Conrad Posted September 23, 2016 Report Posted September 23, 2016 Alright, my plane is out of annual and needs only one thing: a compass swing! It has finally come time to banish the longest standing of problems. So far I have good-faith reason to believe that the regulations can be interpreted to say that a normal A&P who has prior experience with the procedure can legally adjust the calibration and write the correction card. The local jet center offered to do it for $550 I believe. Presumably their cost involves renting a master compass and two technicians' time: one to be in the aircraft and another to operate the master unit. Is it possible to beat their cost?
XXX Posted September 23, 2016 Report Posted September 23, 2016 Dang, my A&P/IA did mine as part of the annual. No extra cost.
bradp Posted September 23, 2016 Report Posted September 23, 2016 So if I'm understanding, at the jet center the DOM swings a giant magnet near your pockets and all your pennies fly out?
carusoam Posted September 23, 2016 Report Posted September 23, 2016 Somebody wrote how they did it around here somewhere. The procedure is not that hard, but you will need your mechanic's signature. Do you have a mechanic that you can work with? Best regards, -a-
Conrad Posted September 23, 2016 Author Report Posted September 23, 2016 Only the canadian quarters actually. Getting advice on finding someone who would be willing to work with me at KOAK is a large part of the reason I posted here.
Bob_Belville Posted September 23, 2016 Report Posted September 23, 2016 As it happens I swung my compass today. Jury rigged a non magnetic screwdriver and synced the whiskey to the Aspen slaved. Cost was the fuel to taxi around for 20 minutes with everything turned on.
carusoam Posted September 23, 2016 Report Posted September 23, 2016 There must be a lot of hangar elves taking care of compasses out that way. My C had the problem of the steal tube getting in the way and throwing a shadow, while turning 360°. This was problematic for IR training. Beyond that the compass didn't get much work with a working navigator like a GPS. Best regards, -a-
Bob_Belville Posted September 23, 2016 Report Posted September 23, 2016 Just now, carusoam said: There must be a lot of hangar elves taking care of compasses out that way. My C had the problem of the steal tube getting in the way and throwing a shadow, while turning 360°. This was problematic for IR training. Beyond that the compass didn't get much work with a working navigator like a GPS. Best regards, -a- I have not consulted the whiskey compass since I upgraded my panel with an Aspen 4 years ago. 3
Marauder Posted September 23, 2016 Report Posted September 23, 2016 9 minutes ago, bradp said: So if I'm understanding, at the jet center the DOM swings a giant magnet near your pockets and all your pennies fly out? No, that is the penny pincher shops. These guys are using full shop vacuum and are sucking wallets and jewelry off of poor Conrad.
Marauder Posted September 23, 2016 Report Posted September 23, 2016 4 minutes ago, Bob_Belville said: As it happens I swung my compass today. Jury rigged a non magnetic screwdriver and synced the whiskey to the Aspen slaved. Cost was the fuel to taxi around for 20 minutes with everything turned on. My mechanic used some sort of device in a box to calibrate my mechanical compass. The Aspens in my plane are always within a couple of degrees of each other -- the magnetic compass on the other hand seems to go off to see the wizard occasionally.
takair Posted September 23, 2016 Report Posted September 23, 2016 27 minutes ago, Conrad said: Alright, my plane is out of annual and needs only one thing: a compass swing! It has finally come time to banish the longest standing of problems. So far I have good-faith reason to believe that the regulations can be interpreted to say that a normal A&P who has prior experience with the procedure can legally adjust the calibration and write the correction card. The local jet center offered to do it for $550 I believe. Presumably their cost involves renting a master compass and two technicians' time: one to be in the aircraft and another to operate the master unit. Is it possible to beat their cost? Most avionics shops and many mechanics can do it. 20 min to 1 hour if you don't have serious issues. $550 is a lot for a straight swing. Most shops who do it have a master compass or a compass rose.
Bob_Belville Posted September 23, 2016 Report Posted September 23, 2016 Just now, Marauder said: My mechanic used some sort of device in a box to calibrate my mechanical compass. The Aspens in my plane are always within a couple of degrees of each other -- the magnetic compass on the other hand seems to go off to see the wizard occasionally. If I lost the Aspen, the GTN, the 696, the KX155, Garmin Pilot on the tablet, and the phone GPS I would go the old IFR - I fly rivers, road, rails - before I'd go to the compass.
StevenL757 Posted September 23, 2016 Report Posted September 23, 2016 24 minutes ago, bradp said: So if I'm understanding, at the jet center the DOM swings a giant magnet near your pockets and all your pennies fly out? No, just the non-copper, high-value stuff.
Bob_Belville Posted September 23, 2016 Report Posted September 23, 2016 Curious, has anyone had a CFI or an examiner, or a ramp check look for a compass deviation card or ask about your compass?
carusoam Posted September 23, 2016 Report Posted September 23, 2016 CFII that was having me do 360° Standard rate turns using the compass, couldn't figure out the huge lead lags that my C was giving. They were outside the usual NANDs (?) insert proper lead lag acronym here... Best regards, -a-
helitim Posted September 23, 2016 Report Posted September 23, 2016 1 hour ago, Bob_Belville said: Curious, has anyone had a CFI or an examiner, or a ramp check look for a compass deviation card or ask about your compass? Bob, The local DE from my area did. He refused to let a commercial student use the plane for a checkride until the compass deviation card was posted and the he grounded the plane on the spot until the oil was changed because there is an unusual requirement that it fly with 100W Plus and it only had 100W in the engine. This was just a few weeks ago. I full understand the rationale for rules but I can't help but believe this guy went a bit overboard. Tim 1
Guest Posted September 23, 2016 Report Posted September 23, 2016 If their shop rate is $550 per hour then it's about right, it shouldn't take more than an hour, for one mechanic and you in the pilot seat. For those of you with Aspens, have you had the magnetometer calibrated? I check mine with the annual compass swing and have had to adjust it? Clarence
mooniac15u Posted September 23, 2016 Report Posted September 23, 2016 7 hours ago, helitim said: Bob, The local DE from my area did. He refused to let a commercial student use the plane for a checkride until the compass deviation card was posted and the he grounded the plane on the spot until the oil was changed because there is an unusual requirement that it fly with 100W Plus and it only had 100W in the engine. This was just a few weeks ago. I full understand the rationale for rules but I can't help but believe this guy went a bit overboard. Tim Does an examiner have the authority to ground a plane?
Bob_Belville Posted September 23, 2016 Report Posted September 23, 2016 8 hours ago, helitim said: Bob, The local DE from my area did. He refused to let a commercial student use the plane for a checkride until the compass deviation card was posted and the he grounded the plane on the spot until the oil was changed because there is an unusual requirement that it fly with 100W Plus and it only had 100W in the engine. This was just a few weeks ago. I full understand the rationale for rules but I can't help but believe this guy went a bit overboard. Tim Tim, that's interesting. I guess I should not be surprised. Curious what engine/air frame has such a restrictive oil spec. (I run 100W with CamGuard rather than Plus in my Lycoming IO360.)
Bob_Belville Posted September 23, 2016 Report Posted September 23, 2016 3 hours ago, M20Doc said: For those of you with Aspens, have you had the magnetometer calibrated? I check mine with the annual compass swing and have had to adjust it? Clarence Clarence, what do you use to calibrate an Aspen? We do not have a compass rose on MRN and it's my impression that there are not many around anymore. We do know runways headings to 1 degree from approach plate, is that adequate? Can we line up a plane to the center-line 1 degree accuracy?
Andy95W Posted September 23, 2016 Report Posted September 23, 2016 3 hours ago, Bob_Belville said: Tim, that's interesting. I guess I should not be surprised. Curious what engine/air frame has such a restrictive oil spec. (I run 100W with CamGuard rather than Plus in my Lycoming IO360.) Most likely it is a Cessna 172N with the O-320 H2AD engine, used from 1976-1980 or so. Due to cam/lifter spalling, this engine has an AD that requires use of a special Lycoming additive to the oil. This additive is included in Aeroshell 15W50 oil, as well as the 'Plus' oils. 1
Conrad Posted September 23, 2016 Author Report Posted September 23, 2016 It only took 5 phone calls! Mather Aviation, based at KHWD, is the proud owner of a properly calibrated master compass. They are willing to let me do the taxiing in circles (the local jet center is not) and, if necessary, they will send someone to KOAK to perform the procedure for a nominal extra cost.
Guest Posted September 23, 2016 Report Posted September 23, 2016 5 hours ago, Bob_Belville said: Clarence, what do you use to calibrate an Aspen? We do not have a compass rose on MRN and it's my impression that there are not many around anymore. We do know runways headings to 1 degree from approach plate, is that adequate? Can we line up a plane to the center-line 1 degree accuracy? In Canada we have to preform an annual magnetic compass swing, when doing that I note the Aspen compass as well. Clarence
helitim Posted September 24, 2016 Report Posted September 24, 2016 You are correct that it was the H2AD engine. One of the club 172's. I've never understood taking part of your check ride in a 172 and the rest in a retract. Mexifornia is just strange like that I guess. Be so glad when I can retire and get out of this oppressive, overly tax burdened state. If the money wasn't so good, I'd already be gone.
N201MKTurbo Posted September 24, 2016 Report Posted September 24, 2016 A master compass is the way to go. You can make one by taking an old compass and removing the compensating mechanism. Mount it to a board with one brass screw so you can rotate it. Go to a compass rose and sight along the N-S line with the edge of the board, rotate the compass so it reads N, draw a reference line along the mount and then sink another screw in the mount to hold it to the reference line. It will be as accurate as anything you will find.
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