Today I made a disturbing discovery.
Some time ago I checked that my pitot static systems were leak free.
Pitot would hold pressure over a few days, static, with much more
instruments coupled to it, would hold it over a few hours. I tested this
with a syringe connected to the tubes that went to the pitot- static probe.
So, with much confidence I went today to the official mandatory pitot
static test. To my dismay, the static system appeared to have a massive
leak, with the altimeter set to 1000 feet, it would go down to 0 within
a few seconds, pegging the VSI in the corner.
Tracing down the leak, it didn't take long before I discovered that the
static probe itself was the culprit! (I had not included it in my own
test because it was sort of difficult to connect a tube to it, and it
was of metal after all so I somehow trusted that this thing would be ok).
The static probe consists of a tube with an inner tube inserted into it
to allow a standard diameter hose to be fit. This was where the leak
was: between the two tubes. When I tried to disconnect my test hose from
the tube, suddenly the inner tube came out of the probe!
It is unclear if and how the inner tube was secured to the outer tube. I
can't see traces of solder or welds, nor from any type of glue.
As this is a piece of equipment originally delivered by Europa with my
kit, it may well be possible that other pitot-static probes have the
same problem. It might go unnoticed for a while, and maybe after a while
it starts leaking. If that happens, the static system will now be fed
with air from the inside of the wing, and this pressure might be far
---From neutral.
So, if you a bored, you might screw off the probe and have a good look
at it, and maybe as a precaution, use some sealant over the joint
between the two tubes.
Frans
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