On the last trip to Kalamazoo our GRT HX system began acting up. Elizabeth is starting to have flashbacks to flying with the Blue Mountain EFIS, which is not a good thing. To be fair, I’m not convinced it’s their fault yet, but it’s disconcerting when your display goes blank in flight. I’m feeling better about installing backup steam gauges everyday. 😉 Here’s what I know so far.

We’ve had quite a string of hot weather here in SW Ohio as of late, and on the last couple of flights we’ve had issues with our GRT HX screens overheating and shutting down in flight. We’ve been planning to fly to Airventure, but we will likely won’t if we can’t quickly find a solution to the issue.

GRT tell me that the screens should run ‘about 30 degrees’ above ambient, that they will shut down at 160 F, and you can see the internal temperature by going to setup menu (Display Maint, Analog Input page). It’s been right at 100 F here, real temperature, for the last few days, and I can confirm that on the ground they warm right up to 130 F. We went around the pattern and in less than two passes they were shutting down! I went to the setup page, and sure enough, they were reporting in the mid 150s. At least it’s real, and I’m pretty sure this is the cause.

GRT believes that if I add vents to my glareshield the issue will resolve itself, but I have already tried a large (68 CFM) computer fan aimed at the back of the displays, which only relieved about 1 degree F of temperature, and tried routing cooling air from the nose fresh air vent to the back of the displays to no effect (the screens still shutdown in flight). I believe my situation is unique because I mounted a second oil cooler in the nose for winter recirculating air usage (rather than cold outside air), and have checked this cooler is, in fact, getting quite hot. On my last flight it was over 200 F even though the one on the nose NACA was below 180, so I think this cooler is just filling the nose area with hot air. Net, I’m going to pull that cooler, and at some point put vents in the glareshield, but that’s a fair amount of effort the way I have it mounted. FlightLine says they’ll add the vents at no extra cost, aside from shipping and the down time… we’ll see…

Second Oil Cooler overheating the nose?

Vents in an RV shield

Posted By: Brett Ferrell
Sunday July 8th, 2012 at 10:24 PM

Categories: Blog
Tags: Blue Mountain (BMA) Instrument Panel

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