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This weekend, flying back to Seattle, directly over the Sawtooth mountains over Salmon Idaho, fat dumb and happy, on auto pilot at 16.5k feet in VFR conditions, I hear in my headset, "GPS Unavailable," after which my moving map Chelton re-boots itself, turning white, then black, then black with text, then it finally re-boots itself with all of the information except the ground map representation, which returned after a few minutes.
It was nice to be able to refer to my iPad on my lap for navigation backup.
It wasn't really a panic because I was at altitude and in VFR, but it would have been a panic if I had been on an IFR departure out of Seattle, like I had two times earlier that week, where the overcast starts hard at 500 feet and goes up to 8,500 feet. If I had been in that position and had Seattle Center telling me to go to a particular intersection (Like SUMMA with two M's on the J5 south out of Seattle) and couldn't find the intersection because my Chelton decided to re-boot right then....... Now THAT my friends could have been a distraction.
So I love the EFIS and use the heck out of it, and it's anything but bullet proof. Why mine rebooted for no reason what-so-ever, right when it did, over the Sawtooths, I do not know.
Glad it didn't happen on climb out out of Seattle in the muck.
John Hafen
IVP N413AJ 320 hours
On Aug 8, 2011, at 7:40 PM, Brent Regan wrote:
When we create the conformal document set (drawings, specifications, etc.) for certified hardware we try to lock down every aspect of the design so that vendors do not "improve" a component and cause an unforeseen problem. One man's improvement can be another man's nightmare. Case in point.
A friend with a Chelton IDU-I manufactured about 10 years ago (by Sierra Flight Systems in Boise) was having a problem where the display would intermittently lose vertical synchronization and start flipping. I disassembled the unit to find the problem. It seems the LCD display vendor, Panelview, who also added the Anti Reflection (AR) coating, decided to add a metalized sticker to the display. Seems innocent enough, right? Well, with time and temperature cycles the sticker started to peal and came in contact with the backside of an inter-board connector that happened to be carrying the V-SYNC signal. With heat and vibration the aluminum layer of the sticker was exposed and shorted the signal pins. The attached pictures clearly show where the pins rubbed on the sticker.
A freaking sticker?!?!?! Really?!?!?! That is one for the books.
It is not the known knowns that get you. It is rarely the known unknowns that get you. It is the unknown unknowns that get you.
It is experiences like this that are the basis for my advice that, despite your best efforts, sooner or later it may all go very wrong. And not for a big obvious reason but for a stupid little tiny sticker of a reason. Ask your self now, in the comfort of your office chair, what is your plan for when it does go very wrong?
Regards
Brent Regan
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