Wednesday, August 06, 2008

LOA Hell

Going through the FAA Academy, the Tower and RTF courses touched a little bit on Letters of Agreement. The LOAs they used for AAC airport and Academy Approach were very simplified and stripped down, but - like the facilities they covered - served to introduce newbie controllers to the concept of an LOA.

For those who have yet to see an LOA, if the 7110.65 is the "Big Bad Book of Rules", Letters of Agreement tell you how to apply those rules between your facility and others. I've been trying to think of an analogy to compare them to the 7110.65. The closest one I can think of is, well, driving.

When you learned to drive, you became familiar with all of the rules and regulations necessary for operating a motor vehicle. You studied the handbook issued by the Department of Motor Vehicles, quizzed yourself, and took the written exam to get your learner's permit. By learning those rules, you now knew how to drive safely.

However, while those regulations tell you what's legal and what's not, they don't actually tell you how to get from point A to point B. If you want to drive from Miami to New Jersey, the DMV handbook won't point you in the direction of I-95 and tell you "go north". However, it will tell you about speed limits, passing slower vehicles, exit signs, usage of mirrors and other things that you will use along the way to make your journey safe.

The 7110.65 is like that handbook: the basic rules of driving remain the same everywhere you go, but how they're applied changes from facility to facility. That's where LOA's come in; they tell you what to do, and the 7110.65 tells you how to do it safely.

Down to the Letter

At our facility we have 28 letters of agreement with other facilities and operators. A sampling includes:
  • En Route procedures between us and Jacksonville Center, Houston Center, Mobile TRACON, and Eglin RAPCON
  • Tower procedures with Pensacola Regional, North Whiting NAS, South Whiting NAS, and Sherman Pensacola NAS
  • Other Procedures dealing with flight school and banner towing operations.
To be truly proficient, you need to go beyond familiarity and have an actual working knowledge of them. These LOA's are just as important as the 7110.65 in working traffic effectively, because they bring order to your traffic. You do not want to handoff an airplane to another facility in a manner that does not comply with the LOA, unless you coordinate otherwise.

"Climb and maintain [altitude]" and "Turn right heading [heading]" is said the same at every ATC facility. However,what the [altitude] and [heading] are completely depends on the LOAs.

LOA's between radar facilities such as TRACONs and en route generally outline boundary crossing procedures, including altitudes, crossing points, headings, and speeds. They also spell out who has control for turns or climb/descent prior to boundary crossings. LOA's with towers typically define the tower's area of responsibility (a.k.a. airspace), missed and practice approach guidelines, and datablock usage (a.k.a. what you need to put in the aircraft's scratchpad so the tower knows what to do with him). Procedures vary if the aircraft is arriving, departing, or an overflight.

It's all about predictability. In a career where anything can happen at any time, it's good to have least some order. The basic point of an LOA is so that parties on either side of the handoff have a good idea what to expect from the other facility. It takes out a whole lot of question marks. You know that if you get an arrival strip with a certain type of aircraft arriving from a certain direction landing at a certain airport, he will be within a certain altitude range, a certain speed range, and on a certain heading. Now, nothing is written in stone and anything can be accomplished with coordination, so you need to be flexible enough to work aircraft that are operating outside the things outlined in the letter.

The Practical Examples

As usual, I'll provide a couple quick examples.

TRACON to Tower: We're working the Pensacola West sector and Pensacola Regional is landing runway 17. We have a Cessna 172 that wants a practice VOR approach to Runway 8, so we need to inform the tower of their intentions. Per our LOA with PNS tower we do the following:
  • Scratchpad Entry: Specify an approach type, a climbout, and frequency. the only climbout we can give him is a west climbout, which will keep him from crossing the active runway. The LOA requires us to put the following in his scratchpad: RWW - (R) VOR approach, (W) West climb out, and (W) West frequency so that tower knows what he's doing, where to miss him, and who to switch him to.
  • Handoff: The LOA requires that aircraft landing or doing an approach to PNS be handed off to the tower prior to 10 miles from the airport.
  • Separate: He will also be sequenced with other arrival traffic dependent on the weather conditions. If the weather is good, the tower will provide visual separation. Otherwise, it's up to us to do it.

That's just a small fraction of the information within the letter. But as you can see, it outlines responsibilities and procedures for both facilities. They know what to expect from us, and we know what to expect from them.

En Route to TRACON: Jacksonville Center generally feeds us airliners from the northeast and northwest. Our LOA with them specificies that jets landing at PNS will be:
  • Descending to 11,000
  • Slowing to 250 knots
  • Direct to the PENSI fix (right in the middle of the chart below)
Now, notice what the letter does not say: it does not differentiate between westbound or eastbound aircraft. No matter where they're coming from, they will always be at 11,000, 250 knots, and pointed at the same fix.

So, if that hasn't clicked yet, picture this: An MD-88 from the northeast, a CRJ-700 from the west, and a Cessna Citation from due east, all descending to the same altitude, pointed right at each other. Now, before you say "That's crazy!", they do start out about 70 miles away from each other. They're not about to swap paint the moment you get them. However, it is obviously a situation that calls for action. When you're talking 500 knot closing speeds and jets loaded with passengers that take time to turn, you'd better make your move.

The idea behind this procedure, of course, is to get the aircraft around the multitude of MOA and restricted areas in our airspace, while simultaneously getting them setup for an approach into our main runway. That PENSI fix that I mentioned before? That's the initial approach fix for Runway 17 at PNS.

Now, in practice, the second these aircraft cross our boundary we're usually turning at least one of them. However, there will often be times where the aircraft are much higher and faster than they're supposed to be (like, oh, 17,000 feet and 420 knots versus 11,000 and 250kt). There's not much you can do about that other than just work with it and make the sequence happen.

TRACON to TRACON: Like other approach controls, we have what are called Gates - otherwise known as Departure Transition Areas/Arrival Transition Areas (DTA/ATA). Like the name suggests, these are specific areas where aircraft cross back and forth between facilities. On the east side of our airspace, we have two gates with Eglin AFB:
  • To the north, we have the Crestview gate, named after the Crestview VORTAC (CEW) in the middle of it.
  • The south one on the coast is called VARRE, after the Navarre bridge and VARRE fix.
Here's a quick overview of some of these DTA/ATA's:

Eglin AFB has a huge amount of activity. This affects us in that they are constantly shutting down different areas in order to conduct their operations. Our LOA with Eglin therefore takes this flexibility into account by creating different routing for our inter-facility traffic. These different routing conditions are as follows:
  • Randoms: Gates are not used. We can send our aircraft across the boundary at any point.
  • Gates: Gates are required. All aircraft, regardless of destination, must be routed via either CEW or VARRE.
  • Flow: The most restrictive. All aircraft landing east of Eglin's airspace must go via CEW. Aircraft landing within it can go via CEW or VARRE.
Eglin also has the option to close off the coast and not permit any traffic whatsoever. Even if we are "Flow" and the aircraft is landing within Eglin's area, we have to route them to CEW. Sometimes, however, they'll strike a compromise where they'll only close certain altitudes along the coast instead of closing it off completely.

It's not uncommon to see the following on our status screens: "RNOC GSOC CST CLSD AOA 70". In Pensacola TRACON-speak, that means "Random procedures north of the coast. Gate procedures south of the coast. Coast closed at-or-above 6000 feet." As it states, north of the coast our eastbound aircraft can cross the boundary at any point. South of the coast, aircraft need to go through the VARRE gate but must be below 5000 feet.

Working With the Pilots

Say we're on "Gates" with Eglin and we get an eastbound Baron from Mobile who is on his way to Jacksonville. When the pilot checks in, we tell him something along the lines of: "Baron 123, due to Eglin flow restrictions, eastbound traffic must proceed via the coastline at VARRE or over the Crestview VOR. Say intentions." I've been looking for the best phraseology to use per the 7110.65, but sometimes plain English works best. In any case, we leave it up to the pilot to decide his route.

Once he makes his choice, we get him pointed in the right direction. Let's say the Baron chose VARRE. If the aircraft is GPS-equipped, we spell out the fix for him so he can type it into his GPS and go direct. If he has no GPS, we put him on a heading that will take him out the gate. The situation changes each time. You just need to remember which aircraft is direct and which is on a heading, as the latter can get you in trouble.

A Little Homework

Where I'm at right now in my training is learning how to apply these LOAs in the new sectors, and it's been an uphill fight. There's just so much to absorb and apply. It really sucks when you start getting busy and you're being held up because you can't remember what altitude or heading you need to use for a certain flight plan.

As you all know, I'm a fan of visual aids. I've been working on a chart that I'm using as a study guide. This image below represents only three out of the 28 letters, namely the ones dealing with Jacksonville Center, Houston Center, Mobile Approach, and Eglin RAPCON. And even then, it only covers a few of the basic procedures for each of the facilities.

Hopefully this gives you an idea of the knowledge you need to keep on tap at all times.


Anonymous said...

I was an Air Traffic Controller at Egin AFB. I was fully rated in Eglin Tower, Duke Field Tower, and all positions in the Eglin Radar Approach Control and Mission Control Facilities. I am also a pilot. This site is hilarious. You obviously have a lot of free time on your hands. Thanx for the laughs. It isn't that difficult goober. Good Luck Geek. I hope you're not working me when I fly through. But, you're probably one of those controllers that "has to use the bathroom" when the strip bay fills up...aren't ya?

Anonymous said...

If you know the aircraft you worked, and can list them on a website...

Please go do something else for a living.


No really.