Drive Belt Failure
By: John W. Davis
Well, this drive belt failure was my own fault.
A few years ago I had the old, low-drive system on my Challenger and wanted the high drive. So as luck would have it, I ran across a good deal where this guy had a high drive and belt, and he wanted the low drive, So here we go. We traded.
He could not tell me anything about this belt but it looked like new to me. I put this high drive and belt on, and I have been doing a lot of training with it ever since.
Around 250 hours later, this belt failed with me and a student. I had just finished one student and was on the last touch and go for the second. The wind was blowing kinda hard this day, 15 to 20, gusting 25 to 28, and my students were having a hard time staying in the traffic pattern. We were landing on runway 23, and if anyone knows Lee County airport, there is nothing but trees on this end, with the exception of one small field.
We were just about to turn on base from a downwind where the wind had blown my student way off course, away from the runway, when all of a sudden, a bad vibration started to reverberate though the whole plane.
I looked out each side and back at the engine and I did not see anything wrong. So I asked my student, "Do you feel the vibration?" And he said, "Yes I do!"
I told him not to touch the throttle and make a very shallow turn towards the runway. Just about the time I got that out of my mouth, it started squealing. So I told him to shut it off and give me the controls.
The only place close enough to land at this point was this one small field with a dirt road right down the middle. So I headed for it and landed on one of the roughest dirt roads I think I've ever seen.
After landing, I got out, and then I saw what had happened. The cog belt was still on, but no cogs. It was completely slick!
So we moved the Challenger to the side of the dirt road and checked it out. No damage at all except one of the gussets on the nose gear was broken. Thanks, Dave G., for a great design. This is an easy fix.
The next day, I put a new belt on and then flew it off that dirt road, back to the home base. The student called and asked when the next lesson was? He was very impressed with the handling of the Challenger, how it glided with the engine off, and its ability to take such a rough off field landing. He then told me he was so impressed with the safety of the Challenger that he had made his decision to order one.
Never use a used belt unless you know the history of it.
Always check the belt tension and condition.
Replace the belt per QCU's recommendations.
P.S.: I always do a very good preflight inspection of my belts. It gave no signs of being bad and the belt tension was right. It was an old, used belt, and the belt itself just failed.
It was my fault for not changing it; the Gates belt and QCU is NOT in any way at fault. I think this may be the 3rd belt that has ever failed on a Challenger. That is not bad, with over 3,000 flying.
John W. Davis