Why no DME?

[smv]

How can this approach not be a "DME REQUIRED" approach? I get that you can run a timer from FAF to MAP, but does that make sense to be the only way to identify the MAP?

 

[N1120A]

You couldn't do the arc, but you could do the straight in (to the VOR, not a runway) with a timer.

 

[Jim K]

What's the problem? You can identify the FAF without dme (obviously). You only need one way to identify the MAP, and one of those is time, which is just as precise as a crossing radial from another VOR. Probably more so.

 

[Jim Carpenter]

This set-up used to be quite common for non-precision approaches. Probably every NDB approach that uses (used) the LOM (outer marker) beacon as the navaid for the approach relied on timing from crossing the station to MAP, there is nothing else that could be used. With VORs, some used for approach similar to the one shown, the VOR may not have been a VOR/DME at all. Others, like this one with a VOR/DME may have 2 sets of minimums, where DME is uses for step-down fixes inbound, so if equipped with DME, it may be flown to lower minimums after positive ID of each fix, whereas without DME capability, approach could be flown, but higher minimums. It's of course easier and "more precise" with DME, timing is based on ground speed, which in a bare-bones equipped plane, say, single VOR without DME, (or, ADF radio for use with NDB approach) is only an estimate, thus making fix crossing a bit more "fuzzy" than with DME or crossing radials.
I might guess that this Dickinson VOR-A approach was left as-is, that way it's available to aircraft without DME (or GPS) on board, yes there are still a few!

 

[RussR]

Since you can identify the MAP using timing, DME is not REQUIRED. Why do you think it should be?

If you do have DME, you can use it to identify the MAP at 3.6 DME, but you don’t have to have it, therefore it’s not required.

 

[ja_user]

As has been said, it is possible to fly this approach without it (not from every IAP obviously) so therefore it is not required.

 

[aterpster]

As has been said, it is possible to fly this approach without it (not from every IAP obviously) so therefore it is not required.

Think you mean "every IAF" not "every IAP."

 

[ja_user]

Think you mean "every IAF" not "every IAP."

You are correct.

 

[Ravioli]

And an actual question for @smv and @aterpster(who knows this stuff inside out):

Why would we WANT more equipment requirements when not needed for regulatory or safety needs on an IAP?

 

[N1120A]

I guess the comment was deleted, but DIK is a VORTAC. The TACAN portion provides DME.

 

[aterpster]

And an actual question for @smv and @aterpster(who knows this stuff inside out):

Why would we WANT more equipment requirements when not needed for regulatory or safety needs on an IAP?

We don't, nor do the FAA designers. (well, there are some exceptions in the latter case.)

 

[smv]

And an actual question for @smv and @aterpster(who knows this stuff inside out):

Why would we WANT more equipment requirements when not needed for regulatory or safety needs on an IAP?

Who said I wanted it to be DME Required?

I am having a hard enough time finding enough available approaches in this area that can be done in a /U. This one, the VOR-A at KBIS, and the four VOR approaches at KMOT are about all we got. Everything else requires DME, GPS, or even ADF (for an ILS, no less). None of which we have.

 

[Larry in TN]

I am having a hard enough time finding enough available approaches in this area that can be done in a /U.

Times have changed.

I did my initial instrument rating in 1985 in a 1960 C-310E. It was equipped with two King KNX-170B NAV/COMS, one ADF receiver, and a mode-c transponder. No DME and that was completely normal. Only the fancy corporate airplanes had DME and only a very few of those had the wizardry of the King HNS-80 course-line computer RNAV.

BTW, I had to pay $78/hr wet for the C-310! It was so expensive we'd speed through the taxi, runup, and takeoff to keep the cost down.

 

[iamtheari]

Who said I wanted it to be DME Required?

I am having a hard enough time finding enough available approaches in this area that can be done in a /U. This one, the VOR-A at KBIS, and the four VOR approaches at KMOT are about all we got. Everything else requires DME, GPS, or even ADF (for an ILS, no less). None of which we have.

I found a few ILS's for you, but most aren't terribly close:

• KGFK ILS or LOC RWY 35L (can be flown with radar, DME, or ADF; 166 nm from KMOT)
• KPIR ILS or LOC RWY 31 (236 nm)
• KATY ILS or LOC RWY 35 (263 nm)
• KAXN ILS or LOC RWY 31 (280 nm)

You can also fly the ILS's at KMIB, KRDR, and KRCA, with DME or radar service. But ... don't land.

 

[smv]

I found a few ILS's for you, but most aren't terribly close:

• KGFK ILS or LOC RWY 35L (can be flown with radar, DME, or ADF; 166 nm from KMOT)
• KPIR ILS or LOC RWY 31 (236 nm)
• KATY ILS or LOC RWY 35 (263 nm)
• KAXN ILS or LOC RWY 31 (280 nm)

You can also fly the ILS's at KMIB, KRDR, and KRCA, with DME or radar service. But ... don't land.

I appreciate that but we are not actually flying out of KMOT, we are flying to KMOT (~90nm). KXWA is the closest "big" airport but everything there requires either GPS or DME.

Whereas radar vectors would work just fine for making actual approaches, I am trying to find approaches without radar and within the capabilities of the airplane for my students to fly from IAP to MAP sans vectors.

Given today's prevailing conditions, these are the ETEs from homebase to each of them:

KPIR > 2:45
KGFK > 2:52
KATY > 3:51
KAXN > 4:02

Even KBIL is >2 hours away...

Looks like it might be time to talk to the owner about upgrading the panel a little...

 

[smv]

You can also fly the ILS's at KMIB, KRDR, and KRCA, with DME or radar service. But ... don't land.

As a primary student with like 20 hours in the books I got to do a T&G at PGUA. That was cool crusing past all those B-52s.

 

[iamtheari]

I appreciate that but we are not actually flying out of KMOT, we are flying to KMOT (~90nm). KXWA is the closest "big" airport but everything there requires either GPS or DME.

Whereas radar vectors would work just fine for making actual approaches, I am trying to find approaches without radar and within the capabilities of the airplane for my students to fly from IAP to MAP sans vectors.

Given today's prevailing conditions, these are the ETEs from homebase to each of them:

KPIR > 2:45
KGFK > 2:52
KATY > 3:51
KAXN > 4:02

Even KBIL is >2 hours away...

Looks like it might be time to talk to the owner about upgrading the panel a little...

There are also major storm cells in the way from your home base in every direction today, but that's beside the point.

My thought is that it is not currently realistic to fly IFR with /U equipment in the upper Midwest. Having an instrument rating and a /U airplane is as useful as having a private pilot license and an airplane without a propeller. It sure looks nice, but it won't go far.

I would not have even been able to take my instrument rating check ride at KBIS without WAAS, since the ILS glideslope was out of service during runway construction that summer. If you can't take the check ride, I submit that it's time for an upgrade.

It's easy to spend other people's money. But ... just get a GPS 175, GNC 355, or (if the plane also needs ADS-B) GNX 375. It will turn the instrument rating into a real travel tool just like having a private pilot license and an airworthy airplane.

 

[smv]

There are also major storm cells in the way from your home base in every direction today, but that's beside the point.

Ha! Ya... Something about "Tornado Warning" that just kinda takes the motivation away... I was working outside this morning with a watchful eye over my shoulder. About the time the air started to crackle I moved my operations indoors.

My thought is that it is not currently realistic to fly IFR with /U equipment in the upper Midwest. Having an instrument rating and a /U airplane is as useful as having a private pilot license and an airplane without a propeller. It sure looks nice, but it won't go far.

I would not have even been able to take my instrument rating check ride at KBIS without WAAS, since the ILS glideslope was out of service during runway construction that summer. If you can't take the check ride, I submit that it's time for an upgrade.

It's easy to spend other people's money. But ... just get a GPS 175, GNC 355, or (if the plane also needs ADS-B) GNX 375. It will turn the instrument rating into a real travel tool just like having a private pilot license and an airworthy airplane.

We are using the /U for now to ensure basic instrument flying is under control. He is very excited about the whole thing and really enjoyed the 0.5 IMC we got Sunday morning doing an actual VOR approach from IAP to Full Stop. We have another airplane that has been at the shop for eight weeks getting a panel upgrade. When it is done it will have at least a GNX375 and maybe a couple other new goodies. Hopefully they are also going to replace the S-Tec 30... It will become our primary IFR machine but there is no reason to not get the basics done in the /U while we wait.

 

[iamtheari]

We are using the /U for now to ensure basic instrument flying is under control. He is very excited about the whole thing and really enjoyed the 0.5 IMC we got Sunday morning doing an actual VOR approach from IAP to Full Stop. We have another airplane that has been at the shop for eight weeks getting a panel upgrade. When it is done it will have at least a GNX375 and maybe a couple other new goodies. Hopefully they are also going to replace the S-Tec 30... It will become our primary IFR machine but there is no reason to not get the basics done in the /U while we wait.

True enough. Aviate, navigate, communicate. You don't need the radio for the aviating.