Interesting GPS approach at KMTV

[aterpster]

That's something "new" to me. Not trying to argue the point, but what I remember is first was a diverse study, then apply restrictions and finally a "route" procedure if absolutely necessary. Since routes are much less flexible for operators I would think they would still be a last resort.

The visual departure at MTV allows you to be at 2700' over the airport with another 800 feet to climb to MEA of 3500' and right on the centerline of V103. At 200'/nm, you'll be 4 nm north which is 1.3 nm south of HENBY by the time you reach MEA. That's under 40 nm from ROA--a safe procedure even with minimum climb gradient and no enroute progress during the climb. At 3B1, and Milton, NY, IIRC, Boston won't (wouldn't?) grant a clearance under similar circumstances unless you're in the privileged class (RNAV). But, we digress...

dtuuri

Here is the pertinent language:

8260.46D:
The primary goal in ODP development is to retain standard takeoff minimums
with standard climb gradient to the extent possible. See table 2-1 for recommended ODP
development combinations.

ODPs must be developed with primary emphasis given to using the least onerous
route (see appendix G) to the en route structure or at an altitude that will allow random (diverse)
IFR flight, while accommodating commonly used routings out of each airport to the maximum
extent practicable. Procedure designers must consider the impact on local ATC operations when
using the phrases "before turning" or "before proceeding on course." ODPs must be coordinated
with ATC to ensure flight safety and compatibility with the local operating environment and the
en route structure.

Note that, where possible a route ODP can become diverse rather than proceeding all the way to the en route structure.

 

[poadeleted20]

It was here in Post #63, assume you were cleared as filed and being very user friendly, ATC will clear you for whatever approach you ask for after BUVBE, if they can hear you that is:

Again, you're giving generalizations, and the details do matter. Either give me the exact clearance and tell me when and where ATC gave it to me, or stop bothering me.

 

[dtuuri]

Again, you're giving generalizations, and the details do matter. Either give me the exact clearance and tell me when and where ATC gave it to me, or stop bothering me.

Ok, I can see you don't want to play. I wonder what Nosehair would do?

dtuuri

 

[poadeleted20]

Ok, I can see you don't want to play.

You're right -- I'm not being trolled today.

 

[dtuuri]

Here is the pertinent language:

8260.46D:<snip>

I don't find that to be at odds with Table 1 of the same document where "route" is used like this, "route/sector". Doesn't flying a heading qualify as a sector restriction? It was spelled out better in the original 8260.3, as I remember. So, according to Table 1, diverse is still first, restrictions (like sectors) next, or specific routes if you have to. But if a route is used, it means positive course guidance which isn't available at many places and a highly specific direction of flight which isn't very operationally flexible. I don't see any advantage to wanting that.

dtuuri

 

[John Collins]

Procedure development guidelines have changed over time. I would guess that many approach procedures don't meet the current design guidelines. As the FAA reviews these procedures they are slowly brought up to more current standards, but not always. Approaches designed now a days often have restrictions on their use and not every approach may be joined from all possible airways or on random routes from all possible directions. Many procedures have notes to this effect.

The current NAS enroute system is predominantly based on airways and Jet Routes. Most approaches are designed with either a Feeder or an IAF to take an aircraft from the airway structure to the approach. RNAV navigation opens up new choices such as random routes and TAA feeder segments. Note that the TAA segments are designed to have the airways pass thru them and then the RNAV equipped aircraft proceeds to the relevant IAF via the TAA segment which acts in effect as a feeder route from the airway. Although I haven't seen an example, there are no other Feeder routes from the airway structure when a TAA is used except in the case where the TAA doesn't encompass an airway. I am told there are examples in Alaska.

For random routes, the HILPT supports getting established when not using a feeder route. In most cases, a random route requires radar monitoring, but even this will be changed shortly. Without a feeder, or route, or HILPT or PT to get aligned, it often requires radar vectors to join the approach.

Not all approach feeder routes are limited to 120 degree turns. I use the ILS 24 at KHKY http://155.178.201.160/d-tpp/1310/00706IL24.PDF as an example, look at the feeder route from BZM, you turn the shortest way from 219 degrees to the outbound course on the localizer of 61 degrees, which is most likely accomplished with a 180 degree left turn to intercept the outbound course with a 22 degree intercept.

 

[dtuuri]

Not all approach feeder routes are limited to 120 degree turns. I use the ILS 24 at KHKY http://155.178.201.160/d-tpp/1310/00706IL24.PDF as an example, look at the feeder route from BZM, you turn the shortest way from 219 degrees to the outbound course on the localizer of 61 degrees, which is most likely accomplished with a 180 degree left turn to intercept the outbound course with a 22 degree intercept.

In that example there's a prescribed course reversal after the IAF (LOM). The murky thing we're talking about is when there isn't, like at MTV and OMH. Radar isn't required at either place and there are no notes restricting the approaches to certain arrival airways. It begs the question, "Is this a mistake or am I protected if I just make an ordinary turn at the fix to intercept the inbound course?" Pilots shouldn't be left wondering, it should be crystal clear, imo.

dtuuri

 

[aterpster]

I don't find that to be at odds with Table 1 of the same document where "route" is used like this, "route/sector". Doesn't flying a heading qualify as a sector restriction? It was spelled out better in the original 8260.3, as I remember. So, according to Table 1, diverse is still first, restrictions (like sectors) next, or specific routes if you have to. But if a route is used, it means positive course guidance which isn't available at many places and a highly specific direction of flight which isn't very operationally flexible. I don't see any advantage to wanting that.

dtuuri

Change the location to KSVC and your span can can't make good the climb gradient. You are Part 135 and the wx is 100-1.

 

[aterpster]

Not all approach feeder routes are limited to 120 degree turns. I use the ILS 24 at KHKY http://155.178.201.160/d-tpp/1310/00706IL24.PDF as an example, look at the feeder route from BZM, you turn the shortest way from 219 degrees to the outbound course on the localizer of 61 degrees, which is most likely accomplished with a 180 degree left turn to intercept the outbound course with a 22 degree intercept.

That's a feeder route to a procedure turn. There is no limit on the angle of intercept into a procedure turn area.

 

[aterpster]

I sure as heck am. I'll use anything I have in the cockpit to stay alive. I once used the terrain following radar in the F-111 to stay alive when a Turkish controller misidentified us and tried to send us into the mountains below the tops. My pilot didn't want to turn away from them since the controller was insisting the vector was correct, but I did manage to convince him that there wouldn't be anyone else out there to hit at 400 AGL in the clouds amongst the rocks even if we climbed above our assigned MSL altitude.

Military ops have a different set of tactical requirements.

I'm not sure we are on the same page about TAWS in civil operations. It is a life-saving device, not a navigation tool.

 

[dtuuri]

Change the location to KSVC and your span can can't make good the climb gradient. You are Part 135 and the wx is 100-1.

Perhaps we're both saying the same thing then. My point is a diverse departure has the shallowest climb requirement through the greatest azimuth possible and therefore is the ideal situation. When that's not possible, the choices are higher minimums, steeper climb gradients, restricted sectors or positive course guidance along just one specific track. Somebody needs to make a decision that optimizes the most benefit for the most operators, I'd think, which would inevitably make some folks unhappy sooner or later. But it's better to not have only one track like the ODP out of JAC, that went 50 nm west, which led to the Mooney pilot killing himself and his sons because he wanted to go east and didn't fully understand the implications of not following the single safe track the opposite way (among other reasons).

dtuuri

 

[aterpster]

Perhaps we're both saying the same thing then. My point is a diverse departure has the shallowest climb requirement through the greatest azimuth possible and therefore is the ideal situation. When that's not possible, the choices are higher minimums, steeper climb gradients, restricted sectors or positive course guidance along just one specific track. Somebody needs to make a decision that optimizes the most benefit for the most operators, I'd think, which would inevitably make some folks unhappy sooner or later. But it's better to not have only one track like the ODP out of JAC, that went 50 nm west, which led to the Mooney pilot killing himself and his sons because he wanted to go east and didn't fully understand the implications of not following the single safe track the opposite way (among other reasons).

dtuuri

KJAC used to have an ODP predicated on the JAC VOR, which did a tear drop departure to cross JAC at an Omni direction safe altitude. But, the airlines wanted something more efficient, thus the RNAV ODP you mentioned.

That violated policy because the VOR "loop" ODP was still viable.

But, the folks in OKC wanted to accommodate the carriers so they should have retained the VOR loop ODP and also developed an RNAV SID for the airlines and other high end operators.

Needless to say, the Mooney pilot was operating way outside his capabilities.

Having said all that, the airport should still have VOR ODPs, but it doesn't. OKC speak with forked tongue.