GPS In Lieu Of NDB On A Missed Approach???

CaptainTeezy · 10-13-2008, 02:24 PM

I am going to have to fly the KRBD ILS 31 approach on a check ride and can't figure out if I actually have to have an onboard ADF for the missed approach segment. Here is the approach plate. http://204.108.4.16/d-tpp/0810/00742IL31.PDF If you actually had to do the missed approach you would have to use an NDB bearing to hold. The aircraft the school uses does not have and ADF.

*In the AIM 1-2-3 a(1) says you can substitute RNAV (GPS) for VOR, NDB, DME, or compass locators.

*In the AIM 5-4-5 3(b) says if you see big bold ADF REQUIRED on the approach plate then it is required (IE on a missed approach)

*According to an FAA publication NOTE 3 towards the bottom makes it sound as if you dont need to worry about ADF REQUIRED in big bold letters. Use of Area Navigation

And my last question...if you don't have an ADF but you have an IFR certified GPS how would you hold on an NDB bearing with the GPS??? I tried experimenting by using the OBS and trying to select a "radial" (basically turn it into a VOR) in the GPS in the sim but it was very complicated and not easily accessible.

Another side note...when I was an instructor a student and I asked a DE, The JEPP company, and 2 different FSDO's. The end result was nobody knew for sure and we got 2 different answers from the FSDO's.

coldpilot · 10-13-2008, 02:34 PM

Quote:

Originally Posted by CaptainTeezy

I am going to have to fly the KRBD ILS 31 approach on a check ride and can't figure out if I actually have to have an onboard ADF for the missed approach segment. Here is the approach plate. http://204.108.4.16/d-tpp/0810/00742IL31.PDF If you actually had to do the missed approach you would have to use an NDB bearing to hold. The aircraft the school uses does not have and ADF.

*In the AIM 1-2-3 a(1) says you can substitute RNAV (GPS) for VOR, NDB, DME, or compass locators.

*In the AIM 5-4-5 3(b) says if you see big bold ADF REQUIRED on the approach plate then it is required (IE on a missed approach)

*According to an FAA publication NOTE 3 towards the bottom makes it sound as if you dont need to worry about ADF REQUIRED in big bold letters. Use of Area Navigation

And my last question...if you don't have an ADF but you have an IFR certified GPS how would you hold on an NDB bearing with the GPS??? I tried experimenting by using the OBS and trying to select a "radial" (basically turn it into a VOR) in the GPS in the sim but it was very complicated and not easily accessible.

Another side note...when I was an instructor a student and I asked a DE, The JEPP company, and 2 different FSDO's. The end result was nobody knew for sure and we got 2 different answers from the FSDO's.

The approach that you provided says ADF REQUIRED in big bold letters in the top left of the plan view. Simple enough.

rickair7777 · 10-13-2008, 07:23 PM

The FAA Pub seems to authorize the use of (certified) GPS in lieu of ground based navaids, except for localizer final course guidance. This would seem to supercede "ADF Required" on the approach plate.

This makes sense, since any functioning GPS will be AT LEAST as accurate as an NDB

As to tracking a radial with the GPS, the knobology for that is manufacturer specific...check the manual.

CaptainTeezy · 10-14-2008, 12:58 AM

Thanks RickAir...it just shows how unorganized the FAA is...I swear if the FAA ran the show "survivor" they would put up a fence in the desert around the only water supply and then have a big sign saying IF YOU CROSS THIS LINE YOU WILL BE SHOT...and then they verbally ask you, "Hey are you thirsty, do you want some water? What are you waiting for come get some water!" All while one guy is holding a Bible and the other is loading a rifle.

Ewfflyer · 10-14-2008, 06:02 AM

You're golden with the GPS, just verify that the appropriate waypoints are in the database. Garmin 430/530 makes this procedure extremely easy, but it is still very manageable in a KLN90B also. I haven't flown enough KLN94's to remember what they do with MAP's and holds

Yeffro · 10-14-2008, 07:49 AM

It appears you cannot legally accomplish the Missed Approach Procedure without an ADF. Here is an excerpt from the KLN-94's Manual.

Quote:

On the APT 8 page showing
the list of approaches, remember
that non-approved
approaches do not have the
letters “GPS” after the
approach name. In figure 651,
the ILS 01L and the VOR Figure 6-51
01L approaches are not
approved for GPS.
6-35

Chapter 6 Approaches and DP/STARs

•
When a non-approved
approach is selected, a page
as shown in figure 6-52 is displayed
to remind you that the
KLN 94 can only be used to
provide situational awareness Figure 6-52
for monitoring the approach.
You must acknowledge the page by pressing F. Approved navigation
equipment such as VOR/ILS, DME, ADF, etc. must be used
as the primary source of navigation.
•
Since another navigation source is providing primary navigation
guidance, the KLN 94 may not be driving the CDI or HSI. One consequence
of this is that if the OBS mode is used, such as for a
missed approach procedure, the selected OBS course will have to
be manually entered by pressing B and using the right inner knob
to enter the desired value.
•
The unit will NOT enter the approach active mode. It will remain in
approach arm (APR ARM) or terminal (TERM) mode depending on
how the unit has been configured (see section 6.2.1).
6.2.13. USING GPS DISTANCE AS A SUBSTITUTE FOR DME ON
LOCALIZER-TYPE APPROACHES
The FAA allows the use of GPS distance as a substitute for DME on local-
izer-type approaches when the DME facility is stored in the GPS
database. The KLN 94 stores DME’s associated with localizer-type
approaches using the navaid identifier of the approach. For example, the
DME facility associated with the ILS DME Rwy 33 approach for Burlington
International airport is stored in the KLN 94’s database as IVOE (figure 653).
These DME’s are stored in the intersection part of the database.

NOTE: Approach DME facilities are not stored as waypoints that are part
of an approach procedure so you can not gain access to them by calling
up the associated approach. For example, IVOE is not included in the
waypoints that would be loaded into FPL 0 if you selected the ILS 33 for
Burlington International. To get distance from the IVOE DME facility enter
IVOE as a normal flight plan waypoint or direct to waypoint

ppilot · 10-14-2008, 09:05 AM

Quote:

Originally Posted by Yeffro

It appears you cannot legally accomplish the Missed Approach Procedure without an ADF. Here is an excerpt from the KLN-94's Manual.

I don't understand how you come to that conclusion based on what you've quoted?

rickair7777 · 10-14-2008, 11:49 AM

Quote:

Originally Posted by Yeffro

It appears you cannot legally accomplish the Missed Approach Procedure without an ADF. Here is an excerpt from the KLN-94's Manual.

I disagree. He is not using the GPS to shoot the approach, he wants to use the GPS in lieu of an ADF to identify the holding fix for the missed.

The FAA advisory seems to allow you to use GPS as a substitute for ground-based navaids, except that you cannot replace a LOC final approach course with the GPS.

But for the OP, you should probably discuss this with the DPE on the ground to make sure he is OK with this interpretation.

Yeffro · 10-14-2008, 12:47 PM

Quote:

Originally Posted by ppilot

I don't understand how you come to that conclusion based on what you've quoted?

With this: KLN 94 can only be used to
provide situational awareness Figure 6-52
for monitoring the approach.

Since you can't use the gps as primary for the ILS approach, and the missed approach procedure is a segment of the approach; I interpret that you are using the GPS as not only the Sole, but primary means to identify the missed approach holding fix.

That's just how it came across to me. I'd like to be able to do it too, but would DEFINITELY get clarification before the checkride.

Yeffro · 10-14-2008, 12:56 PM

Just to add to my (possibly jacked up) logic here...

If the Missed Approach Holding Fix were a fix defined by a specified DME from a VORTAC then I would agree that you could use the GPS to hold.

To me that is what GPS in lieu... authorizes.

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