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Garmin GSA 28 Servo Service-Life Extension (Service Bulletin 23038)

g3xpert

g3xpert

Well Known Member
Advertiser
Good Morning,

We released a Service bulletin today that outlines a Service-Life Extension program for our GSA 28 Autopilot Servos. Garmin has implemented several design and manufacturing process improvements to improve GSA 28 reliability. The latest update has been added to a consolidation of all past improvements into a single effort that will best serve our G3X, G3X Touch and G5 autopilot customers. The Service-Life Extension Program allows up to five years to exchange, under warranty, all affected GSA 28 servos for servos marked with Mod 1.

While we are pleased many of you enjoy the seamless operation and utility your autopilot provides, we know some have experienced servo issues. As a result, Garmin has implemented several improvements within the current production servo design and manufacturing processes and we are confident these improvements will increase the reliability of the servo.

GSA 28 Part Numbers covered under this program:


  • All 011-02927-00 and 011-02927-11 GSA 28 units
  • All 011-02927-20 and 011-02927-21 GSA 28 units that are not marked with Mod 1

We’ve created a single location with instructions on how to locate serial numbers on your displays, compare those to known affected part numbers/serial numbers and instructions for the most efficient next steps to move forward. If your initial installation occurred before the Fall 2022 timeframe, your aircraft is likely impacted.

For those with servos in the affected serial number range, you can perform the servo replacement at a time of your choice, pending servo availability, like a regularly scheduled maintenance event. We are providing a 5-year window to exchange the servos, and from the time you process the exchange, a 6-month (or remaining factory warranty period if applicable) warranty period will begin.

Garmin will prioritize aircraft with the replacement of all servos, should one become inoperative.

For those that have already paid for servo replacements outside of warranty, please email [email protected].

Please send any questions you may have our way!

Thanks,

Justin
 
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Warranty Period

It is five years from the date of this Service Bulletin. You can exchange your servos at your convenience, any time in the next 5 years. When you process the exchange, a 6 month warranty will go into effect, unless you have more than 6 months remaining on your original factory warranty. The greater of the two is applied.

Thanks,

Justin
 
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I'm just getting around to installing a pair of GSA 28's which I've had sitting on the shelf for months into my -6. The on-the-ground setup is complete but have not flown yet. One thing I found odd is there's about 3-4 deg of radial slop (backlash) in the shaft when the clutch is engaged. Both servos are the same, so I assume that's normal. Are the revised servos tighter in that regard?

Also, it would be great if you could implement a "hot swap" type of arrangement where you send us new servos first and then we send the old servos back in the same packaging. You could require payment up front which is refunded upon old servo receipt if you wanted.
 
Hot swap

hgerhardt said:
I'm just getting around to installing a pair of GSA 28's which I've had sitting on the shelf for months into my -6. The on-the-ground setup is complete but have not flown yet. One thing I found odd is there's about 3-4 deg of radial slop (backlash) in the shaft when the clutch is engaged. Both servos are the same, so I assume that's normal. Are the revised servos tighter in that regard?

Also, it would be great if you could implement a "hot swap" type of arrangement where you send us new servos first and then we send the old servos back in the same packaging. You could require payment up front which is refunded upon old servo receipt if you wanted.
Click to expand...

Great comment and worth clarifying. For the G5 recall Garmin provided “hot swap” service and worked well.
 
Serial Numbers

Stupid question,
my serial numbers tarts with 2PG... but the part number is 010-

Am I affected?

Is there a safety of flight issue?
 
The single location link just goes to a survey question for me. Assuming you will not ship the servos in advance of receiving the old ones. How do I insure that availability exists before I remove and ship you the old ones. Would like to minimize down time.
 
Servo Coverage

PilotjohnS said:
Stupid question,
my serial numbers tarts with 2PG... but the part number is 010-

Am I affected?

Is there a safety of flight issue?
Click to expand...

Your servos are covered by the bulletin. This Service Bulletin describes an extension of warranty coverage, and not any kind of safety issue.

Thanks,

Justin
 
lr172 said:
The single location link just goes to a survey question for me. Assuming you will not ship the servos in advance of receiving the old ones. How do I insure that availability exists before I remove and ship you the old ones. Would like to minimize down time.
Click to expand...

I just went through the exchange process with my servos. This is how it was handled in my case.

1. Get an RMA from Garmin.
2. Give them your CC info and the new replacement servos are sent immediately. Your CC will be charged the full price of the replacement servos.
3. Ship your old servos to Garmin with RMA # written on box. Your CC will be credited for the full amount.
 
Servo issues

I’m on my third set of servos …. The ones in the plane are eligible for replacement under Garmin’s current news release. My issues with the servos were somewhat tied to the elevator trim wired through the pitch Servo . After wiring directly to the trim I haven’t had any “ Messages “ on my 460 screen.
Garmin is giving a 5 year window to replace servos ….. my question is if a Servo works good in service for 7 years why should I replace it (5 years from now ) for a unit that has a 6 month warranty????? Most of my failures are “Infancy Failures “
It would be nice to know the issues that Garmin is trying to address so users can make an educated choice.
 
Older units?

I have an older system. My SN# 010-01068-00
Is there an update or change I should make? Thanks
 
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Servo Identification

rockwoodrv9 said:
I have an older system. My SN# 010-01068-00
Is there an update or change I should make? Thanks
Click to expand...

This FAQ link includes directions for identifying if your servos are affected.

g zero said:
I’m on my third set of servos …. The ones in the plane are eligible for replacement under Garmin’s current news release. My issues with the servos were somewhat tied to the elevator trim wired through the pitch Servo . After wiring directly to the trim I haven’t had any “ Messages “ on my 460 screen.
Garmin is giving a 5 year window to replace servos ….. my question is if a Servo works good in service for 7 years why should I replace it (5 years from now ) for a unit that has a 6 month warranty????? Most of my failures are “Infancy Failures “
It would be nice to know the issues that Garmin is trying to address so users can make an educated choice.
Click to expand...

We made modifications to the servo hardware that will improve the long term reliability of the equipment. In contrast with making this new design available for purchase for existing customers, you can exchange them any time in the next 5 years for free, and you will have the most up to date hardware in your aircraft. There is no requirement that you do so.

Thanks,

Justin
 
I have download3d all the bulletins and determined my servos are affected, Serial numbers begin with 2PG. Whatphone number do I call at Garmin?
 
GSA 28 failure strategy

Mine are also affected but from what I can tell you have 5 years to exchange them. Unless one goes tango uniform during that time my plan is to wait. Most likely they will do a hot swap and you can get one very soon and replace at your leisure. For the next year my guess Garmin will have more than they can keep up replacing these. Unless they break why replace?
 
I had to wait almost a full year for the avionics to show up for my RV-12iS project. Are the replacements in stock? If not, what is the anticipated timeframe?

Thank you.
 
GSA 28 Exchange Information

LettersFromFlyoverCountry said:
I had to wait almost a full year for the avionics to show up for my RV-12iS project. Are the replacements in stock? If not, what is the anticipated timeframe?

Thank you.
Click to expand...

Please give us a call at 1-866-854-8433. You will want to set up an exchange for your servos, that coincides roughly with the date you will be installing them. If that date is within weeks, that will not be a problem, we can schedule it for then.

laz said:
I have download3d all the bulletins and determined my servos are affected, Serial numbers begin with 2PG. Whatphone number do I call at Garmin?
Click to expand...

1-866-854-8433. You have 5 years to initiate the exchange for your servos. Once you process the exchange, a 6 month warranty period will begin on the new equipment.

dmattmul said:
Mine are also affected but from what I can tell you have 5 years to exchange them. Unless one goes tango uniform during that time my plan is to wait. Most likely they will do a hot swap and you can get one very soon and replace at your leisure. For the next year my guess Garmin will have more than they can keep up replacing these. Unless they break why replace?
Click to expand...

If a servo fails, we will prioritize the replacement servos for that aircraft. The 5 year period provides plenty of flexibility to initiate the exchange for installations that are not experiencing any Autopilot failures.

Thanks,

Justin
 
Thank you!

Great customer support, and the 5-year swap period is excellent.

Thanks Garmin!

ds
 
I was able to check my servos and they do fit in the replacement group. I sent an email to Garmin late last night and received an email this morning asking when I want to do the replacement. I schedule for the end of August to match my annual. I have had no problems so replacing in September will work great.

I am really impressed with Garmin. My system only has 220 hours but was purchased in 2015 and it is still top of the line equipment.
 
2PG servos
g3xpert said:
Your servos are covered by the bulletin. This Service Bulletin describes an extension of warranty coverage, and not any kind of safety issue.

Thanks,

Justin
Click to expand...

If the 2PG servos are covered in the SB (like mine, purchased in 2021), why are they not listed in the SB? Are there any GSA 28's manufactured before September 2022 that are NOT covered? It seems the intent is to replace the servos manufactured before this date.

As and A&P/IA I would incorrectly tell a customer that the SB does not apply to his 2PG servos. Please correct the SB.
 
Garmin Aviation has confirmed the below summary, via email:

Garmin Autopilot? Please read. This year Garmin released Service Bulletins 23038 RevA (non certified) and 23024 (certified). These service bulletins apply to all GSA 28 smart servos, shipped before September 1, 2022; that are NOT marked with "MOD 1". Anytime between now and 2028 (5years) Garmin will replace, for free, your Garmin GSA 28 servos. For certified aircraft, they will pay for labor. There is some confusion with the part and serial numbers listed in the SB. Regardless of what the SB states, if your unit is not listed and you don't have a "MOD 1", Garmin will most likely replace it. This is based on recent emails I've had directly with Garmin Aviation.

https://support.garmin.com/en-US/aviation/faq/6SJZO0KVTe24EftQtTcOZ9?keywordSearch=gsa+28
 
g zero said:
Servo issues

I’m on my third set of servos …. The ones in the plane are eligible for replacement under Garmin’s current news release. My issues with the servos were somewhat tied to the elevator trim wired through the pitch Servo . After wiring directly to the trim I haven’t had any “ Messages “ on my 460 screen.
Garmin is giving a 5 year window to replace servos ….. my question is if a Servo works good in service for 7 years why should I replace it (5 years from now ) for a unit that has a 6 month warranty????? Most of my failures are “Infancy Failures “
It would be nice to know the issues that Garmin is trying to address so users can make an educated choice.
Click to expand...
I have just experienced what may be a GSA28 servo failure, but I am still trying to assess what is going on --- since you mentioned that your problems appear to be tied to the elevator trim servo (my problem is exactly this), I'd like to know what you have experienced. Several days ago, the elevator trim motor actuated and ran itself to a full trim-up condition -- this occurred right at the point of liftoff. My RV-9A is equipped with dual G3X Touch displays, and the GFC500 autopilot system with a GMC507 control panel. The elevator trim system is controlled by a Vertical Power VPX Pro. I was unable to get the elevator trim to come off the nose-up stop with the trim buttons on my stick (Ray Allen Grip Stick). However, after landing, the trim buttons worked normally!

Today I experienced the same thing on takeoff ---- elevator trim motor actuated and started running to full nose-up. Using the VPX interface on the G3X touch panel, I pressed the "TRIM DN" softkey in an attempt to stop the runaway. The trim motor stopped, however I could not run the trim motor back down with either the VPX softkeys or the trim buttons on the stick. After several minutes I attempted using the VPX softkeys again, and this time I was able to get the elevator trim to run back towards nose down.

I cannot tell if this is a GSA 28 servo problem, or a VPX problem. I've been casting about to find a technical manual for the GSA 28 so I can understand how it functions --- the elevator trim power is supplied by the VPX and is routed through the GSA 28 pitch trim servo -- so the GSA 28 somehow "gates" the power to the elevator trim motor. This is actually a bit disturbing ---- the only way the trim buttons on my stick can operate the elevator trim is when my AUTOPILOT MASTER switch is OFF. When I turn the AUTOPILOT MASTER switch ON, this provides power to the trim servo, and I can no longer actuate the elevator trim, as it now appears to be completely managed by the GSA 28 --- this intuitively does not seem right (or safe) to me.
I'm curious about your experiences. Thank you!

David Fern
N797EJ
 
dfern said:
I have just experienced what may be a GSA28 servo failure, but I am still trying to assess what is going on --- since you mentioned that your problems appear to be tied to the elevator trim servo (my problem is exactly this), I'd like to know what you have experienced. Several days ago, the elevator trim motor actuated and ran itself to a full trim-up condition -- this occurred right at the point of liftoff. My RV-9A is equipped with dual G3X Touch displays, and the GFC500 autopilot system with a GMC507 control panel. The elevator trim system is controlled by a Vertical Power VPX Pro. I was unable to get the elevator trim to come off the nose-up stop with the trim buttons on my stick (Ray Allen Grip Stick). However, after landing, the trim buttons worked normally!

Today I experienced the same thing on takeoff ---- elevator trim motor actuated and started running to full nose-up. Using the VPX interface on the G3X touch panel, I pressed the "TRIM DN" softkey in an attempt to stop the runaway. The trim motor stopped, however I could not run the trim motor back down with either the VPX softkeys or the trim buttons on the stick. After several minutes I attempted using the VPX softkeys again, and this time I was able to get the elevator trim to run back towards nose down.

I cannot tell if this is a GSA 28 servo problem, or a VPX problem. I've been casting about to find a technical manual for the GSA 28 so I can understand how it functions --- the elevator trim power is supplied by the VPX and is routed through the GSA 28 pitch trim servo -- so the GSA 28 somehow "gates" the power to the elevator trim motor. This is actually a bit disturbing ---- the only way the trim buttons on my stick can operate the elevator trim is when my AUTOPILOT MASTER switch is OFF. When I turn the AUTOPILOT MASTER switch ON, this provides power to the trim servo, and I can no longer actuate the elevator trim, as it now appears to be completely managed by the GSA 28 --- this intuitively does not seem right (or safe) to me.
I'm curious about your experiences. Thank you!

David Fern
N797EJ
Click to expand...

HI David, the operating principle is that the GSA28 servo has authority to drive the trim motor for two reasons. First, to auto-trim when the autopilot is on, and second, to provide speed adaptable trim sensitivity. When the GSA28 is unpowered, a relay inside the servo will connect your trim switch directly to the trim motor for safety as a fallback. Its a pretty good system, actually (servo defects not withstanding).
 
georgemohr said:
HI David, the operating principle is that the GSA28 servo has authority to drive the trim motor for two reasons. First, to auto-trim when the autopilot is on, and second, to provide speed adaptable trim sensitivity. When the GSA28 is unpowered, a relay inside the servo will connect your trim switch directly to the trim motor for safety as a fallback. Its a pretty good system, actually (servo defects not withstanding).
Click to expand...
This is accurate. @dfern, both the GSA 28 and VP-X are capable of speed scheduled trim. Our installation manual provides guidance to turn it off on the VP-X side if equipped, and leave it on, on the GSA 28 side. Is it possible you have speed scheduling configured enabled on the VP-X Side?

Please send us a copy of your Flight data log from the flight you described, to [email protected], so we can take a look at it and help provide guidance on the best path forward.

Thanks,
Justin
 
georgemohr said:
HI David, the operating principle is that the GSA28 servo has authority to drive the trim motor for two reasons. First, to auto-trim when the autopilot is on, and second, to provide speed adaptable trim sensitivity. When the GSA28 is unpowered, a relay inside the servo will connect your trim switch directly to the trim motor for safety as a fallback. Its a pretty good system, actually (servo defects not withstanding).
Click to expand...
Hi George -- thanks for the reply, and I think you have answered one question I have about the GSA28 servo --- you say a relay inside it. Is this a mechanical relay or a solid state relay? Based on the way the auto-trim system works, this relay would have to be a NORMALLY CLOSED relay since it must pass the relay motor power being sourced by the VPX directly through to the trim motor output terminals on the GSA 28.

My next question has to do with the VPX interface on the G3X (as I haven't actually tried this experiment yet) ...... will the TRIM UP and TRIM DN soft keys on the VPX screen on the G3X actuate the elevator trim motor if the GSA 28 is powered on? If the answer to this question is "yes", by what method is this accomplished? The VPX receives the TRIM UP or TRIM DN command via the serial data interface that connects the G3X to the VPX, however since the GSA 28 is powered, the auto-trim feature is enabled and so (presumably) that relay in the GSA 28 is OPEN. The VPX cannot talk directly to the GSA 28 since the GSA 28 is controlled via CAN BUS, so to actuate the elevator trim motor the VPX would need to send a message back to the G3X telling it to issue a CAN BUS message to the GSA 28 to do one of two things:

1. Close the elevator trim motor relay so the VPX can regain control of elevator trim
2. I've received a message from VPX asking for elevator trim actuation and the trim motor relay is open, so you, Mr. GSA 28 need to power the elevator trim motor yourself and run it (UP or DN --- depending on the command)

Obviously, if the VPX soft keys cannot actuate the elevator trim motor when the GSA 28 is powered, then the previous paragraph is moot.
 
g3xpert said:
This is accurate. @dfern, both the GSA 28 and VP-X are capable of speed scheduled trim. Our installation manual provides guidance to turn it off on the VP-X side if equipped, and leave it on, on the GSA 28 side. Is it possible you have speed scheduling configured enabled on the VP-X Side?

Please send us a copy of your Flight data log from the flight you described, to [email protected], so we can take a look at it and help provide guidance on the best path forward.

Thanks,
Justin
Click to expand...
Hi Justin --- thanks for the response! I will certainly do that.

I will also be probing the VPX unit this weekend to see what its settings are, as well as performing a close inspection of all the wiring harnesses associated with the elevator trim system. As I had mentioned in my original post, this problem has appeared suddenly, and it only occurs during the takeoff roll. It is possible that an intermittent short circuit caused by the acceleration force on some wire harness is causing the VPX to actuate the elevator trim motor, but to only occur during takeoff and not during any other acceleration event (turning, turbulence, etc.) seems really farfetched to me. I think a far more likely cause has something to do with the speed scheduled trim --- I assume the way that this works is that the G3X is periodically issuing serial data messages to the VPX with airspeed information.

I have owned the aircraft for only six months, so I am still trying to figure out how everything works. I do not know if speed scheduled trim is de-activated on the VPX --- I have downloaded the VPX manual and did read that, if auto-trim is being used that speed scheduling should be disabled. It is always possible that the embedded firmware in the VPX has become corrupted somehow (rare, but bit-flipping does sometimes happen) --- I am an electrical engineer with deep experience in embedded system design and operation.
 
dfern said:
Hi George -- thanks for the reply, and I think you have answered one question I have about the GSA28 servo --- you say a relay inside it. Is this a mechanical relay or a solid state relay? Based on the way the auto-trim system works, this relay would have to be a NORMALLY CLOSED relay since it must pass the relay motor power being sourced by the VPX directly through to the trim motor output terminals on the GSA 28.

My next question has to do with the VPX interface on the G3X (as I haven't actually tried this experiment yet) ...... will the TRIM UP and TRIM DN soft keys on the VPX screen on the G3X actuate the elevator trim motor if the GSA 28 is powered on? If the answer to this question is "yes", by what method is this accomplished? The VPX receives the TRIM UP or TRIM DN command via the serial data interface that connects the G3X to the VPX, however since the GSA 28 is powered, the auto-trim feature is enabled and so (presumably) that relay in the GSA 28 is OPEN. The VPX cannot talk directly to the GSA 28 since the GSA 28 is controlled via CAN BUS, so to actuate the elevator trim motor the VPX would need to send a message back to the G3X telling it to issue a CAN BUS message to the GSA 28 to do one of two things:

1. Close the elevator trim motor relay so the VPX can regain control of elevator trim
2. I've received a message from VPX asking for elevator trim actuation and the trim motor relay is open, so you, Mr. GSA 28 need to power the elevator trim motor yourself and run it (UP or DN --- depending on the command)

Obviously, if the VPX soft keys cannot actuate the elevator trim motor when the GSA 28 is powered, then the previous paragraph is moot.
Click to expand...

Yes, the relay in the servo is normally closed to pass power direct from the VPX to the trim motors. It switches to the GSA28 when the server is getting power.

Yes, the GSA28 passes the command to trim up or down on to the trim servo. It detects the voltage on the trim motor circuit, and relays that over to the trim motor (but applies a speed sensitive power modulation to that signal (PWM I think?)).

When on autopilot, the GSA28 uses its own internal power to run the trim servo on its own commands, not the VPX power.
 
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