Compass Swings

[Right Seat Captain]

I'm looking for the CARs reference that actually states that the compass swing be required once a year. I know it's somewhere, but I can't find it anywhere.

[BusDriver]

Check CAR's 571. But why do you actually care? When was the last time you looked at your compass?

[Aeros]

Standard 625 APPENDIX C - Out of Phase Tasks and Equipment Maintenance Requirements

9. Non-stabilized Magnetic Direction Indicators (MDIs)

(a) Except as provided in (b) and (c), non-stabilized magnetic direction indicators shall be calibrated, and a dated correction card installed for each indicator, at at intervals not exceeding 12 months;

(b) The annual calibration requirement of (a) does not apply to an aircraft operating under an air operator certificate, or to any large or turbine-powered pressurized aircraft, where:

(i) the aircraft is equipped with two independent stabilized magnetic direction indicators in addition to the non-stabilized direct reading magnetic direction indicator; and

(ii) a procedure for monitoring and recording the performance of the magnetic direction-indicators is detailed in the flight training unit's, or in the air operator's approved maintenance control manual approved pursuant to CAR 406 and CAR 706 respectively.

(c) The calibration requirement of (a)(i) can be postponed, for the purpose of flights commencing or terminating within the area of compass unreliability, as defined in the Designated Airspace Handbook (TP 1820), or any of a series of flights conducted within a period of seven consecutive days, where the series commences within the area of compass unreliability.

[Cat Driver]

Whoooo.......this is exciting:

" 9. Non-stabilized Magnetic Direction Indicators (MDIs) "

Am I ever glad that I now know what to call a magnetic compass, I always thought that it would improve my flying if I could smoothly refeer to it with a real honest to goodness acronym that would impress the hell out of everyone....

....can't wait to go flying this afternoon so I can impress the crew by asking them to check their MDI.....

We are constantly learning new and important things in aviation, that is what I love about being part of it.

Cat

[Right Seat Captain]

Thanks for the references!

[hazatude]

Imagine opening your CrackerJack box and finding an MDI at the bottom!

[. ._]

Oh man, that is so cool. I GOTTA refer to the compass as an MDI on my Multi-IFR flight test!

Turning right, ball left, increasing, steady, MDI floating freely about its vertical axis in relation to a line tangent to the curvature of the earth, ADF tracking...

-istp

[Cat Driver]

What really gives me a hardon is describing it as a " non-stabalized magnetic direction indicator " without the non-stabalized bit it sounds lacking in punch..

I bet the guy that dreamed that one up was a full time serious wanker with the lights out not only in his cubicle but in his brain.

Cat

[mellow_pilot]

If you like that, just remember that the attitude gyro has a self-erecting mechanism...

I always loved the knob that says 'quick erect' too... my girlfriend hated flying with me because of it.

[2R]

Don't Forget VD MONA Compass errors memonic

Variation
Deviation
Magnetic Dip
Oscillation
Northerly/Southerly Turning errors
Acceleration/Deceleration errors

With sincere apologies to any Mona's Out there as all the mona's i have ever met were virtuous when i met them

[Beechball]

Can somebody clarify what Transport considers 'Stabilized'? Mine is in a Challenger and it's the gyro type , vertically , mounted compass rose type. No liquid involved.... Is this a 'Stabilized' one?

[iflyforpie]

I'm assuming you mean a dry vertical-card compass. Though it looks like a DG, there are no gyros in it.. which means it is non-stabilized.

They are also a biotch to correct.

[Big Pistons Forever]

They are also a biotch to correct.

Why ? Don't you just put the same made up numbers as last time on the little card ?

[iflyforpie]

ssssshutup!

[DonutHole]

Compass swings are a pain, but the mdi is your last resort and it doesn't need batteries. I do it right every time, not something you want very far off... The whole better to have and not need principle.