Straight-in Approaches

[prelude]

I have a question about when it is possible to conduct a straight-in approach (no PT). I'd like to make it clear that my question is not about when it is possible to use straight-in landing minima.

RAC 9.16 describes straight-in approaches from an intermediate fix. Although poorly written, it explains that if an approach has an IF depicted, a straight-in approach without a procedure turn is permitted. It is also indicated by "no PT".

My first question refers to approaches without a published IF or "no PT". Is a PT necessary in this case?

Example: Cleared for a NDB A Approach. Can you descend to MSA, intercept the approach course, ensure that you are within 10NM (or the PT distance) from the appropriate fix before descending, then continue the approach straight-in?

I've seen the above example done many times in the north. Is it written anywhere stating this can or can't be done?

On a different note, RAC 9.16 mentions that pilots may begin a straight-in approach from any "depicted transition" that intersects the final approach track inside the IF. There are many examples of approaches which include a RNAV fix, say on an ILS. Am I correct in assuming this is an example of a "depicted transition" (flying direct to that fix)? If no transition exists, and you are cleared for a straight-in approach, can you simply fly a heading that will intercept the inbound track?

[Hedley]

See AIM COM 3.16.9

[Rockie]

You can do a straight in on any approach provided you are placed on final by radar vectors. Without radar vectors you have to self navigate to final, and if there is no depicted transition (meaning depicted on the approach plate) to an IF then you have to fly to the FAF and complete a procedure turn. You are correct in saying there is poor wording and little guidance given in the AIM. Unfortunately there is no longer a Canadian Instrument Procedures manual, and Transport Canada has no plans to publish one. But here is the wording from an old one.

Procedure Turns

The pilot must make a procedure turn where no suitable fix is available to construct a straight-in approach procedure or where ATC clearance cannot be obtained for a straight-in approach. In this case the Initial Approach Fix and the Final Approach Fix are the same.

This doesn't preclude you from carrying out a straight in landing at any time if you become visual and are in a normal position to land.

[navajo]

I don`t have too much experience (fresh ATPL) but after 3 years of flying, I understand now that the CARs cannot answer all the legal questions.

I asked that question to a guy from TC in Montreal and he told me I was crazy to ever think about doing such kind of straight in approach... even if my distance from the fix is confirmed with a DME... I understand it`s not legal if you don`t have a certified GPS and if the pilot is not GPS certified and you use your GPS to know your distance from the fix but with a DME, I don`t understand what`s the problem. Anyway, I am sure if I would have asked the same question to TC in Alberta (or just to a different inspector), and he could have told me something completly different. I depends how you interpret RAC 9.16.

I think TC made the CARsso you can interpret it, anyway, that`s how I see it. I interpret RAC 9.16 "you can do a straight in approach and it`s safe to do it if it`s written NO PT on the chart but if NO PT is not written, you can do it only if it`s safe". If they didn`t write "you cannot do a straight in approach unless NO PT is written on the chart", there`s probably a reason. I`m sure the people who wrote the RAC were professionnal and they probably decided it was less trouble let room for interpretation.

[AuxBatOn]

I don`t have too much experience (fresh ATPL) but after 3 years of flying, I understand now that the CARs cannot answer all the legal questions.

I asked that question to a guy from TC in Montreal and he told me I was crazy to ever think about doing such kind of straight in approach... even if my distance from the fix is confirmed with a DME... I understand it`s not legal if you don`t have a certified GPS and if the pilot is not GPS certified and you use your GPS to know your distance from the fix but with a DME, I don`t understand what`s the problem. Anyway, I am sure if I would have asked the same question to TC in Alberta (or just to a different inspector), and he could have told me something completly different. I depends how you interpret RAC 9.16.

AIM - RAC 9.16 is specific to the approaches with an IF (Intermediate Fix). No IF to which you can positively navigate, no Straight-In, unless you're vectored in. I don't see the ambiguity.

EDIT in italic

[stuckmike]

I have asked this question to several TC inspectors on different occasions.

What is unsafe about this scenario?

NDB A Approach into Sumspot, AB. Using an IFR approach approved GPS receiver, with RAIM Available, intercepting the final Approach Course within the PT protected area at sector altitude, stabilized approach, all altitudes and headings and missed approach as published.

Their answer?

(off the record of course) Nothing.

But it's not legal.

In my opinion, this will change.

The full procedure NDB approach is needed to establish both heading and distance(time outbound) to establish your position relative to the beacon.

With a GPS approach capable reciever this requirement is not needed. After all, if it is good enough for a standalone GPS approach, it is good enough for a straight in NDB (with a monitor of the NDB during approach to ensure it is working and to confirm final approach course).

The feeling I got was that the problem is liability. The Feds do not want any cowboys making up their own GPS approaches into these places with NDB only approaches. Keep in mind these regs were drawn up before the widespread availability of approach capable GPS receivers.

The funny thing is, if you fly the approach as stated above, it is actually more precise, and in my opinion, safer. Unfortunately it is not legal so therefore I do not do it........

Opinions?

[Rockie]

RNAV is changing the world, and it is taking Transport Canada a while to catch up. As you say they don't want people inventing their own RNAV approaches, and in the case of navigating your way to final without the benefit of an IF to go to that is exactly what you're doing. Safe...probably. But potentially unsafe if it becomes common practice and people start going wherever they feel like. You could ask ATC for a direct 15 mile final or something, but without an established fix and no radar coverage I doubt they would be willing to clear you. If you have radar coverage just get a vector and that makes it nice and legal.

Question? If you are doing an RNAV overlay of a VOR or NDB approach, why would you bother monitoring the navaid? It isn't anywhere near as accurate or reliable. Especially an NDB.

[Steve Baker]

Safe, almost certainly, legal no. The above posts all bring up good points. Here's another. What was your clearance? Probably to the NDB in question then for an NDB approach. Though I think the airspace is protected, you are deviating from your cleared route prior to reaching the FAF/IF. As a note, if under radar (or maybe not ), at least down south, (Cuba/Mexico/DR) you can ask and be cleared for direct to 8 miles final for a given runway. Of course obstacle clearance is your responsibility.

[Louis]

Stuckmike, one other reason that is somewhat GPS specific could be "approach mode" activation.

GPS units typically won't automatically set their CDI scale down to ±0.3NM unless you're on a database loaded approach. A quick look at the KLN 90B manual states that you're prohibited from doing a GPS-based approach unless its in "approach active" mode, which implies available RAIM and a loaded approach from the database.

But I essentially agree with you.

[stuckmike]

GPS units typically won't automatically set their CDI scale down to ±0.3NM

Very true, however you can manually set them to 0.3nm.

If you are doing an RNAV overlay of a VOR or NDB approach, why would you bother monitoring the navaid?

You are still doing the NDB approach, using the GPS (RAIM Available, 0.3 scale,)to set up a straight in approach. If the NDB goes U/S during the approach, it's a go around.

What was your clearance?

Most of my experience with NDB-A approaches is in the NDA. Clearances I typically receive are... "...... cleared out of high level controlled airspace vicinity of...... report leaving FL230."" Then Uncontrolled to the Airport/NDB/RNAV Waypoint.

Some of these airports in the frozen North can get pretty messy with traffic at times. There is obvious operational advantages with the straight in approach for all of those involved with multiple aircraft arriving and departing at the same time.

Don't get me wrong, I fly by the rules just like everyone else. I just would like to see a change and utilize the GPS/GNSS equipment to the most of it's ability. This whole discussion is becoming increasingly irrelavent as NAVCAN is slowly adding RNAV approaches to the Northern airports. Just wish they'd get the lead out!

Cheers,

Fly safe

[Rockie]

If you are doing an RNAV overlay of a VOR or NDB approach, why would you bother monitoring the navaid?

You are still doing the NDB approach, using the GPS (RAIM Available, 0.3 scale,)to set up a straight in approach. If the NDB goes U/S during the approach, it's a go around.

This is a common misconception I think.

If you are doing an NDB or VOR approach but using the RNAV capability of your aircraft to fly the approach, the navaid is still the primary reference and RAIM or 0.3 RNP is not required.

If you are doing an overlay ( ie. NDB (GNSS) RWY 08), and using RNAV to fly the approach, then it is your primary reference. You require RAIM and 0.3 RNP, but you do not need the NDB. So if you happen to be monitoring it while conducting an overlay approach and it goes off the air, then continue with the approach. Because you can do either RNAV or a conventional navaid approach, you cannot do both.

[Hedley]

I'm not sure if I should laugh or cry, reading this thread.

Regardless, do keep in mind that if you have an IFR GPS,
there can be no doubt that you can use it to determine
your distance from a waypoint (eg NDB) in it's database
which in turn indisputably determines whether or not you
are within the specified PT distance on the approach plate.

You are NOT using the GPS for lateral guidance - that's
what the "high precision" ADF is for - merely as a DOT-
approved method to establish when you are within the
specified PT distance.

And do keep in mind that there are many different procedure
turns which can be conducted.

[ahramin]

I'm not sure if I should laugh or cry, reading this thread.

No kidding.

The AIM specifically states that when using RNAV you may be able to bypass the procedure turn and do a straight in.

However, I have seen this maneuver screwed up many times. If you are not used to vectoring yourself onto final in 3d, practice in good weather first.

[duplicate2]

The AIM specifically states that when using RNAV you may be able to bypass the procedure turn and do a straight in.

Do you have a reference section for this please?

[Hedley]

Any pilot who is unable to intercept and track inbound
the final approach course should not have an instrument
rating. It's that simple.

Established on the final approach course inbound:
1) at 25nm from the fix, descend to the MSA sector altitude.
2) at the PT distance, descend to the PT altitude.
3) at the fix, descend to the MDA.

My God, are instrument-rated pilots with PPC's flying
70x ops with moving-map IFR GPS really mentally incapable
of performing the above?

How could a non-precision approach be any simpler?!

I guess I'm getting old or something.

[Donald]

Simpler still, level off at the 25 mile safe with just enough distance to slow down and begin to configure before intercepting a pseudo-glideslope (always respecting altitudes over intermediate fixes if applicable) down to MDA or DDA or DA or whatever you are calling mins.

Note: If you can do simple 3-1 math, the pseudo-glideslope is not necessary, but it sure is nice.

SCDA when done right, is a thing of beauty.

[AuxBatOn]

Hedley, I don't think the discussion is about how hard it is to navigate on the final approach course and go for the straigh-in. It's about the legality of doing it, without an IF you can positively navigate to (ie: you have the required equipment on board to navigate to it).

[ahramin]

The AIM specifically states that when using RNAV you may be able to bypass the procedure turn and do a straight in.

Do you have a reference section for this please?

COM 3.16.5.2.2

[Hedley]

It's about the legality of doing it, without an IF you can positively navigate to (ie: you have the required equipment on board to navigate to it).

Once more, with feeling ....

If a instrument-rated (and likely PPC'd 70x) pilot is actually capable
of intercepting and tracking the final approach course to the fix using
the underlying navaid (this seems to be a task of legendarily Herculean
proportions) ...

AND if the aircraft is equipped with an IFR GPS that has the fix in
it's database ....

THEN by AIM COM 3.16 (see my original response to this thread
at the top) the pilot can establish, in a legal manner, when he
is at the PT distance from the fix, using his IFR GPS as a legal
DME substitute.

He does NOT use the IFR GPS for tracking. That would be immoral,
illegal, carcinogenic and fattening. No, he uses the far superior
ADF (or whatever original 1950's junk) for that purpose.

At the published PT distance, he may then descend to the published
PT altitude and drive inbound. Crossing the FAF, he descends to the MDA.

Enlighten me as to what specific CAR is violated by performing the above.
If you get yet another registered letter from Enforcement, what will you
be charged with?

[navajo]

The AIM specifically states that when using RNAV you may be able to bypass the procedure turn and do a straight in.

Do you have a reference section for this please?

COM 3.16.5.2.2

"In many cases, the pilot can bypass the procedure turn and fly directly to the FAF for a more efficient approach, as long as minimum sector altitudes are respected."

"GPS overlay approaches are traditional VOR- or NDB-based approaches that have been approved to be flown using the guidance of IFR approach-certified GNSS avionics. GPS overlay approaches are identified in the CAP by including “(GPS)” in small capitals after the runway designation [e.g. NDB RWY 04 (GPS)]."

We just have to be patient, TC started to approve these overlay approaches maybe 5 years ago (I don't fly since that long so I'm not sure). Give them another 10-15 years and they should be done approving every approaches to be flown with the GPS.

[AuxBatOn]

The AIM specifically states that when using RNAV you may be able to bypass the procedure turn and do a straight in.

Do you have a reference section for this please?

COM 3.16.5.2.2

All that talks about is overlay approaches. It doesn't talk about non-overlay approaches (ie: no (GNSS) after the approach title)

[Rockie]

It's about the legality of doing it, without an IF you can positively navigate to (ie: you have the required equipment on board to navigate to it).

Once more, with feeling ....

If a instrument-rated (and likely PPC'd 70x) pilot is actually capable
of intercepting and tracking the final approach course to the fix using
the underlying navaid (this seems to be a task of legendarily Herculean
proportions) ...

AND if the aircraft is equipped with an IFR GPS that has the fix in
it's database ....

THEN by AIM COM 3.16 (see my original response to this thread
at the top) the pilot can establish, in a legal manner, when he
is at the PT distance from the fix, using his IFR GPS as a legal
DME substitute.

He does NOT use the IFR GPS for tracking. That would be immoral,
illegal, carcinogenic and fattening. No, he uses the far superior
ADF (or whatever original 1950's junk) for that purpose.

At the published PT distance, he may then descend to the published
PT altitude and drive inbound. Crossing the FAF, he descends to the MDA.

Enlighten me as to what specific CAR is violated by performing the above.
If you get yet another registered letter from Enforcement, what will you
be charged with?

That is a perfectly legal way of doing it Hedley, but the key is having a waypoint (IF) on final to navigate to that establishes you on the final approach course first. In the absence of a waypoint then radar vectors accomplish the same thing legally. If there is no waypoint and no radar then you have to go to the fix (FAF) and do a procedure turn, and I'm pretty sure that's the only clearance you will get from ATC. Unless you give him a lat/long equivalent on 15 mile final and he takes the time to program it into his equipment. I don't think that's likely but you never know.

[Rockie]

Thought I would get the definitive answer from the NavCanada Manops.