apodino
Topic Author
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PHL Rnav Departures

Mon Jul 25, 2011 5:46 pm

A couple of years ago, PHL started publishing RNAV departure procedures for most of the departure fixes. I believe these were used briefly but standard still seems to be the PHL 8 with the RNAV's not even being used at all.

I read in another forum that these procedures were suspended indefinitely due to a possible conflict with the HOLEY intersection that ATC frequently uses to hold LGA arrivals.

My question is, does anyone else have any more information on this, and when we might see these procedures used again? You have to think that USAirways is screaming to get these procedures reinstated as they do save fuel, plus with the airplanes flying on such a tight route, in thoery this should give ATC more airspace to play with in an area where airspace is at a premium.
 
wagz
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RE: PHL Rnav Departures

Mon Jul 25, 2011 9:13 pm

Long story short is that US' aircraft had issues with them, A321s in particular. They couldn't actually make the climb profile on them, and the procedures actually were more flying miles than we would vector other aircraft normally. The old 733s and at the time NW/DL DC9s also couldn't use the RNAV procedures which created issues as well. The design with separate procedures for 9 or 27 operation was very troublesome as well.

In the meantime there is an airspace reconfiguration occurring next year so there will be all new RNAV departures at that time.
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IAHFLYR
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RE: PHL Rnav Departures

Mon Jul 25, 2011 9:40 pm

I love the RNAV concept, but as wagz mentions above there are a number of reasons for the old vector out the departure route initially at least still the most efficient for all. And then you get into the different boxes and how they act on a procedure and lateral route containment. Putting vertical guidance on a SID gets tricky as well to make certain all the operators can make the constraints every time.

IMHO the concept is fabulous but yet to mature fully with numerous criteria changes, confusion on different flows at the airport, the coding of the procedure and making sure all the boxes and database providers get done correctly.....and then you have the "what do we do with conventional aircraft" and those who don't file the correct ICAO format flight plan leaving off the ICAO airport ID's to not filling in box 18 for the RNAV capability which will put a high end RNAV/RNP airplane on a conventional route every time.

Fix some of these issues and it will work very well.
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apodino
Topic Author
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RE: PHL Rnav Departures

Tue Jul 26, 2011 3:20 pm

Quoting wagz (Reply 1):
Long story short is that US' aircraft had issues with them, A321s in particular. They couldn't actually make the climb profile on them, and the procedures actually were more flying miles than we would vector other aircraft normally. The old 733s and at the time NW/DL DC9s also couldn't use the RNAV procedures which created issues as well. The design with separate procedures for 9 or 27 operation was very troublesome as well.

I noticed the separate procedures for each runway and did find that a bit odd. If climb issues were a problem, I imagine the CRJ's would be part of that too since they don't climb quickly either. But you make an interesting point. My understanding of PHL is if you are departing off of 27L, and the planes first fix would either be PTW or DITCH, don't you guys keep them on Departure heading until the arrivals are clear (Downwind on either side for 27R), and then steer him toward the departure fix?

That is a great explanation though. Thanks. Do you guys have similar issues with the RNAV arrivals since it seems like when I am in the jumpseat going into PHL we get vectored more than we are kept on the arrival. (Of course most of those times we land 35, so we would have to be vectored for that  )

Quoting wagz (Reply 1):
In the meantime there is an airspace reconfiguration occurring next year so there will be all new RNAV departures at that time.

Awesome. Can you shed some light on more of the changes that this reconfig will bring us?
 
wagz
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RE: PHL Rnav Departures

Wed Jul 27, 2011 3:35 pm

The headings on departure are based on your departure fix. In VFR arrivals on the parallel are irrelevant since we can see both aircraft and provide visual separation (that's a great tower rule). If we're IFR than there are rules regarding waiting til an arrival within 3 miles is in sight.

The RNAV arrivals are great when traffic is light, although some controllers just like to use vectors. Since the arrival sectors have to feed traffic to the downwind with certain spacing depending on conditions, merging traffic where the two RNAV arrivals merge requires vectoring to achieve the desired spacing. Personally I like to have traffic resume the arrival so I don't have to worry about turning them downwind.
I think Big Foot is blurry, Its not the photographers fault. Theres a large out of focus monster roaming the countryside
 
wagz
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RE: PHL Rnav Departures

Wed Jul 27, 2011 7:20 pm

Sorry, I didn't see the last part there and can't edit my post anymore. Basically we are being mandated to use more headings for departures off the airport for noise mitigation. In order to add headings further south, our south departure sector needs more airspace, which in turn pushes the south arrival airspace further south. So the whole southern half is moving 8 or so miles south from what I understand where we're taking some airspace from DOV, ACY and ZDC. All the south RNAV arrivals are being re-drawn and the RNAV departures are being re-done to use the extra headings and whatnot. Supposedly there won't be separate procedures for 9 and 27 operation this time.

Also I may have misunderstood your question earlier about the departures and headings. When a plane is turned to PTW is dependent on other traffic and its climb performance. The 9000' restriction on the GRDEN1 RNAV is to top North Arrival's airspace where BUNTS arrivals show up at 8000'. A321s in the hot summer months are notorious for their terrible performance (hence their problem with the RNAV SIDs - US actually didn't permit them to accept it). DITCH departures are a similar situation, LH's A343 every afternoon being a highlight. Everyone makes fun of A340 climb performance on this site, and its absolutely true despite what some fanboys will argue otherwise.
I think Big Foot is blurry, Its not the photographers fault. Theres a large out of focus monster roaming the countryside

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