Do all approaches get re-evaluated during a site survey?

Trogdor

Trogdor

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Trogdor
For any of the TERPS folks out there:

What is the process for a site survey? Do all approaches need to be reevaluted? What about obstacles?

I ask because my home airport (N51) for instance had 04's threshold modified. As a result, a Safety NOTAM was issued to restrict straight-in minimums on the LNAV. What we don't understand is that after a new site survey happened and they updated the runway slope, the restriction wasn't lifted. When we inquired on why we got:

"THE AIRPORT HAS DISPLACED RWY 4 THLD WITHOUT PRIOR NOTIFICATION TO THE FAA/EFPT/ADO FOR PROCEDURE RE-DESIGN/DEVELOPMENT...UNTIL FURTHER DOCUMENTATION AND EVALUATION CAN BE OBTAINED AND CONDUCTED THE RESTRICTIONS WILL REMAIN IN PLACE. THIS WAS AN EFPT REQUEST FOR SAFETY NOTAMS."

But if they did a site survey, shouldn't all published procedures be also re-evaluted? Or is that not required? Anyone know?
 
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I have no specific knowledge about this case other than what you've posted. I do see that Amdt 1 of this procedure was published on 11/30, and the existing NOTAM was sent on 11/30 as well.

From the FAA's response, it sounds like the threshold was changed without prior notification to the FAA. In other words, they didn't know about it. Because the data (like runway coordinates, etc.) were now unknown, the procedure was NOTAMed NA for the straight-in portion. A new survey would contain all the new data, and once the survey is complete, the procedure can be modified as appropriate. Until it is, however, the NOTAM will remain in effect. Redesigning a procedure for new data can take up to a couple of years as it is fit into the existing production flow.

Ideally, any runway construction/modification is coordinated well in advance with the FAA procedures folks so the new procedure is ready to be published when the construction is complete.
 
So basically even though a site survey had been completed, the new data still has to trickle through the TERPS process before the NOTAM can be lifted. And that can take a couple of years? Correct?
 
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TERPS

(or did they change it when I wasn't looking?)
 
Trogdor said:
So basically even though a site survey had been completed, the new data still has to trickle through the TURPS process before the NOTAM can be lifted. And that can take a couple of years? Correct?
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Well, again with the caveat that I don't know anything about the particulars of N51, just going by what was posted...

The NOTAM cannot be lifted until the procedure is redesigned with the new data (runway coordinates, etc.) - because the existing procedure is not valid, after all the threshold moved. So the MAP needs to move. Maybe this changed the final approach course a little. Maybe with the MAP moved the FAF has to move a similar amount. That could bring in a new obstacle, raising minimums - or eliminate an obstacle, lowering minimums. Etc. This work has to be fit into the production schedule, and since an amendment like this would have to be flight inspected, that needs to worked into the flying schedule as well. Of course, there isn't a dedicated N51 TERPS guy just waiting around to do work on N51. So it needs to be added to the production schedule when there is room for it. And there is always a lot of work going on, the volume of changes each publication cycle is surprising to most. And, of course, prioritization of work may be a factor.

There are actually quite a few moving parts with any survey data update/procedure amendment, all with their associated timelines. A new procedure has to be developed, quality checked, coordinated, sent out for public comment, flight inspected, published, disseminated via various databases, etc. The process can be a minimum of maybe 6 months or as long as years and years. Which is why a well-coordinated effort before such changes are made to the runway and/or facilities helps things go much smoother.

From the user/airport standpoint, the best way to speed the process along is for the airport manager to get involved.

Bob Noel said:
TERPS

(or did they change it when I wasn't looking?)
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It's TERPS. I figured it was just a typo.
 
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It was. On phone. EDIT: On computer, corrected.
 
What are the steps generally speaking of a site survey? Is there a document or reference material to read about the subject?

I've always thought a good book about TERPs is sorely lacking in the industry.
 
Trogdor said:
What are the steps generally speaking of a site survey? Is there a document or reference material to read about the subject?

I've always thought a good book about TERPs is sorely lacking in the industry.
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Airport survey guidance is in AC 150/5300-18B. It's an exciting read.


I have not heard of a "pilot-friendly" book about TERPS. I wonder how possible that would even be. I do know the various online training blogs and such have occasional articles about TERPS-related topics (like BruceAir and boldmethod). Of course, there's always the FAAO 8260.3E itself, which is a real page-turner, although more than a little opaque without someone guiding you through it:


And the several other auxiliary TERPS-related orders like the 8260.58C for RNAV, the 8260.46J for departure procedures, the 8260.19I for documentation, etc.
 
Yeah, 8260 is a tough one without any help. I'd love to learn and write about it to be honest.
 
RussR said:
Airport survey guidance is in AC 150/5300-18B. It's an exciting read.


I have not heard of a "pilot-friendly" book about TERPS. I wonder how possible that would even be. I do know the various online training blogs and such have occasional articles about TERPS-related topics (like BruceAir and boldmethod). Of course, there's always the FAAO 8260.3E itself, which is a real page-turner, although more than a little opaque without someone guiding you through it:


And the several other auxiliary TERPS-related orders like the 8260.58C for RNAV, the 8260.46J for departure procedures, the 8260.19I for documentation, etc.
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Actually, looking at the document, can you explain the survey matrix? For example, for thresholds, non-precision is not required?
 
Trogdor said:
Actually, looking at the document, can you explain the survey matrix? For example, for thresholds, non-precision is not required?
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Nope, that stuff is well outside my area of expertise. Anything I said would just be a guess.
 
Trogdor said:
What are the steps generally speaking of a site survey? Is there a document or reference material to read about the subject?

I've always thought a good book about TERPs is sorely lacking in the industry.
Click to expand...
TERPS concepts and procedure development used to be a relatively regular topic in rotation for Belvoir publications like IFR and IFR Refresher. Back when WAAS LPV was relatively new, I used to do outreach to the GA community about SBAS approach procedure design and development. I even took a few TERPS classes to familiarize myself. Killed a lot of trees with the various orders mentioned above.

The topic is a quite esoteric and appeals only to a small percentage of instrument pilots who really geek out over the details. The truth is that pilots only really need to know that instrument procedures are designed around the performance of the aircraft, the reliability and precision of the avionics providing guidance, the associated terrain and obstructions, and the quality of the data (aeronautical data and surveys) being used to design the procedure.
 
I totally agree with this assessment. But it would still be nice for more TERPS literature to come out for pilots. Where can you take TERPS classes?
 
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