Missed GPSRNAV Approach at YWOL
Thread Starter
Missed GPSRNAV Approach at YWOL
I'm having an issue with KLN89B GPS. Would appreciate advice from someone who is expert.
When flying the RNAV (GNSS) RWY16 approach into YWOL and executing a missed approach after passing WOLNM, I press GOTO (WOLNH - missed approach holding point) and ENTER, then when between the missed approach point WOLNM and the missed approach holding point WOLNH the GPS flips back to the final destination YWOL rather than continuing to guide to the missed approach holding point WOLNH.
Is this normal
Am I doing something wrong?
When flying the RNAV (GNSS) RWY16 approach into YWOL and executing a missed approach after passing WOLNM, I press GOTO (WOLNH - missed approach holding point) and ENTER, then when between the missed approach point WOLNM and the missed approach holding point WOLNH the GPS flips back to the final destination YWOL rather than continuing to guide to the missed approach holding point WOLNH.
Is this normal
Am I doing something wrong?
Um maybe....firstly I am not familiar with the KLN89B GPS.
When you load the RNAV approach the GPS should recognise all of the available waypoints for that approach, including the missed approach holding point (WOLNH).I assume that you didn't have to press goto for all of the other waypoints? so why would you need to press it for the missed approach holding point? On the Garmin 430/530 at the missed approach point the GPS goes into a 'suspend' mode to allow the pilot to sort his/her s**t out, then the pilot must elect to continue with the missed approach. On the GARMIN 430/530 series this is done by pressing the OBS button. The gps then switches back into navigation mode and takes you to WOLNH
Is there a similar 'OBS' button on the KLN89B GPS?
My guess is that in order to load/activate the RNAV approach you had to either have been 'going to' YWOL or it was the last waypoint in your flight plan. When you hit the 'GOTO' button, the first thing it loads is the last place you were heading to, in this case YWOL.
Hope this helps
Alpha
When you load the RNAV approach the GPS should recognise all of the available waypoints for that approach, including the missed approach holding point (WOLNH).I assume that you didn't have to press goto for all of the other waypoints? so why would you need to press it for the missed approach holding point? On the Garmin 430/530 at the missed approach point the GPS goes into a 'suspend' mode to allow the pilot to sort his/her s**t out, then the pilot must elect to continue with the missed approach. On the GARMIN 430/530 series this is done by pressing the OBS button. The gps then switches back into navigation mode and takes you to WOLNH
Is there a similar 'OBS' button on the KLN89B GPS?
My guess is that in order to load/activate the RNAV approach you had to either have been 'going to' YWOL or it was the last waypoint in your flight plan. When you hit the 'GOTO' button, the first thing it loads is the last place you were heading to, in this case YWOL.
Hope this helps
Alpha
Thread Starter
When you load the RNAV approach the GPS should recognise all of the available waypoints for that approach, including the missed approach holding point (WOLNH).I assume that you didn't have to press goto for all of the other waypoints?
On the Garmin 430/530 at the missed approach point the GPS goes into a 'suspend' mode to allow the pilot to sort his/her s**t out, then the pilot must elect to continue with the missed approach
Is there a similar 'OBS' button on the KLN89B GPS?
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From experience with KLN90 series GPS' they can do some funny things occasionally. It has been recomended to me to enter the destination (eg YWOL) TWICE and then load the RNAV - this seems to produce trouble free transitions. 
Don't know if this will help you or not - try in VMC first!
Don't know if this will help you or not - try in VMC first!
I have just flipped thru the KLN89B user guide, to find that you are correct.
In your case when you hit the 'GOTO' button at the missed approach point is the WOLNH point highlighted? or is YWOL?
I am guessing that the WOLNH waypoint is highlighted, or this would be a 'where did the WOLNH waypoint go?' thread. So after you confirm 'GOTO' WOLNH I am assuming it gives you track guidance to WOLNH, or does it flip across to YWOL straight away? If it does give you guidance to WOLNH, how long after this does it switch to YWOL?
Ever had any issues with this GPS on other RNAV approaches?
In your case when you hit the 'GOTO' button at the missed approach point is the WOLNH point highlighted? or is YWOL?
I am guessing that the WOLNH waypoint is highlighted, or this would be a 'where did the WOLNH waypoint go?' thread. So after you confirm 'GOTO' WOLNH I am assuming it gives you track guidance to WOLNH, or does it flip across to YWOL straight away? If it does give you guidance to WOLNH, how long after this does it switch to YWOL?
Ever had any issues with this GPS on other RNAV approaches?
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I never found KLN89B user friendly but in order to go to WOLNH, I believe you scroll to the FPL page and then press DTO. The single cursor in the middle will light up and you must then scroll into the other waypoints on your pre-programmed flightplan, and when the correct one appears (WOLNH in your case), press ENT. It should then automatically revert to the NAV page to take you there. To cancel an unwanted OBS mode, press OBS so that the screen reverts to NAV to take you to WOLNH.
Hope that helps.
Hope that helps.
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I have seen several instances of this problem on both KLN89B and KLN94. It can certainly be frustrating, especially in the rain and when you have other issues to consider.
You understand that the waypoint sequencing from WOLNM to WOLNH is not automatic and you are correctly doing a D--> to WOLNH, so you are way in front of most!
I think what you are seeing, as it appears to "strangely" go "back" to YWOL following the the D--> to WOLNH on the missed approach, is that the geometry of your position line to WOLNH and that to YWOL satisfies the KLN89B’s conditions for passage of WOLNH in LEG mode and causes it to automatically sequence to YWOL, which will be the last waypoint in your flight plan assuming it ends at Wollongong. This will happen even before you thought you had reached WOLNH if the geometry is right.
This is particularly likely if you flew the approach in a reasonable north-westerly and have got to the south-east of WOLNH faster than you realised. Allowing for a bit of wind, and some work to get on the missed approach, the courses outbound to WOLNH and then from there back to YWOL are not very far apart, although in completely opposite directions. The KLN 89B "thinks" you have passed WOLNH long before you think that way, and because sequencing in LEG mode is automatic, it replaces WOLNH as the active waypoint with YWOL, but before you consider that you ever really reached or passed WOLNH.
You can avoid the problem by selecting OBS mode once you have D--> selected and are established on track to WOLNH, and then, having reached it (or very close), reverting back to LEG mode and, (only if necessary), doing a D--> to YWOL as required. However, if you use this solution, make sure you remember to go back to LEG mode, otherwise you might easily fly right past WOLNH and way out to sea… and then there might be all sorts of other problems!
Hope this helps.
OTD.
You understand that the waypoint sequencing from WOLNM to WOLNH is not automatic and you are correctly doing a D--> to WOLNH, so you are way in front of most!
I think what you are seeing, as it appears to "strangely" go "back" to YWOL following the the D--> to WOLNH on the missed approach, is that the geometry of your position line to WOLNH and that to YWOL satisfies the KLN89B’s conditions for passage of WOLNH in LEG mode and causes it to automatically sequence to YWOL, which will be the last waypoint in your flight plan assuming it ends at Wollongong. This will happen even before you thought you had reached WOLNH if the geometry is right.
This is particularly likely if you flew the approach in a reasonable north-westerly and have got to the south-east of WOLNH faster than you realised. Allowing for a bit of wind, and some work to get on the missed approach, the courses outbound to WOLNH and then from there back to YWOL are not very far apart, although in completely opposite directions. The KLN 89B "thinks" you have passed WOLNH long before you think that way, and because sequencing in LEG mode is automatic, it replaces WOLNH as the active waypoint with YWOL, but before you consider that you ever really reached or passed WOLNH.
You can avoid the problem by selecting OBS mode once you have D--> selected and are established on track to WOLNH, and then, having reached it (or very close), reverting back to LEG mode and, (only if necessary), doing a D--> to YWOL as required. However, if you use this solution, make sure you remember to go back to LEG mode, otherwise you might easily fly right past WOLNH and way out to sea… and then there might be all sorts of other problems!
Hope this helps.
OTD.
I am with Barleyhi
I have a KLN90B. If I load the approach into the flight plan (planning VOR to VOR), it will load the approach but the VOR remains in there.
That causes issues so I then have to delete the VOR from the flightplan after the approach has loaded.
I suspect your airport idetifier is still in the flight plan. Get rid of it and I think it will be fine.
I have a KLN90B. If I load the approach into the flight plan (planning VOR to VOR), it will load the approach but the VOR remains in there.
That causes issues so I then have to delete the VOR from the flightplan after the approach has loaded.
I suspect your airport idetifier is still in the flight plan. Get rid of it and I think it will be fine.
Thread Starter
In your case when you hit the 'GOTO' button at the missed approach point is the WOLNH point highlighted? or is YWOL?
So after you confirm 'GOTO' WOLNH I am assuming it gives you track guidance to WOLNH, or does it flip across to YWOL straight away? If it does give you guidance to WOLNH, how long after this does it switch to YWOL?
Ever had any issues with this GPS on other RNAV approaches?
"onthedials" may have hit the nail on the head.
The WOLNH waypoint is coded in a GPS as a 'flyby waypoint and not a 'flyover' waypoint. When the gps senses that a waypoint is approaching, it calculates a distance to turn anticipation. When the tracks are the same but in opposite directions the distance to turn anticipation is infinite. The out bound track to WOLNH will be very close to the inbound track back to YWOL and so the distance to turn anticipation will be quite large.
So the scenario is this.....
You get to the missed approach point and decide to continue missed approach. You then press 'GOTO' WOLNH. The system sends you off in the direction of WOLNH, but also calculates a turn at WOLNH to go back to YWOL. Lets say distance from missed approach point to WOLNH is about 6nm. Turn anticipation for a reciprocal course may be about 4-5 miles. You are still tracking to WOLNH, then about 4-5 to run to WOLNH you pass the turn anticipation point and because inbound and outbound tracks are so close together you also pass the midpoint of the turn. This forces to system to assume you made the turn, and 'flewby' the WOLNH waypoint, thus sending you back to YWOL.
If you remove YWOL as the last flightplan waypoint, or pick some other waypoint....you shouldn't have a problem.
This is the problem with different GPS receivers. The GPS coding specification doesn't define what to do if the turn at a waypoint is greater than 120degrees. So each manufacturer can code their recievers differently. It would appear BENDIX/KING recievers always calculate a turn anticipation distance. I think in the same scenario GARMIN recievers would make you fly a course reversal at WOLNH, thus eliminating this problem. I have flown this approach with a GARMIN 430/530 and not had any problems.
Alpha
The WOLNH waypoint is coded in a GPS as a 'flyby waypoint and not a 'flyover' waypoint. When the gps senses that a waypoint is approaching, it calculates a distance to turn anticipation. When the tracks are the same but in opposite directions the distance to turn anticipation is infinite. The out bound track to WOLNH will be very close to the inbound track back to YWOL and so the distance to turn anticipation will be quite large.
So the scenario is this.....
You get to the missed approach point and decide to continue missed approach. You then press 'GOTO' WOLNH. The system sends you off in the direction of WOLNH, but also calculates a turn at WOLNH to go back to YWOL. Lets say distance from missed approach point to WOLNH is about 6nm. Turn anticipation for a reciprocal course may be about 4-5 miles. You are still tracking to WOLNH, then about 4-5 to run to WOLNH you pass the turn anticipation point and because inbound and outbound tracks are so close together you also pass the midpoint of the turn. This forces to system to assume you made the turn, and 'flewby' the WOLNH waypoint, thus sending you back to YWOL.
If you remove YWOL as the last flightplan waypoint, or pick some other waypoint....you shouldn't have a problem.
This is the problem with different GPS receivers. The GPS coding specification doesn't define what to do if the turn at a waypoint is greater than 120degrees. So each manufacturer can code their recievers differently. It would appear BENDIX/KING recievers always calculate a turn anticipation distance. I think in the same scenario GARMIN recievers would make you fly a course reversal at WOLNH, thus eliminating this problem. I have flown this approach with a GARMIN 430/530 and not had any problems.
Alpha
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We use the kln-90b in the 1900 and it is definately not a Garmin unit.
Our SOP's state for us to select the next waypoint, allbeit a hold or a fly over waypoint in the hilighted field in fpl0 or on the super nav 5 page so that when you commence the mapp, ie: climb and start the turn- if required then you can go direct to/ goto, (however you want to say it) the next waypoint in the missed approach as the kln90b does not provide waypoint sequencing onto the mapp.
Once you have done that then you have an active waypoint so selecting obs mode will allow you to set the correct course to be flown on the mapp.
Having it hilighted makes the process easier to follow when you are low to the ground and in the murk...
Our SOP's state for us to select the next waypoint, allbeit a hold or a fly over waypoint in the hilighted field in fpl0 or on the super nav 5 page so that when you commence the mapp, ie: climb and start the turn- if required then you can go direct to/ goto, (however you want to say it) the next waypoint in the missed approach as the kln90b does not provide waypoint sequencing onto the mapp.
Once you have done that then you have an active waypoint so selecting obs mode will allow you to set the correct course to be flown on the mapp.
Having it hilighted makes the process easier to follow when you are low to the ground and in the murk...
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The reason that it keeps defaulting to the destination is because there is no waypoint sequencing on the mapp, but once you have selected the first waypoint in the mapp then it will sequence you thru subsequent points, if there are any, to the end of the mapp which after the hold(if not in obs) will be to the destination, again.
Hope that helps. It should be the same over there as it is here, god knows we do enough of the bloody things.
Hope that helps. It should be the same over there as it is here, god knows we do enough of the bloody things.
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If the particular mapp requires a turn to the left, delay going direct to the next waypoint untill you have started the turn. The previous crap about the reciprocal and 5-6 nm intercept is irrelevant as THERE IS NO WAYPOINT SEQUENCE ON THE MAPP ON THE KLN90B...
THERE IS NO WAYPOINT SEQUENCE ON THE MAPP ON THE KLN90B
Likewise after reaching the missed approach holding point the next waypoint in the sequence would appear to be the destination (YWOL).
Agree the KLN series are no where near as user friendly as Garmin.
Bentleg sounds to me like the receiver is indeed providing you turn anticipation to the destination prior to you reaching the holding point.
Remember if a plan is active ie FPL#0 and you choose direct to a point in that plan the the receiver will automatically sequence as per FPL#0 after reaching the direct to waypoint or the anticipated turn point.
You can disable turn anticipation if desired FPL page 4 i think, or remove the destination from the end of FPL#0.
Agree this should also work.
Yes the KLN89 will not allow you make a reversal at an IAF, only at the FAF... eg if you try to load your approach when approaching IAF from the south the KLN will skip the IAF and go straight to the FAF. I believe the manual doesnt explicitly say it will do this but it does say reversals are only available at the FAF. When it happened to me i couldnt get the IAF into the plan so i hit obs and selected the desired inbound radial to the FAF from the IAF then used the range to FAF for a fix.. remember to go back to leg mode prior to FAF to proceed with the approach. 
Bentleg sounds to me like the receiver is indeed providing you turn anticipation to the destination prior to you reaching the holding point.
Remember if a plan is active ie FPL#0 and you choose direct to a point in that plan the the receiver will automatically sequence as per FPL#0 after reaching the direct to waypoint or the anticipated turn point.
You can disable turn anticipation if desired FPL page 4 i think, or remove the destination from the end of FPL#0.
It has occurred to me, yet to try it out, if I set the CDI to 036 (heading desired at WOLNH) and press OBS, after doing the GOTO bit, that might work, but the manual doesnt say to do that.
Ever had any issues with this GPS on other RNAV approaches?