USMCFLYR

80Kts -

It seems you are stating that they were ON-PATH of the PAPI yet still impacted terrain. Is this your supposition?

USMCFLYR

Nothing personal here. This is TERPS and charting conventions - not flight inspecting. I try to talk about what I know from the job, provide some information that might not be readily available to the masses and usually learn a few things in the process. Now if you are talking about a few pages back where I protested the idiotic statement that nobody in the FAA cared about safety - then yes - that was personal. You hear it all the time in the airline - we hate management but what a great group of pilots I work with. Well.....talk what you will about upper FAA management (especially the political side of any gov't organization) but to equate that to the 'pilot group' (workers in this case) is uncalled for and simply wrong.

Right. Now back to TERPS.

On-path VGSI will keep you clear of obstacles all the way to the threshold - which is exactly one reason why an approach like this might be NA when VGSI is inop or during a circling approach where you can't keep sight of the VGSI throughout the approach.
Here is a little test though. How many know the 'service volume of a VGSI' without looking it up (lateral, vertical, and distance from the source)? I certainly didn't, though I admit to NOT flying a lot of VGSIs except for a meatball for 20! That obstacle evaluation is for the service volume of the system - NOT necessarily out the way out to the limits of the system (for instance at night).

I'm not sure where it is written in the TERPS manual - but there is also an assumption that from the DA(H) or MDA/VDP - that you will visually sight all obstacles if there is a penetration of the OCS during the VISUAL portion of the final approach segment.

EXCELLENT POINT! There is much discussion about the *safety* of providing this. One thing that I know is that the USER asked for this because they want something to fly - especially with all of the hype on stabilized approaches. I have been dropping many cautions in this thread and others about the details that many do not understand about ADVISORY glidepaths. My hope is that is has opened someone's eyes. It isn't dangerous if you understand the limitations and they are spelled out fairly clearly as more and more of the notes have been put into the approach plates.

Those ADVISORY angels and the VGSI angels very well may NOT be coincident and as they are not REAL angles - are not TERPS'ed or have the same note about coincidence that precision approaches have in the plates.

FlighTimeBarbie

Recently, while reviewing VDP's in preparation for my upcoming schoolhouse visit, I came across the (linked) eye-opening article which has caused me to begin reassessing some comfort zones and the assumptions upon which they were based. Perhaps unrelated, but this tragic accident in KBHM may well further that reassessment.

?Fly The Plate and You Won?t Get Hurt? | Aviation International News


“Fly The Plate and You Won’t Get Hurt”
Aviation-International-News/August-2012/J. Huddleston



Excerpt:
Documents provided by Saratoga County showed that every runway and every approach had trees penetrating the Obstacle Clear Line, and documents proved that these discrepancies were known about as far back as 1999. One document dated September 1999 stated, “Obstruction analysis study of Runway 5 identified ‘numerous penetrations’ to the approach surfaces, both on and off airport, and determined that ‘to maintain a clear 20:1 approach surface, the Runway 5 threshold would have to be displaced 946.5 feet’ [almost twice the 500 feet calculated initially].” Numerous documents and emails from the Saratoga County Department of Public Works and New York’s DOT were written between September 1999 and (more than two months after our incident) October 2008 addressing the issues, but no action was taken.

Two years earlier, in April 2006, one email stated: “FAA flyover inspection shutdown VASI on Runway 05. Flight Inspection Report states, ‘Obstacle clearance unsatisfactory due to trees near threshold.’” While no one took any action, these trees were growing at a rate of three to five feet per year. From September 1999, when obstacle issues were first identified, until the night of our incident on July 13, 2008, not a single tree on the approach to Runway 5 was topped or removed. An August 2008 email from NY DOT about the results of its inspection stated: “RWY 05-Trees +89’, 1035’ from RWY end, 9:1 slope.”

KC10 FATboy

Scary. Good post. Eye-opening.

rickair7777

I fly into several places where the VGSI has published limitations. In some cases you have to be very close in to get terrain clearance.

Just because you can see the VGSI doesn't mean you'll have terrain clearance if you're way off centerline.

KC10 FATboy

I think the VGSI only provides obstacle protection within 10 degrees of runway centerline and within 4 NM.

Signal Delta

Yes, the notes at the top state when VGSI inop procedure not authorized at night, but look closer and tell us what you see in the lower right corner under "Night" for the KBHM LOC Rwy 18 on the UPS custom Jepp 11-2 page. What is the charted MDA and the minimum required vis to shoot this instrument approach at night?

aflouisville

Yes, you are right. The Jepp LOC 18 Plate says "Night NA". But the note at the top referencing the VGSI takes precedence. FDC notams were published and Jepp just had not removed the "Night NA". RWY 18 LOC NOS charts do not have the restriction. They would take precedence because they are what Jepps are based on.

Swedish Blender

There is an amendment that allows it at night. Jepp hasn't update their charts.

UnusualAttitude

Wow. Scary stuff.