Alpine Soaring - By Barry Wrenford
Jindabyne airstrip started as a Snowy Mountains Scheme airstrip of 2 runways. It was part of the network of airstrips servicing the various dam sites under construction, using Beavers and later on, Pilatus Porters.
When it became idle, the land reverted to the Lands Department, and in 1977 it was available for lease and sought after by both golf course enthusiasts and local aviation interests. The Department of Civil Aviation (DCA) banned its use for powered aviation because “it was the most dangerous strip in all the Snowies”, because of the rotor conditions that existed during strong winds. Apparently Ansett even sent a Fokker Friendship in to assess the strip for commercial use unfortunately during a strong westerly. Lacking the knowledge that rotors existed, it set up for a long flat final in the downdraft of the rotor. The pilot described bending the throttles in a not very successful attempt to keep above the runway, and aborted the trial. It seemed that the strip was destined for use as a golf course, where it probably would be now, in other circumstances.
Having a background of both power flying and gliding since 1955, and having already used the standing wave conditions from Berridale to achieve gliding flights over 25,000ft with club camps there, I also was interested in setting up a gliding centre specifically for advanced glider pilots for high altitude gliding, to obtain diamond height awards and records. Pilots in the past had to visit New Zealand to obtain these, and training and cross country soaring centres in Australia were thriving at the time, so it seemed to be an opportunity to good to miss.
The Lands Dept was supportive but referred me to the Department of Civil Aviation. DCA flatly banned powered aircraft from using the strip, and described the strip as being the most dangerous of the Snowy strips in the mountains. They wouldn’t allow tow aeroplanes to be used for the gliders, but if glider winching was to be used then it was the responsibility of the Gliding Federation of Australia (GFA) to make the decision. We pointed out that we had experience with wave and rotors and had researched and obtained extensive advice from overseas wave soaring sites. The crux of the matter was that local knowledge of the flying conditions was the key to safety. By progressively assessing the conditions this knowledge could be built up and passed on to others. GFA supported the project and the lease went ahead.
So in 1977 my 28 year job as a research chemist was put on notice, and a family business was set up called Alpine Soaring. This involved myself and Robyn, with the help of the two older boys, David and Ian. We had to dismantle the old fences and re-erect them around the newly selected airstrip boundaries. Much clearing was done, a hangar was built, and Mike Litherland was hired to extend and rework the 2 strips into 3 landing strips with an all over surface between for emergency glider landings. Initially we drove down from Sydney on every weekend and holidays and lived in a tent while working. This was mid winter and we slept under 2 dooners, waking up with ice on the pillows from our exhaled breaths. We kept warm with bonfires from dead timber from the clearing. Then we built the hangar and moved the tent into that, which was pure luxury. Later on the residence was built to lock up stage from a modular kit home in 3 weeks, with the help of my sons David and Ian, which included accommodation for visiting glider pilots.
The main strip was lengthened from 800 to 960 metres with the help of Mike Litherland’s dozers and grader, and a German ‘Tost’ glider winch was ordered plus a Twin Astir fibreglass sailplane. The Tost winch was selected as a high power automatic professional winch because of the relatively short 960 metre strip. Australian winches were all custom built by the clubs, and were too low in power needing around 1500 - 2000 metres of cable to obtain the required heights. Robyn became “der winchenfuhrer” as she was dubbed by a visiting German pilot, and the "winch wench" as known by me. A direct radio contact was set up between the glider and the winch which was used to control the entire launch. Here the Twin Astir was accelerated to 60 knots in 4 seconds and initially climbed at a 60° angle at some 5000ft/min. Heights of around 1300ft were obtained in the launch which was usually sufficient to contact available thermal lift. On windy days we could obtain up to 2000ft but it turned out to be difficult to use the rotor lift on these days to climb into the overlying standing waves. One day a military jet came over the field at 500ft while we were operating, so we sent the RAAF a sample of the braided steel winch cable and a description of the launch - they gave us a wide berth after that.
In 1980 we reapproached DCA for permission to operate tug aircraft on a trial basis using the accumulated gliding experience gained. This was approved, and we used visiting glider club’s Pawnee towplanes during wave flying camps until late 1982 when we purchased a Maule Rocket for on site aerotowing. Also in 1982 we purchased a Grob G109 powered sailplane which removed the limitations of the winch, and enabled launches to anywhere rising air was to be found. The winch was subsequently sold. At later times we had a PIK20E self launching single seat sailplane, and a Grob G109B which had a better climb performance and was more sophisticated. The Maule was replaced with a Pawnee hired together with an ASK21 during winters after the Twin Astir was sold.
After DCA’s OK, requests were made by local pilots to be able to use the strip and base their aircraft there. We asked permission from DCA, and after consultation with our insurance company, Mike Litherland, Chris Randall and Ron Clarke were given the OK to do this gratis. A cutting was excavated by Mike Litherland at the SE end and later enlarged to provide a wind shelter for their aircraft. Stan Biertus and Peter Coventry were also invited to use the strip but asked not to compete with us. Because of insurance liability, operating safety limitations were set to the same standards as the gliders, but which were the cause of later dissentions. Later on helicopters and commercial pilots were added to this list,
Gliding operations fell into two categories. There were the gliding club visits during the winter to obtain diamond height awards, which required a height gain of 5000 metres over the launch. These involved towing to between 6000ft to 9000ft asl (2500 to 5500 ft agl) depending upon the conditions, with flights to 25,000ft or more. These were rigorously monitered by radio, and only experienced pilots were allowed to launch solo, some 5 hours of briefing were given beforehand, and oxygen systems were prechecked. Continuous flow oxygen systems with rebreather bags were the usual systems which allowed flights to 25,000 ft with short forays up to 28,000ft where climbs had to be aborted. Demand systems were less common but allowed flights to much greater heights. The maximum attained here was over 32,000ft and only aborted due to oxygen levels running low. A number of height records were broken here, and no accidents occurred during our 13 years of operations.
For the rest of the year we flew the Grob, taking passengers over the mountains as an instructional flight. Strictly speaking we weren’t supposed to conduct joyflights. However we made them genuine TIF’s, by climbing over the mountains to around 7000ft, cutting the motor and giving flying lessons on the way down. In almost all cases we could have the passenger flying straight and level and turning during the approach. Power pilots wanting to experience mountain and wave flying were accommodated and it was interesting to watch their reactions when the motor was shut down. Usually one could see them looking in vain beneath them, to see where the heck they were going to land, instead of the strip in the far distance. In the early 80’s people had plenty of money to spend and in holiday periods we were flat out on flyable days. Robyn resumed teaching to provide us with a steady income, while I operated the soaring centre. The result was that Robyn’s holidays were my busy time, so for 8 years we had no holidays.
We were approached by the military for permission to use their Caribous, Nomads, and later their helicopters on our strip for mountain training. We said OK, and as we were in the SES we proposed that they also conduct joint operations with the SES. This was enthusiastically received and many exercises were conducted into the mountains, including joint operations with police and fire brigades. Most remembered was a 2 night snow survival exercise by the RAAF into the Gungartan Peaks, where the personell dug themselves a home inside a snow drift, which included rooms, kitchen benches and beds all illuminated by cyalumes embedded into the snow ceilings. The SES camped outside and mock searches using the helicopters from the peaks were conducted.
Avdev Airlines wanted to operate a charter service into the strip using their Nomad, and as they had DCA approvals, their own insurances, and the Council proposed it, we gave permission for them to do so, using our facilities free of charge, as a community service. Avdev did minor reworking of the strip for their own safety reasons, and used our accumulated local flying knowledge to set up operations. One needs to remember that winter weather conditions were more severe in those days with both cloud and wind, and it was interesting that when heavy cloud cover existed elsewhere, they were able to descend in clear air through the fohn gap over the lake, while Ansett couldn’t land at Cooma. In strong NW winds they would make a close in circuit with a very steep final and had no major problems with the operation. Heinz Gloor provided the ground transport for their arrival.
Eventually Ansett used their political clout to stop Avdev competing and operating from Jindabyne.
In 1985 Australia floated the dollar which devalued to 25% of its overseas value overnight. Suddenly imported aircraft became four times more expensive. Fortunately I had a new Grob G109B powered sailplane on the water being delivered so I was only caught by the freight costs. A second much higher performance powered glider on order had to be cancelled. So we were able to continue operating, but had to raise costs accordingly.
Aerotowing. This was conducted in all sorts of conditions from calm up to gale conditions. Often in west or NW rotor conditions, the back flow of an overhead rotor roll of about a 3000ft diameter, would reduce the ground winds significantly and allow takeoffs. The ground wind could be 15 knots with 45 knots of wind at 1000ft, with the uprising air at the upwind end of the strip, and sinking air at the other. The usual launch encountered strong turbulent lift off the end of the strip, which in NW winds could be maintained by following the Round Hill ridge towards Thredbo. Up to the inversion height of around 2500 to 3000ft above the strip the tow was in rotor turbulence, and above this one abruptly entered calm rising air. This was often just in front of a rolling line of rotor cloud extending to Thredbo above this ridge. Here the glider released, dived briefly to notch the barograph used to record the flight, and then continued the climb. The tug however had to descend in lift which often exceeded 1000ft/min.
The Maule unfortunately was fuel injected and required a cooling period at reduced power, and while this was happening often outclimbed the glider, gaining another 1000ft or so. In these cases, when the rotor cloud fell below, one would turn downwind, cross over the top of the cloud and descend quickly in the waterfall of air at its back, which corresponded with the downwind end of the airstrip. The glider would gain as much height as possible in this section of the wave, say 8000 to 10,000ft asl and then fly at high speed forwards to contact the next bounce of the wave over the Thredbo Valley, and work his way up to Thredbo for maximum height. In NW conditions it was often possible during the climb to run into strong rotor turbulence at any height between 10 - 20,000ft, where out of phase wave systems existed above and below an upper inversion, and the two clashed. These would prevent higher climbs.
In westerly wave systems, launches were made anywhere from the east side of the lake, upwind to Sawpit Creek or even Perisher. Best climbs were almost over the west face after a sawtooth approach through the secondaries up to the primary wave.
When fronts were approaching and winds were light on the ground, it was possible to have calm wind aerotows over the Snowy river to the west of Charlottes Pass, where the glider could be released in weak wave lift to hold about 9000ft. The whole fleet could be launched in these conditions until the front came closer, when all would start climbing up to their diamond heights.
Rates of climb could vary from 100ft/min up to a couple of thousand ft/min. One flight in a SW wave went all the way to 25,000ft by just circling in weak rising air. It took so long with the air temperature probably below -20°C, that when the pilot came down he couldn’t feel his feet, which was probably the onset of frostbite. We dipped his feet in barely lukewarm water, and had to put up with his howls that the water was burning him!
In another aerotow we sorely misjudged the wind velocity at altitude, and the tow combination was in severe turbulence, in a fixed position in the sky, just behind the upper face of the rotor with 80 kts indicated IAS at 3000 ft above the strip. They finally penetrated forwards into the calm air. The glider released and was at 23,000ft cloud base in less than 20 minutes from launch and was told to land at Berridale as being the safer alternative.
Tying aircraft down. Everything had to be tied down very, very securely. In spite of this, from time to time the winds would pick up during the night, and would descend in cyclic rotor gusts which one could hear roaring towards us like an express train, with velocities well exceeding 60 knots. The everyone would have to turn out in these early hours to check out their aircraft. The Super Cub and Pawnee tugs were vulnerable, and as they jerked and twisted on their tiedowns, one could watch them gradually loosen. They had to be doubled up and resecured. One night a Nimbus glider with 20 metre wingspan was securely fixed by the wingtips, but with every gust, the wings bent and the fuselage rose a foot off he ground then gently lowered itself as it passed. The owner was persuaded to tie the nose down!
Many GA and airline pilots visited us, and many stories were told. One involved a check flight in a twin in a strong westerly, where the aircraft was in an 80 knot climb at 8000ft in dead smooth air, but was stationary in the sky with zero ground speed and zero rate of climb with the command pilot totally unaware. Only the check pilot eventually noticed. He was in the downdraft of the standing wave! We watched a Cherokee on another day climb his way down a couple of thousand feet in rotor downdraft before giving up and heading back to Cooma. There was another story of a commercial pilot in a Cessna 182 giving his passengers a thrill by skimming the main range from the east with a strong easterly tailwind. As he crossed the escarpment with its 6000ft drop off, the airflow was behaving exactly as water flowing over a waterfall. So the aircraft of course fell with it at a couple of thousand feet/minute descent, with the pilot in full throttle climb mode, in a panic, with his exhilerated passengers hollering for joy.
This being uncontrolled airspace we would always advise power pilots crossing towards the west in strong wave conditions to use the same technique as the gliders. If the aircraft is having problems in maintaining height in the secondary waves then he must gain height in the rising part of the wave using climb power, and go forwards at cruise speed in the sink to reach the next wave. If one slows to climb speeds in sinking air the dwell time there is greatly extended and one is likely to descend below the inversion into the rotors where sink is increased and turbulence is severe. Generally wind speeds accelerate 150% when they are compressed upwards over the mountains, and for example a 40kt wind forecasted at 7000ft is accelerated to 60 knots over the mountains.
During all wave flights a detailed study was made of the conditions and much information obtained which was not published anywhere, and was virtually unknown at that time. This was collated and disseminated in the gliding magazines, and included in the lectures for visiting pilots.
From 1985 there was a noticeable steady decline in passenger flying, as in all the tourism attractions around, although the gliding clubs still came. In the late 80’s there were four separate proposals to build commercial airstrips in the area, two of which would have closed ours to all operations, as we would have been within their circuit areas. There was also a proposal to buy our strip lease, develop it for commercial use and allow us to retain the gliding operation. All of these came to naught after some years of heartburn, and finally there was local pressure for the Council to resume the lease and turn it into a public airstrip.
In 1990 council & other aviation interests used political pressures on the Lands Dept to resume the lease, resulting in the Lands Dept raising our rent some 40 times to over $12,000 per year, far beyond our means. Council took over our lease without recompense, and the newly formed Aero Club, financed by local businesses, organised for the strip to be reworked. The strip was closed for 18 months to upgrade the surface to commercial standards, destroying the all over glider landing facility and the third emergency gliding strip and Alpine Soaring ceased operating.