Wednesday, April 13, 2011

2011 Annual Inspection (iv)

Mike the IA has finished inspecting N631S and there are a couple more non-trivial items to mention. For one, the right brake line managed to get itself badly chafed and will have to be replaced. The right main gear tire is significantly worn but we decided that it's still serviceable so it will be reinstalled and I'll watch it. The most interesting
item involves the Emergency Location Transmitter (ELT).

I've touched on ELT's in earlier posts on this blog, here and here and here. In brief, the world is slowly migrating to 406 MHz ELT's but for the time being the old 121.5 MHz units are compliant with regulations. Based on the kind of flying N631S and I do I've felt no urgency to make the change - at a cost of about $2,000. Now I've needed to revisit the subject.

At left are the mortal remains of N631S's dead 121.5 MHz ELT. The battery pack (that's the gray cardboard box) has failed and leaked corrosive material out into the housing of the ELT. The white powder in the ELT case is the product of corrosion, and you can see the hole in the plate at the bottom of the battery space that goes into the circuitry compartment. This ELT is, in a word, toast.

The first suggestion was that I ought to acquire a 406 MHz ELT as a replacement. They run about a grand and you can expect to spend another grand getting it installed. And, as I said, I am not highly motivated to make this change if I can avoid it. And I can.

I asked Jared, Three Wing's Avionics Manager, if he had any serviceable 121.5 MHz ELT's that had been removed from aircraft as a result of installing 406 MHz units. Yes, it turns out that he does.

Jared has a nice Pointer ELT Model 3000-11 unit (left) that he can let me have for a very reasonable price. Getting it installed will require a little bracket creativity but it will serve the need quite nicely without breaking the bank. Mike the IA is going to check around a bit to see if a used unit of the same make and mark as the old one can be found, as that would be a "drop in" replacement. But I'm not optimistic about that as the unit is a very old design. I believe it came with the airplane 34 years ago. So I'm guessing that I'll wind up with the Pointer unit in N631S.

And finally, in the ongoing quest to improve the performance of N631S's electrical charging system, we are going to replace the old voltage regulator (which seems not to be regulating so very well these days) with a new unit from Zeftronics.

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