MooneyBob Posted February 22, 2014 Report Posted February 22, 2014 I have notice today than my HSI (KI 525 ) acts weird. It is slaved to the compass and it matches to the compass first but then after while it doesn't keep the same direction. It is way too off. When I " unslave " it ( free gyro mode) and then slave it in again the HDG flag will appear then disappear and it will synchronize with the compass but after while it will be off again. Is it ready for overhaul or what should I check? Thanks Bob Quote
laytonl Posted February 22, 2014 Report Posted February 22, 2014 It is probably the gyro and it is time for a repair. How does behave in a 360, 45 degree turn? Does it "hang up" any or is it just off heading at the completion of the turn? Hanging up would indicate a potential problem with the HSI itself. Being off from the compass heading is mostl likely the gyro. I would send both for IRAN. Bob Bramble at Aerolab Aviation is good, quick, and reasonable. Still, it is not cheap. Let us know what you find. Lee Quote
MooneyBob Posted February 22, 2014 Author Report Posted February 22, 2014 I didn't pay too much attention to it as I have stayed in the pattern today. The wind was direct crosswind ( wind 230 runway 32) at 17knots gusting 22knots. I made 12 landings ( two go arounds ) and now I know what those guys are talking about if they say rudder on the floor. This was my third flight in the mooney ever. Anyway, I am going up tomorrow and I will take a closer look in turns. But it feels like somebody have to take a look at it and bench test it anyway. Thanks. Quote
Randy_B Posted February 23, 2014 Report Posted February 23, 2014 About 2 years ago I had my gyro (KG-102A) act up as well. On a previous flight the NAV flag dropped on the HSI for just a second. That was its first indication of impending failure. During the follow flight we were practicing a LOC approach, in VFR conditions, autopilot (KAP-150) was on, flying the heading bug to pickup the localizer. The AP kicked out and would not reengage. At about the same time I noticed that the HSI was slowly rolling to the right. And we were not. At that point the failure was obvious. Both the gyro and HSI were tested. The gyro was rebuilt and the HSI had to be replaced with a latter model. The unit I had was too old to accept the mods that were available and there was a tooth or two missing on the glide slope indicator. 3 AUs latter it was back together and has worked fine since. Best of luck, Randy 2 Quote
AndyFromCB Posted February 23, 2014 Report Posted February 23, 2014 capitalavionics.com does a pretty good job too doing IRAN instead of full overhauls as well Quote
carusoam Posted February 23, 2014 Report Posted February 23, 2014 Astel, I was wondering if you were seeing this... Randy, Do you know how many hours were on the gyro when the trouble started? Best regards, -a- Quote
Randy_B Posted February 23, 2014 Report Posted February 23, 2014 I checked the log book and my KG-102A had been replaced with a overhauled unit 413 hours prior to failure. Quote
JohnB Posted March 2, 2014 Report Posted March 2, 2014 I have exactly the same issue with my HSI, and its intermittent, seems to only happen sometime randomly during the first 30 minutes or so of my first flight of the day, then it straightens out. (I had my HSI replaced last year). I too cycled the slave/ free mode and that does seem to correct it, but its exceptionally annoying when it occurs on the first takeoff of the day when its around 30 degrees off and the compass in a climb has a normal precession error. Im using my portable gps heading as a backup on first takeoff until i have time to take it to my avionics shop, so I'm very curious as to what you find out from yours when you get it looked at. John Quote
MooneyBob Posted March 2, 2014 Author Report Posted March 2, 2014 I have exactly the same issue with my HSI, and its intermittent, seems to only happen sometime randomly during the first 30 minutes or so of my first flight of the day, then it straightens out. (I had my HSI replaced last year). I too cycled the slave/ free mode and that does seem to correct it, but its exceptionally annoying when it occurs on the first takeoff of the day when its around 30 degrees off and the compass in a climb has a normal precession error. Im using my portable gps heading as a backup on first takeoff until i have time to take it to my avionics shop, so I'm very curious as to what you find out from yours when you get it looked at. John Ok. I will keep you posted when I find out. I have to get it fixed as I am about to start my IR. Quote
Awful_Charlie Posted March 2, 2014 Report Posted March 2, 2014 With all the glass installs happening now, maybe it's time to pick up a serviceable second hand unit as a spare - or join in with the glass Quote
philiplane Posted March 3, 2014 Report Posted March 3, 2014 The HSI is just a display for the remote gyro. If the heading is erratic, the problem lies in the KG-102 remote gyro. They are well known for hiccups like this. 1 Quote
MooneyBob Posted March 3, 2014 Author Report Posted March 3, 2014 The HSI is just a display for the remote gyro. If the heading is erratic, the problem lies in the KG-102 remote gyro. They are well known for hiccups like this. That looks like a case. Thanks. Quote
BorealOne Posted March 4, 2014 Report Posted March 4, 2014 500h to failure is what I was getting on my KG-102 and KI 525 units too. Have since gone glass and haven't looked back. Quote
JohnB Posted April 28, 2014 Report Posted April 28, 2014 Lee, Bob, You two were right on.. It was my KG102 gyro that needed replacing. Kaching. All good! (for now Quote
shamsbro Posted June 23, 2015 Report Posted June 23, 2015 Anybody know where the KG 102A Directional Gyro is located in the M20K 231? Thanks! Quote
KSMooniac Posted June 23, 2015 Report Posted June 23, 2015 In the tailcone/avionics bay that is accessed on the left side behind the wing. Sent from my VS985 4G using Tapatalk Quote
Alan Fox Posted June 23, 2015 Report Posted June 23, 2015 If anyone needs a 525A system , I sell -07 mod 7 systems for 2K ........ Quote
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