On an earlier post I mentioned the IAS errors which I've encountered in doing prop testing on RVs. Someone told me of a quick check of the static port location and errors. Set your altimeter on the ground, and note, if available, your GPS altitude. Fly down the runway at high speed and note your altimeter and height above the runway, either judged or from the GPS. The one who told me about this said that the altimeter read 50' under the runway when 50' above it; that's a 0.1" error which will give lots of additional IAS errors. BTW; it helps to have someone along to record the data so you can concentrate on flying the plane!
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Static port/IAS errors
- Thread starter elippse
- Start date
Kevin Horton
Well Known Member
GPS altitude might be stable enough for this if you have WAAS. Maybe. But if you don't have WAAS, GPS altitude varies quite a bit. The GPS altitude from my Lowrance hand held sometimes GPS varies by more than 100 ft over the course of a few minutes, which is not nearly accurate enough for this type of check.
Determining altitude via eyeball out the window is probably a better check, if you are low enough. Certainly if the altimeter shows you below ground when you are clearly above ground that points to static system error, or a leak.
Low passes down the runway bring their own risks, which must be considered.
Determining altitude via eyeball out the window is probably a better check, if you are low enough. Certainly if the altimeter shows you below ground when you are clearly above ground that points to static system error, or a leak.
Low passes down the runway bring their own risks, which must be considered.
