Static system problem

simtech

simtech

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Simtech
Flying along yesterday fat dumb and happy. I make a descent to an airport and my altimeter starts bouncing all around. When I leveled off to pattern alt it smoothed back out. Fuel up and take back off. An hour into the flight and just about coming out of imc my vsi drops all the way down and my altimeter was crazy bouncing. Vsi finally came back but altimeter was still bouncing around. Was not fun to say the least as I didn't know what altitude I was truly at. What in the world could this be? I just had my pitot static check done and I flew it with no problems the day before this flight. Any ideas? Avionics guy can't look at it until monday.
 
Most likely water got into the system via the static port(s).

No "Alt Static" on your plane?

In any case a pretty easy fix - blow the water out. Technically a job for an A & P, but pretty straightforward.
 
No alternate static...yet! The first time it did on descent I was never imc. But it did get worse after imc.

Mechanic said to take it back up and fly it to blow the water out. Got me. I'm in another state right now and all the shops closed for the weekend. I mean dallas is a big area and no shop is open on the field. So I'm gonna fly it around tomorrow and see what's up.
 
I had the same thing happen in my mooney. Found a loose static port hose on the left static port (I have 2), and it seems to have solved the problem. It didn't cause full deflection, but it was bouncing a lot.
 
Hm.

When you wash a plane, would letting the water roll down the side be okay for the static ports or do you have to specifically tape over them? In other words, could you do that to a static port by just washing or would you have to turboblast the stream directly at the port?
 
A while back Cirrus owners were having a heck of a time with water in their static ports. It may have been a contributing cause in at least one fatal and one chute pull, if not more.

I made a pair of devices for my plane I called F.E.S.P.W.I.P.D.'s

(Fast Eddie Static Port Water Incursion Prevention Devices)

I offered them to all Cirrus owners for the price of postage. Over the years I probably sent out close to 100 pair as a public service.

I can't offer that here, but if you have a fuselage-mounted static port(s) and smooth paint adjacent, they're pretty easy to fabricate from a bicycle spoke cut in half, two suction cups and a ribbon of some sort.

They evolved over the years, but this was my first prototype:

21459032833_25cb39708f.jpg


The idea was not to seal the port, just cover it.
 
k2-_99e39f6a-486d-4520-9d1e-dd704d7857c6.v1.jpg-9b88208b4537acf6689edc6ea01ba6a54b9f218f-optim-450x450.jpg


try a piece of this tape over your static ports and pitot tube holes. It'll withstand 1 wash job and will peel off without leaving a residue (well, ...maybe a tiny bit of very easily removable residue).
 
overdrive148 said:
Hm.

When you wash a plane, would letting the water roll down the side be okay for the static ports or do you have to specifically tape over them? In other words, could you do that to a static port by just washing or would you have to turboblast the stream directly at the port?
Click to expand...
I doubt that water flowing past the ports would enter the system but if you direct any stream of water at the ports it's likely some of it will get in.

If you do tape the port(s), take another piece of tape and fasten the keys to the top of the glareshield to serve as a reminder to unblock the ports. Don't untape the keys until you have verified the ports are clear.
 
wilkersk said:
k2-_99e39f6a-486d-4520-9d1e-dd704d7857c6.v1.jpg-9b88208b4537acf6689edc6ea01ba6a54b9f218f-optim-450x450.jpg


try a piece of this tape over your static ports and pitot tube holes. It'll withstand 1 wash job and will peel off without leaving a residue (well, ...maybe a tiny bit of very easily removable residue).
Click to expand...

Lost a 757 off the coast of Peru that way.
 
flyingron said:
Lost a 757 off the coast of Peru that way.
Click to expand...

Wasn't that one begun by missing "Pitot Heat - ON" on the checklist?

Or am I thinking of another one?

In any case, a thorough preflight would catch tape in place.

Anyway, that's why all of the devices I sent out had "REMOVE BEFORE FLIGHT" ribbons, or equivalent, attached. Though the suction cups that covered the static ports were only held there loosely and would likely not obstruct the flow of ambient air pressure to the instruments.
 
FastEddieB said:
A while back Cirrus owners were having a heck of a time with water in their static ports. It may have been a contributing cause in at least one fatal and one chute pull, if not more.

I made a pair of devices for my plane I called F.E.S.P.W.I.P.D.'s

(Fast Eddie Static Port Water Incursion Prevention Devices)

I offered them to all Cirrus owners for the price of postage. Over the years I probably sent out close to 100 pair as a public service.

I can't offer that here, but if you have a fuselage-mounted static port(s) and smooth paint adjacent, they're pretty easy to fabricate from a bicycle spoke cut in half, two suction cups and a ribbon of some sort.

They evolved over the years, but this was my first prototype:

21459032833_25cb39708f.jpg


The idea was not to seal the port, just cover it.
Click to expand...

That is really cool of you to do that. :yes:
 
CTx


Sent from my iPhone using Tapatalk
 
simtech said:
No alternate static...yet! The first time it did on descent I was never imc. But it did get worse after imc.

Mechanic said to take it back up and fly it to blow the water out. Got me. I'm in another state right now and all the shops closed for the weekend. I mean dallas is a big area and no shop is open on the field. So I'm gonna fly it around tomorrow and see what's up.
Click to expand...

You always have an alternate static source. Break the glass on the altimeter or VSI.

I never thought much about alternate static sources. My Cessnas have had one and it's been something I check occasionally to make sure the needles bounce when I open it. My Cub didn't have one and I never missed it. Huh.
 
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FastEddieB said:
Wasn't that one begun by missing "Pitot Heat - ON" on the checklist?

Or am I thinking of another one?
Click to expand...
Must be a different one. This one was purely a static issue.
In any case, a thorough preflight would catch tape in place.
Click to expand...
The mechanic who placed the tape violated policy and used duct tape which was very close to the aircraft color rather than the high visibility tape color that was the standard procedure.
 
If your duct tape is too sticky, just get it a little dirty and it won't stick as hard.

A better option is blue painters tape - it is designed to release easily.

Or just know where the ports are and don't spray there.

I do like Fast Eddy idea though. :D


But the problem as described in the OP could well be something loose in the P-S system.
 
I'd use something other than blue painters tape on my plane. My plane is about the same color as the painter's tape. (See the avatar <---).

Of course, VFR it's not too much of a problem. Over the years I've hard two pitot blockages and a few static system blocks. The last static failure was the day (after five weeks) I finally got to flush my plane out of VKX after 9/11. I told ATC that the mode C was almost certainly wrong and after inquiring if I had good ground contact they told me to stop altitude squawk and get out of the airspace. The only tricky part was figuring out how to determine when I got to Vle but the combination of the AWOS wind speed and the GPS ground speed got me to a comfortable value.

You should try throwing a towel over your instrument panel and landing some time. You should be able to do it in the things like the Navion or your RV.
 
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