IFR approach question - KLS

[Ghery]

The attached plate is for the NDB or GPS-A approach to KLS. Assume you are coming south on the feeder route from MALAY, heading for the NDB.

The profile view shows leaving the NDB on a course of 351 degrees, decending to 3300 MSL, executing the procedure turn, crossing the NDB at 1800 MSL, turning to 149 degrees and making the approach.

Is this necessary? Can you cross the NDB coming in from MALAY, turn directly to 149 degrees and make the approach? If so, when do you decend from the 3700 foot minimum altitude for the feeder route to the 1800 MSL minimum altitude for crossing the NDB if you had gone north and made the procedure turn, followed by a descent to 1800 MSL? And if you are going to go for the procedure turn, do you cross the NDB at 3700 MSL, turn right to intercept the 351 degree radial from the NDB?

I talked with my CFII about this and I'm still a bit confused.

 

[pemora]

The attached plate is for the NDB or GPS-A approach to KLS. Assume you are coming south on the feeder route from MALAY, heading for the NDB.

The profile view shows leaving the NDB on a course of 351 degrees, decending to 3300 MSL, executing the procedure turn, crossing the NDB at 1800 MSL, turning to 149 degrees and making the approach.

Is this necessary? Can you cross the NDB coming in from MALAY, turn directly to 149 degrees and make the approach? If so, when do you decend from the 3700 foot minimum altitude for the feeder route to the 1800 MSL minimum altitude for crossing the NDB if you had gone north and made the procedure turn, followed by a descent to 1800 MSL? And if you are going to go for the procedure turn, do you cross the NDB at 3700 MSL, turn right to intercept the 351 degree radial from the NDB?

I talked with my CFII about this and I'm still a bit confused.

Not a CFII or a CFI but I am IR. Yes, executing the procedure turn is required (with some notable exceptions but you did not specify them in your text). Let's say that you only have an ADF (no GPS and no DME). Due to terrain avoidance, you must fly at 3,700' on the feeder route. When you get to the NDB, only then do you know that it is OK to decend. Yes, you turn right and fly outbound on the inital approach leg and decend to 3,300'. Do the procedure turn and fly back on the intermediate approach leg, etc.

You asked about intercepting the 351 at the NDB and then landing? From the feeder route, you would be at 3,700' and you want to land from the FAF at 3,700'? If you were in IMC, would you be able to do that? If you went missed and you were diving for the runway in IMC and you shocked cooled your engine, would you be able to depend on the engine to get you back to 3,300' when flying the missed approach?

I bet one of the things you are missing is that flying an instrument approach in IMC is not the same as flying with the foggles and looking out when you want. You want a very stable and easy to fly approach and don't want things happening too quickly. Best of luck once you get your IR!

 

[EdFred]

Not a CFII or a CFI but I am IR. Yes, executing the procedure turn is required (with some notable exceptions but you did not specify them in your text). Let's say that you only have an ADF (no GPS and no DME). Due to terrain avoidance, you must fly at 3,700' on the feeder route. When you get to the NDB, only then do you know that it is OK to decend. Yes, you turn right and fly outbound on the inital approach leg and decend to 3,300'. Do the procedure turn and fly back on the intermediate approach leg, etc.

You asked about intercepting the 351 at the NDB and then landing? From the feeder route, you would be at 3,700' and you want to land from the FAF at 3,700'? If you were in IMC, would you be able to do that? If you went missed and you were diving for the runway in IMC and you shocked cooled your engine, would you be able to depend on the engine to get you back to 3,300' when flying the missed approach?

I bet one of the things you are missing is that flying an instrument approach in IMC is not the same as flying with the foggles and looking out when you want. You want a very stable and easy to fly approach and don't want things happening too quickly. Best of luck once you get your IR!

Ghery, flying it on your own (no radar vectors from ATC) you would fly to the NDB from MALAY (or anywhere else for that matter), fly back to the north on the 351, do the PT, then fly back to the NDB and make the turn to the airport. Maintain 3700 from MALAY, starting the PT outbound descend to 3300, once inbound, down to 1800, then to 1120.

 

[Clark1961]

The attached plate is for the NDB or GPS-A approach to KLS. Assume you are coming south on the feeder route from MALAY, heading for the NDB.

The profile view shows leaving the NDB on a course of 351 degrees, decending to 3300 MSL, executing the procedure turn, crossing the NDB at 1800 MSL, turning to 149 degrees and making the approach.

Is this necessary? Can you cross the NDB coming in from MALAY, turn directly to 149 degrees and make the approach? If so, when do you decend from the 3700 foot minimum altitude for the feeder route to the 1800 MSL minimum altitude for crossing the NDB if you had gone north and made the procedure turn, followed by a descent to 1800 MSL? And if you are going to go for the procedure turn, do you cross the NDB at 3700 MSL, turn right to intercept the 351 degree radial from the NDB?

In general I agree with pemora and Ed.

Unless a feeder route is labeled NoPT, the PT is required when flying the full procedure. Vectors to final eliminates the PT requirement and you can always verify that with the controller.

The feeder route must be flown at or above the feeder route altitude as it is depicted on the plate. The descent to 3,300 can begin once outbound from the NDB. Some folks have told me that the descent cannot be started until inbound from the PT but that is not true (as I understand it). Maybe some of the more experienced folks can shed a little light on that particular argument. I've heard it suggested that someone might be on the approach ahead of you (inbound while you're outbound) but I think that shouldn't happen on a pilot navigated approach.

 

[gismo]

The attached plate is for the NDB or GPS-A approach to KLS. Assume you are coming south on the feeder route from MALAY, heading for the NDB.

The profile view shows leaving the NDB on a course of 351 degrees, decending to 3300 MSL, executing the procedure turn, crossing the NDB at 1800 MSL, turning to 149 degrees and making the approach.

Is this necessary? Can you cross the NDB coming in from MALAY, turn directly to 149 degrees and make the approach?

I talked with my CFII about this and I'm still a bit confused.

The simple answers to your first 2 questions are yes (it's necessary) to the first and no (you cannot) to the second. The issue you raise with your third question is actually one of the reasons why. An exception might exist if radar coverage extends low enough that you could get vectored onto the approach, in which case that would still occur somewhere north/east of the NDB.

First of all, while it may appear that one or more alternative paths besides the charted ones might work, you have no way of knowing this for certain. All approaches are planned using specific rules and procedures that are intended to insure that what they publish is safe. Then some actually goes out and flies the approach using extra instrumentation to determine if the navaid guidance etc is working properly in the areas that matter. Any time you deviate from the published approach on your own you may be eliminating all of these safeguards.

Second, you do need adequate time/distance to descend and the procedure turn provides that. Finally, with only 1.8 nm from the NDB to the runway you need to be pretty well established in your NDB tracking and the larger turn from the feeder to the final segment would make that more difficult. Normally the intermediate segment and PT would be more aligned with the FAC but in this case there must be some obstruction(s) that dictate a bend at the NDB and those rules of approach procedure construction limit how much of a bend is allowed which is likely why the intermediate segment isn't aligned with the feeder.

If so, when do you decend from the 3700 foot minimum altitude for the feeder route to the 1800 MSL minimum altitude for crossing the NDB if you had gone north and made the procedure turn, followed by a descent to 1800 MSL? And if you are going to go for the procedure turn, do you cross the NDB at 3700 MSL, turn right to intercept the 351 degree radial from the NDB?

The normal sequence for descent would be to fly the feeder to the NDB at or above 3700 ft. Then make the turn to the outbound segment and begin your descent to 3300 once you are established on that course. Then make the PT and begin your descent to 1800 once you are established inbound to the NDB on the 171° course segment. After crossing the NDB you can descend to the MDA.

Keep in mind that you should never descend to the next lower altitude on an approach until you are clearly "established" on the appropriate segment of the plan view. In this case established on the outbound means you are within 10 degrees of the outbound course of 351 and on a heading that's either paralleling that course or bringing you closer at an angle of less than about 30 degrees. Same thing coming out of the PT, you don't start down to 1800 until you are certain you are tracking the inbound course within those parameters. There's a reason that the PT altitude is 3300 ft, and chances are if you were down at 1800 and much more than 10 degrees off the inbound course you could encounter some very dense air (aka rocks or steel).

Also, these are the minimum altitudes for each portion of the approach, which apply once you are cleared for the approach without further altitude restrictions. For instance if you were assigned 5000 MSL coming into MALAY and didn't receive an approach clearance until some time after crossing that intersection, you'd have to stay at 5000 until cleared for the approach.

 

[Ghery]

You asked about intercepting the 351 at the NDB and then landing? From the feeder route, you would be at 3,700' and you want to land from the FAF at 3,700'? If you were in IMC, would you be able to do that? If you went missed and you were diving for the runway in IMC and you shocked cooled your engine, would you be able to depend on the engine to get you back to 3,300' when flying the missed approach?

I have On Top configured like the 182 I fly. All steam gauges, no GPS, do have DME. You have noted my concern with flying to the NDB on the feeder route, then heading for the runway. 3700 to 200 MSL in 1.8 nm just doesn't sound like fun at all. And I couldn't see any way to get to 1800 MSL on the feeder route.

We would have flown to KLS a week ago, but weather suggested that we might not liked the conditions (expected the freezing level to be at or below our cruise level, and we would have been in the clouds) so I cancelled that plan and we filed to HQM and shot the ILS instead. So this has only been an On Top exercise so far. And I haven't changed the defaults for clouds yet and haven't seen KLS. I keep executing the missed instead. Oh well, NDB holds are good practise, as well.

 

[ghogue]

It has been stated several times in this thread that you need to be outbound on the PT before beginning descent from 3700'. That is incorrect for this approach and in fact for the majority of approaches. On this approach, flying the feeder from MALAY, you may begin descent to 3300' as soon as you pass KELSO, even while south of the fix and turning to fly the PT. You may certainly wait until outbound if you wish, but it is legal and perfectly safe to begin the descent immediately after the IAF. This is because it does not have a restricted entry for the PT. See the AIM entry below and take a look at the figures listed.

From AIM 5-4-9. Procedure Turn and Hold-in-lieu of Procedure Turn

2. Descent to the procedure turn (PT) completion altitude from the PT fix altitude (when one has been published or assigned by ATC) must not begin until crossing over the PT fix or abeam and proceeding outbound. Some procedures contain a note in the chart profile view that says “Maintain (altitude) or above until established outbound for procedure turn” (See FIG 5-4-14). Newer procedures will simply depict an “at or above” altitude at the PT fix without a chart note (See FIG 5-4-15). Both are there to ensure required obstacle clearance is provided in the procedure turn entry zone (See FIG 5-4-16). Absence of a chart note or specified minimum altitude adjacent to the PT fix is an indication that descent to the procedure turn altitude can commence immediately upon crossing over the PT fix, regardless of the direction of flight. This is because the minimum altitudes in the PT entry zone and the PT maneuvering zone are the same.

 

[TangoWhiskey]

Look at that MSA circle. 9500' in the quadrant from which you arrive via MALAY. There's foothills under you even at 3700' coming into Kelso. Not sure I'd want to stray from the charted altitudes til I had a good, known position (crossing over the NDB provides that).

 

[gismo]

It has been stated several times in this thread that you need to be outbound on the PT before beginning descent from 3700'. That is incorrect for this approach and in fact for the majority of approaches. On this approach, flying the feeder from MALAY, you may begin descent to 3300' as soon as you pass KELSO, even while south of the fix and turning to fly the PT. You may certainly wait until outbound if you wish, but it is legal and perfectly safe to begin the descent immediately after the IAF. This is because it does not have a restricted entry for the PT. See the AIM entry below and take a look at the figures listed.

That's true but I'm just not comfortable with it, especially if I'm not very familiar with the underlying terrain. While there is indeed a fair amount of room in the vicinity of the NDB to turn it seems I'm usually going faster than I like (big turn radius) until turning outbound. And there won't be any problem getting from 3700 to 3300 before halfway through the PT so there's not much incentive, at least in this case. But it is good to know the real limits.

 

[poadeleted20]

Look at that MSA circle. 9500' in the quadrant from which you arrive via MALAY. There's foothills under you even at 3700' coming into Kelso. Not sure I'd want to stray from the charted altitudes til I had a good, known position (crossing over the NDB provides that).

The fact that there is nothing higher than 2200 feet within 10nm of Kelso NDB is probably why there's no limiting chart note, so I wouldn't break a sweat on a procedural level about leaving 3700 for 3300 immediately on first crossing of Kelso from MALAY.

Of course, I teach Turn-Time-Twist-Throttle-Talk as being sequential, not simultaneous, since descents in turns like this are where inexperienced folks often get over-focused on either the turn or the descent and blow though the other. So, if I were working with an IR trainee on the described transition and approach, I would have my trainee delay starting the descent until the turn to intercept the Kelso 351 bearing had been completed (i.e., rolling out on 021 or whatever to generate the intercept, not the actual intercept of the bearing). But that's technique, not procedure.