You've made it almost all the way to your destination, in the clouds and lost comm ... what now? How do you get down, and how does ATC figure out what you're going to do once you decide? AVweb's Don Brown is as confused by the rules as you are.
June 22, 2005
Don Brown worked his way through high school and college as a lineman at the Spartanburg (S.C.) Downtown Airport (SPA), graduating from the University of South Carolina (Spartanburg) in 1980. Hired by the FAA in November 1981, he graduated from the FAA Academy in Oklahoma City the following February 1982, and was certified as a Full Performance Level Controller in August 1984, at the Atlanta Air Route Traffic Control Center (ZTL). Don has spent his entire career at ZTL, earning numerous Letters of Appreciation and four Letters of Commendation, including an Outstanding Flight Assist, during his tenure. Don was also one of the initial founders of the National Air Traffic Controllers Association, and was the very first general (non-officer) member. He was appointed the NATCA Facility Safety Representative for Atlanta Center in 1997 and has served in that position since. He also serves on NATCA's Southern Region Safety Committee. A full-time controller, you can find Don in front of a scope and on the frequency five days a week, just like every other controller at the Atlanta Center.
The rest of Don's "Say Again?" columns are available here.
If you'll remember, last month I left you hanging over the Snowbird VOR, in the clouds, with no radio communication. This month's task is to get back on the ground. Let's review.
Here's the flight plan we filed:
Dep. KHKY (Hickory, N.C.)
Arr. KTYS (Knoxville, Tenn.)
And here is a low-altitude en route chart of the last part of the route (click the graphic for a larger version):
After the initial confusion of discovering the radio didn't work, we got back on V20 and have been flying at the MEA ever since. The MEA has been gradually increasing as we flew over the mountains. Although the flight plan was filed for 6,000, we had to climb to 7,000 between RIGEL and MUMMI and then to 8,000 for the route segment between MUMMI intersection and the SOT VOR. We now find ourselves over SOT, at 8,000 feet, joining V136 to the VXV VOR.
Descent of Faith
The MEA between SOT and PITTE intersection is 7,000. It's time to start back down.
AIM 6-4-1: Two-Way Radio Communications Failure; (c)(3) IFR Conditions
(b) Altitude. At the HIGHEST of the following altitudes or flight levels FOR THE ROUTE SEGMENT BEING FLOWN:
(1) The altitude or flight level assigned in the last ATC clearance received;
(2) The minimum altitude (converted, if appropriate, to minimum flight level as prescribed in 14 CFR Section 91.121(c)) for IFR operations; or
(3) The altitude or flight level ATC has advised may be expected in a further clearance.
If you'll remember, before departure we were assigned the HICKORY ONE Departure Procedure. It says, "... Expect filed altitude/flight level 10 minutes after departure." We filed 6,000, and 10 minutes into the flight has long since passed, so now the governing rule is (b)(2), the "minimum altitude ... for IFR operations." In that the MEA is now 7,000 and we filed for 6,000, we now descend to 7,000. Between PITTE and AUBRY intersections the MEA is 6,000. So at PITTE you begin a descent to 6,000. Between AUBRY and the VXV VOR the MEA goes to 5,000 and we switch rules. Instead of (b)(2), you now use (b)(3): "The altitude or flight level ATC has advised may be expected in a further clearance." The "highest of the following altitudes" is now the altitude you were told to "expect" from the HICKORY ONE Departure: 6,000. So even though the MEA now drops to 5,000, we stay put at 6,000 all the way to the VXV VOR.
So far, things have been running pretty smoothly. Now it's time for the interesting part: shooting an approach. Let's check the rules and see what we need to do.
AIM - 6-4-1: Two-Way Radio Communications Failure; (c)(3) IFR Conditions
(c) Leave clearance limit.
(1) When the clearance limit is a fix from which an approach begins, commence descent or descent and approach as close as possible to the expect further clearance time if one has been received, or if one has not been received, as close as possible to the Estimated Time of Arrival (ETA) as calculated from the filed or amended (with ATC) Estimated Time En Route (ETE).
(2) If the clearance limit is not a fix from which an approach begins, leave the clearance limit at the expect further clearance time if one has been received, or if none has been received, upon arrival over the clearance limit, and proceed to a fix from which an approach begins and commence descent or descent and approach as close as possible to the estimated time of arrival as calculated from the filed or amended (with ATC) estimated time en route.
Houston, We Have a Problem
I've told my readers many times that I learn more from writing these articles than they learn from reading them. Maybe now you'll believe me. The language above about the clearance limit doesn't agree with how I was trained, nor any other controller I can find at Atlanta Center. I was taught that a NORDO aircraft would go to the VOR (or Initial Approach Fix), hold until the EFC or ETA and then commence descent and the approach. That is very close to what paragraph (1) says above.
However, paragraph (2) will be the controlling language with 99 percent of the aircraft we work because the clearance limit we give virtually every aircraft is the airport. And the airport is "not a fix from which an approach begins." As a matter of fact, I've made the argument before that an airport isn't a fix at all. It's an airport. It certainly isn't an Initial Approach Fix. There might be a VOR or an NDB located at the airport that is an Initial Approach Fix, but the airport itself isn't one. At least not on any approach plate I've ever read.
Just to be clear about the situation, the FAA's paperwork is in order. The controller's guidance for NORDO is found here:
FAA 7110.65 10-4-4. COMMUNICATIONS FAILURE.
1. When an IFR aircraft experiences two-way radio communications failure, air traffic control is based on anticipated pilot actions. Pilot procedures and recommended practices are set forth in the AIM, CFRs, and pertinent military regulations.
In other words, controllers base their control actions on what the pilot is going to do. What the pilot should do is listed in the AIM, which quotes the FARs.
The only discrepancy is in what I thought I knew and what the book actually says. As I said before, I've asked several controllers at work (including some instructors) and they were taught the same thing I was taught. What's really bugging me is that this section doesn't make sense (to me). If you had been cleared to VXV to hold (a "clearance limit ... from which an approach begins") -- and then went NORDO -- the book says you commence the approach from that fix. But you weren't. In our scenario, our clearance limit is the TYS airport ("not a fix from which an approach begins"). I don't know if the language was changed or if we were all just taught wrong. Whatever the case, the book says what it says and we don't have the luxury of debating it right now. We've got to get the airplane on the ground.
Round and Round We Go
So here we go. You leave VXV (a perfectly good Initial Approach Fix) and fly to the TYS airport. (How the FAA expects you to navigate there in a /A aircraft is as unknown to me as it is to you.) Looking at the en route chart, I don't see anything in the way if we stay at 6,000. The MEA for the three airways southwest of VXV are all well below 6,000 (for a while) and the MSA (Minimum Safe Altitude) on the approach plates is only 5,100 so I think we're good. I hadn't planned on doing any off-airway flying, but here we are. Because of those rules, we're supposed to proceed to the clearance limit -- the airport.
Hopefully, if you ever find yourself in this situation, you'll have formulated a plan long before you ever reach this stage of the flight. For instance, which approach are you going to try? For me it's a no-brainer: I would shoot the one with the best minimums. If the airport has an ILS, then that's the one I'll use. For this scenario, I've chosen the ILS 23R at TYS.
"... Leave the clearance limit ... upon arrival over the clearance limit, and proceed to a fix from which an approach begins ... " For us that means after getting to the airport, we go back to the VOR for the procedure turn and the full approach. Let's not debate whether this little round trip from the VOR to the airport and back is a waste of time; it's what the rules say.
" ... commence descent or descent and approach as close as possible to the estimated time of arrival as calculated from the filed or amended (with ATC) estimated time en route." We don't have an "expect further clearance" time, so all we've got to go on is our original ETA. We certainly haven't been able to amend it with ATC since we took off. I don't know about you, but in this case my timing is going to be perfect. I'm shooting the approach as soon as I get back to the VOR.
You see a lot of arguments about this among pilots discussing NORDO procedures. Some interpret the rules to mean you should hold (somewhere) until your ETA. That's a reasonable interpretation. I would do everything in my power to avoid implementing it, though. First, I'd do my best to come up with a good ETA when I filed a flight plan. Second, if I discovered en route (and NORDO) that I was going to be really, really early and I was really, really worried about it, I'd slow down. If I got a clearance to hold and an Expect Further Clearance (EFC) time from ATC -- and then went NORDO -- I'd hold until the EFC. If I haven't (and in this scenario we haven't) I'd do my best to arrive over the IAF at or after my ETA -- because if there is any chance ATC can't see me on radar, that's the only way they can guess where I am at a particular time; and they're working hard enough to get planes out of our way.
The only thing left to decide is when to leave 6,000 for the approach. In this case, descending from 6,000 to 4,000 (the initial approach altitude) during the outbound leg of the procedure turn isn't a problem, so that is when I'd leave 6,000, crossing VXV outbound, which should be "as close as possible to the estimated time of arrival."
For aircraft flying at the higher altitudes, this is where NORDO becomes problematic for ATC. Imagine a NORDO aircraft at FL410. That is a lot of altitude to lose -- somewhere -- because, as we stated above, they have to stay at the highest of the various altitudes (AIM 6-4-1). In our case, I'm more worried about terrain than I am about what time it is.
This is the major thing I want you to see about the NORDO procedures. It's really just a framework to provide some guidance where you can (hopefully) make some logical decisions. After all, the whole NORDO section of the AIM does start with this little tidbit (in case you haven't read it):
AIM - 6-4-1: Two-Way Radio Communications Failure
a. It is virtually impossible to provide regulations and procedures applicable to all possible situations associated with two-way radio communications failure. During two-way radio communications failure, when confronted by a situation not covered in the regulation, pilots are expected to exercise good judgment in whatever action they elect to take. Should the situation so dictate they should not be reluctant to use the emergency action contained in 14 CFR Section 91.3(b).
In other words, this isn't a "one size fits all" regulation. It's more of a "one size fits most" or "one size fits the most likely" regulation. After all, which is most likely to have a total loss of communications: A basic IFR trainer or an airliner?
Meanwhile, Back on the Farm
I want to get back to a subject that we touched on earlier. What is ATC doing during all this? Quite a lot, as it turns out. The first thing they'll be working on is reestablishing communications.
10-4-4. COMMUNICATIONS FAILURE
Take the following actions, as appropriate, if two-way radio communications are lost with an aircraft:
a. In the event of lost communications with an aircraft under your control jurisdiction use all appropriate means available to reestablish communications with the aircraft. These may include, but not be limited to, emergency frequencies, NAVAIDs that are equipped with voice capability, FSS, Aeronautical Radio Incorporated (ARINC), etc.
These are all pretty straightforward. We'll try every frequency we can think of. For those of you using GPS, please note that we will be trying on the voice frequencies of local NAVAIDs.
Here are several methods of communication that have been used successfully in the past with pilots who have lost just their transmitter:
c. Attempt to re-establish communication by having the aircraft use its transponder or make turns to acknowledge clearances and answer questions. Request any of the following in using the transponder:
1. Request the aircraft to reply Mode 3/A "IDENT."
2. Request the aircraft to reply on Code 7600 or if already on
Code 7600, the appropriate stratum code.
3. Request the aircraft to change to "stand-by" for sufficient time for you to be sure that the lack of a target is the result of the requested action.
The next thing controllers will do is start arguing about what you are going to do. Most controllers don't have the NORDO procedures memorized any better than most pilots do. Controllers know instinctively that the best thing to do is just keep all other traffic out of your way.
We'll get the supervisor to call Flight Service to get your filed ETA. Hopefully, while we have FSS on the phone, we'll get your alternate too. Neither piece of information is routinely posted on the Flight Progress Strip we have about your flight.
Light 'Em Up
In today's world, the next thing someone will worry about is terrorism. In our example, Knoxville is awfully close to Oak Ridge, Tenn. The thought of a NORDO aircraft heading towards a nuclear plant is going to concern some folks in government. There's nothing you can do about it (other than studying the intercept procedures), so don't waste your time worrying about it. Someone in the government will worry for you.
Did you ever wonder what would happen if you were NORDO at night? It'd be kind-of tough to get the pilot-controlled lighting at an uncontrolled field turned on without a radio, wouldn't it? Not to worry:
10-4-2. LIGHTING REQUIREMENTS
a. EN ROUTE. At nontower or non-FSS locations, request the airport management to light all runway lights, approach lights, and all other required airport lighting systems for at least 30 minutes before the ETA of the unreported aircraft until the aircraft has been located or for 30 minutes after its fuel supply is estimated to be exhausted.
b. TERMINAL. Operate runway lights, approach lights, and all other required airport lighting systems for at least 30 minutes before the ETA of the unreported aircraft until the aircraft has been located or for 30 minutes after its fuel supply is estimated to be exhausted.
Have you ever wondered why the FAA wants to know your "fuel on board?" In time (hours and minutes)? Now you know at least one reason. (Another reason is so they know how far you'll get if you don't show up at your destination.) Don't let me mislead you by my question about it being dark. Notice that 10-4-2 didn't say anything about it being dark. We'll leave the lights on.
That about wraps things up. We'll either see the airport (and land) during the approach or we won't. If we don't, things are really going to to get interesting. Sure, we'll shoot the missed approach. But what happens after that? Another approach? Divert to our alternate? How will we get there? By what route? At what altitude? There are a million questions and there are no set answers.
What, Where, When
|Mt. Mitchell, N.C.
For me, that's what the NORDO procedures are all about -- limiting the number of questions and their possible answers. The reason I conducted this scenario on the airways is that it simplifies the process. We could have filed a direct routing, but it makes life a lot more complicated. Just take this one for instance: HKY direct TYS takes you right by Mt. Mitchell. It's 6,684 feet high. How high do you climb to get over it? If you didn't answer 8,700 feet then we're playing on a different page. And I still don't know where you'd start that climb or when you'll start back down.
Will we work it out? Sure we will. As I said earlier, controllers aren't going to let anyone get close to you. As long as you miss the mountains, we'll miss you with the airplanes and everything will work out fine. As long as your transponder and our radar are working, it's really not that hard. If they aren't, well, it gets a lot more complicated.
I hope you'll run through some "what if's" and see what you can come up with. Talk them out with other pilots and see if your solutions match what is in the book. You'll be surprised what you learn while you're searching for answers. I know I always am.
Have a safe flight.
Facility Safety Representative
National Air Traffic Controllers Association