Today's misadventures, pitot and fuel tank vent-wise

[MuseChaser]

Finally flew my Cherokee home from it's temporary (five weeks) home at my A&P's airport back to it's home base. It was parked outside for that time, and only started and taxied for about 20 minutes once during that time. Did a thorough preflight (of course) today, and found some unwelcome things...

1. Water in both tanks, especially the one that was only had five gallons of fuel in it (we had removed that one due to a slow leak, recompressed the rivets, reinstalled it, then put five gallons back in as a test). Repeated sumping and rocking of the wings eventually got the water out. I've NEVER seen water in fuel before. If you think it can't happen, it can. There was a LOT.. more than a cup of water in one side. We had some VERY hard rains during that time so it's possible I've got a leaky cap. In any case, caught, and no issue.

2. Checked for clogged pitot/static ports. The pitot port had been filled by a mud dauber or other ne'erdowell, DESPITE me having a cover on it. Cleared it out the best I could with what I had available, but was concerned that I may have pushed some crap back in further whilst trying to extricate it.

3. Checked fuel vents .. seemed clear.

AND... upon takeoff.. it became obvious that the pitot port was still plugged. I now had two altimeters, although one was marked in MPH for some reason... ;( .. Oh well, no biggie, I knew the "numbers," it was a short hop home to a big runway that would allow for a little extra speed/safety margin, so I just flew home. Had backup altimeter info on GPS and ESG, and it was severe clear VFR. For some strange reason, had one of my best landings in a long time.

Upon landing and refueling, the left tank hissed like crazy when I took off the cap. Investigated the vent further.. it, too, was clogged by those @#$@#$ mud thingies, but farther up than I had originally checked.

Sooo.... besides the obvious "use some fine safety wire" tip, how do I clear these two things (pitot port and tank vent) without forcing more garbage where I REALLY don't want it.. and.. is it too late and did that clot in the pitot migrate further upstream? What to do? Heading back to the aircraft early tomorrow AM.. any tips much appreciated. Plane is '65 PA28-140 Cherokee, if that helps w/ that pitot-specific design.

Thanks..

 

[DesertNomad]

I had a possible blocked fuel vent line on my Dakota and my A&P advised me to use a non-ferrous material to try and clear it. He suggested something like a tiny plastic straw like comes with WD-40 or other aerosol.

How are you checking the fuel vent since I can only see in an inch or two on mine?

 

[luvflyin]

Putting in just 5 gallons is a test for leaks??????? Glad we're reading from you about this and not reading about you.

 

[wsuffa]

Pipe cleaners - long ones - worked well on the fuel tank vents on my commander.

 

[MuseChaser]

Putting in just 5 gallons is a test for leaks??????? Glad we're reading from you about this and not reading about you.

Easy there... I'm probably the most paranoid pilot you'll ever meet. The other tank had 15 gallons in it, it was a 25 minute flight, and I burn 8.5 gph, give or take. The leak, when we had one, was a seep at best..no drops or drips..just dampness along one short length of a seam. Yes, putting a couple gallons in isn't a pressure test, but it was enough to tell if reseating the rivets helped (it did). I'll keep an eye on it, and I had already contacted and made arrangements to drop off the tank for rebuilidng/resealing if necessary. So far, so good.

 

[luvflyin]

Easy there... I'm probably the most paranoid pilot you'll ever meet. The other tank had 15 gallons in it, it was a 25 minute flight, and I burn 8.5 gph, give or take. The leak, when we had one, was a seep at best..no drops or drips..just dampness along one short length of a seam. Yes, putting a couple gallons in isn't a pressure test, but it was enough to tell if reseating the rivets helped (it did). I'll keep an eye on it, and I had already contacted and made arrangements to drop off the tank for rebuilidng/resealing if necessary. So far, so good.

Ok, I’m calming down. It was that it had been removed and reinstalled that mostly had me thinking a full test should have been done. The vent being plugged I thought was the most concerning issue. That can make fuel in the tank unusable. Anyway, glad you had safe outcome to the flight and hope all works out well with plane.

 

[Clip4]

Finally flew my Cherokee home from it's temporary (five weeks) home at my A&P's airport back to it's home base. It was parked outside for that time, and only started and taxied for about 20 minutes once during that time. Did a thorough preflight (of course) today, and found some unwelcome things...

1. Water in both tanks, especially the one that was only had five gallons of fuel in it (we had removed that one due to a slow leak, recompressed the rivets, reinstalled it, then put five gallons back in as a test). Repeated sumping and rocking of the wings eventually got the water out. I've NEVER seen water in fuel before. If you think it can't happen, it can. There was a LOT.. more than a cup of water in one side. We had some VERY hard rains during that time so it's possible I've got a leaky cap. In any case, caught, and no issue.

2. Checked for clogged pitot/static ports. The pitot port had been filled by a mud dauber or other ne'erdowell, DESPITE me having a cover on it. Cleared it out the best I could with what I had available, but was concerned that I may have pushed some crap back in further whilst trying to extricate it.

3. Checked fuel vents .. seemed clear.

AND... upon takeoff.. it became obvious that the pitot port was still plugged. I now had two altimeters, although one was marked in MPH for some reason... ;( .. Oh well, no biggie, I knew the "numbers," it was a short hop home to a big runway that would allow for a little extra speed/safety margin, so I just flew home. Had backup altimeter info on GPS and ESG, and it was severe clear VFR. For some strange reason, had one of my best landings in a long time.

Upon landing and refueling, the left tank hissed like crazy when I took off the cap. Investigated the vent further.. it, too, was clogged by those @#$@#$ mud thingies, but farther up than I had originally checked.

Sooo.... besides the obvious "use some fine safety wire" tip, how do I clear these two things (pitot port and tank vent) without forcing more garbage where I REALLY don't want it.. and.. is it too late and did that clot in the pitot migrate further upstream? What to do? Heading back to the aircraft early tomorrow AM.. any tips much appreciated. Plane is '65 PA28-140 Cherokee, if that helps w/ that pitot-specific design.

Thanks..

Remind me to never fly with you.

 

[bflynn]

Remind me to never fly with you.

Or buy your airplane.

I was always told never to try to poke a mud dauber nest out of the pitot because there’s no pace for the crud to go. You might have just pushed it further inside the actual tube and created a blockage. Or forced into your altimeter where it’s now going to grind in the gears. Smart A&P said that, I trust him.

 

[chemgeek]

Put brightly colored pipe cleaners in the fuel vents to keep insects out. Remove before flight. Common Grumman trick in susceptible climes. If you forget to remove them, nothing bad happens. Mud daubers are pretty rare here in CNY. In Alabama, they will clog up any available crevice quickly.

 

[1RTK1]

Remind me to never fly with you.

Little harsh, no?

Is the best way to remove it by blowing it out from the back side through the line?

 

[DesertNomad]

Little harsh, no?

Is the best way to remove it by blowing it out from the back side through the line?

That's not easy to do on a Cherokee as I think you'd have to remove the tank and slide it forward to get to the other end of the vent line.

 

[bflynn]

Had many mud daubers in the pitot, never one in the fuel vent. There’s a significant size difference.

 

[Clip4]

Little harsh, no?

Is the best way to remove it by blowing it out from the back side through the line?

No, he found his plane is un-airworthy, didn’t bother to get a mechanic to help him out , improperly tried to resolve the issues and after a potentially fatal flight goes on the internet to get advice on maintenance is is not allowed to perform. For all we know the vent line and/or the pitot / static lines are obstructed due to an improper fuel tank installation.

 

[Ravioli]

The water in the tank doesn't surprise me, and not necessarily the cap. 5 gals on a 140 is what... about 1/3 full? All of that vapor space was ripe for condensation. And you mentioned rain (moisture in the air) and there were heat/cool cycles (days/weeks). 15 gals in the other tank is pretty close to capacity. Much less vapor space, much less condensation. You've proved out what we all read during PPL training.

 

[Timbeck2]

The water in the tank doesn't surprise me, and not necessarily the cap. 5 gals on a 140 is what... about 1/3 full? All of that vapor space was ripe for condensation. And you mentioned rain (moisture in the air) and there were heat/cool cycles (days/weeks). 15 gals in the other tank is pretty close to capacity. Much less vapor space, much less condensation. You've proved out what we all read during PPL training.

Each tank holds 25 gallons. 18 to the tabs

 

[Skip Miller]

The water in the tank doesn't surprise me, and not necessarily the cap. 5 gals on a 140 is what... about 1/3 full? All of that vapor space was ripe for condensation. And you mentioned rain (moisture in the air) and there were heat/cool cycles (days/weeks). 15 gals in the other tank is pretty close to capacity. Much less vapor space, much less condensation. You've proved out what we all read during PPL training.

I don't believe you can get 1+ cups of water from condensation alone in one fuel tank in a 140. One cup of condensation in 20 gallons of air? There must be a bad seal on the cap gasket.

-Skip

 

[Kenny Phillips]

Or buy your airplane.

I was always told never to try to poke a mud dauber nest out of the pitot because there’s no pace for the crud to go. You might have just pushed it further inside the actual tube and created a blockage. Or forced into your altimeter where it’s now going to grind in the gears. Smart A&P said that, I trust him.

The altimeter likely uses some sort of sealed tube, and if dirt (or air) escapes into the meter mechanism, you've got serious issues!

 

[1RTK1]

That would make sense or you would constantly have bugs and dirt entering the system

 

[NordicDave]

2. Checked for clogged pitot/static ports. The pitot port had been filled by a mud dauber or other ne'erdowell, DESPITE me having a cover on it. Cleared it out the best I could with what I had available, but was concerned that I may have pushed some crap back in further whilst trying to extricate it.

The altimeter likely uses some sort of sealed tube, and if dirt (or air) escapes into the meter mechanism, you've got serious issues!

Besure to blow out the pitot and static lines from the inside out. If debris is cleared from the outside, small particles will remain in the line and can get blown into the instruments. I'd take the pitot tube apart, clean it , and blow it out with air. Separately blow out the static line.

 

[Dan Thomas]

The altimeter likely uses some sort of sealed tube, and if dirt (or air) escapes into the meter mechanism, you've got serious issues!

Yup. The altimeter and airspeed both have sealed aneroid capsules fed by the static and pitot lines respectively. Crud can't get into any mechanisms unless the aneroid is ruptured, and that only happens if someone blows air into the ports. The VSI has the static line connected to its case, and crud could get into critical mechanisms there, but IIRC there's a filter inside that stops debris so that the calibrated leak in its aneroid isn't fouled.

 

[MuseChaser]

No, he found his plane is un-airworthy, didn’t bother to get a mechanic to help him out , improperly tried to resolve the issues and after a potentially fatal flight goes on the internet to get advice on maintenance is is not allowed to perform. For all we know the vent line and/or the pitot / static lines are obstructed due to an improper fuel tank installation.

Clip4, I appreciate your concern, but you are assuming a lot of things that are just false. Neither I, nor my A&P who was onsite and with whom I discussed my findings preflight, found the plane un-airworthy. He is an authorized A&P/IA, and I DID "bother" to get him to help and advise. In the fifteen years I've been flying (admittedly sporadically), I've had the pitot plugged once before while I was still a student pilot and my CFI showed me how to clear it w/ safety wire years ago when the plane was LAST parked outside, and that's what I did this time. If that is "improperly tr(ying) to resove the issues," then OK, but it's what i was taught. I checked the tank vent lines prior to start up and they were clear based upon the way I was taught to check... a gentle probing of the vent. My discovery/assumption upon refueling that the vent may have been plugged was the hiss when removing the gas cap. As far as the vent line and/or pitot/static lines being obstructed due to an improper fuel tank installation, that's just wrong. The tank we (WE, meaning an A&P/IA and I) removed was the right tank. The left tank was untouched, and that's the tank that hissed, and also the side the pitot/static blade is. There has not been an issue w/ the pitot nor the vent other than the previously plugged pitot port fifteen years ago, and pitot/static instruments have ALWAYS worked fine. This time, the pitot was plugged with mud from an insect. I already told you that.

Again, I am a very careful pilot, and tend to over-analyze and over-scrutinize, if any of that is possible, everything. I posted for a couple reasons. One of the main reasons, of course, was to get some ideas for further exploration. The other was to be helpful to anyone else and to show that even the most careful of preflights doesn't always catch every thing. We all know pilots who routinely perform preflights much less thorough than the one I did, unfortunately. I've seen lots of people do extremely poor preflights, including my first CFI who I only flew with a couple times... very much a "kick the tires/light the fires" kind of guy. He is NOT the one to whom I referred above. My current CFI is fastidious, exacting, and unrelenting.. a perfect fit. Not saying I did everything right, but given the situation I identified a couple problems, remedied them with the advice and guidance of a respected A&P/IA, ran the engine and did several very thorough runups without any incident, and flew home without any issues. An inop airspeed indicator is not a death sentence, nor is a plugged fuel vent, and even if everything went completely to hell I was flying over farm country with fields virtually everywhere. I'm not even sure I DO have a plugged vent; probed it further with safety wire this morning and it seems clear as far six inches in. DO the fuel caps hiss on Cherokees? In hindsight, I should have done a fast taxi, then stop and taxi back prior to taking off; that would have shown that the airspeed indicator was not working, at which point I would have terminated the flight and had my A&P investigate further.

In any case, I understand where you're coming from and am trying to do nothing but appreciate your comments, but your judgemental attitude is misplaced in my humble opinion... I'm here to learn, and am happy to learn from everyone. I don't know everything. Those that do, well.. usually don't either.

 

[Eric Lehto]

One minor quibble from me.....I always verify airspeed alive early in the takeoff roll.

 

[steingar]

Yeah, we had a pitot blocked by some sort of arthropod infestation years back. Aborted the takeoff, gave it to the mechanics. Hadn't heard about the safety wire trick, good idea that. Could have probably flown without, but I'd rather not.

 

[benyflyguy]

Wow. What a mess.

 

[Ravioli]

I don't believe you can get 1+ cups of water from condensation alone in one fuel tank in a 140.

I suspect the measure given was neither scientific nor accurate.

Kind of like when I've had to "Hold short forever."

 

[IK04]

...Hadn't heard about the safety wife trick, good idea that. Could have probably flown without, but I'd rather not.

Wow. Really bad typo. Gonna get some quibbling over that!

 

[Clip4]

Clip4, I appreciate your concern, but you are assuming a lot of things that are just false. Neither I, nor my A&P who was onsite and with whom I discussed my findings preflight, found the plane un-airworthy. He is an authorized A&P/IA, and I DID "bother" to get him to help and advise. In the fifteen years I've been flying (admittedly sporadically), I've had the pitot plugged once before while I was still a student pilot and my CFI showed me how to clear it w/ safety wire years ago when the plane was LAST parked outside, and that's what I did this time. If that is "improperly tr(ying) to resove the issues," then OK, but it's what i was taught. I checked the tank vent lines prior to start up and they were clear based upon the way I was taught to check... a gentle probing of the vent. My discovery/assumption upon refueling that the vent may have been plugged was the hiss when removing the gas cap. As far as the vent line and/or pitot/static lines being obstructed due to an improper fuel tank installation, that's just wrong. The tank we (WE, meaning an A&P/IA and I) removed was the right tank. The left tank was untouched, and that's the tank that hissed, and also the side the pitot/static blade is. There has not been an issue w/ the pitot nor the vent other than the previously plugged pitot port fifteen years ago, and pitot/static instruments have ALWAYS worked fine. This time, the pitot was plugged with mud from an insect. I already told you that.

Again, I am a very careful pilot, and tend to over-analyze and over-scrutinize, if any of that is possible, everything. I posted for a couple reasons. One of the main reasons, of course, was to get some ideas for further exploration. The other was to be helpful to anyone else and to show that even the most careful of preflights doesn't always catch every thing. We all know pilots who routinely perform preflights much less thorough than the one I did, unfortunately. I've seen lots of people do extremely poor preflights, including my first CFI who I only flew with a couple times... very much a "kick the tires/light the fires" kind of guy. He is NOT the one to whom I referred above. My current CFI is fastidious, exacting, and unrelenting.. a perfect fit. Not saying I did everything right, but given the situation I identified a couple problems, remedied them with the advice and guidance of a respected A&P/IA, ran the engine and did several very thorough runups without any incident, and flew home without any issues. An inop airspeed indicator is not a death sentence, nor is a plugged fuel vent, and even if everything went completely to hell I was flying over farm country with fields virtually everywhere. I'm not even sure I DO have a plugged vent; probed it further with safety wire this morning and it seems clear as far six inches in. DO the fuel caps hiss on Cherokees? In hindsight, I should have done a fast taxi, then stop and taxi back prior to taking off; that would have shown that the airspeed indicator was not working, at which point I would have terminated the flight and had my A&P investigate further.

In any case, I understand where you're coming from and am trying to do nothing but appreciate your comments, but your judgemental attitude is misplaced in my humble opinion... I'm here to learn, and am happy to learn from everyone. I don't know everything. Those that do, well.. usually don't either.

Thanks for the explanation, I am glad you did get hurt.

 

[MuseChaser]

Thanks for the explanation, I am glad you did get hurt.

Thanks for reading. I'm going to assume that you meant "didn't get hurt..."...