resolved KSAN PAPI lights issue for 27

[Nicrative]

Hello,

The approach for runway 27 (LOC and RNAV) has 3.5 degree glidepath on them. I feel that the PAPIs are programmed to show 3 degree glide path which I think is incorrect because it would not correlate with any of the published approaches and the purpose of PAPI is to provide visual guidance for the correct glide path.

Here is an example picture where you can see 4 white PAPIs while I am perfectly on the 3.5 G/P on LOC 27 approach. (click for bigger picture)

 

Other than that, absolutely amazing job with the scenery and performance on it. Definitely one of my favourite ORBX airports now overall.

 

[FalconAF]

2 hours ago, Nicrative said:

…..and the purpose of PAPI is to provide visual guidance for the correct glide path.

 

 

If you are flying "on" an Instrument Approach, you follow the Instrument Approach glide path requirements until you transition to a Visual Approach condition.  PAPI lights are VISUAL approach aids, and will not necessarily align with the Instrument Approach vertical glide path for the aircraft location.  Almost all PAPI systems are aligned for a 3-degree VISUAL approach path, regardless of the Instrument Approach glide path associated with the runway.

 

Look at the chart for the LOC 27 approach.  Your MDA is 680 feet.  Which means you could be "in the clouds" until you were that low before you must execute a missed approach.  You would NEVER even SEE the PAPI lights in that case, and rightfully so because you do not use the PAPI lights AS PART OF the Instrument Approach procedure (at least in the way you are interpreting it).  In your picture, your aircraft is still at 740 feet...60 feet above the MDA for the Instrument Approach...and you can already see the runway.  But you still have your autopilot engaged flying the Instrument Approach for you, so you should NOT be using the PAPI lights for vertical guidance (they are for VISUAL approach guidance only).  You are now capable of transitioning to a VISUAL Approach where you could use the PAPI's for VISUAL vertical guidance the rest of the way to the runway.  Make the transition.  You have the "runway in sight" now and can terminate the Instrument Approach and legally descend below the glide path and the MDA VISUALLY if you want to NOW using the PAPI's as a VISUAL guidance tool.  Get the "red/white" aligned the way you want them VISUALLY at this point, but only AFTER you commit to terminating the INSTRUMENT Approach (ie - by disengaging your autopilot that is flying the Instrument Approach glide path to the MDA).

 

The LOC 27 Instrument Approach is not a Cat II or Cat III "hands off" approach all the way to the runway.  You must have the runway in sight long before that to transition to a visual approach, and no later than at the MDA.  Once you have the runway in sight, THEN you can use the PAPI's for glide path guidance to the runway.  Note in the link below, PAPI's are there to provide visual guidance for a NON-precision approach...even though their acronym stands for "Precision Approach Path Indicator".  You don't use them UNTIL you have gone "visual" on the approach.  The LOC 27 approach chart tells you the Instrument Approach glide path WILL be 3.5-degrees, and that is designed to "alert" you to the fact it will be steeper than normal...which should also alert you to the fact the PAPI lights won't "look right" as long as you are still on the 3.5-degree Instrument Approach glide path. (Note:  Some approach charts will actually include a statement saying the visual and Instrument glide paths are not the same, which is a reminder NOT to use any PAPI's while still on the Instrument Approach glide path).

 

https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/lsg/papi/

 

[Nicrative]

1 hour ago, FalconAF said:

Almost all PAPI systems are aligned for a 3-degree VISUAL approach path, regardless of the Instrument Approach glide path associated with the runway.

Sorry to break it with you after your long explanation on how PAPI works but that's not how PAPI works. It's almost always angled with the instrument approach to allow easy transition from instrument flying to visual flying without need to adjust any angles during the most demanding phase of the flight. I am not here to argue though. You can read all about it from https://www.faa.gov/documentLibrary/media/Order/FINAL FAA Order 6850.2B.pdf#page=39 (sections 500-503) which explains all the rules when it comes to the PAPI angle. 

Anyways, the PAPI angle for runway 27 is 3.5 degrees and that information is directly available here: https://www.airnav.com/airport/SAN under "Runway Information".

[FalconAF]

I won't argue with you either, because it won't serve any useful purpose.  But I'll quote the FAA document you linked so you might better understand what I was saying (not to mention your own "ALMOST ALWAYS angled with the instrument approach" reference):

 

1.  Para 500a:  "The system is intended primarily for use during visual flight rule (VFR) weather conditions."  As in, after you get the runway in sight during an instrument approach.  Or if you have been cleared for a Visual Approach instead of using a full ILS approach.  Could a pilot "cross-check" the PAPI red/white display against what his ILS glide slope was indicating?  If there was a discrepancy between the two, which one would you follow?

 

2.  Para 501:  "If the runway has an electronic landing system glide slope already established, the PAPI is installed as described in paragraph 502 so that the visual glide path angle will coincide with the electronic glide slope.  If there is no electronic glide slope on the runway, the PAPI glide path angle is chosen as described in paragraph 503."  A LOCALIZER ONLY approach does not have a GLIDE SLOPE.  It is not a continuous sloped ILS approach.  It has fixes with their own intermittent altitude restrictions.  You could stair-step descend between those separate fixes if you wanted to as long as you didn't descend below the NEXT fix's altitude restriction while still IMC.  You referenced the LOC 27 approach.  It is not an ILS.  It doesn't have the kind of "glide slope" you are thinking it does.

 

3.  Para 502:  "Siting PAPI on a runway with an electronic ILS glide slope."  When siting PAPI on a runway with an established electronic glide slope, the PAPI visual approach path should coincide, as much as possible, with the one produced electronically."  Again, two keys points here.  The LOC 27 approach does NOT have an "electronic glide slope" as in the way an ILS approach would.  And the "as much as possible" part, even if it DID have an ILS.

 

4.  Para 503.  "Siting PAPI on a runway without an electronic glide slope."  When an electronic glide slope is not present, determine a position and aiming for the PAPI which will produce the required threshold crossing height and clearance over obstacles in the approach area."  THAT'S what a PAPI is used for.

 

Nothing I said in my post was inaccurate.  There are MANY times a PAPI is not aligned with an "Instrument Approach" slope.  You interpreted my post the ways you wanted to.  And it's the kind of interpretations that can get pilots killed sometimes. 

 

Peace.

 

EDIT:  I'll grant you the AirNav information states the KSAN runway 27 PAPI is (should be) aligned at 3.5 degrees.  But you could still be between fixes on the LOC 27 approach using the localizer where the PAPI lights would not necessarily indicate the "correct" glide slope for the Instrument approach.  If the KSAN airport scenery has the wrong PAPI elevation slope, then yes, that may need to be corrected.  But I was responding to your other included things in your post that aren't necessarily true...as explained in the FAA document you linked to yourself.

[Nicrative]

On 8/20/2018 at 7:10 PM, FalconAF said:

Almost all PAPI systems are aligned for a 3-degree VISUAL approach path, regardless of the Instrument Approach glide path associated with the runway.

@FalconAF Note that I used words almost always.. There is a correlation between Glide path angle and PAPI angle.

https://www.faa.gov/documentLibrary/media/Order/Order_8260.3D_vs3.pdf#page=79

Anyways, the rules are pretty clear on that order that defines the difference between glide path angle and PAPIs. GPA can only be 0.20 higher than the VGSI (PAPIs include in this category) angle unless there is a special permission (2-6-2 a.). So in theory the PAPIs could be 3.30 degrees I give you that, but what is the point given that VGSI and GPA are linked as per what I just said.

Anyways, all the information is available out there if you just dig it out a little bit.  All I have done is given you FAA orders because in most cases I trust only first hand information or information that is well sourced combined with common sense. This sourcing is something I learnt when I trained for my pilot's license.

Back to the topic. ORBX can you please have a look at this. Also while you at it, could you check if the 09 PAPI is correctly angled at 3.30 degrees.

[Nick Cooper]

Hello,

 

As I have not really understood the discussion, I do not feel qualified to comment other than:

It would appear that according to the Airport Design Editor there is no glide slope on 27 and

according to ADE, the angle on 09 is 3.2.

In both cases, the ILS is reported as "Stock", I assume this to be what is built into the simulator.

 

 

[Nicrative]

1 minute ago, Nick Cooper said:

Hello,

 

As I have not really understood the discussion, I do not feel qualified to comment other than:

It would appear that according to the Airport Design Editor there is no glide slope on 27 and

according to ADE, the angle on 09 is 3.2.

In both cases, the ILS is reported as "Stock", I assume this to be what is built into the simulator.

There is no ILS approach for runway 27. But the PAPIs are angled at 3.5 degrees. I don't have any expertise on scenery design though or the tools used to design sceneries. So you believe that the PAPI information is coming directly from default simulator files which uses ILS as PAPI guidance, and if there is no ILS then it uses standard 3 degree glide on the simulator?

There must be a way to change the PAPI angle even if there is no ILS somewhere if it's possible to create all these extremely nice sceneries.

[Nick Cooper]

Hello,

as stated, I have no expertise in ILS, either in the real world or in the simulator.

You are probably correct in your assumption about the PAPI lights but certainly,

the simulator ILS is as set by Microsoft in FSX.

Again, looking at ADE, the runway is set to have PAPI lights apparently both with a pitch

set  at three degrees which doesn't seem to agree with what you wrote.

 

 

[Nicrative]

Yeah, the direct information of the angles is confirmed here: https://www.airnav.com/airport/SAN with 09 being 3.30 degrees and 27 being 3.50 degrees. So hopefully this can be fixed in one of the future updates as I hope you are still planning to release some small fixes over time

[Nick Cooper]

 

I can change the angles of the PAPI lights in ADE and you can try

the modifications if you wish.

[Nicrative]

5 minutes ago, Nick Cooper said:

 

I can change the angles of the PAPI lights in ADE and you can try

the modifications if you wish.

Sure thing Nick! Happy to help if I can.

[Nick Cooper]

Please bear in mind that I have done nothing except amend

the angle of the PAPI setting to match what you wrote.

Before you use the attached file, set the KSAN control panel to 

Without Static Aircraft.

Then rename ORBX\FTX_NA\FTX_AA_KSAN\Scenery\KSAN_V2_ADEX_ADE.bgl

to KSAN_V2_ADEX_ADE.bgl.disabled and paste the attached file into its place.

To be honest, I have no idea if this will work or not.

 

KSAN_V2_ADEX_ADE.bgl

[Nicrative]

@Nick Cooper

The PAPI angle is now correct with your file.

[Nick Cooper]

Do you want the file that gives you statics as well?

[Nicrative]

That would be preferred. Love to have some life at the airport

[Nick Cooper]

This time, please set the control panel to With Static Aircraft.

Rename KSAN_V2_STATIC_AIRCRAFTS_ADEX_ADE.BGL to

KSAN_V2_STATIC_AIRCRAFTS_ADEX_ADE.BGL.disabled and

copy the attached file into its place.

KSAN_V2_STATIC_AIRCRAFTS_ADEX_ADE.bgl

[Nicrative]

Thanks a lot for the help Nick!

[wulfbindewald]

To Nick,

I tried the ADE Static aircraft bgl file in FSX and got an immediate CTD. So I went back to the original one.

Furthermore I was surprised, that both modified bgl files are about 25% bigger than the originals.

I guess the modified files work in P3D V4 exclusivly.

[Nick Cooper]

Yes, the files are for P3D v4 and intended to address the particular problem reported in this topic.