FreqFlyrJr
Pre-Flight
My father and I were on our way back from a short dinner-hop last night (as a good-tasting way for me to build some time) and we were on an IFR flight plan. At the time of this story, we were in Visual Conditions and kept visual for the remainder of the flight.
About half way through the flight, the one's needle in our altimeter began bouncing about 50-feet high, then 50-feet low, then repeated. It would do this consistently with about three bounces a second.
My first instinct was the pull the alternate static, which did not have any effect on the altimeter; however it did show the expected changes on the airspeed and VSI. So it wasn't the static source.
I looked on my GPS units and noticed that our Pressure Altitude was 4,200ft while we were indicating 4,000. We were about ten miles from the destination airport, so we canceled IFR and continued VFR.
Another note we found before landing was that the altimeter showed an accurate non-bouncing indication during climbs and descents more than about a hundred feet. However, in straight and level, it oscillated.
Any ideas?
About half way through the flight, the one's needle in our altimeter began bouncing about 50-feet high, then 50-feet low, then repeated. It would do this consistently with about three bounces a second.
My first instinct was the pull the alternate static, which did not have any effect on the altimeter; however it did show the expected changes on the airspeed and VSI. So it wasn't the static source.
I looked on my GPS units and noticed that our Pressure Altitude was 4,200ft while we were indicating 4,000. We were about ten miles from the destination airport, so we canceled IFR and continued VFR.
Another note we found before landing was that the altimeter showed an accurate non-bouncing indication during climbs and descents more than about a hundred feet. However, in straight and level, it oscillated.
Any ideas?
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