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Source: adsbexchange.com

Today I learned that at KPHL (Philadelphia) simultaneous converging approaches are used. (Note that AAL is faster, which narrowed down the time gap by the time it landed.)

Those planes are approaching to runways 35 and 27R.

But, those two runways do not have "converging" approach plates (red paths below). The published ones are for 09R and 17 – ILS V RWY 09R (CONVERGING) and ILS V RWY 17 (CONVERGING) – with missed approach paths that diverge like so (blue paths):

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Source: skyvector.com; modified

By checking JO 7210.3BB - Facility Operation and Administration:

SIMULTANEOUS CONVERGING INSTRUMENT APPROACHES

(...)

The requirements for conducting SCIA operations to converging runways are:

(...)

SIAP specifically titled "Converging" and is published in parenthesis after the title of the procedure, for example, ILS V Rwy 17 (Converging).

With those charts not available, how would the pilots anticipate and plan where to go? Are they available but not public, or are the pilots notified by radio on what to expect? How does it work?

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The reason you don't see similar charts for the north+west operation (i.e. 35 + 27's) as for those that you pointed out for the south+east (i.e. 17 + 09's) operation has to do with the way the runways are set up, and what ATC has to do to clear aircraft for the approaches in the first place.

In the case of the south+east approaches -- i.e. landing to the south on 17 + to the east on 09R -- the runways shown never intersect, so aircraft can be cleared for the respective ILS approaches without regard for the timing involved.... most of the time, they'll each land, roll out normally, and exit the runway, and they never get anywhere near each other -- even if one or both roll out to the end of their respective runways.

In the case that the weather suddenly goes down & they have to go missed, that's when a deconfliction has to happen, and it's handled by creating the missed approach paths to turn as you showed so that separation is maintained.

So far, so good, and you got all of that already, I suspect.

What differs in the case of the north+west operation that you asked about & illustrated in red is that the paths of the two aircraft absolutely will cross, every single time, and probably at very similar altitudes when landing on 35 + 27L/R. So ATC has to do a lot more when they clear aircraft for these approaches: they compute (with computer assistance) a separation IN TIME at the point when they will each reach the crossing of the runways. (And, if the speeds change enough that the separation looks like it won't be maintained, they have to send one or the other around... not common; the controllers there can build in plenty of buffer to avoid that scenario.)

Thus, it doesn't matter if the weather goes down & the aircraft have to go missed... they will still reach that crossing point separated in time. So they can both go missed straight out.

On the south+east scenario, they don't NEED the "separation in time" constraint (which gets applied to EVERY pair of approaches landing north+west), so they just get a "separation in space" via missed approach routing to keep planes apart in the case of simultaneous missed approaches.

And, to consider the follow-on question, "what about a north+east or south+west scenario"... the south+west scenario (17 + 27's) would probably require separation in time just like the north + west scenario would -- the runways cross (and 17 is probably too short to publish LAHSO), so the timing has to keep the planes apart on roll-out. Which would also keep them apart in the event of go-arounds. And the north+east option probably isn't used, because if the long runways (i.e. 09L/R) are departing east, aircraft landing to the north (on 35) shut down departures from both the 9's, in a way that doesn't happen when departing to the west. (West departures don't cross the 35/17 centerline the way that east departures do.) So in lieu of publishing charts to cover that scenario, ATC simply doesn't use simultaneous converging approaches in that configuration.

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  • $\begingroup$ Thanks. Almost there :) My head spun in the last two paragraphs, north+west confuses me every time and I go to the start to check if you meant coming from north or going to north, can you edit it in runway numbers style? I don't wanna mess it up $\endgroup$ – ymb1 Apr 14 '20 at 20:51
  • $\begingroup$ A "north operation" or "north flow" means aircraft moving north (for takeoff + landing), so runway 35. I'll edit that in, but in places like DEN or LAX where you can have multiple parallel runways, "north flow" or "west flow" is easier than spelling out "35L/R + 36 L/R" or "24L/R + 25L/R" every time. $\endgroup$ – Ralph J Apr 14 '20 at 20:55
  • $\begingroup$ Got it, no need for the edit, I'll stick flow when reading it :) thanks $\endgroup$ – ymb1 Apr 14 '20 at 20:58
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    $\begingroup$ Too late -- read your comment after saving the edits. It's all good. $\endgroup$ – Ralph J Apr 14 '20 at 20:59
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First lets start with what is a Simultaneous Converging Instrument Approaches (SCIA), 7120.3BB section 10-3-15 Go-Around/Missed Approach states:

Facility air traffic managers may develop procedural mitigations for non-intersecting converging runways when a 1 NM extension of the runway centerline crosses the centerline of the other runway or the 1 NM extensions of a runway cross the extension of another runway.

As Runway 35 and Runway 27R intersect they are not SCIA. Additionally Runway 09R and 17 do not intersect and the extension of the Runway 17 centerline would cross 09R centre line prior to it passing 1NM.

This is the reason why no Converging plate for 35 and 27R

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  • $\begingroup$ Thanks again for the info. There is a slight issue, the quote here is from a different chapter. From the one I linked, being intersecting still allows SCIA, but with higher weather minima, I now think the keyword is "simultaneous". $\endgroup$ – ymb1 Apr 14 '20 at 22:53
  • $\begingroup$ Yeah it is a different chapter. The information I provided is right at the bottom of the page. $\endgroup$ – Bullfrog Apr 14 '20 at 22:55

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