ILS approach

[ark 1,291]

27 minutes ago, JRBarrett said:

GPS is not part of the ILS infrastructure, but many ILS approaches ( at least here in the US) now require GPS to define the IF, IAF and missed approach holding fix. If ATC radar is not available it is not legal to fly the approach “as published” unless the aircraft is equipped with an IFR-certified GPS.

Very interesting, I no longer fly "for real" and was not aware of this. I now understand what sd_flyer was saying although I don't see any need for GPS for the ILS R24 at KCRQ.  I'll take a look at KELM.

Thanks,

Al

[sd_flyer 6,047]

8 hours ago, ark said:

Thanks, but as a instrumented rated PPL (in my younger days) I am well aware of that. That's why I was surprised by the response and was asking the question.  Since the context of my post was about ILS approaches I thought that was what the response was referring too.  Age problem! 😉

Al

EDIT: Based on the next post below, it looks like GPS is required in some cases to identify fixes associated with an ILS approach.

Most if not aircraft in out fleet were stripped of DME long time ago. GPS is next next alternative. So it's been used widely for approaches.

Just look at one of our GPS approach LPV minimum pretty much like ILS

[JRBarrett 3,080]

7 hours ago, ark said:

Very interesting, I no longer fly "for real" and was not aware of this. I now understand what sd_flyer was saying although I don't see any need for GPS for the ILS R24 at KCRQ.  I'll take a look at KELM.

Thanks,

Al

The KCRQ ILS requires DME according to the notes at the top of the approach plate.   All of the fixes on the approach are defined as DME distances from I-CRQ. In most cases, an IFR-certified GPS can legally be substituted for a DME in a case like this if the named approach fixes are present in the GPS’s approach database as named GPS waypoints. 

Usually, a note for a specific type of equipment on an approach plate such as “DME Required” or “ADF Required” does not apply if ATC radar vectors/guidance are available. These equipment mandates do apply when flying the full published approach without ATC guidance - such as late at night at a smaller controlled airport when many towers/approach control facilities are closed between local midnight at 6:00 AM. (That is the case at KELM).

Nowadays, an IFR GPS (preferably with WAAS/LPV capability) is almost a “must” for any GA aircraft that wants to fly IFR in the modern airspace system. VORs (and associated VOR approaches) are rapidly disappearing. Many Victor airways defined by VOR’s are being replaced by RNAV “Q” airways. Likewise, many NDBs are being decommissioned, and as mentioned, marker beacons are becoming as rare as hen’s teeth.

For an example of a more “old fashioned” ILS approach refer to the ILS 35 at KSLN. (Salina, KS). This approach still has an LOM (a paired NDB and outer marker), and does not carry any notes for mandated equipment (such as DME or ADF), but as a practical matter, there are limited options for how one can commence the approach without ATC guidance, and without GPS or DME.

The approach has 5 IAFS. Two of them, ZIDIB and ZOMON are defined as DME distances on specific radials of the SLN VOR and are followed by DME arcs. GUTER requires DME. ANTON is an RNAV waypoint and requires GPS (or IRS with an FMS). 

The only way to enter this approach without ATC, and without GPS or DME is to fly direct from the SLN VOR to the LOM FLORY, and fly a holding pattern to intercept the localizer - and that requires a working ADF receiver and (preferably) a marker beacon receiver.

Edited November 22, 2021 by JRBarrett

[ark 1,291]

2 hours ago, JRBarrett said:

Likewise, many NDBs are being decommissioned,

Yes, I know, and part of me hates to see this. I've always enjoyed the mental challenge of flying NDB approaches. There are still plenty of them outside the US, such as in Russia, and I like to fly these in the sim. If I was still flying real IFR though, I'd go with an ILS or LPV approach for sure!  🙂

Al

[JRBarrett 3,080]

Just now, ark said:

Yes, I know, and part of me hates to see this. I've always enjoyed the mental challenge of flying NDB approaches. There are still plenty of them outside the US, such as in Russia, and I like to fly these in the sim. If I was still flying real IFR though, I'd go with an ILS or LPV approach for sure!  🙂

Al

Yep. When I got my instrument rating in 1993, it was in a C172 with two VOR receivers, (one with glideslope), an ADF and a marker beacon receiver. That was all that was required. The practical test standards for the checkride (at that time) required the pilot demonstrate an ILS approach, a LOC-only approach, a VOR approach and an NDB approach. All were easily done locally. The VOR approach was at nearby Ithaca (KITH). That VOR no longer exists. The NDB approach was at ALP NDB at KELM. The NDB still exists, (for now) but there is no longer an NDB approach associated with it. 

I no longer actively fly either, but would certainly prefer to use LPV or ILS. The LPV approaches at KELM runway 6 and 24 have the same minimums as the corresponding ILS.

[ark 1,291]

5 minutes ago, JRBarrett said:

When I got my instrument rating in 1993, it was in a C172 with two VOR receivers, (one with glideslope), an ADF and a marker beacon receiver.

Same for me, except in my case it was in the mid 70s (that's the 1970s just to be clear!) and the a/c was a Piper Cherokee. The autopilot was just a wing leveler. Do you remember the training exercise of having to identify an intersection defined by two VOR radials with just a single Nav radio.  Things seem to have changed a wee bit!  😉

BTW, my flight training was through an Air Force aero club when I was stationed at Griffiss AFB (now KRME) in Rome, NY -- not to far from your home area of Elmira. Griffiss had B-52s, KC-135s and F-106s, so I was well schooled in wake turbulence issues. And the runway was almost 12,000ft long -- 'adequate' for a Piper Cherokee.

Al

[LouP 116]

Well, I am certainly showing my age here, also.  I guess I can toss that instrument rating for the 70s out the window.  🙂

LouP

[ryanbatc 12,859]

21 minutes ago, LouP said:

Well, I am certainly showing my age here, also.  I guess I can toss that instrument rating for the 70s out the window.  🙂

LouP

You can still fly approaches and airways like you would have before hehe!  I use skyvector to hunt for approaches sometimes.  For an NDB approach (very rare in the US these days) just look for the symbol on the low alt ifr enroute chart...and then search airports in that area....they're likely to have an ndb approach.  Still plenty of VOR approaches as well.  I'd say ILS is still very common in the USA at least.  I prefer to give a pilot an ILS - almost every aircraft is so equipped for one.  Not everyone is equipped for RNAV(GPS) approaches but they are taking over for sure.  Including an example pic as well.  Right click on any airport and it will show a list of approaches

rcx by Ryan Butterworth, on Flickr

Edited November 22, 2021 by ryanbatcund

[ark 1,291]

34 minutes ago, ryanbatcund said:

Right click on any airport and it will show a list of approaches

I use Sky Vector for approach charts, but did not realize you could get a list of approaches like that off the low IFR chart. That's a handy tip -- thanks.

Al

[Roy Warren 426]

I can't speak for the real world but for this sim I've missed a lot more approaches with ILS than RNAVs. I usually use RNAV as my first choice.

  Roy

[ryanbatc 12,859]

1 minute ago, ark said:

I use Sky Vector for approach charts, but did not realize you could get a list of approaches like that off the low IFR chart. That's a handy tip -- thanks.

Al

Oh, skyvector is amazing for free.  Hover your mouse over the airport (after that little menu pops up in my screenshot) and it'll populate a list of approaches.

[ronmarks 13]

Hate to see VHF nav fade. I know 'er well.

DME IS the replacement for the marker beacons. All or most ILS's now have a DME associated with the ILS freq, or will have. A standard low powered DME transponder was developed for airports and has a cost advantage over the marker systems, since no off airport real estate is necessary and the hardware and installations are simple. The ground box is actually less complicated than the corresponding airborne units needed to complete the system.

However,  it is my opinion that the FAA pulled the plug too soon on the marker beacon system.  Most general aviation aircraft do not have DME, and affordable new designs have not been developed.  This leaves the function to a GPS position. Legal GPS nav boxes are $5000+ and the install needs to be certified. And if you do have the GPS system, then both ILS and GPS approaches are gone on GPS jamming.  No GPS, no approach.

I know there are practical work arounds, maybe some one current can comment. 

ILS is not going away in the USA, though. It is still the primary approach system for larger airports.  It is the official redundant and necessary approach backup for GPS if GPS goes toes up.

Ron CPSMEL

 

 

[langly 129]

Oh nice, another thread that devolves into a "look at how old I am".

Seriously, nobody cares.

[Stearmandriver 2,304]

ILS systems are not going away anytime soon.  Certainly for smaller airports, the cost/benefit analysis leans towards GPS LPV procedures. 

Those don't *quite* equal the standard cat I ILS though; while they may have 200 and 1/2 minimums,  there's never a provision for a visibility reduction.  Most cat I ILS mins can be reduced to 1800RVR either as a Special Authorization approach, or as a normal approach with the use of autopilot, flight director or HUD to mins.  Often the difference between 2400 and 1800RVR makes the difference as to whether a commercial operator can accept the approach. 

Then there are cat III / III ILS procedures.  No sat based procedure comes close to cat II mins, and no aircraft in existence is certified to autoland using sat based guidance.

Enroute navaids are definitely being phased out, and so are ILSs at airports without much in the way of commercial ops.  But for commercial-use airports, ILSs aren't going anywhere. 

[Ray Proudfoot 8,964]

5 hours ago, langly said:

Oh nice, another thread that devolves into a "look at how old I am".

Seriously, nobody cares.

I didn’t realise you speak for everyone. If you have nothing of value to say I suggest you refrain from posting.