[Flying again!]

I have never had a problem with the Sport SX in the 3.5 years I have owned the -10, until yesterday.

I was doing a short flight to get some cheap gas and warm the oil for an oil change. After starting the engine and letting the EFIS align, I dialed up ATIS and tried to set the altimeter to 29.93. I dialed it in but it would not take. In fact the setting changed to 31.92 and jumped around randomly to 29.92, 31.11 etc. I tried this several times and decided to taxi to the runway since I have a round dial Altimeter and ASI as a backup. I noticed the numbers stopped jumping in the kollsman window of the GRT and tried to set it again. This time it worked. It was fine for the flight to and from KSWI and allowed me to change alt setting as usual.

Has anyone had this happen and any suggestions on how to stop it happening again?

Thanks

 

[TomVal]

Have you checked this 2010 SB from GRT?

http://www.grtavionics.com/SB-0001(1).pdf

A loose set screw on this knob could cause your problem.

Regards,

 

[Flying again!]

Thanks. Tom,

I'll check it next time I am at the airport. I think the knob is ok since I could set the correct altimeter setting in the box, it was just that it would not "take" it and would change randomly, but it is worth checking. The GRTs were purchased around the time of the SB so they may not have had the fix implemented.