I’ve had the Traffic on my Avidyne MFD pop up as FAIL in flight
Has anyone any suggestions as to why this might happen?
Is there a set button or is it a sign of something more sinister?
… happens.
Pull the Circuit Breaker (1st one in the last row) and reset it and check if it works again.
With my old Skywatch i first had that happen every now and then - until it happened twice on every flight and finally would not work at all. The processor was bad and L3 wanted close to $ 4000 for the overhaul (plus shipping). I found a very good used unit for half that price and solved it this way. Sometimes there’s one on ebay … I got mine from Dave (Nexair).
The ground connection to the skywatch antenna is going bad. This causes the skywatch transmitter to overheat (high swr). Sooner or later, the transmitter will die if this is not fixed. Then is will cost a lot to fix the skywatch.
On the member side, there are extensive posts and pictures how to resolve this antenna ground problem. Some have printed these posts out and had an avionics shop follow the directions - which fixed the problem.
My Skywatch failed as described although the grounding of the antenna and everything else was perfect. We checked and measured everything three times …
Had the same event as you describe happen about a month ago. I did have loose bolts on the cabin top antenna which came about because the shank on the bolts had the nuts bottom out before the antenna was tight. By adding washers and cleaning the bolts I was able to get good contact. Caution, don’t over tighten. Alas, this didn’t help. Took 4 AMU’s to fix the problem. Wish I had seen Alexis’s suggestion before sending mine in for repair.
mb
Thanks to everyone for your prompt replies. It is nearly midnight here in Oz so I’ll have to try some of your suggestions tomorrow.
Yes a skywatch transmitter can fail from other causes as well.
The ground connection can be go bad just from oxidation between the antenna bolts and the foil. The airplane’s vibration can improve the connection temporally (if the bolt & nut are not completely loose).
My guess is that is why the skywatch will fail at the beginning of the flight and later start working after a fuse reset (as the skywatch ground improves from vibration).
The skywatch 100 watt transmitter is quite powerful so any ground issue could quickly damage the output transistors. So I would pull the skywatch circuit breaker until the antenna ground is cleaned up.
Note that the resistance between the ground and bolt head should be 20 milliohms or less. It takes a good digital meter to make this measurement. That is 0.02 ohms.
Thanks Paul
one question. When pulling the circuit breaker should the unit be switched on or off?
The skywatch is always on when the avionics switch is on.
So you can pull the skywatch circuit breaker (on the electrical panel, pilot’s right leg) any time.