Quote:
Originally Posted by JackZ
A few observations:
Altitude is about 600 feet higher consistently on my GRT Sports than on my ipad gps derived altitude. (at approx 10000 ft)
The wind when flying into it are always a lot higher than when flying with a tailwind acording to the efis's or is that efi? They are separate ahrs. buit the read the same.
The temperature probe seems to read 4 celcius high.
The pitot static system has recently been tested and adjusted by a certified shop. o leaks and both altimeters and all three air speeds match.
TodayI was indicating 147Kts with 169 ktas and 194kts gs temp -18 c and 10800 ft, the ipad showed 10200 ft
is the problem position errror or temperature error or both?
[i] would appreciate the brighter folks than I to chime in. ( that means just about everybody )
Jack
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As noted above, gps measures true altitude, altimeter is barometric altitude. They agree only on a ‘standard day’. 600’ difference at 10,000’ seems a bit much, though, unless it was very non-standard.
Does your temperature reading look okay, on the ground, engine off? Is there any way it can see hot exhaust?
The wind calculation depends on the TAS calculation (efis) and the ground speed data (gps). Try this: slowly turn, constant altitude, determine the direction of the wind using gps ground speed (min speed = headwind). Fly into the wind, note ground speed. Turn 180 deg (tail wind), note ground speed. Average the two ground speeds. Result should equal the true airspeed.
Static port check. Set altimeter to field elevation. Do a high speed pass down the runway at a known elevation (maybe the top of the tower as a guide). If the altimeter does not read the tower elevation, there’s a static port error.
Edit. Wow! 6 posts while I was typing (and watching football).