vistas are, this impressive terrain is even more impressively trying to throw every possible challenge at you and the airplane that you could imagine.
Shortly after passing EKS airfield at Ennis/Big Sky, I initiate a climb to 9,500ft on the altimeter. I say ‘on the altimeter’ for good reason: Up here, it becomes obvious that the daytime heat is beginning to become a factor with air density and how it registers on my instruments and overall aircraft performance. Air typically cools as it rises, and even though it also loses pressure as it rises, cooler air retains some density. But, when summer daytime heat begins to simmer the air (and moisture) in proximity to the ground, these valleys full of vegetation turn into giant furnaces, boiling the air above, and creating their own weather patterns within. The thermal currents radiate vertically many thousands of feet up, and when the heat source of the earth is already at elevations exceeding 7,000 to 10,000 feet, the effect this has on the air trapped within the bowls of these mountain valleys creates extreme density altitudes that power upwards of the service ceilings of these small piston-engine aircraft.
So how does this hot, low-density air affect me? At my current flight altitude of 9,500 ft, the pressure altitude corrected to 9,880 feet, and the outside air temperature of 21 degrees Celsius further calculates a density altitude upwards of 11,700 feet.
Well, this is the altitude of air that the airplane is actually ‘feeling’ like it’s flying through, even though you’re actually only at 9,500 feet above sea level (which on it’s own is a relatively high altitude to be flying a piston single). But, with the engine ‘feeling’ like it’s flying even higher at 11,700 feet, the power output decreases significantly. Full throttle yields as much as 30% power reduction, depending on the severity of the ambient air’s heat. Your engine is virtually suffocating. And, your propeller effectiveness is reduced; it’s biting into much thinner air. Even your wing is marginally less efficient, producing noticeably less lift for a constant airspeed.
In other words, high density altitudes are the worst performance conditions you could ever subject your airplane to, while still remaining in controlled flight. The engine is working it’s hardest, only to produce the least amount of power: This must be cautiously accounted-for when flight planning.
After all these considerations regarding how heavily the high density altitude is weighing on airplane performance, I still have to keep flying, and now begin to concentrate on engine performance. Shortly after leveling-out at 9,500, it’s time for me to lean-out the air/fuel mixture for peak-RPM as indicated, all-the-while becoming increasingly nervous as my fuel mixture control inches ever-closer to the idle/cut-off position.
For those that don’t know, pilots have the ability to constantly adjust the air/fuel ratio feeding the engine, because we need to. In order for the engine to keep ‘firing’, the air/fuel chemistry must be kept relatively constant. And, as we fly higher, the air is obviously thinner, therefore proportionately less fuel is required for the engine to achieve it’s most efficient power output. But here, in these extreme density altitudes, I have the mixture leaned so far back, it’s almost at the idle/cut-off position (this would kill the engine)! I’ve certainly never had the mixture this far back before and for reasons unbeknownst to me, the rugged dangerous terrain that surrounded me presented very little concern. However, having the mixture control almost all the way back had me quite on-edge, most likely because I’ve never run an engine in these extremes before!
In these flight conditions, where an excessively leaned-out fuel mixture is required, I’ve got to keep constant watch on the EGT (exhaust gas temperature), because this will indicate to me how rich or lean my engine is running; an an overly-lean (less fuel) mixture will literally cook the mechanical parts of an engine from overheating, leading to premature failure; something I certainly don’t want to happen in-flight. So why not just leave the mixture rich? Because, leaning the mixture, and doing-so properly, is vital at these altitudes to achieve enough engine power to remain in flight. A heavy-rich mixture results in significantly less engine power output, severely limiting your airplane’s performance, something you drastically need.
Additionally, on the mechanical side-of-things, a rich mixture causes carbon deposits to form on the spark plugs and other internal mechanisms, and over the duration of possibly only minutes, this can further reduce engine power output, or worse, could leave you with entirely failed spark plugs. Dead spark plugs result in dead cylinders; something else you really can’t afford at high altitudes.
To add even more urgency to the engine-monitoring requirements, I have my throttle lever virtually at the ‘full’ position to squeeze every last ounce of air into the carburetor, something that’s virtually never required at lower flight altitudes. But now with full throttle, the engine is struggling to maintain only 2,200rpm at peak-lean, a loss of over 30% horsepower compared to what it would achieve in thick lower air where 2500rpm is a normal power setting. This is almost comparable to running with one dead cylinder. The engine certainly works for it’s money up here in these hot conditions, and because of this, steady monitoring of the oil temperature and pressure indications, and any other engine instruments, is extremely vital.
Here’s where knowing your airplane pays dividends, as you require an acute knowledge of expectations for the airplane and it’s unique systems. The ability to spot any irregularities in the engine’s operation in a prompt manner can be the difference between a diversion or a forced landing. Without that engine, your climb-rate is negative, and you’re landing in that field ahead, if there is one.
Thankfully, with a properly trimmed engine, and a properly trimmed airplane, I’m are rewarded with a slight climb-rate of maybe 300fpm (feet per minute) as I steer between the peaks of the Madison Valley. With a heavily-loaded piston-single, this poor climb performance should always be accounted-for, especially up here near 10,000 feet; A 2,000-ft climb that normally takes me 2 minutes, just became 8 minutes or more. That’s greater than 15 miles of distance traveled in the climb … Am I going to clear that mountain ridge on the horizon? Always be 2-steps ahead of the airplane.
Speaking of mountains, now was a good time to switch the Garmin 430 GPS into ‘terrain’ display mode. The valley floor was getting higher and the mountains tops were squeezing tighter. Now is an excellent time to arm myself with the most accurate information regarding what lay immediately ahead. The display on the G430 unit can be selected to offer colored-map terrain and obstacle awareness, which is great, because I’m about to fly at 100-mph within 1 mile of sheer rock in these final 30 miles to Yellowstone…
Welcome to Yellowstone!Now it’s time to soak in the beautiful Montana afternoon, and bask in the smells of the fresh mountain air. The remainder of the afternoon is spent setting up camp at Yellowstone Airport!
PART 4 – Flying Yellowstone
An aerial tour above the geological features of the Yellowstone Plateau, thermal areas, valleys, canyons, rivers and lakes.
I woke up early this beautiful July morning in my tent perched adjacent to the ramp at West Yellowstone Airport to the sound of an old Cessna 170B doing touch and go’s, the morning dew dripping down the edges of the tent canvas as I unzipped the door to poke my head out and survey the sky. Cool and humid, clear and blue. Perfect.
Engage flight planning.
I launched ForeFlight on the iPad, which was tethered to an internet connection via my iPhone, and surveyed the weather information for the day all before even leaving the tent. The day looked great: visual meteorological conditions, low chance of poor weather, with only a very slight possibility of some convective weather towards the evening hours. The sky seems alright for this morning’s flying adventure. Time to gear-up for another amazing journey, a ‘loop’ around Yellowstone National Park from half-a-mile above the vistas atop a super volcano.
This Is It, The Apocalypse
Before we fly over, perhaps it would help to learn a little bit about Yellowstone National Park and what lies beneath the surface. Designated as a park in 1872 for it’s pristine natural beauty & abundant wildlife, Yellowstone was the first plot of reserved public land in the world, well before the days of the National Park System (NPS) in the USA. Decades later, it became a National Park when the NPS was formed. It wasn’t until more recent times that modern science would be able to closely examine the unique geology of the area and uncover her hidden secrets below the surface.
A massive lava cauldron exists many miles below the disguised caldera, measuring roughly 30 miles by 50 miles in size. The caldera was formed when the super volcano collapsed into itself during past eruptions, the most recent being around 600,000 years ago. All of this lava below the surface manifests into absolutely stunning geological features on the surface. Nowhere, however, does lava actually flow to the surface here. Rather, the lava cauldrons far below act as heaters to the underground water caverns, and through many complex networks of watersheds the subterranean thermal vents make their way to the surface in many stunning ways across various parts of the region. Each thermal feature appears unique to it’s neighbours, with different colors of bacterial formations and varying levels of mineral-stained acidic streams meandering across the surface
The entire region is truly a natural wonder unlike anywhere else on earth, containing more geysers than the rest of the world combined.
The grim reality though, is that in due time Yellowstone will erupt again. And when it does, humanity in it’s entirety might not fare too well. An eruption the size of what Yellowstone is capable of producing would be classified as a super-eruption, ejecting enough material into the atmosphere to severely block out the sun for incalculable amounts of time. Crops the world-over could fail. Half of the North American continent could be buried by a blanket of ash. Human-kind could possibly be placed on the brink of extinction. Hard to think, given the absolute magnificence of this place. Have a look at a few sights from above the most beautiful apocalyptic place mother earth has to offer us …
Flight #3: Around A Super Volcano
Depart: KWYS West Yellowstone /// Arrive: KWYS West Yellowstone
via// (as planned) // Distance: 128nm //Air Time: 1h18 (planned), 1h21 (actual)
Fuel On Board: 35gal (3.5 hrs) // Fuel Burn: 12.5gal (actual)
Wind: 130 @ 3 / Vis >10m / Sky: Clear / Temp: 19C / Dew: 10C /
Press: 30.28” / DensAlt: 8,396ft
The weather was fine that day, but it was bumpy air that morning over West Yellowstone. A gusty upper wind from the northeast made for some turbulent air in the wake of the rugged mountain ranges that surround the Yellowstone Plateau in virtually every direction. The out-of-focus images are a good indication of how bumpy the air was; though only light shakes, they were steady and relentless, making it difficult to hold the camera steady, even with fast shutter speeds (remember, I’m actually moving at over 100mph while capturing these images, too!).
To compound the matters, the smokey fog that plagued the skies along the entire journey still lay lightly scattered across the entire area. With the low morning sun reflecting brightly at a shallow angle against the lingering ash particles, dazzling vistas were illuminated by a strong glow in many places, and poor image results followed from all that glare. All was not lost, and with the power of photo editing software, I was able to piece together an encapsulation of this flight over the park. Have a look …
The Madison Valley
The Norris Geyser Basin
The Yellowstone Valley
The Grand Canyon of Yellowstone
The Yellowstone Plateau
After the bumpy, yet absolutely surreal trip 2,000 feet above the fascinating geology and topography that Yellowstone beholds, it’s time to relax from the airplane for a while. Now, we stick to ground-level and embark on a little bit of foot-adventuring and road-tripping up here on top of the super volcano.