How WOONS? (Coyote Imitation?)

[Dan Smith]

Finally, a great New England flying weekend! After flying BTV to IWI (Wiscasset, ME) on Saturday, I had to run a friend down to New Bedford (EWB) Sunday morning to pick up a car. Another beautiful day, but I filed in order to ease the transition through the BOS area and to help with traffic watching. The route down was V139, nice view all the way.

Here's the question: the clearance for the return was: "after departure direct WOONS, direct BOS, direct PSM, direct ENE, maintain 2K, expect 7K", etc. Although I have VFR Loran and GPS, and getting to WOONS wasn't a problem, how did ATC figure I was going to get there as a /U filer? The only route that makes any sense from EWB is direct PVD, 345 radial to HEFTY, to WOONS, and I can't believe that they really wanted me to head for Providence or they would have put PVD in the clearance. It all worked out fine, but I'd like some feedback from anyone interested on what they might have intended, and whether I should have tried to clarify the clearance before accepting it.

Another interesting thing was when approaching PSM: BOS approach says "proceed direct IWI". When I said that as /U I'd need "heading XXX, radar vectors" to be legal, they said "oh... never mind, maintain current clearance". Then PTL gave me direct IWI before reaching ENE, and bit on the radar vectors agreement. It seems like ATC just kind of assumes that anyone in the system can go direct these days.

Dan

 

[bbchien]

Although I have VFR Loran and GPS, and getting to WOONS wasn't a problem, how did ATC figure I was going to get there as a /U filer? It seems like ATC just kind of assumes that anyone in the system can go direct these days.
Dan

If he was overlaoded he wans't going to issue "vectors". Yes, it's easier for a controller if you can go /U direct 'cause there's only one communication to issue.... sigh.

 

[Ed Guthrie]

the clearance for the return was: "after departure direct WOONS, ..." Although I have VFR Loran and GPS, and getting to WOONS wasn't a problem, how did ATC figure I was going to get there as a /U filer? ...It seems like ATC just kind of assumes that anyone in the system can go direct these days.

Based on what I've heard on the frequencies, ATC and /U IFR pilots share the same misconceptions regarding /U aircraft flying direct. How does a VFR GPS and LORAN make proceeding direct WOONS IFR not a problem? With respect to proceeding direct WOONS in a /U aircraft how does one legally comply with 91.205(d)(2)? How does a VFR GPS or LORAN change that answer?

Ref: 91.205(d)(2)

§ 91.205 Powered civil aircraft with standard category U.S. airworthiness certificates: Instrument and equipment requirements.

(d) Instrument flight rules. For IFR flight, the following instruments and equipment are required:
(2) Two-way radio communications system and navigational equipment appropriate to the ground facilities to be used .

 

[Dan Smith]

Ed,

I meant that using the Loran/GPS to find WOONS was not a problem in the practical sense only; it's the legal sense that my question pertained to. I don't have a misconception concerning the limitations of /U, but I agree that ATC frequently does.

Having said that, can you answer my original question? Was there a proper way to head for WOONS, or should I have requested clarification on the clearance? On departure, there were no vectors provided, although I did receive a routing direct BOS before I had gone very far towards WOONS.

Dan

 

[Ed Guthrie]

Having said that, can you answer my original question? Was there a proper way to head for WOONS, or should I have requested clarification on the clearance? On departure, there were no vectors provided, although I did receive a routing direct BOS before I had gone very far towards WOONS.

Dan, first, apologies if I came off preachy, snippy, or whatever--definitely not intended. I asked the question(s) I did hoping the above question/discussion or something similar would occur.

Now, as to WOONS, I will admit I'm too far from my library so I can't find WOONS and therefor can't offer specifics tailored to WOONS. However, lets propose a hypothetical in which WOONS is northeast of PODUNK VOR on V123, and your current routing includes V123 NE of PODUNK. As an assist to cut the corner, the controller clears you direct WOONS. The correct reply is "We are /U today; unable direct WOONS, but we could accept fly heading xyz to intercept V123 northeast of PODUNK." In the above clearance the heading xyz just happens to be what the VFR GPS indicates as direct WOONS, so in essence you are indeed navigating direct WOONS, but the clearance you proposed is perfectly legal for your aircraft whereas direct WOONS is not.

BTW, a good ATC controller will offer the second clearance to a /U without prompting--which is how I learned what to request.

 

[jdwatson]

I used to go to High School not far from WOONS, in Woonsocket, RI.

 

[bbchien]

Congratulations, JD!

 

[Arnold]

Now, as to WOONS, I will admit I'm too far from my library so I can't find WOONS and therefor can't offer specifics tailored to WOONS. However, lets propose a hypothetical in which WOONS is northeast of PODUNK VOR on V123, and your current routing includes V123 NE of PODUNK. As an assist to cut the corner, the controller clears you direct WOONS. The correct reply is "We are /U today; unable direct WOONS, but we could accept fly heading xyz to intercept V123 northeast of PODUNK." In the above clearance the heading xyz just happens to be what the VFR GPS indicates as direct WOONS, so in essence you are indeed navigating direct WOONS, but the clearance you proposed is perfectly legal for your aircraft whereas direct WOONS is not.

Is it not legal to DR a course while IFR? If it is legal then why can't you refine your DR heading using a VFR GPS and then accept the clearance? I am not suggesting that DR to an intersection is even a remotely comfortable exercise, but I'm not sure it is unlawful. I did once DR on an IFR flight plan from Nuk Greenland to Goose Bay Canada, but that was eons ago.

 

[Dan Smith]

I used to go to High School not far from WOONS, in Woonsocket, RI.

I was wondering where that intersection name came from; that explains it, thanks!

Dan

 

[jdwatson]

Congratulations, JD!

Thanks.

 

[Ed Guthrie]

I am not suggesting that DR to an intersection is even a remotely comfortable exercise, but I'm not sure it is unlawful.

I don't believe a DR is IFR legal else there would be no requirement for IFR certified navigation equipment enroute--one could simply DR to every fix, no?

 

[Arnold]

I don't believe a DR is IFR legal else there would be no requirement for IFR certified navigation equipment enroute--one could simply DR to every fix, no?

It think the answer is yes. I've looked and I cannot find a reference in 14 CFR or in the AIM that states that the only way to navigate between fixes when on an IFR flight plan is via xxx. What the regulations seem to establish is a) if you use ground stations you must be able to receive them and b) if you are navigating between fixes you need to go via a 'direct course' (rhumb line? Great Circle?).

We will have a fine time splitting hairs here, but bear with me.

91.205(d)(2) - states that you must have the 'navigational equipment appropriate to the ground facilities to be used.'

91.181 Unless otherwise authorized by ATC, no person may operate an aircraft within controlled airspace under IFR except as follows:

(a) On a Federal airway, along the centerline of that airway.

(b) On any other route, along the direct course between the navigational aids or fixes defining that route. However, this section does not prohibit maneuvering the aircraft to pass well clear of other air traffic or the maneuvering of the aircraft in VFR conditions to clear the intended flight path both before and during climb or descent.


AC-90-94


As for GPS IFR certification standards, note that the purpose of those standards is not to imply that only through the use of approved RNAV equipment can one accept or fly an off airway route, it just means that if you are going to navigate using GPS it must meet certain standards.


Note that the AC, to my mind, is quite clearly concerned with the question - 'Can I use my GPS in place of VOR/DME when navigating in the NAS on a clearance that specifies fixes defined by VOR/DME including federal airways?' The AC then goes on to explain what is required. Specifically you need the 91.205(d)(2) equipment, but you only need to monitor it if you have a RAIM warning, in other words, even with a known accuracy deficiency you are allowed to utilize GPS, you just need to back it up. I don't see how this differs significantly from a well calculated DR heading.


Again, I do not read any of this as prohibiting an individual from navigating off airway direct between two points without using IFR approved RNAV equipment, in other words, DR.


So back to the original scenario. The pilot is flying /U aircraft and is cleared from a known position direct WOONS. The pilot says 'I know where I am, I know the winds, I can do that, I'll fly heading 025 for now and set my VOR reciever(s) to identify WOONS. When I get close I'll make an appropriate correction, if one is required.' On the other hand if the only way you have to identify WOONS is the VFR only GPS and you are on an IFR flight plan, then you've got a problem. But so long as you can comply with 91.205(d)(2) then how you get from 'here to there' is seemingly irrelevant so long as you follow a 'direct course.'


One last caveat - 135, or 121 you can't do this as your ops specs will be very clear about off airway navigation authorizations and the equipment required in the ops specs.


Your suggestion (made in other forums?) that one turn the responsibility back to the controller by saying. 'Can you clear us heading 025 until Woons?' is not unsound, I just don't think it is required.


Anyway, that is my two cents worth.

 

[Ed Guthrie]

We will have a fine time splitting hairs here, but bear with me.

91.181 Unless otherwise authorized by ATC, no person may operate an aircraft within controlled airspace under IFR except as follows:

(b) On any other route, along the direct course between the navigational aids or fixes defining that route.
...
So back to the original scenario. The pilot is flying /U aircraft and is cleared from a known position direct WOONS. The pilot says 'I know where I am, I know the winds, I can do that, I'll fly heading 025 for now and set my VOR reciever(s) to identify WOONS. When I get close I'll make an appropriate correction, if one is required.'

"(A)long the direct course" does not mean "along the approximate direct course". IOW, just my opinion, YMMV, but the fact that you suggest an unseen error might occur and require later adjustment somewhat proves that you know in advance that you can not actually comply with 91.181(b).

 

[Arnold]

"(A)long the direct course" does not mean "along the approximate direct course". IOW, just my opinion, YMMV, but the fact that you suggest an unseen error might occur and require later adjustment somewhat proves that you know in advance that you can not actually comply with 91.181(b).

Point taken. But VOR navigation is rife with errors, from signal scalloping to receiver calibration to sloppy airmanship.

Oh well, just an academic exercise really. I would instruct students to fly IFR without the use of DR in the interest of safety.

 

[kath]

I don't see how using DR to get from place to place IFR can possibly be legal. Maybe it's good enough in terms of navigation (sure, you'll get to WOONS eventually!), but how can it possibly be good enough for separation? Suppose you're in a non-radar environment... how is ATC supposed to keep you separated from others in the clouds when neither you nor they can pinpoint your location? VOR scalloping and the like are at least quantifiable errors, and ATC can build those errors into separation requirements... but how would you do that with DR?
--Kath

 

[jdwatson]

If you're using Dead Reckoning (DR), you'd better not be in the clouds. Isn't DR all about compass, time and a *visual* landmark or something like that ? I fly a lot of IFR in VFR conditions. I like the precision of the flying and the background "noise" that ATC provides.

 

[Ed Guthrie]

Isn't DR all about compass, time and a *visual* landmark or something like that ?

All but the visual landmarks part is correct:

Ref: Pilot/Controller Glossary

DEAD RECKONING - Dead reckoning, as applied to flying, is the navigation of an airplane solely by means of computations based on airspeed, course, heading, wind direction, and speed, groundspeed, and elapsed time.

 

[Arnold]

I don't see how using DR to get from place to place IFR can possibly be legal. Maybe it's good enough in terms of navigation (sure, you'll get to WOONS eventually!), but how can it possibly be good enough for separation? Suppose you're in a non-radar environment... how is ATC supposed to keep you separated from others in the clouds when neither you nor they can pinpoint your location? VOR scalloping and the like are at least quantifiable errors, and ATC can build those errors into separation requirements... but how would you do that with DR?
--Kath

GPS/RNAV Direct doesn't work in a non radar environment anyway so I don't think ATC will give you the clearance irrespective of equipment. <Caveat - I'm talking US Domestic. Across the ocean it is all time/speed/distance and formal position reports for separation).

The quality of a DR heading is dependant on the quality of the winds aloft data. The more accurate the winds the more accurate the course. When I completed my DR trip across the North Atlantic I quietly thanked the MET guys in Greenland.

If you are IFR and you have a VFR GPS which you use as a tool to calculate your DR course to a fix, have you violated any regs? I can't find the reg that is violated, but that doesn't mean I'm right, it just means I can't find it.

So the mystery continues - I'm not suggesting that anyone adopt the practice.

 

[Arnold]

I don't believe a DR is IFR legal else there would be no requirement for IFR certified navigation equipment enroute--one could simply DR to every fix, no?

On further reflection the following occurs:

ATC will be clearing you along a route they define (even the route direct to xyz is ultimately defined by ATC at the moment they issue the clearance). So while one could simply DR to every fix, it would not be an efficient system, so we have NAVAIDS.

Is there any reason that an aircraft equipped with only an ADF can't file a route such as heading 060 until able direct (distant ADF). I don't see why not, you may not get it, but it would be legal and you have all the required equipment.

Is DR high workload and fraught with uncertainty. Well it can be. Is it or should it be anybody's first choice? Probably not. But is it unlawful - I don't think so.

But as I said over on the "Red" board, this will likely need a Chief Counsel opinion to straighten it out.

 

[kath]

GPS/RNAV Direct doesn't work in a non radar environment anyway

Why not? As long as ATC knows that there's no other IFR traffic that you'll run into (because they're faithfully following navaids within known tolerances and giving position reports, etc.)...

--Kath

 

[Ed Guthrie]

Why not? As long as ATC knows that there's no other IFR traffic that you'll run into (because they're faithfully following navaids within known tolerances and giving position reports, etc.)...

--Kath

The main reason is because ATC just isn't set up to handle it, so if you fly an RNAV route and fall off radar ATC will push you back onto an airway routing.

 

[wsuffa]

The main reason is because ATC just isn't set up to handle it, so if you fly an RNAV route and fall off radar ATC will push you back onto an airway routing.

Kath,

To expand on Ed's answer, suppose there are two airplanes on off-airways routes in the airspace, and ATC doesn't have radar. ATC can't see (or visualize) the relative timing of those two if their paths cross, or one is following the other. Likewise, if other traffic is on an airway and you're on a direct route across the airway, they have no idea if you two are close or not.

Don Brown's columns on AvWeb are pretty good on this topic.