Compass Malfunction

[rcpistonhead 47]

Hello,

 

On my last few flights I have noticed that the compass appears to be "off" or "out of alignment". In other words, the compass sits sideways / off camber for the entire duration of the flight as if it has failed, is off, or has malfunctioned. The weird thing is that the compass still rotates and accurately indicates the current heading while in flight. I have checked in the FMC for any service failures and there are none active in any system.

 

Any thoughts or ideas? Any help will be greatly appreciated!

 

Thank you,

[WestAir 2,522]

Pics or it didn't happen.

 

 

[scandinavian13 5,192]

Any thoughts or ideas? Any help will be greatly appreciated!

 

Flight One Registry Repair Tool

 

It can be found here.

[rcpistonhead 47]

Pics or it didn't happen.

Wow.

 

Flight One Registry Repair Tool

 

It can be found here.

 

Thank you very much Kyle! I will give this a try tonight when I get home.

[scandinavian13 5,192]

Wow.

 

Haha - it's actually a valid request. As you said "compass" and not Nav Display, you could have been referring to the old whiskey compass up above the MCP. Those actually have errors inherent in their operation because of all of the electronics and general motion of the aircraft. A screenshot could've cleared that up quickly (and in general, they always help in some way). It's an internet thing to use the phrase "pics or it didn't happen" to request any sort of picture.

 

Thank you very much Kyle! I will give this a try tonight when I get home.

 

You're welcome. That should have you set. Make sure to run it as an admin and all that.

[rcpistonhead 47]

Haha - it's actually a valid request. As you said "compass" and not Nav Display, you could have been referring to the old whiskey compass up above the MCP. Those actually have errors inherent in their operation because of all of the electronics and general motion of the aircraft. A screenshot could've cleared that up quickly (and in general, they always help in some way). It's an internet thing to use the phrase "pics or it didn't happen" to request any sort of picture.

 

Lol sorry for that...as I have mentioned before I am much more of an aviator than I am a computer wiz. I am very uneducated on forum terms

 

I actually am referring to the whiskey compass above the MCP. The Nav display is fine.

 

It is the mechanical compass in the top middle of the windscreen that has malfunctioned.

 

Thank you!

[Flamin_Squirrel 71]

You're not seeing the affects of magnetic dip are you? If so it's not an error.

 

[rcpistonhead 47]

You're not seeing the affects of magnetic dip are you? If so it's not an error

Hi Jordan. I don't think so but I suppose that could be a possibility?

 

I see now why a picture will be very helpful. I will get a screenshot when I get home and post it for all to see.

 

Thank you,

[WestAir 2,522]

Wow.

 

Kyle pretty much summed that one up. I wasn't intending to be rude at all. I was running under the impression that the other forum guru's would be able to help you better if they had a screenshot showing the error/glitch in progress. "Pics or it didn't happen" is just a common internet meme - sort of tongue-in-cheek.

 

Once we have a screenshot, if the FLIGHT1 Fix doesn't help you, we should be able to work from there. ^_^

[scandinavian13 5,192]

Lol sorry for that...as I have mentioned before I am much more of an aviator

 

One of the fundamental lessons you learn in basic aviator training is minor compass errors, as they affect you wherever you are. The major one you learn about in Private Pilot training is that of magnetic variation, or magnetic declination. This is the result of the magnetic north pole being different from the actual rotational pole. The effects of this vary by area and can be seen on your nav charts.

You can also see it here: http://www.airnav.com/airport/KIAD (in the location information).

Since IAD is listed as 10W, if my compass points at 360, I'm really flying 010.

 

Additionally, as Jordan pointed out, there is another error called magnetic dip, or magnetic inclination. This error shows up as the compass wanting to point along the lines of magnetic force (as in the picture). In order to counter this tendency, compasses are normally weighted. Because of this, accelerative forces will make the compass lag or lead, and turns towards north or south headings are made difficult (again, the compass lags or leads).

 

 

 

So, the compass isn't malfunctioning, per se. It's behaving like the real one does. After all, if the compass were accurate, what would be the point of having a directional gyro that you have to reset every so often in smaller aircraft?

[rcpistonhead 47]

One of the fundamental lessons you learn in basic aviator training is minor compass errors

 

Hi Kyle,

I completely understand the fundamentals of magnetic compass operation. I am positive this is a computer glitch or software hiccup. I did a couple flights last night and everything (of course) was operating normally. Have you ever had a fever and when you get to the doctors your temp is 98.6? Or had an intermittent mechanical problem with your vehicle that happens every time you drive it but when the mechanic gets in nothing happens? Well that is exactly what I am experiencing with this odd problem. As soon as I get a screen shot captured I will post it up here. I really appreciate everybody's input. Thank you!