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Hashes on a SID

kmac

FLIP Maker
pilot
Super Moderator
Contributor
TB AVN 1-2130SP...but it's an Army pub dated 2001.
View attachment 24931
Ding ding ding. The intent of having the cross-hatches is to indicate a high or low altitude procedure. But there's a caveat...

I understand high and low approaches. I don’t understand high and low SIDs.
Exactly. What is a low or high (or lo/hi) SID? If you think that a high altitude instrument approach starts in the high enroute structure, then it's plausible that a SID that ends in the low or high enroute structure is therefore a low or high altitude procedure. For foreign procedures, the cross-hatching indicates this.

However, in the US...

A high altitude approach design does not have starting altitude (or enroute structure) criteria. Rather, it has descent gradient criteria (i.e., penetration descent). NAS Corpus Christi has examples of high procedures that start in the low enroute structure. Furthermore, FAA SIDs may end in the high enroute structure but they don't have cross-hatches. So what's the point? For CONUS, the half cross-hatching is to indicate that the procedure can be found in both a low altitude book and a high altitude book.

So there you have it... different answers for different parts of the world. With that said, do you find the SID cross-hatching valuable at all?
 

nittany03

FUBIJAR
pilot
None
Super Moderator
Contributor
NAS Corpus Christi has examples of high procedures that start in the low enroute structure. Furthermore, FAA SIDs may end in the high enroute structure but they don't have cross-hatches. So what's the point? For CONUS, the half cross-hatching is to indicate that the procedure can be found in both a low altitude book and a high altitude book.
This is just reinforcing my belief that anyone who designs an excessively convoluted instrument approach should be forced to fly the full procedure to minimums with compound EPs.
 

kmac

FLIP Maker
pilot
Super Moderator
Contributor
This is just reinforcing my belief that anyone who designs an excessively convoluted instrument approach should be forced to fly the full procedure to minimums with compound EPs.
Procedure designers typically have no flying experience. They mostly come from the ATC world.

Have you ever noticed that some of the notes on a procedure don’t add any operational value? Example: “DME REQUIRED” on a TACAN procedure.

Or how minimum climb gradients are given in percentages rather than feet per nautical mile?

Or that holding pattern entries are depicted on high instrument approaches but not low?

There is a lot of good intentions with the mentality “aircrews are going to need to know this.”
 

kmac

FLIP Maker
pilot
Super Moderator
Contributor
If you have any questions on any procedure, don’t hesitate to ask.
 
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