Static Port Cover Ideas

[dstates]

TL;DR: What do you use to cover your static port when parking outside (in the rain)?

I had some bad luck at Airventure this year. My 170 was parked facing north and the rain we got early in the week came from the west. This apparently pushed quite a bit of water into my static port. I'm still not sure how that much water got in there, but it did. When I went to fly out on Wednesday my airspeed indicator and altimeter had visible moisture showing (quite a bit). Well, this ended up causing me to remove these instruments and send them to Keystone for cleaning/repair. It caused enough corrosion after a few weeks in my altimeter that it stopped working.

Anyway, now that I'm on the backside of that issue with my repaired instruments coming back today, I want to avoid this again in the future. I'm going to see my avionics shop can add one of those water collection bottles to the static system this winter. I still need to do some research on parts, but that should hopefully be straight forward.

My real question for everyone is: What do you use to cover your static port when parking outside (in the rain)? I have a cover for my pitot tube. The best thing I can thing of right now is to tape something over the port. I don't want to put adhesive on the port, so maybe some sort of rubber "band aide".

I'm open to suggestions.

Thanks,
Doug

[cessnut]

If I really wanted to cover my static port I would consider keeping a roll of red electrical tape in the plane and applying a large X over the port. Before I did that I would install a moisture bottle appropriately and alleviate most of the need to cover it.

[GAHorn]

Brightly colored painters tape.

[n2582d]

Doug,
Thanks for sharing the photos. It’s amazing to me that that much moisture can enter a tiny hole into a closed system. I suppose it’s possible that some of the water in your airspeed indicator entered the pitot tube (assuming it wasn’t covered during the rainstorm). I see they make tape specifically to cover static ports here. Overkill as previous suggestions would work fine. Aircraft Spruce sells a cover but it has terrible reviews. I was wondering about a suction cup with a “Remove before Flight” streamer attached but doubt that it would hold a vacuum with the static port hole in the center. At work years ago we had an Airbus A-300 depart after a new paint job with the static ports taped over. Triple redundancy doesn’t help when they’re all covered. SK175-8 covers the installation of these sump bottles. They also have some poor review on Aircraft Spruce but they’re not that expensive. Gotta love this five star review: “This cheap plastic some made for assassin aircraft is literally a piece of s**t just look to see how many you folks Sala year and it tells you that they break all the time you would think at some point somebody would smarten up and make one better or some thing out of a different material.”. Wonder what his one star reviews are like!

[GAHorn]

THE ORIGINAL PITOT tubes…the ones which are described in the Service Manual which are merely 1/4” aluminum tubing …curved to meet the relative wind…..which 98% of all 170s have…. Consist of a DEFECT…. that usually causes Zero problems.

However, upon occasion..especially after a heavy rain accompanied with high-winds…. can introduce water into the Pitot system. (not the static system)

When the airplane is parked in a “Tail Low” position …. water may collect in that pitot-tube at it’s lower end. (see fig 16-3 of the 100 Series Service Manual)
It can be introduced to the tube…but cannot climb uphill to the horizontal length which leads to the cockpit left/forward door post.

The pre-flight inspection reveals no issue. BUT…. After departure, the relative wind can DRIVE the water uphill and into the pitot system…which is displayed as a WILDLY FLUCTUATING Airspeed Indication…. until the moisture dries out from exposure.
Complaints to the maintenance facility may not reveal a problem afterward because the water has evaportated.

I have personally experienced this TWICE.

A “sump bottle’ installed on the Static side will have no benefit as regards this issue.

Also, It’s more common the “sump jar” is not intended as static “drain”…or “collector”….as it is a reservoir to accommodate minor or momentary fluctuations in pressure (perhaps from line-condensation which should self-drain). *The one in my 172 was found during the pre-buy annual-inspection to be damaged when the prior owner had it re-upholstered…and the upholstery shop had run a PK screw through it and cracked the plastic jar. The system operated normally (as one might expect) …but was found when the interior was removed for the inspection.)

IMG_2994.png

At ANY RATE the sump jar is higher than the static port and any water introduced via that port would simply self-drain…and should cause no problem.

[dstates]

Gary, George and Cessnut, thanks for the info and ideas. I did have the pitot tube covered the entire time I was parked at Oshkosh. I used one of these https://www.aircraftspruce.com/catalog/ ... ights3.php

Like George's comments about airflow pushing water through the pitot system

I was also surprised at how much water got in the static system. Like George's comments about airflow pushing water through the pitot system, sicne this was static system maybe a pressure change occurred while water was in the line. I still don't understand how that much made it up to the instruments when there really isn't airflow in that system. While the instruments were out I did blow out the tubing and I should get the overhauled instruments back today. I have my 24 month altimeter check coming up in a month or so and I'll get one of those moisture bottles installed. Thanks for the info, Gary!