One chance to get it right: inadvertent IFR flying

It had been a great trip into New Zealand’s Fiordland wilderness in some of that beautiful early autumn weather. Our little tourist operation had been conducting walking tours down the Hollyford Valley for about six years and we were in a period of consolidation. The flyout option was becoming increasingly popular with our clients.

A lodge had been established halfway down the valley near Lake Alabaster and another out on the wild west coast, at beautiful Martins Bay – just downriver from Lake McKerrow. We had established a good airstrip right beside the Martins Bay buildings and most of our resupply and passenger flying was conducted to and from this area.

Super Cub
The perfect place from which to operate a Super Cub.

At the end of this particular trip we were due to fly out one of the clients to catch the coach back to Milford Sound. Her name was Ursula and she was an extremely well-known and respected person in social and repertory circles in the south. She loved the outdoors and had been on one of our original trips. We were privileged to have her return again as her opinion, should she enjoy the trip, would undoubtedly be spread widely by word of mouth amongst her wide social circle.

Because this lady lived in my hometown of Invercargill and as I was travelling out of the area at the end of the day, I offered her a ride home in the backseat of my little workhorse Piper Cub. This would save her a vehicle trip home. The offer was made with the proviso that she would be prepared to wait until the end of the day when I hoped to have several local jobs finished.

She agreed and so it was that late in the day, with about three hours until it would be dark, we set off homeward for the expected one and a half hour flight. Communications out of this remote area were by High Frequency radio only, as the usual aviation VHF radios only work over line of sight and in those days there were no repeaters on any of the mountains that lay between us and any aeradio ground stations. I had checked the weather on the south coast at Invercargill and it was good. High overcast at about 10,000 feet with a light southeast wind. In hindsight I should have made more note of the dewpoint and temperature relative to the light onshore wind and the time of year.

The initial stage of the journey was virtually due south through the Hollyford Valley until we came to the low passes over the main divide – that gap in the spine of the Southern Alps mountains that run right down the western side of the South Island. Flying conditions were perfect: high overcast as expected but no wind or rain showers. The setting for an uneventful flight!

As we climbed over a 5000-foot pass just to the north of the Mavora Lakes I noted a little bit of stratus cloud forming below me in the valley. I was not concerned as with the forecast I had obtained from the controllers at Invercargill airport there was no low cloud at all. At this point I was only about 60 nautical miles north of my destination.

Onwards we droned at around 100 miles per hour. After about another ten minutes, I started to become concerned that the cloud below was not decreasing in intensity; in fact, it was filling in quite quickly, and looking away to the south I could not see Bluff Hill, the only high point just 15 miles south of the airport.

I tried calling the airport radio operator for a weather update, but after two unsuccessful attempts realised that at that time of the year the control tower had gone off watch. But I was not on my own.

We had an HF radio base station set up at my home in Invercargill and I had already notified my wife that we were on our way and our track intentions. She kept a listening watch for the operation most of the time. The radio was in a cupboard between the kitchen and living room and I do recall her saying that if she ever got a bit fed up with me at times all she had to do was shut the cupboard door and communication ceased!

However, she was fortunately listening that night as when I called up and expressed my concern about the unforecast low cloud, she checked on the telephone with some guys still out at the aero club who informed her that a band of low cloud had come in very quickly from the southeast and the base was rapidly lowering. It was presently estimated to be about 800 to 1000 feet above the airfield (at sea level).

I immediately knew that my current situation was extremely serious. I was currently flying at 4000 feet and was trapped between two layers of cloud in a wide band of clear air. This “meat in the sandwich” scenario at the end of the day, in a low speed, basically instrumented aircraft with a relatively low-time pilot was about as bad as it could get. I immediately ripped into a 180-degree reciprocal turn and started back along the way I had come to what I hoped would be better weather conditions. After all, it had been OK only a short time before!

However the further I flew back north, the thicker the cloud beneath me formed. Very quickly I realised that I was going to not get underneath the cloud, daylight was drawing in and if I did not make some definite decisions soon available fuel would become an additional problem.

Piper Cub panel
Not the panel for IFR flying…

My instrument flying time was very limited to that required for a Commercial Pilot’s licence, but I was not in current practice. The aircraft did not have an artificial horizon, vertical speed indicator, bank and turn indicator or any radio navigation aids.

It was about as basically equipped as any aircraft could be, but normally that was all that we required in visual flight rules in a bush operation. Put bluntly I was up a certain creek without a paddle.

Yet three things were still in my favour. I had radio communications and could ascertain the cloud base, secondly the Southland Plains area around Invercargill is very flat with no hills within about a 12-mile radius ,and thirdly I knew what my average ground speed was due to my elapsed time from takeoff and distance flown relative to known points along the way .

With that knowledge and knowing that I was only going to get one chance at pulling off a successful outcome, I turned around again and resumed my original homeward path. Fortunately for me, the tops of the Takitimu Mountains were clear to the west of me and with good local knowledge of the countryside and by tracking a compass course with a slight offset to the east to allow for the light on-shore wind, I was confident I was definitely going in the right direction. After a known high point in the Longwood Hills to the south of the Takitimus had passed at around 90 degrees to my track and about 15 miles away, I knew I had to be right out in the Southland Plains and that I was going to have to do an instrument descent through the cloud below me as soon as possible. A final radio check confirmed the cloud base around Invercargill to be at least 800 feet above the ground.

My heart was pounding as I slowed the aircraft to 70 mph, lowered the flaps halfway and trimmed for a constant attitude. I remember resting my right arm on top of my leg to steady it as I gently reduced power, set up what I thought was about 500 feet a minute rate of descent and with my eyes rapidly scanning from compass to the small slip indicator eased the little aircraft down into the cloud.

It would have been very easy to panic given the circumstances, but I had enough background knowledge of instrument flying to make just the tiniest control alterations. The compass course and speed remained relatively constant but it must have been nearly four minutes before, with great relief, I saw terrain below me and burst out the bottom of the cloud layer a few miles west of Winton and nearly on track. My Invercargill friends at the aero club had been just about right with the cloud base, as it was just on 800 feet. The cloud layer I had just been through had obviously been nearly 2000 feet thick if my rate of descent had been constant at what I had calculated.

Jules Tapper
Lived to tell the story – but barely.

It was at this point that my legs started to get what climbers call “riding the bicycle,” an uncontrolled tremor. No one needed to tell me how lucky I had been and it was with forced nonchalance that I reassured my bewildered passenger that occasionally these sort of things happened.

My wife Jenny met us at the hangar at the airport when we landed shortly thereafter. As darkness fell, a dense fog formed over the Invercargill estuary and drifted over the airfield, clothing all in a grey, moist, all-encompassing, aircraft-destroying air mass. Thirty minutes later and we would have been a goner and another sad aviation statistic.

Looking back, I know I immediately understood aspects of those meteorological lectures I had attended not so long before. Since then I have been very vocal in expounding the relationship of dew point and temperature and on shore marine influences, especially in the autumn at the beginning and end of a day. However, just a few years later in northern Canada, I had another encounter not of our own making, where on an IFR flight, with the best of planning and everything done right, my brother and I got caught past our “Point of no Return” during a long ferry flight, leaving us with only one long shot option as an out.

But that’s another story and it will be told another time as we obviously pulled it off successfully. However, in this case, it was only teamwork and a very capable and cooperative Flight Service radio operator that combined to give a happy outcome.

1 Comment

  • A thrilling ride with my friend, Jules Tapper. He’s clearly come a long way since that earlier flight. I’d fly anywhere with him, and that’s saying a lot!

    Keep flying, Jules …………… and do keep writing!

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