The static system in the SF260 is a fiasco. Although there is a sump drain on the bottom of the fuselage it is almost worthless. When water collects it gets into the static lines and works its way up to the airspeed, the altimeter and the encoder altimeter.

Having been prewarned I drained my static system but it still had water in it. Next I disconnected the static line at the altimeter and opened the sump drain. I forced air into the system and water dripped out. Next I disconnected all of the static lines and connected a vacuum line to the sump. I would occlude each line individually and while the vacuum was working and got more water out of the static lines. Then I hooked everything back up and still had problems. I finally flew home with all of the static lines disconnected. This worked perfectly. Later I had to have both airspeed indicators and both altimeters rebuilt. I had to replace the encoding altimeter and the rate of climb.

Warning pilots about the problems does not seem to help. Perhaps they have an aversion to getting dirty and think that getting under the plane and finding the sump drain is for mechanics. Well, guess what, a non SF260 mechanic will not bother with the sump system either.

Just opening the drain will only remove some of the water. And even if no water comes out there may still be water in the system. The system must be purged by opening the alternate static vent. Then you have to remove the drain cock and let the remainder of the water escape. If you do not have an alternate static vent then just disconnect one of the static lines in the cockpit.


I always drain the static lines everytime I make my preflight checks! If any water is showing, I use to open the drain at the beginning of the preflight, and close it when I'm finished.

I've never had serious problems with the static lines, but it's very important to drain them everytime you can. If the airplane is not hangared it's very important to use the static vents cover, but even using it, if it rains or if the weather is very humid, some water can get in, and some moisture can form in the lines as well.

Leaving the drain open for some time (even days) between your flights, if the airplane is hangared, should be enough to get rid of any water in it.

Carlo Cattoni

From Ray Myllyla- A&P/IA. Very experienced SF260 mechanic.

Where does he get the water in the system? As far I can see it can only get in through the static ports, one or both of them. If this is the case, he can install water trap in tail where the static lines come together or one after each static port. I have hard time figuring out how the water can enter the system and travel all the way into the instruments (I think it is uphill some of the way). It has to be forced in there under some pressure or maybe condensation, but even this will flow to the lowest point, the drain, if not blown in. I personally have not found this to be a major problem, but then we do not see too much rain. When washing the plane cover the static ports before spraying water on the sides of the airplane.

Just a note, sounds like he has a lot of water in his system, more than just normal condensation, he had to spray it in through the static ports or there is something not correct in his system. I can not remember if the manual is very clear in how to route the lines from the rear to the panel but it should be fairly straight forward. When the plane is in rest on the wheels the nose should be higher than the drain port in the belly and if the lines are fairly straight water should run down to the drain so it can be drained.


Dr. Bill Vitale responds
My own response to your encounter with water in the Pitot/Static System:
I, also had the exact same problem occur a few years back after having flown for many hours through a widespread tropical storm system between Maryland and Florida. Both ways! And I, also, had to have the damaged instruments rebuilt. Fortunately, the instruments were affected while on the VFR approach to my home airport at KMTN - and almost as fortunately, perhaps, my insurance company footed the bill.

When I finally did get down on my hands and knees and actuated the quick drain under the fuselage, there was, lo and behold and with all due respect to Peter Leffe, not more than a couple of ounces of water on the ground. Apparently that's all it takes to work itself up into the instrument panel.

Lessons learned the hard way: 1. Get down and open the quick drain from time-to-time during Preflight, especially after having flown in rain. Or even after having been tied down in rain.
2. Do what the Bonanza pilots have done for eons, turn the Pitot Heat to ON whenever flying in visible forms of moisture - especially tropical storms.
3. Avoid tropical storms like the plague!

I understand that some of the earlier models of the SF.260 (like the Bonanzas) do not have quick drains for the Pitot/Static System. I haven't the foggiest notion of what their take is on this potential problem which can be a very serious issue during some dark and stormy night! My best armchair advice is to get the S-Tec online fast. Also, be sure the Turn Coordinator is In the On position and forget about Altitude Hold!

Bill Vitale

This came from an Italian pilot who bases his SF260 C modified to a D in London.
Hi again Dudley,
Water on the Static systems has been very instructive and interesting reading. This problem occurre to me a couple of times. Both times were after flying into stormy and icing weather and parking the aircraft outside (where some extra rain could be collected despite the static covers!).
The best warning I could notice when some drops are in the static system is an erratic behaviour of the rate of climb/descent: when indicatons are "bouncy", excessive or not responsive, then THERE IS WATER IN THE SYSTEM! Another symptom is when moisture appears into the instruments.

The nasty thing about the whole ordeal is that you cannot rely on your anemometers: when it happened to me they were indicating a much faster speed than reality, and I can assure you it is no fun on approach. As you certainly know a low speed stall while in a landing configuration in a 260 will make you fly inverted in a funny attitude just inches from the ground: little or no room for recovery. So be careful of the stall indicator and the aircraft's reaction to stick input!

Unfortunately I noticed that the drain system does not work very well. So even if during the pre-flight one opens the drain valve, it might happen that no water comes out even if there is some in the system. My solution when I suspect the problem might arise is to fly with the pitot heater on and the drain valve in the open position. This causes some slight false reading on the air speed above 150Kts. There is no assurance the valve will remain in the open position during the whole flight.... Apart from that, my 260 always rests in the hangar when at home, so that if I suspect something I will leave the drain valve open for a few days (with a possibility of arousing insects and spiders curiosity...)
So as you can see no ideal solution was found by me. I imagine that the novice pilot's own awareness should not be overlooked on this subject.
Friendly yours

"From Ron Keilin"
This has happened to me twice in the last 20 years with my marchetti..Both times while sitting out in heavy rain. Even after draining the belly drain there was still water in the system.I removed the drain completely and got more water out. Then I installed an alternate static drain under the pannel like most other Cessnas and Pipers..If while in flight, I experience problems with airspeed or altimiter, just turn on the alternate static source,

I do have a suggestion to offer that might be of some help. Crawl into the tail someday and look at how the static lines are routed. What would be of some help is if you form a loop that goes from the static ports up to the top of the empenage and then down to the sump. When I say a loop I mean in the marine sense of the word, an inverted "U" shape. Since water has a very tough time flowing uphill only moisture that has some pressure behind it could get up the loop and down again. This is the same thing that is used all the time on boats to keep water from flowing back into the hull from the thru-hull fittings.

If you make any substantial changes be certain to get a 337.

And now, from Jan Morgan:
Water in the static system is common on any aircraft operated in rain, or operated in various environments and altitudes, as an aircraft would should it be flown on a long cross country.

Leaving an aircraft out in the rain or washing the aircraft can also cause water to flow into the static ports, adding moisture to the system.

The Marchetti and other aircraft have P/S drains, and they should be checked. It takes only a drop of water in the wrong place to render a P/S system useless.

My Mooney 231 was flown at FLs often, and any excess water in the system would occasionally freeze causing problems with the instruments. Of course, the aircraft had an alternate static source. So this was a minor annoyance.

I also checked the routing of the P/S lines so that there would be little chance that fluid could reach a low spot and cause a real problem. Then, I made sure that the system was drained at every preflight, and inspected during regular service checks. Easy enough to do. All you need to do is look at the lines, and check for drips of moisture. If any are encountered, blow them out by blowing through the static port with the drain pressed open. In any case, I had only one problem with fluid, and regular draining of the system, and regular inspections cured the problem.

On a Marchetti, DRAIN THE SYSTEM EVERY FLIGHT. If you do this, you will find that water cannot migrate UPHILL to the instrument panel, Even in inverted flight.

Pipers, Bonanzas, Mooney's and my Marchetti had problems with water in the P/S system, and each was flown for many hours per year in rain. (I never found that rain alone was a reason to postpone a flight. I have better than 1000 hrs flying rain). Before each flight, I would drain the P/S system where a drain and collator was installed. such as that on the Marchetti. I would also occasionally blow through the static port to clear the collator of moisture.

On aircraft without P/S drains, I would visually inspect the static lines for water, and blow them out if necessary. This was done at 25 Hr inspections during which I made many rain flights, and at 50 hour inspections if no rain was encountered. Since I flew not less than 300 Hours per year, these inspections and pre flight draining of P/S moisture occurred quite often.

All aircraft have problems with moisture in the P/S system, and if you let it get to the point that it caused damage to the instruments, then SHAME ON YOU. My guess is that the system was never checked for moisture during normal inspections, and your mechanic should be knee capped.

Some have described aircraft as "16,000 individual parts flying in close formation". This means that you really need to check a lot of stuff during inspections. Check the P/S system , and blow out any moisture if it is found. This is something that needs to be inspected more often than your bi yearly P/S recertifications.

Know and understand the aircraft's systems. It is your best insurance against pilot error in the face of mechanical difficulty. If we fly in rain, or wash the aircraft, there is always the possibility of water intrusion into the P/S system with any aircraft, regardless of manufacturer. Knowing this makes it easy to remember to drain the systems should a drain be installed in the aircraft (Mooney and Marchetti have P/S drains, as do others), and do this EVERY preflight, along with the fuel drain check. You know that the little drain is there. Now stop ignoring it

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