HI/DG - Reg On Precession?
04-02-2011 | 05:47 PM
#1
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A Second Past V1
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HI/DG - Reg On Precession?
OK, we have all had the rule of precession regarding the directional gyro/heading indicator/whatever you want to call it beat into our skulls:
3 degrees in 15 minutes. Outside of that it is not reliable.
My question: is this merely a suggestion or a black and white IFR regulation?
Everything I have scoured makes note of this rule (of thumb) but no reference to an actual rule. Anyone have the ultimate answer?
(side note, I was going to say 'f it,' but decided to APF it instead...)
3 degrees in 15 minutes. Outside of that it is not reliable.
My question: is this merely a suggestion or a black and white IFR regulation?
Everything I have scoured makes note of this rule (of thumb) but no reference to an actual rule. Anyone have the ultimate answer?
(side note, I was going to say 'f it,' but decided to APF it instead...)
04-02-2011 | 07:48 PM
#2
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OK, we have all had the rule of precession regarding the directional gyro/heading indicator/whatever you want to call it beat into our skulls:
3 degrees in 15 minutes. Outside of that it is not reliable.
My question: is this merely a suggestion or a black and white IFR regulation?
Everything I have scoured makes note of this rule (of thumb) but no reference to an actual rule. Anyone have the ultimate answer?
(side note, I was going to say 'f it,' but decided to APF it instead...)
3 degrees in 15 minutes. Outside of that it is not reliable.
My question: is this merely a suggestion or a black and white IFR regulation?
Everything I have scoured makes note of this rule (of thumb) but no reference to an actual rule. Anyone have the ultimate answer?
(side note, I was going to say 'f it,' but decided to APF it instead...)
04-03-2011 | 04:56 AM
#3
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I was actually thinking this the other day while on a long IFR cross country. It seemed like we had to reset the thing every few minutes, and I can't even count how many times ATC asked if we were on the correct heading. It really made for a long trip. I haven't found any actual FAR on determining if it needs to be fixed or not though.
04-03-2011 | 07:27 AM
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I was actually thinking this the other day while on a long IFR cross country. It seemed like we had to reset the thing every few minutes, and I can't even count how many times ATC asked if we were on the correct heading. It really made for a long trip. I haven't found any actual FAR on determining if it needs to be fixed or not though.
04-04-2011 | 09:40 PM
#5
New Hire
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From: md-11 c
04-04-2011 | 10:37 PM
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Gets Weekends Off
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From: C402, on the side with the switches!
04-08-2011 | 10:11 AM
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As other said, it's not a reg. I'm not even sure I'd necessarily classify it as a recommendation.
What I think of it as is information: a normally operating DG will precess about 3 degrees over 15 minutes. If it precesses substantially more than that, the pilot is increasing the risk of having it go inop in flight.
The regulatory issue, I guess, comes into play if you take off into the soup with a DG that precesses a lot and end up having a problem as a result.
What I think of it as is information: a normally operating DG will precess about 3 degrees over 15 minutes. If it precesses substantially more than that, the pilot is increasing the risk of having it go inop in flight.
The regulatory issue, I guess, comes into play if you take off into the soup with a DG that precesses a lot and end up having a problem as a result.
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