Wind shear

The last two weeks have been totally routine. Even the weather has barely changed.

A steady diet of clear skies and light winds has taken some of the sting out of spending more than week living out of a hotel, covering for a pilot whose normal run starts and ends in Aberdeen.

Only the afternoon turbulence intrudes on flying Nirvana. The 310 is notorious for it's annoying dutch roll tendencies in even the lightest of turbulence, making hard work out of every atmospheric ripple.

But as evening comes on and the air turns glassy smooth, as it has done every day for the past two weeks, life is good.

It's the kind of weather that lulls me into near total relaxation. The airplane perfectly trimmed, staying on course and altitude with no input from me, the engines droning on with both propellers in near-perfect synchronization, the setting sun reflecting off of the hundreds of lakes the slip beneath me as I fly the same route day after day.

Approaching Fargo the sunset is particularly spectacular thanks to the haze created by the numerous grass fires and the first rain I have seen in more than a week.

Fargo itself is dry, the rain is still well to the West filtering the last rays of sunlight. I look at the rain and don't like what I see. It has the look of a windy, turbulent mess.

Not to worry, it is still well West of the airport and the winds are light and the air perfectly smooth.

Pre-landing checks are complete and the airplane is in perfect trim, exactly on speed with gear and flaps down flying hands off down the glide path with the power set to 17 inches of manifold pressure. It is magic. Nothing left to do but ease out the last bits of power and flare.

My thoughts turn to the landing and I decide to work for an absolute greaser. The evening is too pretty, the air too cool and smooth to ruin the moment with anything less than a gentle chirp of the tires against pavement.

At 300 feet I place my hands on the controls, add full flaps and adjust the trim. It is still perfectly smooth.

At 200 feet my world, quiet and serene just a few seconds earlier, tilts instantly and distinctly off it's axis. I am stunned.

The first jolt of turbulence is strong enough that I bang my head against the top of the cabin. I am now fighting to control an airplane that just a few feet ago was in perfect harmony with the atmosphere. Now, that same atmosphere is trying to kill me.

I am starting to drop below the glide path. Out of the corner of my eye I catch the airspeed indicator. I have lost 15 knots in the span of a second, perhaps two.

I add power but we are still sinking and my airspeed is still low. It is a fight to keep the wings level and the thought of crashing runs through my head.

I shove the propellers and throttles full forward. Finally, I am no longer sinking and I am getting my airspeed back. I am suddenly deeply in love with the 310 as 570 horsepower begins to carry me toward salvation.

Satisfied that the worst is over I ease the throttles back.

The wind, which was light and slightly from the left just a few seconds ago is now raging and almost 90 degrees to my right. I contemplate going around but by now everything is once again back under control so I fight the wind down to the runway and instead of the greaser I was contemplating what seems like an hour ago settle for an inelegant, albeit it safe, thunk.

From start to finish the entire saga has lasted perhaps 15 seconds.

As I taxi in I report the wind shear to tower. I am strangely annoyed when they reply that they just noticed a wind shift and leave it at that. Even a quick "wind now 360 at 21 knots" while I was on final approach would have alerted me to the possibility of the wind shear that was waiting for me.

I've been fortunate enough to have encountered wind shear enough that I can recognize it when it happens. Usually it's benign, perhaps a five knot swing or so, and occurs on windy, gusty days so I'm already locked and loaded to deal with it.

What made this encounter so shocking was there was no warning, I just happened to arrive over the runway at the same time the wind was shifting more than 90 degrees. Three minutes earlier or later and I'm sure it would have been a totally unremarkable approach and landing.

After dropping my freight I fired back up and launched into moderate turbulence which lasted until 5,300 feet. Like a light switch the atmosphere was suddenly perfectly smooth again and stayed that way for the 45-minute trip back to Aberdeen on a beautiful spring evening.

The learning continues.

Routine

With thunderstorm season approaching I've started flying with my handheld GPS as a means of getting weather, in particular thunderstorm cells and lightning strikes, on board.

The GPS is certainly useful although due to the inherent delays in the way weather is datalinked it's best used as a strategic tool and not a tactical one.

But I do love it and it's just one of those things that I don't want to be without. On good weather days I usually leave it in my flight bag but it's a great aid to have on those days when weather is an issue.

The other neat thing was grabbing my GPS tracks and dumping them into Google Earth. If anything, it shows just how routine freight life is. Even as a floater I pretty much always fly to the same places, along the same routes at the same altitudes.

For whatever reason, over the seven or eight days of flying represented in the image above I was spending a lot of time going to and from Sioux Falls. A quick check with the ruler inside of Google Earth shows a whopping differance of about six miles between all the trips down and back from Sioux Falls.

That's just the difference between which runway I used that particular day and how quickly I was cleared on course. It's probably just the geek in my but I thought it was pretty amusing just how closely one day's path resembles the next.

If you're a Google Earth fanatic like me and want to get a closer view, here's a link to the .KML file.

Hot plate

Finally, the ice has stopped building.

I've changed altitudes three times looking for a sweet spot that will keep more ice from sticking to my airplane. Eventually, Minneapolis Center graciously gave me a block altitude so I can work my way over and under the clouds at will.

A strong low pressure system is centered almost directly above me and has brought with it many of the associated evils that spring-time lows tend to produce. In one short flight, spanning perhaps 200 miles, I managed to fly through snow, sleet, rain, smooth air, moderate turbulence, light icing, no icing, moderate icing, strong surface winds and dead calm.

For the second time in a week I was unable to get to my ultimate destination due to the weather. Rapid City, well to the West of home was hit with a pair of blizzards. The first brought winds above 50 knots and ¼ mile visibilities so the decision not to go there was an easy one.

The second storm was more frustrating because while by the time I was ready to depart for KRAP the weather there was decent and improving the airport remained closed as they tried to deal with the ice left behind.

So instead of going to Rapid I spent both days holed up in a hotel at our intermediate stop on that route, Sioux Falls. By early afternoon the courier company had made their decision: Skip Rapid and come home with a stop in Marshall, MN to pick up freight there.

The trip from Sioux Falls to Marshall was easy and despite a bit of snow, sleet and a touch of rain the airplane remained virtually clear of ice. Even better, the temperatures near the surface were above freezing and as I descended into Marshall on the ILS what little ice there was melted and fell away. At 300 feet the runway oozed into view and I touched down with a slight tailwind.

A few minutes later I was on my way home.

At 5,000 feet there was nothing more than light icing which the airplane quite happily handled as the boots did their job keeping the leading edges clear.

Just 50 miles behind me, 5,000 feet had brought no more than a trace of ice so things had, in effect, gotten worse.

If the trend continued I could find myself in a box, relatively low and unable to climb my way out of the icing. Perversely the temperatures near home were well above freezing, tempting me to stay low and hope that things got better before they got worse.

But still, sticking around for too long in any icing conditions can quickly lead to disaster so I decided to do what the books say and requested a climb to 7,000 to get out of it.

At 7,000 feet the situation was much worse and what had been light intermittent icing at 5,000 was now moderate and continuous.

Still at climb power in level flight I lost 20 knots of airspeed in the span of a few minutes. The wings themselves stayed fairly clean as the boots did their job but the tip tanks now spouted an inch or so of jagged rime as did the engine cowlings.

I couldn't see the nose but by the loss of airspeed I was pretty sure it, along with the windscreen and anything else not protected by boots or heat held a similar amount of rime.

Enough of that then. Go up or go back down?

Normally, up would have been the call but I'd picked up enough drag from the rime that I was now in level cruise flight with climb power set and indicating 140 knots, which normally yields a nice 500 foot-per-minute climb. Not critical but about as slow as I was willing to fly the airplane under those conditions.

So down it was. At 6,500 things were better and I was in and out of clouds briefly and by working up and down within my block altitude I was able to stay mainly in the clear.

30 miles behind me a cargo airplane from a different company had made the same decision and asked for a climb out of 5,000 so I relayed what I knew: 7,000 was bad, somewhere between 6,000 and 6,500 was pretty good and 5,000 was best of all.

By the time I was 60 miles from home ATC had dropped me down even lower and 40 miles from the airport, descending through 3,600 feet the temperature suddenly went positive and I watched in amusement as the airplane began shedding large chunks of ice.

Looking back I should have either stayed at 5,000 or climbed directly to 9 or even 11,000 to minimize the time spent in the worst of it. Instead, it was the exact wrong call but yet another learning experience.

Muffins

It is a break from the routine. Another pilot is stranded in Fargo. The poor guy landed in a snowstorm the previous morning covered in ice, unable to see forward then got stranded when the airport shut down because of the weather.

The snow was so bad he couldn't get to a hotel, despite three valiant attempts, and wound up spending the night on the floor at the FBO. Flying freight is a glamorous job, for certain.

The heater on his airplane has gone belly up so I get to fly a mechanic, some tools and spare parts up. We'll give the poor, stranded pilot our airplane so he can finish his run and get home, fix his airplane then bring it back to base.

It's a beautiful VFR day, but cold. The winds are howling, right on our nose all the way up, and the 145-knot groundspeed makes it a long trip. At least it will be quick coming home.

I chuckle when we realize the heater in our salvation airplane is barely working. The good news for the stranded pilot is that he gets to go home. The bad news is the heater sucks.

In Fargo I leave the mechanic in a chilly hangar to sort out the mysteries of the broken heater and gorge myself on coffee, fresh-baked muffins and the flat-panel plasma television in the FBOs lovely pilot's lounge.

For a moment I feel slightly guilty that I am warm, fed, sipping coffee in a leather recliner and watching a Clint Eastwood flick while the mechanic is freezing in a hangar, crawling around a broken airplane.

The moment passes, however, and I go back to watching Clint dispatch the bad guys. It is a good FBO, they know how to take care of pilots here.

Besides, I have almost no idea what makes the heater actually work, much less what makes it break, so I figure the most efficient course of action is to stay out of the way drinking coffee, eating muffins and watching a big flat-screen plasma TV.

Eventually the mechanic appears. He's young enough that working in a cold hangar doesn't bother him. I'm getting old and soft, a status I'm starting to enjoy. The heater is working again but he's not certain how long it will stay that way.

I brush some muffin crumbs off my chest, finish my coffee and we hustle out, fire up the airplane, pick up our clearance and head for home.

It is toasty warm until we're at 500 feet on the climb out. The gear has just clunked into the “up” position when the heater quits.

The aviation gods are getting their pound of flesh for my muffin-eating, coffee-drinking, plasma-screen-watching indulgence earlier.

Damn, time for a command decision. Oh well, that's what I get paid for, making the big decisions.

“Um, look man,” I say in my best captain's voice, “an hour freezing to death sure beats a night in Fargo.” The mechanic agrees.

Outside, it is -25C at altitude. I have no idea how cold it is inside, but by the time we land back at base my hands are frozen solid. I don't fully warm up until several hours later, huddled under a blanket on the couch at home.

It wasn't the most enjoyable trip home but despite the cold it was safe. Almost as important, I'm home and not spending the night in Fargo.

Snow

The first two days of a three-day trip have been routine. Clear skies, good visibilities and relatively warm for this time of year around these parts. Heaven.

I've been living out of a hotel, filling in for a vacationing pilot whose normal run begins out in the Dakotas, comes home and finishes back out in the hinterlands.

Two days of being spoiled is enough though and I wake up to a snowstorm on day three.

By departure time that afternoon it has stopped snowing, at least where I am. The storm is moving East though, toward home, which means I will spend my evening chasing the tail-end.

Sure enough my first stop, a mere 30 minutes away, is still getting hammered and so begins my own personal version of Groundhog Day.

Launch, fly an approach through the snow, land, walk around smashing ice off the airplane, launch again, fly an approach through the snow, land, smash ice off the airplane.

I briefly consider flying the ILS into Marshall to shave some time off of the trip but prudence trumps expediency. The ILS approach is almost directly lined up with my route of flight but would mean landing with a 20-knot tailwind. Even though the runway is long, that would be dumb enough on a good day. With a snow-covered runway it could easily wind up with me sliding off the far end, which is a poor way to finish a flight.

Instead I elect to fly over the airport, turn around and fly an approach into the wind. All of this adds time but tonight it's the right thing to do.

By the time I'm down safely in Marshall, my penultimate stop for the night, I'm behind schedule. Not helping matters, while the runways are fairly clear the taxiways are sheets of ice covered with snow.

Creeping along to keep the trusty 310 from sliding into the snowdrifts eats up more time. It's a dance of brakes, aileron deflections and differential power to counteract the howling wind that is conspiring to send me sliding off into the drifts. I have never taxied so slowly in my life nor worked so hard doing so.

The ramp hasn't seen a plow and is covered in snow. I try to avoid the deepest spots and eventually get to my parking spot, shut down, smash ice off the wings, tail, nose, tip tanks and a few other spots then run inside to check that the weather at home is good enough that it is legal for me to depart.

It is, although not by much. Back in the airplane, engines running, I call Flight Service to amend my flight plan with an alternate, required on a night like tonight. This is an exercise that almost never goes well.

Tonight is no exception. The Flight Service briefer who takes my amended flight plan can't issue me a clearance so I hang up and call the dedicated clearance number. Normally I depart VFR and pick up my clearances in the air directly from Minneapolis Center but tonight the weather means that's not an option.

The Flight Service briefer who is supposed to issue me a clearance can't. Turns out he can't find my flight plan, which seems to happen more times than not when we call to amend our canned flight plans with an alternate because of the weather. I give him the vitals as he enters a new flight plan for me then there is more bad news.

An airplane is on an approach to my airport and until it lands I can't leave. This is normal at smaller airports without a control tower. It's strictly a one-in, one-out system and until the inbound aircraft has landed, contacted ATC and cancelled their IFR flight plan nobody gets to leave, at least not under IFR.

As we're talking, an airplane swoops in and lands. Trying to get back a few minutes I let Flight Service know. This doesn't work either.

The briefer asks for the tail number, or at least the aircraft type. I explain that I'm sitting on the ground in a snowstorm, at night and all I know for sure is that somebody just landed. No joy on my outbound clearance then so I hang up and promise to call back in a few minutes.

It's a good system, despite the communication difficulties. I don't want to launch unless the airspace is clear of traffic and the only way to know that for certain is for the aircraft on approach to call and let ATC know they're safely on the ground.

While I'm sitting there my cellphone rings. It is the courier company wondering if they are going to see me that night. “I hope so,” I tell them. “If I wasn't on the phone talking to you I could be picking up my clearance and getting the hell out of there.” The message is received.

Finally, after 30 minutes of sitting on the ground with the engines turning I have a clearance. By now it is not snowing as heavily but the wind is still howling. I tiptoe out through the drifts and across the icy taxiways, line up and launch.

Finally headed home, the flight is more of the same although I am no longer picking up ice. It is busy and I'm number five for the airport.

Another approach and I smile slightly when approach control informs me I'm 20 knots faster than the jet ahead of me in the gloom. I may be late, flying a clapped out piston twin in a snowstorm but at least I'm going faster than the fancy bizjet full of the latest and greatest avionics somewhere ahead of me on the approach. I love this job.

The runway is covered in snow and despite my best effort to slam the airplane down - normal on a contaminated runway to get the wheels through the gunk and onto pavement where they can do some good – I wind up with a greaser. Gotta love the ego-soothing effects of having a nice soft cushion to land on.

I'm an hour late, not good, but I'm home safely. It's just been one of those nights.