PAPI usage
How about 2.85° vs 3°, or something meaningful in the terms of this discussion?
Not ILS, but RNP, quibble if you like.
http://155.178.201.160/d-tpp/1312/00546RR3R.PDF
RUNWAY 3R
Latitude: 34-38.787753N
Longitude: 112-25.680282W
Elevation: 5027.8 ft.
Gradient: 1.0% UP
Traffic pattern: right
Runway heading: 028 magnetic, 041 true
Displaced threshold: 379 ft.
Declared distances: TORA:7616 TODA:7616 ASDA:7616 LDA:7237
Markings: nonprecision, in good condition
Visual slope indicator: 4-light PAPI on left (4.00 degrees glide path)
Bloggs, you're like my wife, "You may be right, but that's not what I meant. Show me more."
I agree that one is not co-incident, but the discussion's about ILS vs PAPI, OK465.
Still, on that example, I would have thought visual/PAPI slopes would be more accurate than RNP VNAV, so why the steep PAPI, I wonder? Perhaps the 5268 obstacle affects the PAPI tolerances but not the RNP...
Good luck trying to follow, in any meaningful aeroplane, a 4° PAPI at 5000ft AMSL!
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I flew an MD80 FAA technical engineer standing during a no flare landing to a Calif. hospital airport when he broke his ankle with the impact. The FAA pilot did the landing on a max GW landing test and exceded the descent rate slightly at Palmdale and we flew him from Fox field to SNA. Unfortunately he left his shoe in the Citation Jet so had to deliver it to him the next day. I think that landing broke the fuselage behind the wing and almost fell off back in the 70's.
Here's the video clip:
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Okay, given that at SFO the ILS GS was out of service, and the plane was far below the PAPI, you're going to have to explain to me how the SFO crash has anything to do with non-coincident gs and PAPI
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The centre of that PAPI beam (ie half way between angle C and angle B) is not parallel with centre of the ILS GS. Angle C is parallel with the GS; that diagram indicates that that PAPI is set at 2.75°. They are neither coincident in angle or GPI.
This is from the design manual, so as you can see, there are many factors involved.
EDIT: A squared...I never said it had anything to with the incident, I said it brought the issue of multiple TCH and GPA's to the forefront.
Last edited by underfire; 5th Dec 2013 at 04:11.
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well yes, I suppose that in a broad sense it was a reminder that TCH ought to be a positive number. Other than that, you've still lost me.
Last edited by A Squared; 5th Dec 2013 at 05:28.
Originally Posted by underfire
You are missing the numerous factors involved in the design. There are differences in the assumed eye height vs the antennae height.
Originally Posted by OK465
How 'bout 4.00 degrees at 9000 feet in the biz-jets?
It's a no puss game over here.
It's a no puss game over here.
I better quit while I'm ahead! 
Obviously no FDAP gatekeepers to contend with...
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For that matter, how about London City Airport with it's 5.5 degree ILS and PAPI? It's my understanding that there's a number of jets operating in there on schedules, as well as all the turboprops.
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Bloggs, just for you!
In order for you to see 2 reds and 2 whites on a 3° glideslope...ie to see both the Unit B and Unit C...
(this is the math from the other diagram, they illustrate the same)
Note angle M
In order for you to see 2 reds and 2 whites on a 3° glideslope...ie to see both the Unit B and Unit C...
(this is the math from the other diagram, they illustrate the same)
Note angle M
Last edited by underfire; 5th Dec 2013 at 18:43.
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Thanks for the interesting information guys …
If I may, the point I was trying to make was that airplane attitude is critically important (all the time, but particularly so just prior to landing) such that if the airplane attitude on very short final is rotated up to something like 20° of pitch, with the stick shaker barking and the throttles against the forward stops … but if the pilot stills see’s “2 whites and 2 reds” out the front window, that isn’t going to mean much other than what may be included in the accident report or chiseled on his tombstone.
Originally Posted by Underfire
In order for you to see 2 reds and 2 whites on a 3° glideslope...ie to see both the Unit B and Unit C...
Originally Posted by OK465
How about ILS 3.00 vs PAPI 3.20?
The question is, why would such as situation exist? PAPI put in before the ILS? Surely any terrain limitation would affect the ILS GS tolerances more than a visual PAPI, which can be flown super-accurately where the tolerances between each red/white are very small?
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I agree. Worrying about a fraction of a degree of difference between ILS antenna and visual vasi or papi is like admitting you are an automation or visual guidance dependent pilot. All pilots worth anything should be able to judge a 3 degree glide slope with nothing at night just by looking at the angle to the runway out the window. Yes some runways have an upslope or downslope but you already know that if you did any homework.
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bubbers44:
True to a point. But, the FAA has gotten a lot more nervous about NPAs at night recently. There are now a lot of notes like the one for KBHM Runway 18.
All pilots worth anything should be able to judge a 3 degree glide slope with nothing at night just by looking at the angle to the runway out the window. Yes some runways have an upslope or downslope but you already know that if you did any homework.
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One of our pilots took out the fence at the cliff on the north end of TGU Honduras. Probably because he didn't compensate for the upslope runway. He got low and slow. It had no GS guidance but everybody else had no problems. Keeping up basic flying skills unfortunately now days is on the back burner so more of these incidents will happen unless we go back to when we actually made pilots prove they could fly manually. Asiana crash might get the FAA's attention of poor hand flying skills. We will see.
