Incorrect altitude indication on D10-A

[petere]

I have a D10-A with the latest firmware version installed in my Cessna 172XP. The aircraft has just returned to service after 3 months down time during which a new engine was fitted. On powering up the D10-A all indications were normal except the altitude showed -1200ft. Adjusting QNH made no difference to the indicated altitude. When flying, all other indications on the Dynon (airspeed, bank angle etc) were as expected but the altitude stubbornly indicated -1200ft. The aircraft is hangared so is well protected from weather and, as all other pitot-static instruments worked, I suspect the pitot-static system is properly operational, not blocked etc. What do you think the problem may be and what should I do about it? If you think the altitide sensor is U/S, is it likely your Australian agent, Horsham Aviation Services, can fix the unit or will it have to be returned to you in the USA?
Many thanks and have a great New Year,
Peter E
Australia

 

[DBRV10]

Dynon are on holidays so I will offer my $0.22 inc GST

Have you checked the static port line near the D10A? It might be possible during the work a line has been crimped or similar....or for some strange reason plugged, or left open and a bug built a new home in there.

Where in Australia are you? If around here I might be able to help or maybe point you in the right direction.

If the unit has a failure it will need to go to the USA for a winter holiday.

give me a call on 0416 223 194 if you want to.

 

[petere]

Thanks David. I'll pull the unit out and have a look at the static port line and connectors. I'm in the Byron Bay area. You?

 

[DBRV10]

Brisbane, my hangar is at YCAB......we could take a sneaky peak at it there. How much can we do without a LAME??? hehehehe

Rebuild the whole thing! ;D

 

[dynonsupport]

So if there isn't an obstruction that's causing this, then it has to come back here for repair ultimately. Horsham can help facilitate this for you. The best way to check whether there's something up with the unit is to pop the plumbing off the back of the unit, confirm there's nothing actually in the EFIS itself, and if there isn't, see if the altimeter is still pegged out low. If it is, that's a bad sign. You can also seal your finger over the static input on the EFIS and press. If you don't see the altimeter move, that's also indicative that there's something up with the unit.