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Old February 14th 19, 02:01 PM posted to rec.aviation.soaring
Dan Daly[_2_]
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Default OLC max altitude self censorship

Yes, I have experienced the same phenomenon over mountainous terrain. My primary flight logger is an Oudie2, which is connected to a portable FLARM. The GPS altitudes are typically at least 1,000 feet higher than my altimeter, whenever I climb above about 15,000' or so. The Oudie starts bleating an airspace warning before I even reach 17,000'. This is a nuisance on great soaring days in the mountains. On those days, I sometimes stay below 17,000' just to avoid the nuisance.

I had my altimeter checked and calibrated about a year ago, so I am very confident in its accuracy, as opposed to the GPS altitude. However, without a transponder, is there any record anywhere to prove that I have NOT busted airspace floors or ceilings? If I post an OLC claim with my Oudie, where is my proof that the Oudie altitude trace is wrong? Who is going to take my word about my altimeter on any given flight?


Roy


@Roy - your PowerFLARM Portable is cal'd to the ISA and that's what it records. See the approval doc at http://www.ukiws.demon.co.uk/GFAC/ap...powerflarm.pdf
Some he "...1.6 Pressure altitude sensor. AMS 5540 or MS 5607 Pressure Altitude sensor by MEAS Switzerland SA, formerly Intersema Sensoric SA (www.meas-spec.com) is fitted. This is compensated for temperature variation and calibrated to the ICAO ISA. It is shown in the header record of IGC files in the form: "HF PRS PressAltSensor: MEAS MS5607". The recorder case is not pressure-sealed and "cockpit static" pressure is recorded on the IGC file."

Your PowerFLARM sends pressure altitude to your Oudie2 (mine did before I changed and now my ClearNav vario does). Set up an info box with it. It will diverge from the altimeter setting on your altimeter and the GPS altitude but let you know how you are doing wrt Class A. I don't understand why your Oudie is set to alarm for GPS altitude. Oudie2 Lite running XC Soar doesn't (I assume when you say Oudie you mean SeeYou Mobile?).
Dan