IslandPilot Posted February 4, 2022 Report Posted February 4, 2022 I have a still-new-to-me 1988 M20J 205SE with a legacy panel including King HSI, KAP-150, and Garmin 530W. No add-ons for GPSS. Approaching a flight plan dog leg en route the 530W gives a countdown signaling to adjust the HSI OBS knob to the new bearing. The plane responds accordingly but soon afterwards the plane is several degrees off the magenta line, and the HSI CDI according shows going off track. After experimenting with crosswinds from the left and then from the right, I’ve concluded that my setting of the OBS bearing is acting much like a heading bug. In other words if I want to get onto and stay on the magenta line, I have to play with the HSI OBS to zero in on a setting that will keep me on the magenta line and thus CDI showing centered. If the wind changes, a new OBS setting is needed to stay on the magenta line. And yes, this is with the 530W CDI mode set to GPS. I’ve looked at the 530W’s boot up settings pages, but I’m not sure if the settings are right. I haven’t changed any of it. For classic VOR and ILS navigation the plane tracks good. Shouldn’t my equipment be able to track the magenta line en route? If so, anyone got advice on which 530W boot up settings to check? Required configuration settings for 530W inputs and outputs? Quote
laytonl Posted February 4, 2022 Report Posted February 4, 2022 Do you have the autopilot set to HDG or NAV? It needs to be on NAV. The HSI hdg bug needs to be set on the GPS course. My KAP-150 tracks perfectly without any tweaking. Lee 2 Quote
carusoam Posted February 4, 2022 Report Posted February 4, 2022 Yes… +1 For all that Lee typed in…. Do you have the manuals that explain how all of this stuff works, button push by button push? Best regards, -a- Quote
anthonydesmet Posted February 4, 2022 Report Posted February 4, 2022 9 hours ago, laytonl said: Do you have the autopilot set to HDG or NAV? It needs to be on NAV. The HSI hdg bug needs to be set on the GPS course. My KAP-150 tracks perfectly without any tweaking. Lee @IslandPilotsounds like you’re definitely using HDG to track course. If you have NAV selected your autopilot should lead turn to intercept your outbound course at your waypoint according to the flight plan you have activated on your 530. I have a KFC-200 with 430W. Quote
IslandPilot Posted February 4, 2022 Author Report Posted February 4, 2022 Thank you for the replies. Regarding the KAP-150 mode it was set to NAV. Regarding the HSI course setting I was only using the HSI OBS knob to set the HSI to the GPS's DTK; I was under the impression that the HSI heading bug is only used when the KAP-150 is in HDG mode; next time I fly I'll include setting the HDG bug too. Regarding documentation I have read the King KAP-150 guide, but this documentation is pre-GPS days. I also have Garmin 530 documentation and will revisit that in further depth. Again, thanks for the replies. 1 Quote
carusoam Posted February 5, 2022 Report Posted February 5, 2022 KAP150 was built during the KLN90b days… A selector switch was used to toggle nav1 or GPS to the HSI… with the invention of the G530… all switching was done internal to the box… So the KAP doesn’t quite know the source is either GPS or VOR… You would have gotten a blue light to go with that switch… a reminder that when the light is on GPS is doing the driving… if the light is off Nav1 is doing the driving…. Or the bulb is out, and the pilot may be unsure…. The KAP150 is an incredibly powerful AP capable of intercepting and following a course, and the same for the ILS… It also has the ability to lead turns to stay within the guidance of the Victor highways… As delivered in the 90s… the pilot had to initiate the turn with a push of a button… Today, many ships have picked up a gpss device to automatically initiate the next leg of the flight plan… That and altitude pre-select… can keep you from getting challenges of missed assignments due to distraction… The heading bug is most often used with heading mode… Often used as a memory device… can cause confusion when not set properly…. If you push the heading button first, then set the bug… you may get a bit of a surprise, depending on how far off target the bug was left last… PP memories about the KAP150 with a full BK panel… -a- 1 1 Quote
Will.iam Posted February 5, 2022 Report Posted February 5, 2022 (edited) 8 hours ago, carusoam said: KAP150 was built during the KLN90b days… A selector switch was used to toggle nav1 or GPS to the HSI… with the invention of the G530… all switching was done internal to the box… So the KAP doesn’t quite know the source is either GPS or VOR… You would have gotten a blue light to go with that switch… a reminder that when the light is on GPS is doing the driving… if the light is off Nav1 is doing the driving…. Or the bulb is out, and the pilot may be unsure…. The KAP150 is an incredibly powerful AP capable of intercepting and following a course, and the same for the ILS… It also has the ability to lead turns to stay within the guidance of the Victor highways… As delivered in the 90s… the pilot had to initiate the turn with a push of a button… Today, many ships have picked up a gpss device to automatically initiate the next leg of the flight plan… That and altitude pre-select… can keep you from getting challenges of missed assignments due to distraction… The heading bug is most often used with heading mode… Often used as a memory device… can cause confusion when not set properly…. If you push the heading button first, then set the bug… you may get a bit of a surprise, depending on how far off target the bug was left last… PP memories about the KAP150 with a full BK panel… -a- I have that blue light in my panel and a switch labeled 530w / king which i assume is the kx165 i have. The previous owner did not know what that light did as he never saw it on nor have i. Never thought to check to see if it’s burned out. Just to clarify that light only tells you which source you are driving from not the mode correct? I. E. If on 530w gps light should be on but if i change the 530w to vor the light doesn’t go out right? Only when i select kx165 it should go out? on second thought i wonder how bright that blue light was? Since it would be on the majority of the time and at night could be too bright. That is my one gripe about my speed brake light it is blindingly bright yellow at night when on. There is no way you would accidentally have those out unless the light indicator was burned out. I sometimes put a piece of black electrical tape over the indicator when i know ill be flying at night just to tone it down in the cockpit. Edited February 5, 2022 by Will.iam Added second thought. Quote
81X Posted February 5, 2022 Report Posted February 5, 2022 Odd. Not what you asked for, but GPSS solves a lot of the intercept angle and wandering issues. IMO, the most cost effective way there is with a G5 HSI as it has GPSS emulation (AP in Nav mode). It will make that AP drive like it’s on rails. Quote
Rick Junkin Posted February 5, 2022 Report Posted February 5, 2022 On 2/3/2022 at 8:37 PM, IslandPilot said: For classic VOR and ILS navigation the plane tracks good. Does the CDI center and the autopilot accurately correct for the winds in VLOC? As Anthony @carusoam said the HSI should be getting the same nav signal from the 530W whether you have VLOC or GPS selected on the 530W so if there is a difference in the way the KAP150 acts in in GPS and VLOC I see your reasoning for questioning the 530W soft config. I sent you a PM with some tech data that may help. For clarification, is your A/P giving you steering to parallel the magenta line, or is the autopilot steering diverging from the magenta line? This is a Master of the Obvious thing maybe, but the KAP150 will initially steer you to the uncorrected course you have selected on the HSI, and then add in a wind correction once it starts sensing drift from the desired course. I don't think this is what you're seeing from what you've described but wanted to throw it out there anyway. There is also an adjustment on the KAP150 to center up the CDI, but if your A/P ILS steering is centered I wouldn't mess with it. The adjustment requires a long thin flat head screwdriver is reached through a hole on the front left side of the A/P computer faceplate. Again, if you're seeing a stabilized diverging drift away from the course set on the HSI this adjustment isn't appropriate. However, if the CDI isn't centered properly when you're on the magenta line this could be the adjustment you need. Cheers, Rick 1 Quote
carusoam Posted February 6, 2022 Report Posted February 6, 2022 14 hours ago, Will.iam said: I have that blue light in my panel and a switch labeled 530w / king which i assume is the kx165 i have. The previous owner did not know what that light did as he never saw it on nor have i. Never thought to check to see if it’s burned out. Just to clarify that light only tells you which source you are driving from not the mode correct? I. E. If on 530w gps light should be on but if i change the 530w to vor the light doesn’t go out right? Only when i select kx165 it should go out? on second thought i wonder how bright that blue light was? Since it would be on the majority of the time and at night could be too bright. That is my one gripe about my speed brake light it is blindingly bright yellow at night when on. There is no way you would accidentally have those out unless the light indicator was burned out. I sometimes put a piece of black electrical tape over the indicator when i know ill be flying at night just to tone it down in the cockpit. HSI installs in the early 90s got multiple boxes that supplied inputs… with the G530 VOR,ILS,gps were all in one box… Early GPS use was a bit developmental as they got certified for use in stages… with use for approach being a big step… Adding the blue light was a bandaid to not have to add a better annunciator…. The skilled pilot knows to verify he is receiving the right station when using VOR/ILS… Early GPS users knew to test the reception of the gps signals… before approach… The blue light was used to verify the gps was driving the hsi… verifying switch position is pretty good too… It is attached to the light dimming circuit… and shouldn’t be too much of a hassle… With approach GPS… it didn’t have vertical guidance, so it was common to switch from GPS to ILS in the last minutes of a busy flight… Things have gotten a bit more organized over the decades… and modern GPSi test their own signals… and Vors get labels on color screens… in the end… the blue light is easy to forget it’s meaning… under pressure… PP thoughts only, not a CFI… -a- 1 Quote
carusoam Posted February 6, 2022 Report Posted February 6, 2022 Back to the OP’s question…. A good KAP150 following an HSI will do better than follow the magenta line closely… It will accurately follow the scalloped shape formed between VOR stations if you use a KX165 as the VOR source, and visually follow the results on your iPad’s magenta line… expect that the width of the Victor highways was based on the scalloped shape lines caused by the radio waves used…. PP thoughts only, -a- Quote
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