G1000 Holds
Posted by reddit231200@reddit | flying | View on Reddit | 8 comments
Just studying for my Checkride and realized I’ve never done a published hold that has set distances for the outbound legs. Every time I’ve done a hold it’s been by DME or the standard 1 minute outbound legs. The hold I’m confused about would be a GPS hold with a 4nm outbound leg. When would I turn inbound? Is the answer as simple as when the distance from the fix hits 4nm? (even though it’s slant distance and not the distance of the outbound leg)
Also would I still want to use the timer or is there no need?
ShmupsPDX@reddit
I mean you can kind of just calculate / estimate that if you really want to know. for the 4nm hold you mentioned, if you're doing 110kts it's \~4.16nm from the fix cuz the turn arc diameter is gonna be just over 1nm (1.17nm ish). If you're doing 250kts it goes up to about 4.8nm from the fix.
You're just calculating the hypotenuse (distance from the fix at the far end of your outbound leg) of a triangle with leg A = to the hold distance and leg B = diameter of the circle created by your turns (which varies based on speed).
In practice it's gonna be "basically 4nm" in a trainer or just follow the magenta line because it's calculating all of that for you and probably giving you wind corrections too. A published hold is likely going to be one that you can just load in anyways so it's just gonna tell you when to turn.
ATrainDerailReturns@reddit
Assuming your nav is properly updated you literally just follow the magenta line and turn exactly when it tells you to
It will literally count you done
Turn left to a 150 5 4 3 2 1 150
archer505@reddit
It could not be easier
blacknessofthevoid@reddit
Follow the magenta line.
phliar@reddit
BTW with GPS it's the "real" distance, not slant range; so in a hold when the GPS says 4 it's the right time.
weech@reddit
That’s not what OP meant by slant distance.
I think they mean the straight line (diagonal) distance as viewed from above vs 4nm on the outbound leg itself. Think of the former almost as the “hypotenuse”.
CluelessPilot1971@reddit
It is. Look at the AIP portion about holds, and scroll down to 1.9.2.6, specifically look at 1.5-7. It addresses this exact question.
rFlyingTower@reddit
This is a copy of the original post body for posterity:
Just studying for my Checkride and realized I’ve never done a published hold that has set distances for the outbound legs. Every time I’ve done a hold it’s been by DME or the standard 1 minute outbound legs. The hold I’m confused about would be a GPS hold with a 4nm outbound leg. When would I turn inbound? Is the answer as simple as when the distance from the fix hits 4nm? (even though it’s slant distance and not the distance of the outbound leg)
Also would I still want to use the timer or is there no need?
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