February 3, 2007

Got a map? That may not help....

This post could technically be labeled "Little Airports Part 3", but I chose a unique name instead, as this will act as a transition to another topic.

In my area at Boston Center, we have a joke about the 40N airport. The joke is on Area B (the controllers to our northeast) not knowing what to do with such aircraft. The 40N airport is the Chester County airport in PA, about 30 miles west of Philadelphia (and yes, its completely ironic that the Outer Marker to the ILS Runway 29 approach is named MOSES). Very often, a corporate pilot will be flying along fat, dumb and sufficiently pleased with the ride at FL360 over Albany. Area B flashes the aircraft to us, and we make a phone call to them informing them that they should "treat it like a Philly". They then scramble to dive bomb the aircraft down to FL260 so that we can deliver the aircraft to ZNY over DNY at FL190, just like a Philly. The pilot checks in with us a little perturbed at the fact that we made him spill his coffee just so he could descend sooner than desired.

While 40N is near PHL, why do we have to treat arrivals exactly like a PHL lander? The answer is simple: 40N is within the boundaries of the PHL Approach Control. Every other airport within airspace owned by PHL Approach must be treated in the exact same fashion. While this may seem unfair, and not always the most efficient, it simplifies one aspect of a very complicated system. The only exception to this rule is when the airport inside the approach control is busy enough to justify its own routing for the sake of keeping those aircraft safely away from the aircraft operating at the main airport. Basically, if there are enough planes to get in the way of the main flow, another secondary flow is created. Often, this secondary flow is used for all other airports OTHER THAN the main airport.

Examples: TEB/MMU/CDW are busy enough to require they're own flow apart from EWR. BOS has its own flows into A90 TRACON, and the Satellite airports have another flow which is handed off to a different A90 controller than the BOS arrivals.

But lets get back to the smaller airports. How can you tell which "category" an airport falls into?

Lets take a look at 3 airports in Boston Center, all within 20 miles of each other, but all three are treated completely different because of the airspace structure.

KORE - Orange, MA
KFIT - Fitchburg, MA
KORH - Worcester, MA (pronounced WHUST-uh?)

ORE is a small airport located in an area where ZBW-GDM Sector owns to the surface. This Sector sequences BOS area arrivals, and serves as an approach control for EEN, ORE, and GDM airports. FIT is an airport just inside the A90 TRACON, and thus is treated as a BOS Satellite. ORH is located inside of BDL approach (Y90 TRACON).

Lets see what happens when three aircraft approach from the west of ALB VOR inbound to these three airports.

The FIT arrival is routed via ALB..GDM.V431.LOBBY..FIT and issued a restriction to cross 40 west of ALB at FL290, descended to FL230 about 40 miles east of ALB, and then descended to cross BRONC at 6000, unless Runway 14 is requested, in which case, the arrival is descended lower for the approach.

The ORE arrival is routed via ALB..EEN/GDM..ORE (if not just direct ORE) and descended to FL230 about 30 west of ALB (vicinity of SWEDE), then descended to 11000 40 east of ALB, and then descended for approach by the GDM sector. This flow is meant to be below the BOS Satellite arrivals, avoiding the high altitude sector that feeds the GDM Sector.

The ORH arrival is routed south of ALB via RKA.SWEDE1.ORH. This may be the most obvious of the three routings, as ORH is listed on the SWEDE1 chart. These arrivals cross SWEDE anywhere between FL230 and FL180, then descended to 11000 and handed off to Y90 TRACON about 30 miles southeast of ALB.

What was the question again? Here's the answer:
If you're not sure what route to file into a small airport, take a look at the approach charts. Which facility has its frequencies listed on the chart? That main facility is your clue to how "you'll be treated" and how to file your flight plan. That's how controllers like me figure out where you're going!


1 comment:

Exogenous said...

Interesting and good to know.