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6 Answers

Pitot Tube – Static Holes

Asked by: 5311 views Aircraft Systems, Commercial Pilot, Flight Instructor, General Aviation, Instrument Rating, Private Pilot

Hi Pilots,

looking into all kinds of books and doing plenty of research, I still have not found the answer to my question regarding the static holes which are sometimes located on the Pitot Tube. 

So, does anyone know or have any idea what their purpose is? Again, I do not mean the Drain Hole, no, I mean the Static holes, sometimes located on the bottom of the PT. Apparently not all PT have them though.  

Thanks a lot! 
David

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6 Answers



  1. Alyeska on Jan 01, 2018

    Piper is the only manufacturer I know of that co-located the ram and static pressure ports on the same device, often referred to as the pitot-static mast. They were often heated allowing the aircraft to be certified for IFR.
    From talking to A&P’s over the years, the systems were difficult to maintain and particularly difficult to test. That said, they provided an advantage over the traditional separated pitot tube/static port, where the indicated airspeed and calibrated airspeed spread was very small–basically they were more accurate.
    It also seems that having the static port on the same heated mast, you could likely rely on accurate altitude and airspeed readouts if icing were encountered.

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  2. Mark Kolber on Jan 02, 2018

    A “static port” is intrinsic to the operation of the “pitot-static system” which feeds information to the altimeter, airspeed indicator and vertical speed indicator of an aircraft.

    There are different configurations. In some the pitot tube and static port are completely separate; in others the static port is located on the pitot tube itself. It’s actually pretty common. For example, it’s that way on the ubiquitous PA28 series of aircraft. So I’m really surprised your research and review of all kinds of books didn’t come across it.

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  3. David Menke on Jan 03, 2018

    @ Mark Kolber.. thanks a lot for your answer. That totally does make sense of course. 🙂
    Regarding my research… I’ve been looking into a bunch of books etc, some of them illustrating the Pitot Tube with the holes while others don’t. However, I never read anything about the Static holes located on some tubes. The system itself is always explained, as well as all components of the Tube etc, except for the static holes located on the PT. But maybe I’ve just looked into the wrong boooks… 😉

    @ Alyeska … thanks for your reply as well! Good to know!

    Happy New Year!!! 🙂

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  4. Andro on Feb 09, 2018

    Hi David,

    That\’s a Pitot-Static tube, often called a Prandtl tube, in honour of Ludwig Prandtl, the German aerodynamicist. Here\’s a link from NASA:

    https://www.grc.nasa.gov/www/k-12/airplane/pitot.html

    I am unsure as to what the advantages are over having static ports in the fuselage.

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  5. Andro on Feb 09, 2018

    Looking into the advantages of a Prandtl tube, it is that they are less sensitive to errors caused by yaw and pitch – when the tube is not directly pointing into the relative wind.

    Here’s a really detailed page on error analysis of pitot static tubes:

    http://www.unitedsensorcorp.com/pitot-properties.html

    Like with any engineering device, error calculations and considerations and analysis are of enormous importance. Don’t assume data from pitot tubes is absolute.

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  6. ChristopherShortt on May 08, 2020

    Hi David, my name is Christopher Shortt (a new Epic Flight Academy student for become a Commercial Pilot) and I have to recognize that I had the same concern, so I just found the answer here:

    https://www.grc.nasa.gov/WWW/k-12/VirtualAero/BottleRocket/airplane/pitot.html

    I hope this resolve your question!!

    Greetings

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