Chelton advice request for a friend

Recently Smokey Ray asked me to assist a friend that he helped to buy a 7. Jim is here in Reno, and has been working through a few bugs, but still has a pesky oil temp issue, and is having some issues with his Chelton PFD and associated systems.

We're working through the oil temp issue (moving his baffle-mounted cooler up a bit, and standing it off the baffle a bit...more ideas in the hopper if needed). Efforts on the Chelton have been dead-ends, so far.

My first suggestion was (and is) "call Stein". I think he will, but here's the scenario, and if any Chelton-smart folks have ideas, we're all ears!

Its a single Chelton PFD, with a Crossbow AHARS, and (as I understand it), an integrated, or dedicated GPS. Optional EIS is included, and Jim also has a GRT EIS 4000. Alignment seems slow to Jim, but perhaps its standard for a Chelton. He also has a GMA340, SL-30, SL40 and 496 (all of which work AOK).

The Chelton works fine for about 20 minutes, then begins to give warnings, such as GPS INOP and TAWS (terrain) INOP. Local avionics shop pulled the unit, did some investigation, and was told by one facility that they could inspect the Crossbow AHARS, but if something was found, they could not repair it. Sounds like it is a very expensive AHARS, and its unclear what support is available. Unit is back in the plane, provides a stable ADI, but is plagued with the GPS/TAWS drops and warnings.

Owner may send it to Aerotronics, who did the install, but is looking for any ideas enroute to that decision. Recommendations welcome. Anyone know if an alternate AHARS is available that would work with Jim's Chelton.

Thanks in advance for any thoughts or ideas!

Cheers,
Bob

There doesn't look like there is much activity, but you may want to try posting on:

http://www.cheltonefispilots.com/

I agree with Bob. Post on the Chelton users forum at the link he provided. Perhaps a PM to Tim Olson on that forum or on Matronics would get you some help. Tim is very knowledgable about the Chelton system.

Chelton problems

Bob,
I'd be happy to help. Unfortunately I'm on my way to Sun n Fun tomorrow. I do most of the tech support at Aerotronics and am very familiar with the Chelton system. First of all I'd have to know what model of AHRS you have. If this is a RV-7 with a single screen I suspect it came out of Florida recently. You mentioned an integrated GPS, I assume then its a Crossbow 425 with a small SMA connector on the side going to a GPS antenna. Crossbow provided a small black ( about 1"x1") antenna. If you have this type of antenna I'd suggest swapping it out for a "real" antenna. These small black antennas proved unreliable. I'd have to reference the Crossbow manual to verify the acceptable antenna to try.
Because it seems to work initially, there is always the possibility the problem is elsewhere. Tell ya what, I'm home today and can discuss some possibilities if you want to give me a call. I don't have any of my reference materials here however I think I can give you some things to check.

Jason Smith
406-672-1574

Thanks very much guys...great lead. I'll pass Jim that link, and hopefully that will get him closer to a solution! Much appreciated!

Jason...just saw your post after posting the sentence above...it is the plane out of Florida. I'll get some more info will give you a call later, and pass your number to Jim as well...thanks very much! Have fun at SnF!

Cheers,
Bob

Just off the phone with Jason from Aerotronics. Big thanks for taking the time on a Saturday morning to discuss this!!

Jason knew the panel (had been parted out and re-installed in a second RV), and had several good troubleshooting ideas. He made himself available on a day off, shared his ideas, and will be available to help after SnF. May loan us a spare ADAHRS if troubleshooting points to it. Really nice guy...thanks again!

Are all avionics guys just good dudes? That's been my experience!!

In case anyone researches this down the road, some of the items we'll be looking at are:
- Checking the GPS antenna type. Turns out there is a cheapo one used in some installs that is trouble-prone

- Checking the SMA connector for the GPS antenna at the Crossbow ADAHRS

- Checking the RS-232 wire from the ADAHRS to the EFIS.

- Looking for crimps, bends, shorts, and heat-sink problems in the wiring.

Will post when we have a solution. Thanks guys for the assist, and thanks DR, as always, for the network!

Cheers,
Bob

Solution?

What did you find? Did you get the issues all worked out.
I agree Jason is a real resource.

I'll see if I can find out?haven't had much contact with Jim for a bit, but will see what I can find out.

Cheers,
Bob