Partial panel with a dry compass?

Mattio

Mattio

Well-Known Member
Anyone here have experience doing compass turns with a dry compass? I was teaching my instrument student compass turns the other day and it was my first time using a dry compass for partial panel. The darn thing was so unpredictable. Sometimes on a turn to 360 we would have had to lead the turn by 30 degrees to get it right and other times 70 degrees is what would have worked.

Do you guys know any tricks for dry compasses?
 
What's a dry compass? Are you talking vertical card compass?

In any case, I don't see where compass turns are required anymore. Timed turns using the compass make a lot more sense and that's all I ever taught.
 
DE727UPS said:
What's a dry compass? Are you talking vertical card compass?

In any case, I don't see where compass turns are required anymore. Timed turns using the compass make a lot more sense and that's all I ever taught.
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He must be talking about a vertical card compass. A mini dg if you will.
 
Im so glad you brought this up...we all know about the 0, 10, 20, 30 degree trick for doing htem....so i teach this guy in his 182 and i felt like an idiot cuz the numbers didnt work...what we were able to do was do it enough times to get the right numbers (mostly)...so north and the 30 degree marks are a 20 degree error, while the 60 is like 10 degrees, and E/W still being zero (south, same deal). I do agree though that sometimes the numbers just dont work...5 degrees error is ok, but sometimes it was like 10 or so...

So a question on a question....Can you not do compass turns with a vertical card?
 
I always just take the number of degrees I want to turn and divide by 3 for time. (30 degree turn 10 seconds at standard rate). Unaccelerated flight how did I do? Make another correction if I have to

-Jason
 
ElyJs said:
I always just take the number of degrees I want to turn and divide by 3 for time. (30 degree turn 10 seconds at standard rate). Unaccelerated flight how did I do? Make another correction if I have to

-Jason
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:yeahthat:
 
The whole point of a vertical card compass is to not have the lead/lag erros of a wet compass. The problem is vertical compasses, compii, whatever...are very prone to damage. So much that if you install one with a Magnetic screwdriver the thing is screwed. If you lay a flashlight or a headset next to it...screwed. Errors as much as 40 degrees.
An A&P and I did alot of work with this because when I was a senior instructor at our flight school our piper arrow had a vertical card compass and an examiner failed a student for incorrect compass turns. Student/instructor blamed the airplane, which in turn the school blamed the owner and the owner blamed the mechanic. Turns out if you disassemble the compass the magnet is held in the gimble with a small pin that can easily get dislodged with another magnet being close. To prove it to a examiner we installed a brand new vertical card took it to the compass rose and did a swing test. Then placed a headset next to the compass for 5 mins and did the swing test again. Some headings it was correct and some had errors as much as 30 to 40 degrees.
 
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