Aviation Topic of the Week
By Michael Oxner, August 3, 2003


Introduction
Previous Week's Topic
Following Week's Topic
Aviation in Canada Blog
Archives

This week's topic:
Variety Q & A

I had been looking for some "short answer" questions to do a little variety, rather than a full rant on a topic. Some folks have asked some simple questions over the past few months, and they fit right in to earlier topics, so I addressed them as part of the larger topics written. This week, as a bit of a break from all the work building the topics I have been, I've decided to answer a few of these other questions that I've left out previously. Those who know me also understand that there are slim odds of a short answer to a question asked of me, so I'll stop wasting words and get right to some of them.

IFR Flight Plans - Opening and Closing
    Departures
    Arrivals
Urgency and Emergency -- PAN Handling?
Winds in an ATIS
    Real World
    VatSim World
Initial Call to ATC when Entering Controlled Airspace
    Departing
    Cruising
RNAV STAR, Extra Speed Restriction
Where is IFR Flight Part 5b?
ADDENDUM

IFR Flight Plans

The IFR Flight series has pretty much concluded. There is one topic that I didn't mention, since it wasn't directly related to the any of the topics discussed, and it didn't merit a full topic on its own. The opening and closing of IFR Flight Plans.

Departures

In the real world, flight plans are used for more than just telling ATC who you are and what you want to do. The flight plan includes things like the number of souls on board and the amount of fuel on board. These numbers can be useful if alerting services are required. For an IFR aircraft, you have to be airborne, or at least talk to ATC, within 60 minutes of your proposed departure time or ATC will go looking for you. At an airport served by an Air Traffic Service unit, like a tower or FSS, you have to call them anyway, so they'll be aware of your departure. At an airport without one of these facilities, this time is used since you are allowed to depart and call for clearance in the air. What happens if you attempt to take-off and crash, but nobody knows about it? The flight plan times give ATC a requirement to go looking for, to cover just such a case. The 60 minutes is there to provide you an opportunity to be late and not have Search and Rescue looking for you, since this does stir an awful lot of concern when SAR crews are scrambled to look for you. Once you talk to ATC, they know you're safe and can stand down. If you know you'll be late, call ahead and revise your departure time. If you can't talk directly to ATC, pass your departure message, including your aircraft's callsign, point of departure and time of departure through other means if possible.

Arrivals

For IFR arrivals, you have to file an arrival message to let ATC know you have arrived safely. In the VatSim, you can talk to ATC directly no matter where you are. In the real world, you often land at out-of-the-way airports where you can't communicate directly with an ATC facility like a tower or an FSS. In fact, if they're on the field, you don't even have to explicitly tell them to close your flight plan. They'll automatically do it. If you land at an airport without an ATS facility, you must make contact somehow to tell them you've landed, or they'll alert SAR to go searching for you. This can be done with a phone call to any ATS facility, for example. For practical purposes in VatSim, here's what I'd recommend: If you land at an airport where you're been cleared to land, consider it as having a tower in place, and that your FP is closed for you. If not, after you land, report when you're clear of the runway and that will count as your arrival message, which will close your flight plan.

Urgency and Emergency -- PAN Handling?

I received a request asking about the difference between MAYDAY and PAN, more specifically what would constitute a call for either, rather than their meanings. First off, I'll define each anyway. Right out of the AIP, COM 5.11 Emergency Communications.

Urgency: a situation where the safety of an aircraft or other vehicle, or of some person on board or within sight is threatened, but does not require immediate assistance. The spoken word for urgency is PANPAN and is pronounced 3 times.

Emergency: distress is a situation when safety is being threatened by grave and imminent danger and requires immediate assistance. The spoken word for distress is MAYDAY and is pronounced 3 times.

The first transmission of either communication should be made on the air-to-ground frequency being used at the time. If no contact can be made, the next call should be made on 121.5 MHz (or the equivalent HF of 3023.5 or UHF 243.0) or any other frequency known for use in the area. The distress call shall have immediate and absolute priority over all other calls and any aircraft hearing an emergency call shall immediately cease all other communication on that frequency which may interfere. Sometimes there is very little time between the MAYDAY call and the last the ground station can hear from the aircraft. A good airman will listen out and attempt, workload permitting in the cockpit, to record some details in case ATC, or other personnel, cannot receive all of the message due to distance from transmitters, etc. This will enable an aircraft in flight to extend communications with the one experiencing the problem as long as possible.

The definitions above indicate that both distress and urgency calls can involve outside situations, not just internal to the aircraft. A ship on fire at sea, a forest fire threatening people which doesn't appear to have emergency equipment around, etc. All these could be considered legitimate distress or urgency calls. Since ATC has landlines capable of coordinating with Rescue Coordination Centers across Canada, it is possible to report all kinds of situations and offer information.

Examples of distress requiring a MAYDAY call include loss of an engine, especially for single engine aircraft (though even P-3 which routinely shut down engines in flight will declare an emergency with an engine failure), loss of pressurization (versus pressurization problem requiring descent), sick passenger requiring immediate medical assistance, smoke in the cabin, etc. Emergencies are often declared without the use of the word MAYDAY, too. In fact, I have yet, in 11 years, to hear the word MAYDAY spoken on my frequency. The term, "declaring an emergency" is often used, and the situation is often revealed to be quite dire through the words used. For example, if a single engine aircraft reports an engine failure, it's an emergency. There's no asking the pilot if he's declaring one, it just is one. A VFR aircraft caught in IFR weather conditions is another no-brainer. Statistically, he has, on average, only 117 seconds to live. I'd say his safety is threatened. All emergency situations will be given priority over other operations, including military operations and flights carrying heads of state.

A situation developing on board the aircraft that doesn't require immediate assistance, but may require a diversion, would be an example of urgency. Again, I have yet to hear "PANPAN PANPAN PANPAN" actually said on the radio, and many pilots and controllers don't even know the proper way to use that call. Is what I just said correct, or is it "PAN PAN PAN"? The AIP says it's the first one. Urgency can also be conveyed simply be description of the events or situation as it develops. Urgent situations will be given priority over any normal operations.

Winds in an ATIS

There are two facets to this, the real world and the VatSim world. I'll start with real, and move on.

Real World ATIS

Weather reports such as METAR and TAF report winds in degrees true. In the real world, in Canada anyway, winds are to be reported by ATC in degrees magnetic, except where true headings are used for runway numbering, NAVAID alignment, etc. This includes the ATIS. The ATIS used to be recorded by a controller, reading the weather, NOTAMs, and airport conditions while speaking into a phone. The newer digital ATIS will automatically parse the weather into pre-recorded sound bytes, recorded by a guy named Steve, and assembled into a continuous loop for broadcast. In the process, the true winds reported by the METAR are converted into magnetic.

VatSim ATIS

In our simulated environment, a controller's ATIS is more and more relying directly on the METAR reports. Simple strings used by ASRC for generating an ATIS will automatically update weather without controller intervention, so these are often used. As a result, the true winds are broadcast in a controller's ATIS more often than not. There also seems to be a little glitch in the way FS imports weather, at least as far as SquawkBox 2002 uses it. My testing indicated that Flight Sim 2002 subtracts local magnetic variation when it should be adding it and the opposite is true as well. So, for example, a METAR sequence indicating winds of 31005KT means the winds are 310° true at 5 knots, but Flight Sim recorded those winds as 289° when I set up at Moncton, where variation is 21° west. In fact, FS should be adding a western variation to get magnetic winds, not subtracting as it did. The wind direction should have been reported as 331° magnetic in the simulation to concur with the weather sequence downloaded.

Initial Call to ATC

Some flights begin outside of controlled airspace, but plan to enter controlled airspace. At other times, a pilot find himself in an unstaffed FIR, with ATC available in the next one, essentially providing the same situation. I received one question regarding how to call ATC, and what items should be included. Very simply, call ATC first, to get his attention and give him time to look for your flight plan. The odds are he'll be able to find out many of the details he needs, reducing the need for you to communicate all of this stuff to him in subsequent communications. Then just a brief check-in is normally fine. If you're in uncontrolled airspace, you'll need a clearance, so you should provide ATC what altitude you're requesting as part of it, too. He can get the route from your filed flight plan. I'll walk you through a few scenarios.

Departing an Aerodrome in Uncontrolled Airspace

If your departure point is in uncontrolled airspace, an IFR aircraft can legally take-off in IFR conditions, but must get clearance from ATC prior to entering controlled airspace. Such a case may be an airport immediately underlying controlled airspace, or controlled airspace may be some distance away. At Bathurst, NB, for example, controlled airspace for a westbound flight begins some 60 NM away, but the base of controlled airspace above CZBF is above 12,500 feet. The pilot could, rather than call and ask for IFR clearance prior to departing, take-off and call airborne for IFR clearance. Miramichi, NB, is a little different. While itself in uncontrolled airspace, the base of controlled airspace is 2,200 AGL. Taking off and calling for clearance in the air is a little more difficult, since you have so little time in comparison to Bathurst.

A simple conversation off Bathurst might go like this:

Pilot: "Moncton Center, Cessna 421 Golf Romeo India November"
ATC: "Cessna Golf  Romeo India November, Moncton"
Pilot: "India Romeo November off Bathurst at 1828, out of 4,200. Requesting IFR to CYUL at FL200"
ATC: Provides clearance according to FP...

Or, on the ground at Miramichi:

Pilot: "Moncton, Cheyenne Foxtrot Lima Oscar Papa at Miramichi"
ATC: "Cheyenne Foxtrot Lima Oscar Papa, Moncton"
Pilot: "Lima Oscar Papa ready to taxi now, request IFR clearance to Moncton as filed"
ATC: "Lima Oscar Papa is cleared to the Moncton VOR via A8, maintain 7,000. Squawk 4301"
Pilot: "Lima Oscar Papa is cleared to the Moncton VOR via A8, maintain 7,000. Squawk 4301. We should be airborne in 3 minutes."

Entering Controlled Airspace Laterally

How about if you're in cruise flight, say over Bathurst (controlled airspace based above 12,500), overflying Miramichi (base of controlled airspace 2,200 AGL) en route to Moncton:

Pilot: "Moncton, Golf India Mike Papa, position"
ATC: "India Mike Papa, Moncton"
Pilot: "India Mike Papa over Bathurst at 1257, 5,000 IFR, estimating Miramichi at 1310, Moncton next"
ATC: "India Mike Papa, radar identified over Bathurst. You're cleared to the Moncton VOR via flight planned route, maintain 5,000 while in controlled airspace"
Pilot: Reads back and obeys. The pilot may omits position reports now that he's radar identified.

In VatSim, any situation where a pilot is flying in what would normally be controlled airspace but the area is lacking ATC coverage can be treated like the last example above. ATC may, instead of taking the position report, pre-empt the pilot by asking him to "squawk ident", and in that case, don't bother with the position report, just click on SquawkBox's ident button and wait til he says, "Radar identified". If he still wants the position report, for whatever reason, he can ask for it.

RNAV STAR, Extra Speed Restriction

Here's one that I never did find a good answer for. I  combed the books, but found nothing directly related to this question. The situation proposed to me was this:

You're flying an RNAV STAR (IFR Flight Part 5c: RNAV STAR) and for traffic ATC issues you a speed restriction. Subsequently, he issues you a radar vector. This effectively cancels the STAR, as discussed in the topic referred to above. Does this also cancel the speed restriction? ATC may have issued the speed restriction, then decided it wouldn't work, so opted for the vector instead of allowing you to continue on the STAR. In such a case, he may no longer need the speed restriction. Then again, he may be trying to buy a little extra room, and the vector with the speed restriction may be enough. Certainly if ATC issued a restriction to make a published fix on the STAR at a certain time were issued, that would have to be canceled since the pilot would have no way to judge how far off the STAR he would be vectored, and therefore be unsure of being capable of making good the time previously issued. He may never fly over the fix specified earlier.

The only place I found about a speed restriction being canceled implicitly (i.e., without being stated that it is canceled) refers to issuance of approach clearances. If a pilot has been given a speed restriction, it is automatically canceled by the issuance of an approach clearance unless ATC restates the restriction.

Having said all of the above, I think it would be good airmanship to ask ATC if the speed restriction is still required in such a case, and good practice on the part of ATC to clarify the issue. If anyone has some references to materials regarding this, please contact me so we can clarify the issue. I'm not afraid to learn something. This whole "Topic of the Week" is all about learning, for me included.

Where is IFR Flight Part 5b?

I've been caught. I didn't forget any parts in my series as I planned it, I just made a little booboo in not tracking what parts had been done. Part 5b will remain a mystery to help remind me how a little effort, that should have been put forth in the first place, would have made my work look a little more professional and complete.

ADDENDUM

Greg Phelan, a very knowledgeable and involved simmer, reminded me of an important omission in this week's Q & A about emergencies. In VatSim, the use of 121.5 is regarded very negatively. If you have ATC, please use their frequency when reporting emergencies, and make sure you stay within the VatSim rules regarding emergencies in virtual flight. I'll refer you to the VatSim website to find more information in the Code of Conduct. You should really think at least three times before using 121.5 on VatSim's network. Thanks, Greg, for pointing that out!




If you have any feedback or comments, good or bad, please send them along to me at moxner@nbnet.nb.ca. Thanks for the suggestions, and sorry some of these took a while.