Static leaks in Flight Design

[Madhatter]

When I picked up my 2006 CTSW I was told it was one of the fastest CTs they ever sold. I was not familiar

with the aircraft performance so had no basis to question it. During my flight training I noticed that the analog airspeed indicator was erratic and at times indicated up to 130 - 135 knots and was duplicated on the Dynon. All my approaches seemed slower than the 60 knots indicated and the controls seemed a bit sloppy. When I got the plane home I connected my static tester to the aircraft and found a significant leak in the static system including a case leak in the analog airspeed indicator. After correcting the leaks my indicated airspeed was a steady 118-120 knots.

Almost all non pressurized aircraft develope a low pressure in the cabin, some worse than others. This will cause a false increase in airspeed and altimeter indications. With the side vents open on the CT and a static leak you will be flying up to 10 knots slower than indicated, this could be a big problem on a 50 knot approach

So if you are seeing 130 + knots indicated and erratic airspeed and altimeter fluctuations you might want to have the static checked. It's easy to do with the right equipement however it is easy to destroy static instruments if done improperly.

[sandpiper]

Even without this problem, I wouldn't assume to fly any approach without first determining the indicated stall speed in approach configuration.

[Madhatter]

Static systems made from plastic lines are notorious for developing leaks over time. I have done hundreds of IFR recertifications and have found many to have developed leaks within the 2 year cycle. The CT seems to have a more significant pressure change with the side vents open than a lot of aircraft I have flown. Most older VFR small planes have static leaks because there is no requirement to check them, only for IFR. This is just something to be aware of

[Jim Meade]

Thanks for the tip. Good info.