Nick X

Leaking whiskey compass

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56 minutes ago, carusoam said:

Do you remember yesterday, when...

  • radios were analog technology
  • displays were mechanical
  • VSIs had a lag
  • MP gauges had a calibrated leak
  • Instruments were vacuum driven
  • the tach had an oil cup
  • A failing vacuum system would cause a disparity between the DG and AI (?)
  • A back up vac system was connected to the engine’s intake system and was driven off manifold pressure... and didn’t work in low MP environments... when the engine was at WOT.
  • A back-up vac system that worked was driven by an electric motor, that drove another vacuum pump, and weighed about 20Lbs
  • Peter Garmin called his BK HSI a Swiss watch
  • Xrays were displayed hanging on a light box

Tomorrow...

  • the avionics technicians will be wondering how they got the responsibility to look after a mechanical device like a wet compass...
  • Peter Garmin will be wearing a Garmin digital time piece or maybe even an iWatch... :)
  • Xrays will be displayed on a computer monitor

Everything changes.

PP musings, not an instrument tech or philosophist...

Best regards,

-a-

 

X-rays and MRIs are displayed on computer monitors and recorded on CDs. Everytime I go for an MRI I get a CD of my brain. 

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20 hours ago, Gagarin said:

Compass Swing

Although traditionally the compass swings are done on the ground on a painted compass rose. I do mine in flight at about 3000 feet. As a direction reference I use the roads. I verify the road alignment on the maps. Here in Florida they are all referenced to the true north. I pick one that is true north oriented fly the plane parallel to it and adjust the HDG gyro for N + magnetic variation. Then adjust the compass to the gyro indication. I turn the plane to the different headings for compass adjustment. Unlike the ground swing turning the plane in the air is quick and accurate since the compass is calibrated in actual flight conditions. You will surprised about the compass accuracy on approach.

Using a second magnetic device (like the magnetometer in some self-correcting DG's and HSI's) while in flight is, in fact, one of the suggested techniques for swinging and compensating a compass.

https://www.faa.gov/documentlibrary/media/advisory_circular/ac_43-215.pdf

I see two caveats, though:

  • It requires an A&P from an instrument shop to ride along with you to do it
  • How do you know how accurate the other magnetic device is?

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1 minute ago, jaylw314 said:

Using a second magnetic device (like the magnetometer in some self-correcting DG's and HSI's) while in flight is, in fact, one of the suggested techniques for swinging and compensating a compass.

https://www.faa.gov/documentlibrary/media/advisory_circular/ac_43-215.pdf

I see two caveats, though:

  • It requires an A&P from an instrument shop to ride along with you to do it
  • How do you know how accurate the other magnetic device is?

Your method is essentially  the same method the G5 uses to calibrate its magnetometer.

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I called airpath compass and ordered a new compass, about $200.  Leaked solved,  Swung compass with IA,  problem gone away.

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1 hour ago, jaylw314 said:

Using a second magnetic device (like the magnetometer in some self-correcting DG's and HSI's) while in flight is, in fact, one of the suggested techniques for swinging and compensating a compass.

https://www.faa.gov/documentlibrary/media/advisory_circular/ac_43-215.pdf

I see two caveats, though:

  • It requires an A&P from an instrument shop to ride along with you to do it
  • How do you know how accurate the other magnetic device is?

So really how accurate do you need to be when the lubber line on the compass is 5 degrees wide?

To answer your question I use my phone and my tablet to set the DG and make sure the gear and flaps are up.

I have one of these guys that one day I will haul up to the airport and draw some lines.

Brunson-Byrd-transit1.jpg

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7 hours ago, luv737s said:

I called airpath compass and ordered a new compass, about $200.  Leaked solved,  Swung compass with IA,  problem gone away.

What a sissy attitude. A true CB would buy and install two repair kits before giving up and replacing it. :D

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Does anyone actually use a compass anymore?  Years ago, my HSI gyro failed on a MVFR flight in the LA area. I had to fly from Van Nuys to Chino on the compass with 3 sm viz. surrounded by busy airspace. Not that hard, but it did make me wish fo a vertical card compass which I now have. I took the plane to a compass rose and checked both the Aspen and the compass and they were within 2-3 degrees of each other on all 12 points, but in the air I sometimes see 5-6 degrees difference between the two. IIRC Douglas apparently thought so little of the requirement for a magnetic compass on the DC-9  that they installed it behind the right pilot seat and it could only be viewed through a mirror on the glareshield.

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I got a G5 with a magnetometer. the compass is just there to block my view. 

Replace it with a panel mount:
b135285fd1a614e8b6a8935a82d298a9.jpg


Sent from my iPad using Tapatalk
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14 hours ago, PT20J said:

Does anyone actually use a compass anymore?  Skip

I think ‘no’ might be close, but may be too optimistic...

My HSI went on hiatus... VFR flight... pick something off in the distance using the compass fly to it... repeat...

Plan B: I had the iPad as my chart... it lost contact with the portable ADSB/gps source... bummer. (Antenna decided to get disconnected) CB edition of the IPad didn’t come with the internal gps this time... :)

Plan C: Trusty pocket I-device #2... has GPS location, but the flight plan was in there from months ago...

PlanD: the i-devices have limited power supply when their internal GPS is operating... wiring portable electronics while flying with inop equipment is sub-optimal... having them connected to power is a good idea...

Getting the HSI operational immediately became my next high priority...

So...

If Flying in IMC, on a long flight, be ready to drop back to the compass... because it might just happen one day...

And make sure all your devices have today’s flight plan on them... :)

PP thoughts only, not a CFI or instrument tech...

Best regards,

-a-

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