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Terrance, A most unorthodox choice of substitute for altimeter and a/s indicators. These instruments are primarily there as worst case back up instruments for saving my ass when everything except the engine fails while in IMC. No more GPS, PFDS etc. Maybe the G496 will still work off it's battery. If so that may solve the problem but if not? A purely mechanical AOA might help me to keep from stalling but how could I rely on it to get me out of IMC safely? Lurking, might one quietly suggest that the ultimate backup would be a simple, mechanical AOA vane on the wing? That's all you need to keep from stalling, as you can see the ground. On Dec 19, 2011, at 9:00 AM, John Barrett wrote:
Good question, Jeff. Some more naturally follow: 1. Are you stating my backup instruments are unreliable? 2. If so, what do you find unreliable about them? 3. Assuming they are unreliable, what would you replace them with? I guess the real question is what instrument that gives airspeed or altitude will never fail to provide needed information under any circumstance? From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Jeff Edwards
Sent: Sunday, December 18, 2011 6:30 AM
To: lml@lancaironline.net
Subject: [LML] Re: MGL back up instrumentr Why have unreliable backups? Infinity line MGL instruments – they are intriguing as back up gauges. Looks like the altimeter is Baro sensitive for input but needs electrons for output. I spoke with Matt at their US distributor center and learned that it uses pitot static inputs to pressure sensors that generate output data for microprocessor to turn into altitude readout. Without electricity the gauge does not function, losing the microprocessing component as well as the LCD display output. Does this mean that in order to have good backup one would need to have a totally mechanical altimeter? Have found that two of my cheap 2.25” gauges are failed with case leaks. Have had them awhile but as far as I know they haven’t been mishandled. I know the airspeed gauge is UMA. I suspect the altimeter is the same brand. These are the two failed instruments.
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