An update on Dynon Certified projects

[VIFlyer]

Sorry to report that using 3rd party brackets with Dynon autopilot servos isn't an approved or supported way to install our autopilot.

That's a good question Dynon. Dimensionally are your servos similar to any other brand? This may be a route to install another brand of AP and retrofit just the brains when the Dynon system is finally approved. Please give us some guidance. I installed my system over two years ago and have seen other manufacturers get approval (Grumman AA-5B) during this time. One even works with your system.
Please let us know. Thank you Please explain why other servos cannot be used? If the servos for Trutrak or another manufacturer are approved for a specific plane, isn't it just a three wire connection to the autopilot? How can Trio get an approval before you can to work with your system. Please educate me.

Eric

 

[jessesaint]

The Garmin servos and the TruTrak servos are dimensionally the same as the Dynon servos. The problem is the approval and the way they connect to the airplane controls. TruTrak has gears internally to increase the torque, and in most cases uses a pushrod connected to a cable or bell crank(push/pull). The Dynon uses Capstans that pull on both directions of the cables (pull/pull). The Garmin is more similar to the Dynon connection. The issue is the approval. The Dynon servos are approved in the approved models with the Dynon brackets, only. The fact that Garmin has an approval for a certain model means absolutely nothing for Dynon. They have to get their approval independently. Garmin has in-house approval, and they are the only ones that do in this market. Dynon goes through an ACO office for approval and STC. Bendix/King does too through a different ACO office. Trio does the same through yet a different ACO. One of the big hold-ups with Dynon approvals in the past has been the ACO that we’re responsible for the 737 Max auto pilot debacle, so they are fairly gun shy, plus they are very busy with Boeing projects, I assume.

Trio servos are not dimensionally even close to the other 3 brands.

We just have to be patient and hope the new ACO office will be easier to work with and faster on the approval process than the old one.

 

[TNIndy]

So is Dynon now working with an new ACO other than the one working with Boeing on the 737 Max?

 

[Rhino]

I don't think they get a choice.

 

[JSmith]

At this rate, I don’t understand why anyone who hasn’t pulled the trigger for new avionics on a non STC AP aircraft would hold out for Dynon. I can say, had I not already had my panel done and pre wired for the AP, I would probably go with the forbidden G word.

 

[greentips]

Anybody know if the ARINC interface will interface a Cessna 300 A/P? I have one that works for heading and roll. It keys off the turn coordinator and the heading DG output. I also have access to a a Cessna/ARC 400 A/P head and servos, which would probably work better, but both are senile. I can reinstall the Cessna TC to provide wing leveling, but these autopilots are quite senile and it would be nice to use Dynon outputs the "certified" A/P.

 

[Rhino]

Since the Nav-O-Matic 300 was designed before ARINC was even invented, I doubt it. But someone else can chime in if they know differently.

 

[Dynon]

That's a good question Dynon. Dimensionally are your servos similar to any other brand? This may be a route to install another brand of AP and retrofit just the brains when the Dynon system is finally approved. Please give us some guidance. I installed my system over two years ago and have seen other manufacturers get approval (Grumman AA-5B) during this time. One even works with your system.
Please let us know. Thank you Please explain why other servos cannot be used? If the servos for Trutrak or another manufacturer are approved for a specific plane, isn't it just a three wire connection to the autopilot? How can Trio get an approval before you can to work with your system. Please educate me.

Eric

The short answer is that it's not plausible to make our system compatible with other servos. There are both deeply technical reasons, but even if that weren't the case, certification covers the system from end to end. Changing just the servos means it's an entirely different autopilot system.

 

[Dynon]

Anybody know if the ARINC interface will interface a Cessna 300 A/P? I have one that works for heading and roll. It keys off the turn coordinator and the heading DG output. I also have access to a a Cessna/ARC 400 A/P head and servos, which would probably work better, but both are senile. I can reinstall the Cessna TC to provide wing leveling, but these autopilots are quite senile and it would be nice to use Dynon outputs the "certified" A/P.

It will not, sorry.

 

[greentips]

Since the Nav-O-Matic 300 was designed before ARINC was even invented, I doubt it. But someone else can chime in if they know differently.

I can relate to that, except ARINC was formed in 1929 and the NAV data standard, ARINC 429 has been around since at least 1975 and its precursor 419 since about 1966. The airplane had a Loran C and an ARINC interface until about 2010. I pulled the Loran when they turned off the signal. It tracked both the Loran and the VOR (KX-155). Tracking is a term loosely used with the 300 which I think came out in the late '60s early 70's. It was supposedly a better, but older a/p than the 300B which makes sense because Cessna owned this airplane for 5 years after they built it. There is an ARINC interface in the airplane buried where I can't get to it until I pull the panel apart, but there are leads that run directly between it and the ARC 300 a/p. It is possible it used an older Mil-Spec standard, which I think was 1553, but I'm not sure that was ever used in civilian aircraft.

 

[greentips]

It will not, sorry.

Thanks. Now I'll have to decide whether to keep the vacuum pump and move the DG/TC to the copilot side. I'll probably just pull it and hope for the best from the FAA.

 

[Rhino]

I can relate to that, except ARINC was formed in 1929 and the NAV data standard, ARINC 429 has been around since at least 1975 and its precursor 419 since about 1966....

Yeah, to be more clear, I probably could have said the autopilot was designed in the early seventies, before ARINC 429 came out in the mid seventies. I just didn't realize the minute details would be an issue. Sorry.

 

[lavallejd]

The Garmin servos and the TruTrak servos are dimensionally the same as the Dynon servos. The problem is the approval and the way they connect to the airplane controls. TruTrak has gears internally to increase the torque, and in most cases uses a pushrod connected to a cable or bell crank(push/pull). The Dynon uses Capstans that pull on both directions of the cables (pull/pull). The Garmin is more similar to the Dynon connection. The issue is the approval. The Dynon servos are approved in the approved models with the Dynon brackets, only. The fact that Garmin has an approval for a certain model means absolutely nothing for Dynon. They have to get their approval independently. Garmin has in-house approval, and they are the only ones that do in this market. Dynon goes through an ACO office for approval and STC. Bendix/King does too through a different ACO office. Trio does the same through yet a different ACO. One of the big hold-ups with Dynon approvals in the past has been the ACO that we’re responsible for the 737 Max auto pilot debacle, so they are fairly gun shy, plus they are very busy with Boeing projects, I assume.

Trio servos are not dimensionally even close to the other 3 brands.

We just have to be patient and hope the new ACO office will be easier to work with and faster on the approval process than the old one.

So are you saying that the Dynon servos are low torque as opposed to high torque used on the TruTrac system?

 

[Rhino]

The presence or absence of gears has a whole lot more to do with the inherent difference between a capstan servo and an arm servo than with strength or ability. It doesn't really have anything to do with approvals either. He only mentioned it to highlight just one of the numerous 'reasons' the FAA would use to require a separate approval. Heck, they'd probably require a separate approval if the installer dripped too much sweat into the aircraft during installation because it changed the weight and balance. The point is that Dynon does not have the authority to approve anything not specifically contained within the current STC. Even if the product was completely identical to the original, it couldn't be authorized for use without a new approval process by the FAA. And the FAA does not approve individual parts by themselves. A change of one part in the system requires a new certification process be undergone for the entire system, just as if the FAA had never even seen any of it before. The bottom line is, people keep requesting resolutions from Dynon that they simply don't have the power to give. The problem is the FAA, not Dynon. That same certification nightmare is why we rarely see any new aircraft introduced, why we see very few great products transition from the experimental to the certified worlds, why the exact same products are far more expensive for certified aircraft than for experimental, and why so many pilots are opting for new experimental aircraft over certified. Welcome to big government bureaucracy.

 

[VIFlyer]

The short answer is that it's not plausible to make our system compatible with other servos. There are both deeply technical reasons, but even if that weren't the case, certification covers the system from end to end. Changing just the servos means it's an entirely different autopilot system.

Thank you for the reply.