Blocked pitot.

[jpilot77]

Was in the takeoff roll this morning in my Seneca 1 when the airspeed didn't come alive. I assume that it is a blocked pitot. There isn't any obvious blockage but insects are known to get inside them. Any tips to cleaning it out or do I gotta get an AME to clean it out?

[iflyforpie]

Could be a bug or mud daubers (they are really bad where I am).

You need to have an AME disconnect the pitot line either at the blade or the ASI and blow a little bit of clean shop air backwards through the system (being careful not to over-pressurize the lines). This method has cleared out any blockage I've encountered.

Then the system must be tested for leakage after it is hooked back together.

[niss]

Was in the takeoff roll this morning in my Seneca 1 when the airspeed didn't come alive. I assume that it is a blocked pitot. There isn't any obvious blockage but insects are known to get inside them. Any tips to cleaning it out or do I gotta get an AME to clean it out?

Have you tried politely asking them to leave?

[Heliian]

Ya, your local AME should have you back in the air in no time. I've seen blockages in the tube, but you may also have water in the lines, or the system drain may be open/missing The orifice at the airspeed indicator is quite small and easily blocked. I've also seen the plastic tubing melt closed if located too close to ldg or taxi lites. If you haven't had a pitot-static test done in a while, have them do that but if you don't need one, they can just do a simple leak down check.

ALWAYS INSTALL PITOT COVER AFTER FLIGHTS AND REMOVE BEFORE TAKEOFF

[Jungle Jim]

Niss,

I was out last night for a flight and noticed that the cover on your salami slicer had fallen off. I replaced it but you may have the same issue as jpilot77 on your next flight.


Jim

[SeptRepair]

So for giggles and grins. What does a person think is a reasonable price for a person to pay to get this problem rectified at an AMO. I mean its not a hard job to do, if all it is is a blocked line. Keep in mind to do this job correctly and by the book, there is specialized equipment involved and at least a couple hours labour by the time the log book is signed out and the aircraft is ready for the customer to pick up. 200.00$ including taxes?.... 300.00?

[niss]

Niss,

I was out last night for a flight and noticed that the cover on your salami slicer had fallen off. I replaced it but you may have the same issue as jpilot77 on your next flight.


Jim

Thanks for that! Admittedly that could be an issue but it is a smaller and cheaper problem than if the cover falls off your salami!

[avionicsdude]

Hey,
Do you park the Aircraft out side or in a Hangar?
Do you use Pitot Covers?
It could also be a sticky instrument.
Go to a local avionics shop which has an inventory of loaner indicators etc and ask them to check because they can do a pitot/static leak test as well and sign out the books.

[AEROBAT]

Look in your POH, I am pretty sure there is a static drain on the Seneca 1. It's been 20 years since I flew one but I am pretty sure it was in the walk around check list.

[jpilot77]

Thanks for all the suggestions and help, I'll post what happened after all is said and done.

[jpilot77]

Well it was a Mud Dauber that blocked up my pitot tube. I disconected the rubber hose from the metal hose that is connected to the Pitot. A little shot of air from the compressor got it all out. Purchased and received a Pitot cover!

[SeptRepair]

I couldn't find the maintenance action you performed anywhere in the Elementary tasks section of the CARS. Anyone have a link for me?

[Hedley]

They're listed in CAR 625 App A. Here you go:

http://www.tc.gc.ca/civilaviation/regse ... /a625a.htm

[SeptRepair]

Thanks for the link.

[Hedley]

[mag check]

I couldn't find the maintenance action you performed anywhere in the Elementary tasks section of the CARS. Anyone have a link for me?

Maybe he has a homebuilt seneca

[jpilot77]

When I said I, I should have said my AME. I was the one who pointed to the probable cause(as was suggested on this Forum).

[qa guy]

So for giggles and grins. What does a person think is a reasonable price for a person to pay to get this problem rectified at an AMO. I mean its not a hard job to do, if all it is is a blocked line. Keep in mind to do this job correctly and by the book, there is specialized equipment involved and at least a couple hours labour by the time the log book is signed out and the aircraft is ready for the customer to pick up. 200.00$ including taxes?.... 300.00?

half hr. to blow the line out and 1hr. for a BASIC leak test and logs is fair. (for that a/c)

[jpilot77]

It was about half an hour to get the bugs out, but the rubber hose from the pitot to the metal tubing in the wing was all dryed out and cracked. The AME changed it to clear plastic tubing then did the leak test so it was a little longer than an hour, but not by much.

[jpilot77]

So it was a lot less than $200.