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Airpath compass correction instructions.

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  • #16
    Oh by the way, Airpath does not repair compasses, only manufacturers' them. I emailed and asked. Tim
    N29787
    '41 BC12-65

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    • #17
      Tim we know they sell a repair kit for experimentals.

      Gary
      N36007 1941 BF12-65 STC'd as BC12D-4-85

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      • #18
        Originally posted by PA1195 View Post
        My comment wasn't meant to incite a riot but perhaps a periodic question to the applicant might be in order: "Now that your glass panel and navaids are disabled (by fuse or switch) due the lightning hit where are we and how do we get to the nearest airport?" That might make for a meaningful discussion of alternative methods of determining position and orientation to a desired track.

        Basic nav techniques remain an important skill: How far have we gone based upon our observed groundspeed and in what direction(s)? (Make them write it down periodically). How soon can we expect to see a landmark on the chart given our groundspeed and in what direction should we see that or them? (To temporarily replace the compass by physical orientation). Mark a planned route on a chart with periodic check points to confirm the path and groundspeed. (Have a pencil handy?) And yes only with a chart-terrain visually confirmed and then the compass. Assume the airspeed and static ports are frozen via covers, and the tach cable broke so learn a throttle position via manifold pressure gauge or throttle control position. Make it a learning experience not another tour de jour.

        I've had instructors put me under the hood to practice IFR then remove it and force VFR without all the gadgets. It can happen in real flying so why not prepare?

        Gary
        I am not disagreeing. I have done a fair bit of training in a light sport with glass panel displays. I have been known to completely dim the screens to get the students eyes outside the airplane. For a fairly new student it is amazing how well they can fly when they don't have all that information to look at. I have even covered analog instruments for the same purpose.

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        • #19
          Originally posted by PA1195 View Post
          Tim we know they sell a repair kit for experimentals.

          Gary
          Yeah Gary, but they do not do the repairs themselves. Tim
          N29787
          '41 BC12-65

          Comment


          • #20
            Flying with a compass: Still a good primary instrument and backup to other means of navigation. Some compasses are easier to use than others.

            Compass repairs: Repair kits are functional and the process is not difficult.

            Integrating old vs new piloting: The future is drones and glass. Whether the pilot chooses to use techniques common to both in a conventional airplane is a choice.

            Gary

            N36007 1941 BF12-65 STC'd as BC12D-4-85

            Comment


            • #21
              Originally posted by Robert Lees View Post

              Yes I have, but never the compass. Any instructor conducting a review that did that to me would be invited to step outside. I've had tacho, ASI, Altimeter covered up.

              How on earth would you get home with just a sectional if you don't know the direction you are travelling? That's just silly, Hank.

              Rob
              My instructor did it to me on a cross country but DID NOT cover the compass (never said he covered the compass, but he did cover the heading indicator). A couple of times he shut off ALL electronic nav devices and said "find your way home". Each time I just said "Oh boy! I'm back in the Taylorcraft!" I could point the direction of the nearest three airfields and knew pretty much how long it would take to get there for each. He stopped doing it. Said it wasn't proving anything any more. Situational awareness is KNOWING where you are and using the nav aids to verify, not following a magenta line. Can't really imagine loosing a mag compass in flight at the same time you loose EVERYTHING else!

              On a side note, back in the mid west (Kansas and Nebraska) all of the roads are laid out NS-EW and you really didn't need a compass. The few large roads that weren't on major compass headings made for great landmarks to find your way around. Interstate highways and railroads tended to run from one major city to another. Pretty hard to get lost.

              Hank

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              • #22
                What can happen is a lack of periodic calibration of the compass as reflected by the correction card. I do it annually but even then changing cockpit contents can affect the indications. I've never understood the requirement for having a calibration card available without a similar requirement to periodically insure its accuracy. Just me I guess.

                Gary
                N36007 1941 BF12-65 STC'd as BC12D-4-85

                Comment


                • #23
                  Originally posted by PA1195 View Post
                  What can happen is a lack of periodic calibration of the compass as reflected by the correction card. I do it annually but even then changing cockpit contents can affect the indications. I've never understood the requirement for having a calibration card available without a similar requirement to periodically insure its accuracy. Just me I guess.

                  Gary
                  In the UK (for certificated aircraft) it is a requirement to re-calibrate the compass every 4 years (I think). This probably harks back to Amy Johnson / Alcock & Brown* days (look them up) when all they had was a compass, stopwatch and ruler. And occasionally a chart.

                  In this modern day & age of ATC, Foreflight, GPS, iPad apps etc, I think it's absolutely ridiculous to require a compass to be calibrated within 3 degrees of accuracy.

                  Rob

                  * The first pilots to cross the Atlantic

                  Comment


                  • #24
                    Originally posted by Robert Lees View Post

                    In the UK (for certificated aircraft) it is a requirement to re-calibrate the compass every 4 years (I think). This probably harks back to Amy Johnson / Alcock & Brown* days (look them up) when all they had was a compass, stopwatch and ruler. And occasionally a chart.

                    In this modern day & age of ATC, Foreflight, GPS, iPad apps etc, I think it's absolutely ridiculous to require a compass to be calibrated within 3 degrees of accuracy.

                    Rob

                    * The first pilots to cross the Atlantic
                    With the old bubble face compass, I feel lucky if it is within 20.

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                    • #25
                      https://www.faa.gov/documentLibrary/.../AC_43-215.pdf
                      http://www.faa-aircraft-certificatio...uirements.html

                      Seems +-10* is the requirement in these documents REF Part 23. Whether for not CAR Part 23 applies to CAR 4 aircraft is.......?

                      For Part 91 ops those aircraft certified under CAR 4 (pre-TCDS 1A9 "flight manual" Taylorcrafts), section 04.05803 says "This instrument shall be properly damped and compensated and shall be located ed where it is least affected by electrical disturbances and magnetic influences."

                      For TCDS 1A9 aircraft (Model 19 and newer) Car 3 section 3.758 says: Magnetic direction indicator. A placard shall be installed on or in close proximity to the magnetic direction indicator which contains the calibration of the instrument in a level flight attitude with engine(s) operating and radio receiver(s) on or off (which shall be stated). The calibration readings shall be those to known magnetic headings in not greater than 30-degree increments.

                      Gary
                      Last edited by PA1195; 02-15-2019, 14:06.
                      N36007 1941 BF12-65 STC'd as BC12D-4-85

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                      • #26
                        Click image for larger version

Name:	Brunton.jpg
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ID:	181378 I bought one of these to do my own compass swings... https://www.brunton.com/products/con...nt=36245970258
                        N29787
                        '41 BC12-65

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                        • #27
                          There's a rumor that some have taxied a plane on wheels and floats and used the GPS track to cal the compass.

                          Gary
                          N36007 1941 BF12-65 STC'd as BC12D-4-85

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                          • #28
                            There are ways to accurately calibrate a compass.....and there are the requirements the FAA has for calibrating them. A lot like the requirements for calibrated aircraft scales for weighing a plane. Most electronic bathroom scales (under $20 at WallMart) are more accurate and repeatable than the "approved" scales. safest to use both. If they disagree, put some known weights on each. When I have done it, guess which one turned out to be out of calibration! Remember you want the scale to be accurate close to the weight you will be measuring, NOT at zero! Same for your compass. Do what the FAA regs require, then verify in flight with your GPS or other devices to be sure the compass rose you used was even right. Sometimes even flying over a road is more accurate than a rose that was painted years ago and is no longer accurate. (don't forget to account for wind angle!!!!!)

                            Hank

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                            • #29
                              The North Pole is moving and compass variation will be affected. GPS manufacturers are likely updating their database to reflect that change so incorporate any upgrade they offer. I expect airports to comply with their data soon as well as those that supply instrument flying procedures. A GPS confirmation of our compass may be worthwhile until the ground based upgrades to reference points are effected.

                              https://www.ngdc.noaa.gov/geomag/WMM/
                              https://www.ncei.noaa.gov/news/world...-cycle-release

                              Gary
                              N36007 1941 BF12-65 STC'd as BC12D-4-85

                              Comment


                              • #30
                                Originally posted by PA1195 View Post
                                The North Pole is moving and compass variation will be affected. GPS manufacturers are likely updating their database to reflect that change so incorporate any upgrade they offer. I expect airports to comply with their data soon as well as those that supply instrument flying procedures. A GPS confirmation of our compass may be worthwhile until the ground based upgrades to reference points are effected.

                                https://www.ngdc.noaa.gov/geomag/WMM/
                                https://www.ncei.noaa.gov/news/world...-cycle-release

                                Gary
                                It is always moving. Our airport is going to be remarked this Summer. One of out runways will change its numbers. The other runway was built in the late 1970's, and had changed its number 10 years later.

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