TOWING
Peter Thorpe is an instructor and towpilot with Aviation Sports Club in Auckland.
EVENTUALITIES – IT APPLIES TO
THE TOW PILOT AS WELL AS THE GLIDER PILOT Remember the E at the end of the pre-take off checklist? Do you seriously think about all the possible scenarios you might be faced with during and shortly after take-off? I like to use the check as an opportunity to lift my head out of the cockpit and focus on the big wide world outside and consider what could go wrong. Recently I was lucky enough to be asked to instruct at the NZ Cadet Forces Gliding Course held at Dannevirke in late January. We had a nice long but quiet grass airfield, 19 keen cadets, a bunch of instructors, tow pilots and Cadet Force staff; add in some Army chefs and we were in business. I was sharing a very nice Grob 102 Twin II GNP with Roger Brown from Piako and on about day two the press came to visit and I got to take a local photographer lady for a flight to get some aerial shots of the town. The take off behind a Pawnee was normal and we cleared the sewage ponds (thank goodness) and headed north towards the town. I was chatting to the passenger and noted all looked normal but I became aware that climb rate was low and the airspeed was getting down towards 60 knots. My ageing brain was just starting
36
April 2010
to think that something might be wrong when the tow plane wings rocked violently and an apologetic voice on the radio announced he had an engine problem and was returning to land downwind on the runway in use. After release I found myself at 700 feet on the edge of town so the photographer took some quick piccies and we turned back to join downwind at 400 feet for a low circuit to a normal landing. Not such a big issue for us in the glider. The tow plane meanwhile completed his landing and taxied to the edge of the field leaving a huge trail of black oil on the grass. It turned out the pilot had experienced a loss of power and some vibration that he initially suspected was a carb icing problem. He tried the usual fix of applying carb heat but when the problem got worse he decided to wave me off and return to land. The problem was a completely fractured cylinder barrel such that you could see the piston, but what was interesting was the gradual loss of power rather than sudden failure you might expect. From the glider there was no visible indication that a fault was developing – no smoke or oil yet by the time the tow plane was back on the ground there was oil pouring everywhere. In this case it was the tow pilot who needed to have thought about his EVENTUALITIES and what options he had if things went pear shaped soon after take off when there is not much time to react. He did a good job to get safely back on the airfield with no additional damage to the engine or aircraft and it was in fact back
