KLN-89B GPS question

[JimNtexas]

I've been practicing gps approaches with the approved KLN89B gps in my new-to-me Cardinal RG. I've got the basic proceedure down, but I have a question that is vexing me.

The question is "Is it possible to activate a GPS approach with the KLN-89B when the plane is within 30NM of the airport? If so, how?".

Here is an example using the GPS 19 and GPS 1 approaches at Burnet Muni (KBMQ) in Texas.

I flew to BMQ from Austin. After takeoff at about 45 miles from BMQ I select the GPS 1 approach, the unit displays a list of the IAFs (only one on this approach). I highlight the IAF waypoint AMUSE, press "direct to" and then enter. The GPS loads the approach. The unit goes into Leg mode direct to AMUSE. Nav page four (the stick map display) shows the whole approach. At 30nm the ARM light comes on, I'm prompted for the altimeter, and I just follow the needle and stick map to the final approach fix. Everything works as it should.

At BMQ I decide to go around. I hit the "direct" button, it automatically offers up the missed approach hold waypoint DLORA. I accept this waypoint and navigate towards it, climbing to 3500 feet. Approaching DLORA I select OBS mode and fly the depicted holding pattern using the CDI. DLORA is roughly 13 miles north of BMQ.

At this point I'm feeling pretty smart.

DLORA is on the GPS 19 approach and is south of one of the two GPS 19 IAFs (JIBAJ).

Now I decide that I want to fly the BMQ GPS 19 approach. Again I call up the list of BMQ approaches, this time selecing GPS 19. I get the list of available IAFs, there are two for this approach. I turn inbound in the hold which points me more or less towards BMQ and select the IXANY IAF, and press "direct to". The KLN-89B offers to take me not to IXANY, but to BMQ. "The geometry must be wrong" I think, so I point at IXANY and try again. Same thing, I select the IXANY IAF off the list, but pressing "direct to" and it offers to take me direct to BMQ.

"I must be too close in" I think, so I turn north and fly to the Lampasses airport, which is 14 miles north of the JIBAJ IAF and about 25 miles north of BMQ. I point the airplane at JIBAJ.

I call up the BMQ GPS 19 approach, get a list of the two IAFs, and this time select JIBAJ and press "direct to", fully expecting the GPS to start the approach sequence. But again after pressing "direct to" it offers to take me to KBMQ rather than put me on the approach sequence starting with JIBAJ.

About this time there is a line of thunderstorms coming in from the west, so I retreat back to KAUS.

I have two theories about why I couldn't get the KLN-89B to load the GPS 19 approach. They are:

1) You have to be 30 miles away from the airport to load an approach. Period.

2) Inside of 30NM I should have selected the FAF rather than an IAF, and flown to the FAF in OBS mode.

What do you think?

 

[pilotman2105]

While I'm not expert on the 89B, I have used it a few times and can offer this bit of advice. If there is a way to do it in the airplane (ie: missed approach to a holding point, then direct to the IAF for another GPS approach), then there is a way to get the GPS to do it.

The first thing to check would be whether the GPS is still in leg mode or is in OBS mode. If still in OBS mode from the MAP (which I believe that it automatically cycles to), that may be the source of some of the problem.

Another thing to check is with the flight plan programed into the GPS. After you load the first approach, the GPS would be confused with two approaches being loaded into the flight plan. Thus, the default waypoint after the MAP is the airport itself. Try clearing out the first approach from the flight plan. Then load the second approach.

And if all else fails, there should be a supplement in/with the POH that explains how to use the GPS. Take a gander at it sometime when you're waiting for fuel.

If you would, please post the solution when you get it figured out.

 

[Jedi_Cheese]

Alright, you are on the airport page. Then get to the list of the approaches and hit crsr. Scroll down to the one you want and press enter (I think it's enter, might be direct). Then it gives you a list of waypoints on that approach, select the one you want and press direct.

Once you have a flight plan loaded, you can either add to it (which I have no clue how to do) or you can delete the old one (put direct to the airport you want) and then add an approach.

The direction the aircraft is flying or how far out from the fix doesn't affect the unit's list of options (so far as I know). Sitting on the ground with the master on will allow you to experiment with it if you really want to practice loading flight plans.

 

[JimNtexas]

"Alright, you are on the airport page. Then get to the list of the approaches and hit crsr. Scroll down to the one you want and press enter (I think it's enter, might be direct). Then it gives you a list of waypoints on that approach, select the one you want and press direct."

Yes, that's exactly what I do. I get to the list of approach waypoints, select an IAF and press "direct to".

Whenever you press "direct to" you get a screen that shows the name of the point you are going to.

Now comes the problem. Inside of 30 miles after flying another gps approach, this confirmation screen does NOT show the name of the IAF I just selected.

Instead it shows the airport ID (KBMQ in my example), NOT the IAF ID that I have highlighted with the cursor. It does NOT load the approach waypoints, it does not go into ARM mode, I do NOT collect $200.

Outside of 30 miles from the airport it works fine.

I've been over the manual many times trying to understand why this is happening. The manual several times refers to "rules" programmed into the unit and gives rule numbers. It doesn't list the rules though. There is clearly some rule that activates inside of 30nm, but I don't know what it is.

My partner has the airplane for ten days, when he gets back I will test my theory that close in you can't select an IAF, you must select the FAF and use OBS mode to get you established on the approach and then change to LEG mode.

It may indeed also be the unit getting confused about what is in the flight plan, so I will also try clearning the active plan first.

 

[pilotman2105]

My partner has the airplane for ten days, when he gets back I will test my theory that close in you can't select an IAF, you must select the FAF and use OBS mode to get you established on the approach and then change to LEG mode.

Not trying to dispel your theory, but I'm 99% sure that is not the case. I've activated an approach within 30 NM and had it give me direct to the IAF several times.

Good luck...

 

[Jedi_Cheese]

I am 100% shure that you can load an approach within 30 nm of the airport. On my IR checkride, I loaded the approach into the unit on the ground at the airport I was going to do my approach into.

Lemme dig out my instrument notes and get back to you.

Shameless plug for someone deserving: Jedi Nein (no relation to me) has a book out on GPS units and how to use them.

 

[prpjt]

Quote

"Now I decide that I want to fly the BMQ GPS 19 approach. Again I call up the list of BMQ approaches, this time selecing GPS 19. I get the list of available IAFs, there are two for this approach. I turn inbound in the hold which points me more or less towards BMQ and select the IXANY IAF, and press "direct to". The KLN-89B offers to take me not to IXANY, but to BMQ."


It's sounds as though you've taken great care to retrace the exact steps you took, so I'm reading this very literally.

1. You were heading to DLORA and pulled up the BMQ approach list on the airport page. I assume this since DLORA would be in your active page.

2. You select the GPS19 and it offers the IAF's, you highlight IXANY and press 'direct' and 'enter'... This is not a valid command. What occurred here was the unit just reverted back to the active flight plan '0', which was the GPS 1 approach terminating at BMQ. The sequence of button mashes should have been:

Select GPS 19
Highlight IXANY IAF
Press 'ENTER' - not direct to

You should then get a prompt asking if you want to load that approach to the acive flight plan. Hit 'Enter'

That sequence would load the GPS19 into the # '0' flightplan or active flight plan on the left screen. Go to that screen(FLT PLN '0'), find IXANY, highlight it and press direct.

In your second example you again select the GPS19, then highlighted JIBAJ. Good so far. With JIBAJ highlighted on the right hand screen you should see a flashing 'ENT' at the bottom. This means that if you agree with what is highlighted press ENTER, not direct. . Then you should get the LOAD APPROACH? prompt and hit ENTER again.

The use of any other key other than ENTER, when the ENT symbol is flashing, and the unit will default back to the active waypoint in FLT PLN '0". It sounds like you weren't loading the approach to the active side.

 

[JimNtexas]

Select GPS 19
Highlight IXANY IAF
Press 'ENTER' - not direct to

You should then get a prompt asking if you want to load that approach to the acive flight plan. Hit 'Enter'

That sequence would load the GPS19 into the # '0' flightplan or active flight plan on the left screen. Go to that screen(FLT PLN '0'), find IXANY, highlight it and press direct.

That makes perfect sense, I think you may have identified my problem. I'm going to try again soon and I'll let you know what happens.

On an unrelated matter I also am pretty sure that the "rules" the manual talks about are those spelled out in TSO C129 ( http://www.faa.gov/asd/international/TSO_FAR_AC/129asave.pdf ).

 

[prpjt]

JimNTexas,

I think that should work for ya. The KLN will do some neat tricks after you fiddle with it for a while. One that I use quite a bit is drawing the ILS/LOC course on the stick map when there is no overlay. Gives a good heads up of how far 'til LOC intercept you are, even while the CDI is still full scale.

Sounds like you may be based out of Austin, so I'll throw out a question. Is 'El Azteca' on the south side still around? It's a dive Mexican joint that had some great cabbrito. Got a trip there 9/17 and wanted to eat some charred goat.

 

[SATCFI]

Stop by SAT and pick me up...we'll go up and get it straight. Then over to Llano for Coopers!

 

[JimNtexas]

Stop by SAT and pick me up...we'll go up and get it straight. Then over to Llano for Coopers!

Weather and time permitting I'll try it again this week. If it is still fighting me I may well take you up on that. None of the CFIs I fly with here know anything about it.

Jim