Pitot Tube Covers -- Use Them!

Jay Honeck

Jay Honeck

Touchdown! Greaser!
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Ingleside, TX
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Jay Honeck
I have never been very religious about using a pitot cover, mostly due to sheer laziness. I've been known to park in the North 40 at OSH for 8 days without one, with no ill effects.

So on Tuesday we flew to Marfa, TX. for some R&R, after a wonderful night in San Antonio with friends.

Marfa is on the high desert of Southwest Texas. It's where the movies "Giant", "No Country for Old Men", "There Will Be Blood", and "Sylvester" were filmed, mostly because of its starkly beautiful, desolate landscape.

Here's an example of the terrain, as seen on climb-out:

10408642_691036944265536_2001564840152439870_n.jpg


Anyhow, we were there for a grand total of 48 hours. When I parked the plane on Tuesday, I neglected to put the pitot tube cover on. As I was walking away, I noticed, but thought "Meh, what could live out here?" (It was 98 degrees, with no signs of life anywhere. The moon looked more lifelike.)

When we departed this morning, I noticed that I had no airspeed -- neither the EFIS nor the backup instrument (indicating a pitot failure) -- right around the time I was rotating. I flew the pattern, had Mary call out GPS ground speeds to me (like a good flight engineer), and landed uneventfully.

On my RV-8A, the pitot tube really IS a tube. Basically, it's a piece of 1/4" tubing with a 90 degree bend in it, held on to an AN fitting on the bottom of the left wing with a nut. I looked in the pitot tube and saw no obstructions. I even blew into it, and tried lightly sucking on it -- and noted no abnormal (or icky) stuff.

So, we took off again -- and still had no airspeed. By now I had rediscovered that my EFIS conveniently displayed GPS ground speed right underneath where airspeed would normally be displayed, so I flew onto our destination, Uvalde, TX.

This is what the instruments looked like:

10380287_691034120932485_4539333625682148557_n.jpg


I found it interesting that the EFIS airspeed ribbon failed at the top of the airspeed range. This is opposite the steam gauge, which (or course) displayed zero when dead.

At Uvalde I got the tools out and removed the pitot tube from the aircraft (I love experimental planes) and tried to blow through it. Nothing, nada, zilch -- it was 100% clogged.

I took a piece of safety wire, and carefully reamed out a yellowish goo that looked like insect guts, or eggs, or something. Incredibly, in just 48 hours on that ramp in the desert, something had moved in and clogged that tube.

After reaming, here's what the instruments looked like on the next leg home:

1509076_691034134265817_9187333781522356383_n.jpg


100% normal.

Moral of the story: Use that pitot cover when you're parked outside for any length of time. You might get away without using one for a few decades, like me, but sooner or later bugs really will take up residence.
 
In the northeast it can happen overnight. Pitot tube covers are a must.
 
We had our big party Memorial Day weekend and and the plane out of the hangar so we could show movies in there. When I went to fly Tuesday, the airspeed never came up. Couldn't note anything at the external tube so I pulled the tubing off the altimeter and shot it out with a little compressed air. Margy said she herd something eject from the pitot tube when I did that.

A previous static system plugging was attributed by the mechanic (at least he wrote in this in the log) to a "doober." Now I've got no clue how THAT got into the system.
 
flyingron said:
We had our big party Memorial Day weekend and and the plane out of the hangar so we could show movies in there. When I went to fly Tuesday, the airspeed never came up. Couldn't note anything at the external tube so I pulled the tubing off the altimeter and shot it out with a little compressed air. Margy said she herd something eject from the pitot tube when I did that.

A previous static system plugging was attributed by the mechanic (at least he wrote in this in the log) to a "doober." Now I've got no clue how THAT got into the system.
Click to expand...

I see a lot of bad writing in log entries, 5 days a week. Many mechanics can't write. Very few if any are English majors.

Getting them to fix it can be...frustrating :mad2:
 
Got some sort of bugs in ours once when the aircraft was housed outdoors. Never had a problem since we got our hangar, even sitting in the grass at Osh.
 
I always use a cover even inside.

I also do an airspeed alive callout early on the roll. I don't want to take off into low IMC, night, or some other condition where safety could be compromised by a lack of indication.
 
Imagine if you had sucked that yellow goo out when you were "servicing" that pitot the first time... hehe

Glad you got it all fixed up! Thanks for sharing this, as it's beneficial to learn from each other.
 
Archammer said:
Imagine if you had sucked that yellow goo out when you were "servicing" that pitot the first time... hehe

Glad you got it all fixed up! Thanks for sharing this, as it's beneficial to learn from each other.
Click to expand...

My thoughts exactly, made me pucker when I read that.
 
When I was in Miramar, we had a couple incidents during the summer of wasps building little homes in the pitot tubes overnight (which typically weren't covered during non flying hours). A couple high speed aborts resulted as guys were still seeing "48" kts in the HUD on the takeoff roll since the tubes were clogged. They started covering them at night right after that.
 
I was taught at a early age that during the initial roll out for the first two call outs after the start of roll was tach is good and airspeed alive. If the airspeed was dead it's a abort takeoff item. Since that happens in the first 10 or 20 seconds and first several hundred feet it's not a problem to abort.
 
jtheune said:
I was taught at a early age that during the initial roll out for the first two call outs after the start of roll was tach is good and airspeed alive.
Click to expand...

My CFI taught me to call out three things on the initial roll:

1.) After verifying RPM and MP normal "Engine power good"

2.) Then scan all the other engine gauges "Gauges in the green"

3.) Then verifiy airspeed "Airspeed alive"

And after sucking the gear and flaps up, "Gas caps good" after verifying no fuel being syphoned from the tanks.

I still verbally call all four of these. :D
 
Bill Jennings said:
And after sucking the gear and flaps up, "Gas caps good" after verifying no fuel being syphoned from the tanks.
Click to expand...
I can just imagine trying to see the gas caps from inside the cockpit in my Cardinal... would require some pretty fancy mirror system.

Driving a low wing does have a few advantages I guess...
 
Bill Jennings said:
My CFI taught me to call out three things on the initial roll:

1.) After verifying RPM and MP normal "Engine power good"

2.) Then scan all the other engine gauges "Gauges in the green"

3.) Then verifiy airspeed "Airspeed alive"

And after sucking the gear and flaps up, "Gas caps good" after verifying no fuel being syphoned from the tanks.

I still verbally call all four of these. :D
Click to expand...

It's interesting that you say that, as this mirrors the way Mary and I flew for decades. We had a short list of things to check and verbalize once full power was applied. The main difference was that (in our case) it was the non-flying pilot's job to call out those parameters.

This form of CRM worked wonderfully -- and was blown completely out of the water when we bought a tandem-seat aircraft. In the year we have owned our RV, it's been a sometimes difficult transition back to single-pilot ops, since the co-pilot can no longer see the critical engine instrumentation. The situation has been compounded by the new glass panel, which has given us vastly more information to absorb.

On the other side of the coin, this situation has been helped somewhat by the GRT Horizon's (our new EFIS) ability to duplicate itself on any Android tablet via Bluetooth, which has given the backseat pilot a complete EFIS. Now the GIB (guy/gal in back) can see and detect an airspeed failure, too.

Both of us noticed the failure, a bit late. In our Pathfinder there was always plenty of time to detect a failure, as we trundled down the runway toward rotation speed. Even with full tanks and luggage, the RV-8 accelerates more quickly, and we didn't notice the failure till rotation speed. I opted to continue the flight rather than risk aborting in the high density altitude in Marfa. (8000+'). It all worked out fine, obviously. (In the calm-wind situation we were in, GPS ground speed works just fine.)

As you might expect, however, we will be modifying our takeoff procedure to include an earlier/quicker airspeed check.
 
Many year ago we were flying a rented 172 to Oshkosh. Departing Dulles, my wife was flying and as we were climbing out the airspeed fell to zero. We flew over to the maintenance base and had them blow it out. When we got to Oshkosh we pitched the tent quickly and headed over to Friar Tucks for dinner. While standing in the bar next to another pilot waiting for a table and sucking down a much needed beer and mentioning our earlier experience, he started off on how he had an alternate pitot inside the cockpit. Margy kicked me because she knew I was about to ask him how fast the air was moving inside his cockpit.
 
Well this is all making me feel pretty good having just landed at KAGC where I dutifully put on my pitot cover and cowl plugs. And it happens to be one of those top 10 gorgeous days with temps in the 70s and very low humidity.

I've never had any problem with pitot tubes but I have had birds build nest under the cowl. Once it happened during an overnight trip in the Maule. When I got to the plane to give a few rides I found a couple of birds running a nest building relay. I was able to clean out the debris without removing the cowl but they wouldn't give up. Each time I gave a ride, we went back to the beach house to pick up another ride. 30 minutes later we'd return and have to clear out the cowling again. Then we flew home only to kill a deer with the right hand landing gear but that's another story...

Years later, after a two nighter at 39N, we return to the RV10 to find grass just falling out of the right hand air intake. In two days a complete condo had been built on top of cylinder 3 and 5. The cowling had to be removed, vacuums scrounged and multiple hands enlisted to get the plane cleaned up enough to fly with frying the IO540. Just an unbeleiveable amount of debris had been woven into the cylinders and cooling infrastructure.

So I'd suggest pitot covers and cowl plugs. 99% of the time they are not needed but it just takes once to foul up a trip.
 
Back when we were based at VKX we always had birds attempting to nest in the tail until I hung a "Scare Eyes" beach ball from the rotating beacon with a bit of safety wire.

Somehow, a bird has managed to take up residence in our NC hangar. It has built several nests so I just left the last one (it's on my hydraulic lift). She was in there sitting on the eggs when we got down here this weekend. I have NO idea how she's getting in and out.
 
flyingron said:
Back when we were based at VKX we always had birds attempting to nest in the tail until I hung a "Scare Eyes" beach ball from the rotating beacon with a bit of safety wire.

Somehow, a bird has managed to take up residence in our NC hangar. It has built several nests so I just left the last one (it's on my hydraulic lift). She was in there sitting on the eggs when we got down here this weekend. I have NO idea how she's getting in and out.
Click to expand...
Good chance that's our Carolina Wren. One of the birding books describes them as promiscuous nest buiders that build several nests, make serial visits before abandoning most of them for the most favorable. Little guys can get in just about anywhere... flower pots being a favorite.

The perfect hangar guest bird would eat mud daubers :yesnod:
 
meh, I'd bet in the history of aviation there have been more dead airspeed indications due to pitot covers left on than from bugs crawling in the tube. Leave the plane sit on the ramp or hangar for over 3 days? Okay...put them on. Flying the plane daily or close to? Nah.
 
Bill Jennings said:
My CFI taught me to call out three things on the initial roll:

1.) After verifying RPM and MP normal "Engine power good"

2.) Then scan all the other engine gauges "Gauges in the green"

3.) Then verifiy airspeed "Airspeed alive"

And after sucking the gear and flaps up, "Gas caps good" after verifying no fuel being syphoned from the tanks.

I still verbally call all four of these. :D
Click to expand...

I got $20 that sez your CFI was teaching you how to fly an airplane with a nosewheel.
 
What about the oil breather tube, fuel tank overspill tubes, etc
 
Fuel vents can be problematic as well.
 
flyingron said:
A previous static system plugging was attributed by the mechanic (at least he wrote in this in the log) to a "doober." Now I've got no clue how THAT got into the system.
Click to expand...

Just bad handwriting. Probably a mud dauber, little black wasp-looking critters that build long tube-looking things on the wall that look like mud. Starts with one, can have several side-by-side. Nice and hard, crunches like sun-dried mud. They don't bother people [at least not me], just their nests are annoyances.
 
flyingron said:
...

A previous static system plugging was attributed by the mechanic (at least he wrote in this in the log) to a "doober." Now I've got no clue how THAT got into the system.
Click to expand...

I think he mean dauber as in mud dauber
 
Yeah, my wife told me that's what he meant, but I've still got this vision of him pulling a doober out of the static system (and then wondering what he did with it afterwards, probably smoking it while he filled out my log book).
 
flyingron said:
Fuel vents can be problematic as well.
Click to expand...

I cover both that and the pitot even when in the hangar. I use a tennis ball with a small "X" cut in it. They work great and the rubber "skin" conforms perfectly to the tubes after a few uses.

I cut a small slit in the opposite side and force the middle of a 2' (ish) length of surveyors flagging into it...giving me two one foot streamers.

I've used racquet balls also.
 
I cover them all.

I had a mud dauber clog a gas tank exhaust vent.
Wet wing started to collapse for lack of a better word in flight.

I was very new and had no clue at the time. I literally said "Well it is a new to me plane probably always been like that and I just hadn't noticed the dents before.

Landed and it took a lot of strength to get the gas cap off. WHOOOOOSH!
dents popped out.

Should have switched tanks and landed at that moment. :mad2:
 
Jay Honeck said:
Both of us noticed the failure, a bit late. In our Pathfinder there was always plenty of time to detect a failure, as we trundled down the runway toward rotation speed. Even with full tanks and luggage, the RV-8 accelerates more quickly, and we didn't notice the failure till rotation speed.
Click to expand...

Yep. "Airspeed alive" is my *first* check on the takeoff roll these days, as the Ovation is between 40-50 KIAS by the time I hit full throttle. :goofy:

I opted to continue the flight rather than risk aborting in the high density altitude in Marfa. (8000+').
Click to expand...

What's risky about aborting at high DA? Other than a runway overrun, which shouldn't have been a problem in the RV with over 5300' available?
 
flyingcheesehead said:
What's risky about aborting at high DA? Other than a runway overrun, which shouldn't have been a problem in the RV with over 5300' available?
Click to expand...

Oooh! I think I know this one.

Higher DA == higher true airspeed for a given indicated airspeed. Which means you need to be going faster when you land (true, not indicated). If you use the GPS speed without doing the math, you're off. And if you aren't used to flying at that DA and try to judge it by eye, you'll be off.

At least, that's what I'd be thinking.
 
Mistake Not... said:
Oooh! I think I know this one.

Higher DA == higher true airspeed for a given indicated airspeed. Which means you need to be going faster when you land (true, not indicated). If you use the GPS speed without doing the math, you're off. And if you aren't used to flying at that DA and try to judge it by eye, you'll be off.

At least, that's what I'd be thinking.
Click to expand...

I agree with everything you're saying, but it would all favor the abort, not taking flight.

A takeoff attempt plus abort at high DA will take more runway than it will at low DA because of the difference between KIAS and KTAS, but 5300' of runway should be plenty for an RV-8 to make a safe abort.
 
flyingcheesehead said:
Yep. "Airspeed alive" is my *first* check on the takeoff roll these days, as the Ovation is between 40-50 KIAS by the time I hit full throttle. :goofy:
Click to expand...

If you're hitting 40-50 kts before reaching full power you're wasting runway and not getting the performance the POH lists.
 
Captain said:
If you're hitting 40-50 kts before reaching full power you're wasting runway and not getting the performance the POH lists.
Click to expand...


True, but I'm sure the guys writing the POH were at full throttle prior to brake release.
 
I can't believe we're 33 posts into this thread and nobody has taken Jay to task for departing in violation of 91.205. :)
 
Sam D said:
I can't believe we're 33 posts into this thread and nobody has taken Jay to task for departing in violation of 91.205. :)
Click to expand...

Or that it's likely the reason his ASI didn't come alive is because he didn't do a zoom climb. :rolleyes:
 
Sam D said:
I can't believe we're 33 posts into this thread and nobody has taken Jay to task for departing in violation of 91.205. :)
Click to expand...

Oh, I was thinking it, along with others.
 
flyingron said:
We had our big party Memorial Day weekend and and the plane out of the hangar so we could show movies in there. When I went to fly Tuesday, the airspeed never came up. Couldn't note anything at the external tube so I pulled the tubing off the altimeter and shot it out with a little compressed air. Margy said she herd something eject from the pitot tube when I did that.

A previous static system plugging was attributed by the mechanic (at least he wrote in this in the log) to a "doober." Now I've got no clue how THAT got into the system.
Click to expand...

Mightve meant "dobber" as in mud dobber.
 
Well, I briefly considered declaring an emergency. lol

Most pilots were exposed to flying without an airspeed indicator in primary flight training. For those who think that the loss of an airspeed indicator is a safety of flight issue, I suggest going up with a safety pilot and practicing the pattern without it. You'd be surprised what a non-issue it truly is, especially if you're familiar with the aircraft.

Here's a good article describing this exercise:

http://www.flyingmag.com/technique/tip-week/fly-without-airspeed
 
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