IFR "Fix Minimums" Question: KIPJ

[Jeff_S]

Hello all,

While prepping for an upcoming trip to Lincolnton NC (KIPJ) I was looking at the ILS charts. I noticed a different set of minimums for the localizer approach based on the GATEQ fix. These minimums allow a lower MDA, but it's not clear to me exactly how to use them. The chart is below. Any ideas? What am I missing?

 

[kmyfm20s]

As I read the briefing strip, If you have the local altimeter you can use the lower minimums. If you have to use the Charlotte altimeter you have to use the higher minimums.

[smwash02]

The briefing strip says that if you don't have the local altimeter, you raise the minimums for all.

If you can pick up the GATEQ fix successfully, you can continue to the lower MDA. I believe this is because there's a lateral obstacle that if you continued to descend at the faster rate (to the lower MDA) and were off course, you wouldn't meet the required vertical approach safe buffer requirements (I forget the proper terminology).

 

[N201MKTurbo]

GATEQ can only be defined by DME or IFR GPS. If you have that equipment on board and can identify the GATEQ fix you can use the lower minimums.

This only applies to the MDA on the LOC or Circling approaches. The DA doesn't change for the ILS. 

Edited July 4, 2016 by N201MKTurbo

[M20F]

2 hours ago, N201MKTurbo said:

GATEQ can only be defined by DME or IFR GPS. If you have that equipment on board and can identify the GATEQ fix you can use the lower minimums.

This only applies to the MDA on the LOC or Circling approaches. The DA doesn't change for the ILS. 

Correct answer and if you look to north of the localizer it shows the tower you are avoiding fairly clearly.  Thus also the reason why you have to cross GATEQ at or above 1460.  

[Jeff_S]

Okay, that all makes sense. The funny thing is, this approach says "GPS Required" which technically means you have to have GPS to use it, so why would they even mention this extra set of minimums. There is an ILS Z approach as well that doesn't require GPS, and still lists the GATEQ minimums with GATEQ identified only by DME. (And DME is not listed as a requirement on the approach.) I did see the towers so I buy the logic, but it still seems a bit screwy to me.

[201er]

10 minutes ago, Jeff_S said:

Okay, that all makes sense. The funny thing is, this approach says "GPS Required" which technically means you have to have GPS to use it, so why would they even mention this extra set of minimums. There is an ILS Z approach as well that doesn't require GPS, and still lists the GATEQ minimums with GATEQ identified only by DME. (And DME is not listed as a requirement on the approach.) I did see the towers so I buy the logic, but it still seems a bit screwy to me.

I guess they got tired of people hitting that tower

[Bob_Belville]

1 hour ago, Jeff_S said:

Okay, that all makes sense. The funny thing is, this approach says "GPS Required" which technically means you have to have GPS to use it, so why would they even mention this extra set of minimums. There is an ILS Z approach as well that doesn't require GPS, and still lists the GATEQ minimums with GATEQ identified only by DME. (And DME is not listed as a requirement on the approach.) I did see the towers so I buy the logic, but it still seems a bit screwy to me.

I miss Jepp charts! Lots of info.

I wonder, I do not know, but the other 2 fixes on the LOC are labeled RADAR and are defined by BZM radials. Perhaps the GPS REQUIRED applies to that last fix only since ATC can confirm the other 2 fixes defined by the BZM 143 & 164 radials? (Perhaps both RADAR and BZM are suspect below 1460 MSL.)  

FWIW, the 1280' MDA with GATEQ matches the MDA for the LNAV approach.

So, for some reason you're flying a LOC approach but if you have a GPS you can take advantage of the lower MDA if you can identify GATEQ.

[Bob - S50]

If you compare the Z and the Y you can see some differences.

The Z has cross tuning radials for JIVOM and the Y does not.

The MSA altitudes are different.  If you are at 6000' for the Y, cleared direct JIVOM, and cleared for the approach, you could descend to 4900' within 30 miles and 3000' within 4 miles of JIVOM.  If you are coming from the northeast, it is NoPT so if you need to hold to lose altitude you need to ask for it.  If you are flying the Z, the MSA is 5800' all the way to JIVOM and you will need to use the holding pattern to descend (unless you think you can configure and lose 2800' in 7.4 NM.  Granted, ATC will probably give you something lower than 5800' before you get to JIVOM and clear you for the approach, but theoretically, it could happen.

The holding patterns are different.  The Z is one minute.  The Y is 4 NM.

The missed approaches are different.  The Y you go essentially directly back to JIVOM.  The Z you fly a heading to intercept a radial and then go to JIVOM.

Depending on your GPS, you may or may not have GATEQ in the database.  If not, you can use DME to identify it.  If you don't have DME and you don't have a GS, you have to use the higher minimums.

I think the main reason you need GPS for the Y is for the missed approach.

Interestingly, the way approaches are 'numbered', theoretically, ATC should be spring loaded to give you the Z approach.  You may need to ask for the Y if that's what you want.

Personally, I'd ask for the RNAV approach since the LPV minimums are the same as the ILS.

Bob

[carusoam]

Logic check...?

The tower that is 1028' tall at GATEQ is not very far from the flight path of the approach.

The monochrome nature of the chart doesn't make it stand out very much.

A missed setting of the altimeter increases the hazard.

descending too soon will increase the hazard.

The BZM radials are not used for some reason to identify GATEQ.  Not accurate enough for many VOR receivers / interpreters. (1° from the distance BZM is away = ? Miles)

GATEQ is only 3 DME away from the airport.

Note: my IR is a bit faded. I'm just getting practice in...

Best regards,

-a-

[midlifeflyer]

7 hours ago, Jeff_S said:

Okay, that all makes sense. The funny thing is, this approach says "GPS Required" which technically means you have to have GPS to use it, so why would they even mention this extra set of minimums. There is an ILS Z approach as well that doesn't require GPS, and still lists the GATEQ minimums with GATEQ identified only by DME. (And DME is not listed as a requirement on the approach.) I did see the towers so I buy the logic, but it still seems a bit screwy to me.

Without it, how would you know to stay at or above 1460 until GATEQ? 

DME is not listed as a requirement because it's not required. You can fly the approach without it using the higher minimums.

This is a pretty standard approach chart where there is a DME fix that allows for lower minimums. You still need to level off at 1460 until GATEQ, whether or not you have GPS or DME if you are doing the nonprecision LOC approach. Only if you can identify GATEW, you may go lower.

[Jerry 5TJ]

7 hours ago, Jeff_S said:

Okay, that all makes sense. The funny thing is, this approach says "GPS Required" which technically means you have to have GPS to use it, so why would they even mention this extra set of minimums. There is an ILS Z approach as well that doesn't require GPS, and still lists the GATEQ minimums with GATEQ identified only by DME. (And DME is not listed as a requirement on the approach.) I did see the towers so I buy the logic, but it still seems a bit screwy to me.

I read it as "GPS Required" for the missed approach.  You need it not to remain in the hold, that is defined by the localizer and DME distance, but you need GPS to fly direct to JIVOM.   I think if you have ILS and DME and an IFR approved (not necessarily WAAS) GPS you can fly this approach.  

If you DO have WAAS GPS fly the LPV approach to 23.  The DA is a whole four feet lower than for the ILS.  

[N201MKTurbo]

35 minutes ago, midlifeflyer said:

Without it, how would you know to stay at or above 1460 until GATEQ? 

DME is not listed as a requirement because it's not required. You can fly the approach without it using the higher minimums.

This is a pretty standard approach chart where there is a DME fix that allows for lower minimums. You still need to level off at 1460 until GATEQ, whether or not you have GPS or DME if you are doing the nonprecision LOC approach. Only if you can identify GATEW, you may go lower.

It looks to me like you could descend to 1280 until passing GATEQ and then descend to the airport if you have it in sight.

[midlifeflyer]

1 hour ago, N201MKTurbo said:

It looks to me like you could descend to 1280 until passing GATEQ and then descend to the airport if you have it in sight.

I think you need to look at the chart's's profile view and minimums again. If you still think you can go down to 1280 before crossing GATEQ, what do you think the 1460 is for?

[N201MKTurbo]

45 minutes ago, midlifeflyer said:

I think you need to look at the chart's's profile view and minimums again. If you still think you can go down to 1280 before crossing GATEQ, what do you think the 1460 is for?

I think GATQ has an *

[N201MKTurbo]

There are too many * on this chart. You are right the * at GATEQ is for the higher value if no altimeter. The VDP * is for the LOC.

[Jeff_S]

Ah, screw it. I'll just go to Gastonia instead! (The colleague I'm meeting says there are more options for lunch there as well...)

[Bob_Belville]

Just now, Jeff_S said:

Ah, screw it. I'll just go to Gastonia instead! (The colleague I'm meeting says there are more options for lunch there as well...)

If it is actually IMC Lincolnton would be better. 

KALH has GPS approaches to a 3700' runway and you'll probably be in the Class B unless it's VFR and you can stay under. 

[Jeff_S]

Yes, I was just kidding. I hadn't even looked at the plates for Gastonia yet. I am glad I posted the original topic, though...good refresher training.

[CaptainAB]

Gateq is the final approach fix for a localizer only approach. If you had vertical guidance and the full ILS you would be on the glideslope. Since you don't and you are flying a non precision approach you must maintain the stated altitude until crossing the FAF. At which point you start your timer and descend to your MDA. 

Thats how I'd fly if, though God knows why u wouldn't just fly the full ILS. 

 

Nope that's wrong.....oh well. Don't fly localizer only approaches !

 

 

Edited July 6, 2016 by CaptainAB

[Bob_Belville]

8 hours ago, CaptainAB said:

Gateq is the final approach fix for a localizer only approach. If you had vertical guidance and the full ILS you would be on the glideslope. Since you don't and you are flying a non precision approach you must maintain the stated altitude until crossing the FAF. At which point you start your timer and descend to your MDA. 

Thats how I'd fly if, though God knows why u wouldn't just fly the full ILS. 

 

Nope that's wrong.....oh well. Don't fly localizer only approaches !

 

 

As I opined above, I think the issue, the question, is how do I identify GATEQ in order to use the lower MDA.

ISTM that the reason that the "GPS REQ" is on the plate is that BZM VOR and ATC radar will become unreliable below 600 AGL. In order to descend to 400 AGL you have to have the GATEQ fix plotted by your GPS. You can fly the LOC approach w/o GPS but you cannot descend below 600 AGL until you have the runway environs is sight and are in a position to land or circle.

ICBW 

[midlifeflyer]

15 hours ago, N201MKTurbo said:

I think GATQ has an *

Sorry (Edit):

There are two asterisks in the profile view. The one by GATEQ tells you that the minimum altitude until GATEQ is 1540 when using the Charlotte altimeter.

The other one is identifying the VDP as LOC-only, although that applies to GATEQ even without the asterisk.

 

 

[midlifeflyer]

10 hours ago, Jeff_S said:

Ah, screw it. I'll just go to Gastonia instead! (The colleague I'm meeting says there are more options for lunch there as well...)

Everyone who has glideslope capability will fly the ILS unless the GS is NOTAM'd out of service. In that case, the stepdown/alternate minimums based on GATEQ are irrelevant. Simply not used just as the LOC-only minimums are not used when flying the ILS.

If GS is out of service, you are either going to go somewhere else, choose a different approach, or fly the LOC-only,  in which case, it's probably a good idea to know how to read this simple  approach chart.If you really don't understand it, I would suggest reviewing it with a CFI, perhaps as part of a FR or IPC.  Here it's a tower  to the sideyou might miss even if you do go below minimums. Elsewhere, the intermediate minimums might be there to keep you from hitting a ridge.

[midlifeflyer]

57 minutes ago, Bob_Belville said:

As I opined above, I think the issue, the question, is how do I identify GATEQ in order to use the lower MDA.

 

If that's the question, there are two ways. 3.0 DME off the LOC or GATEQ in the GPS database.

2.5 ways actually since you could load the LOC as a waypoint in a GPS and use 3 miles from that, but, practically speaking, I not sure someone who has GATEQ in the GPS database would do that (or for that matter, use the DME option) at all.

I have seen similar configurations in which the step-down could also be identified via a crossing VOR radial.

[Bob_Belville]

Mark, I suppose that if I loaded and activated the LOC-23 approach in my GTN 750 the GATEQ fix would be depicted and upon crossing it I could step down to the 400 AGL MDA. 

But if I have neither DME or GPS aboard I cannot identify GATEQ (=IPJ 3.0 DME) and I cannot go below 600 AGL. I can step down at JIVOM and CISBU identified either by the BZM radial crossing or ATC using their radar. Correct?