Dave,
I don't really have any meaningful experience in the Tern. I checked out in one WAAAAYYYY back, but never flew it operationally. Politics changed.
We had two of them at one time. They initially had some quality control problems when new that were eventually sorted out. I think Bill had a hard time keeping good folks on when he was basically building aircraft on an order basis, and as a consequence the quality suffered at times, and at other times it was great.
One of the airplanes got bent early on, but I don't remember how or in what circumstance. The other soldiered on till it was just plain wore out up in the Wrangells. They worked it out of Glenallen for many years and many thousands of hours. Knowing the hours they put on their airplanes, I'd bet they must have had a lot of hours on it when they got rid of it. They eventually replaced it with a Husky, I suspect due at least partially to parts availability questions. The guys who flew it loved it, and didn't want to give it up, I can tell you that, and they used it hard, off airport.
They are an interesting design, with a lot of good ideas built in for the bush work. Frankly, I think timing just wasnt' right at that moment for that type airplane.
That's all I know on that subject.
MTV