Bush flying in Alaska

Now I don’t know about you, but I always thought that the best way to short-field land a taildragger was to get her nice and slow on the approach. Then have her hanging over the back of the drag curve with a surfeit of power and drop her on the required spot, followed by some judicious braking, being careful not to tip her on her nose.

If you want to go bush flying in Alaska you need to forget about all of that and learn a whole new technique that really can set the adrenalin racing.

Let’s look at the aircraft first of all?a Citabria 7GCBC with all kinds of aerodynamic mods to get her to fly slower and, more importantly, under full control up to, and into the stall. These include drooped leading edges with vortex generators across the full span, fences between the five-stage flaps and the ailerons, extended wing tips and vortex generators under the tailplane. Most obvious are big, fat, 31 inch tundra tyres with just a measly 8 psi pressure, and a tail wheel that could double as a main wheel on a normal aircraft.

These tyres not only allow you to operate off soft rough ground, they can also handle an eight-inch boulder and, just as importantly, they give extra tip clearance for the propeller?about two feet six?which is really important when you want to operate at full power off a shingle strip with your tail hanging up there in the air.

Most of the bush flying course is to do with landing and taking off from small, unprepared or at least little-maintained outlying strips, miles from the nearest road and frequently any form of habitation. This entails getting the most performance out of your aeroplane, which in turn means scraping around at the bottom of the flight envelope and digging deep into its corners.

Jumping off the ground

The takeoff is only slightly unconventional. Checks are normal except that you use no flap, repeat no flap. Trim is set to neutral and that will be the last time the trimmer is touched at all during the flight. Full power, full forward stick and get that tailwheel off the ground as quickly as possible. Correct for swing as the tail comes up and then focus on zero angle of attack to minimise drag. Now the interesting bit; when the speed hits 42mph, reach down and yank on full flap with the left hand, correcting the left swing with the right boot. The Citabria jumps off the ground like a shot rabbit and hangs there in ground effect as the speed builds. As soon as you get above tree-top height, bleed off the flaps and let her climb at seventy. For full performance we would have held full power on the brakes and then climbed at the best angle speed of 55mph, but in deference to potential prop damage we don’t hold her on the brakes, and in consideration to other traffic we climb at a sensible speed. The important trick to learn is the timing of full flap application: too early and it just slows you down, too late and you are wasting time on the runway.

Most Read

We climb to altitude for some upper air work away from the busy Talkeetna pattern, now teeming with ‘flightseeing’ aircraft on their way to and from nearby Denali (formerly Mt McKinley)?at 20,320ft North America’s highest mountain. The climb allows me to get acquainted with the rudder and this is one area where the Citabria shows some vices. The slip ball seems to have a magnetic attraction to the ends of its travel and normal rudder application seems to have little effect until suddenly it whizzes back across the other side. The simplest thing is to ignore the slip ball unless it is stuck out in the corner and don’t try and keep her dead centre. The Super Cub I had flown on floats the evening before didn’t even have a slip ball so don’t worry, just fly off the seat of your pants. All but the essential instruments are removed to save weight so there is no artificial horizon or turn indicator. There's no gyro compass either, and the magnetic compass has a mind of its own up here in the higher latitudes.

Sharp-toothed spotters

Upper air work consists of a series of stalls at various flap and power settings. We do them with no power, half power and full power at nil flap, half flap and full flap. We enter the stalls slowly and with an abrupt pull up, investigating every kind of combination, and each one has much the same result. The left wing drops but it can be picked up with aileron. At high power settings there is a little shudder before the nose drops. Recovery is focused on getting the wing to fly again, using a little forward stick to re-attach the airflow and extra power at the lower power settings.

So we go back to the circuit with this docile beast. She may complain a little, but she certainly won’t bite you. Setting up the approach is again conventional as we feed in increasing stages of flap downwind, base and final, aiming for 55mph on final. Notice there is no trimming. The stick forces change with attitude, power, flap and speed but no attempt is made to trim them out. So many changes occur so rapidly that it is far better to feel what the aircraft is doing rather than trim away all the feel. This Citabria has beautifully balanced controls with no friction or resistance, just oodles of feedback.

Over the hedge we are aiming to bring the speed back to 50mph and feed in some power to maintain height and overcome the increased drag. The nose is well up even with full flap. We are aiming to touch down on the short little gravel strips between the runway, the taxiway and the connectors between them. At this point I would normally be getting ready to chop the power and drop us tail-first onto the gravel. Not so in bush flying. You are more than likely to rip off the tailwheel and possibly lose directional control on a strip that is only slightly wider than the track. In addition you can’t get on the brakes so hard because the wing is at such a high angle of attack with those big tundra tyres out front that the down-pressure on the tyres is significantly reduced.

Now you have to ignore everything you have ever been taught about landing an aeroplane and you slam the stick forward to drive the wheels on to the ground and hold the wing at negative incidence. I apply some power to hold the them there and to keep the tail feathers alive, and hit the toe brakes as hard as I can while correcting the tendency to nose over with the stick. The tailplane is still flying with full authority thanks to the airflow from the engine at high power. It is all kind of crazy but it works, and we come to a full stop in a tiny distance with full directional control and a tail wheel still attached to the aeroplane. After a few more circuits perfecting the technique we get ready for some ‘off airport’ landings.

Being in Alaska I was quite prepared for the survival kit to be chucked into the back of the aircraft, but I have to admit to being a little surprised when my instructor arrived at the aeroplane with a Browning revolver strapped to his hip next to the Leatherman tool. The gun is for protection from aircraft-spotting grizzly bears that can hang out around some of the strips we were planning to visit!

The plan was to fly into a number of increasingly challenging bush strips out on the muskeg, but the procedures follow some basic rules. First a flypast at 800ft to check for major obstructions like tree trunks, bushes or grazing moose. Then a pass at 500ft holding the GPS groundspeed readout at around 69mph, which is the same as sixty knots. By comparing the GPS with the ASI you can get a good feel for wind speed and direction along the strip. You also measure the length of the strip at the same time by counting the seconds elapsed travelling from one end to the other, as one second at 60 knots is 100ft. Any strip more than 400ft is fine. Anything over 700ft seems like London Heathrow.

The third pass at 300ft is used to check the surface for smaller obstructions and to pick out a clearly visible marker such as a tree trunk or distinctive bush to act as an abort point marker. If you are not on the ground by your abort point then you go round again. Lance, my instructor, was very conciliatory, emphasising that go-arounds are the norm rather than the exception in bush landings, probably in excess of seventy percent of approaches are go-arounds. There is no margin for error?at all!

We set up our final approach as before at the airport, but now the perspective is completely different. The strip is ridiculously narrow and short. As we near the touchdown point the narrow perspective gives an impression of much higher speed than you are used to on a normal runway, especially in near zero wind conditions. You have to focus on driving the aircraft onto the ground and getting onto the brakes as fast as possible, holding the tail up to the last minute, then stopping dead on the strip. Don’t taxi anywhere. Just shut down where you are and get out.

Finding a suitable place to land

First of all you need to inspect the aircraft for damage that may have been sustained on landing?especially the underside of the tailplane and fuselage, which might have been punctured by a bush or stone. Next you pace back the strip checking for obstructions and wind direction as well as establishing a good visual marker as the abort point for the take off that will still allow you enough space to pull up. You recheck the wind direction as it could be quite different here on the ground compared to the 500ft wind measured earlier.

Back in the aircraft you taxi back to the take off point, being careful not to swing the tail around into any bushes, rocks or other obstructions close to the strip. You line up very carefully then put the power on as quickly as possible with the tail up as soon as full forward stick takes effect. Keeping straight on rough and sometimes rutted strips is more difficult than on a normal runway but far more important, as the margin for error is minimal. A quick glance at the ASI and a yank on the flap lever jumps us into the air with a few feet to spare before the abort marker flashes by the side. Repeating this exercise on ever smaller strips increases the rate of go-arounds quite significantly.

We only land on previously reconnoitred strips. The bush around Talkeetna varies from muskeg to tundra on the higher ground. From the air it looks like a badly maintained golf course, but those things that could be fairways are actually soft boggy ground. Anywhere that is dry generally has a tree growing on it, leaving little choice for a wheeled aircraft in the summer.

The other option frequently used in Alaska is to land on a gravel bar in the river. In early June the Chulitna river is flowing deep and fast with milky glacial melt water while the Susitna and Talkeetna, the other two rivers that meet at Talkeetna (three rivers in native Alaskan) are full from bank to bank due to heavy rain. Options for gravel bars are therefore pretty slim.

The main thing to learn is to recognise the good surfaces from the bad. If you can make out individual rocks from 500ft then they are too big to land on. Plain monochrome surfaces are likely to be soft, and dark surfaces are likely to be wet. The preferred option is the mottled surface that indicates mixed gravel and silt. Lance has a good idea where a suitable bar may be found as we fly slowly up-river checking out likely landing options. Almost all of them have to be eliminated because of lack of length, dodgy surface or obstructions caused by grounded tree trunks, growing vegetation or empty cross channels. Eventually we get so far up the river, to the point where it emerges from some rapids, that the rocks are too large to contemplate a landing. We turn and head back for the one likely bar that I had spotted earlier and which Lance then confirms is his preferred option too.

The bar has about 500ft of good surface with a handy bush marking the touchdown point, a big white rock marking the abort point and a hefty log marking the upwind threshold?but there is a bit of run off to one side if it gets ugly. Landing is fun as we approach low past a fleet of river rafters who thought they had the river to themselves. Banging her onto the gravel is almost routine by now and we pull up and stop in two thirds of the available distance.

Back at the field I got signed off for the course. Above Alaska charges a flat fee of $1,899.00 for the course, which includes five to six hours’ flying and two nights’ accommodation. Alaska styles itself ‘The Last Frontier’ and Talkeetna is still a frontier town. This is no Disney creation, it’s the real deal but it has lots of things to do on the river, in the air or out in the bush. It’s a little over two hours’ drive out of Anchorage or there is a daily train service if you have the time. Now I just need a few hundred landings under my belt to get half as proficient as some of those guys who call Talkeetna their home field.

Comments powered by Disqus