GPSS options with 400A
 

Hi everybody, I'm in the steep learning curve of planning avionics upgrades.

I will most likely change to a GTN 750 and keep one of the older nav/com units.

For the time being, I would like to stay with the 400a.

I'm trying to learn what the options are to integrate modern gps nav with the navomatic.

If I keep all the steam gauges, what are the gpss options that work with the 400a? What are your experiences with DAC, Icarus SAM, others?

What about the gpss in the g500 txi? Will this work with the 400a?

Thanks for advice.

DD

With a moving map...
 

I always set my GPS moving map to project a course line ahead by 50 miles or so.

Then, the few times I have used the autopilot at all, I simply slowly turn the autopilot heading bug and as airplane turns watch until projected course hits the next mark.

Done

Thus, all wind/course corrections already adjusted and accounted for.

Works every time.

This won't automatically follow 20 pre-programmed points, but in my own experience the ATC world never works that way anyway. Things are always fluid, so it is less stressful to be flexible. I just fly bearing altitude vectors (perfectly legal) to some next fix the current controller understands, within 200 miles or so, so it is 'IN' their radar scope and familiarity.

When I have heard pilots grip that their elaborate flightplan got totally changed, I try to explain that that's like filing a flightplan for next tuesday through NYC rush hour. File whatever you want, but once enroute that morning, the controller knows there is a truck overturned 50 miles away and will need to work it out anyway. Semper Gumby

Others' experience may vary.

As far as I can tell, you can interface the 400A directly with your Nav/Com/GPS unit's horz/vert deviation outputs or you can provide the inputs from a EFIS. I know the Aspen display will provide GPSS/NAV/HDG selection directly to the 400A, using their ACU to do this (the EA100 is not needed unless they certify the aspen to provide attitude information...which would be an instant buy for me). I presume the TXI would use a GDL43/e to generate the analog signals but same limitations on the attitude signals. Looks like the Garmin G5 specifically calls out the 400A as supported as well.

In another thread there is a discussion about use of GPS Vertical Guidance (VNAV) outputs and the 400A, which Garmin navigators specifically prohibit unless cleared by Garmin or on their list (the 400 IFCS is on the list BTW). I suggest you call your avionics shop about this as the notes are unclear. Also, this may or may not apply if you source the autopilot from the Aspen/500TXI/etc. Someone mentioned this limitation was removed by the Sandal 3308 so it seems possible that this is the case.

I will be doing this on my restoration this year and will post a note about my installation/use then.

Thanks for the replies.

I thought all skymasters with autopilots had the 400a. I didn't realize there was a 400 IFCS option.

How do I know which I have? Looking at pictures online, it looks like I have the 400 IFCS (it does have flight director buttons on the panel). If so, I think that simplifies the garmin options because it appears to be on their list of supported autopilots whereas the 400a is not?

This is a pic of what I currently have:
Attachment 2353

Cheers,

and

Happy new year everyone!

Yes, congrats Dr. Dan, you have the 400IFCS.

The flight director and autopilot mode buttons are the tell-tale indicators.

Rick

Yes, the 400IFCS is the key to keeping it with glass. Without it, the basic 400A, there aren't any options because of the analog attitude and navigation reference. At least, that was a year ago when I paid a shop to sit down and try to figure it out at their hourly rate. Specifically, I wanted to go to the two G5s with my dual 430W as a lead into something greater once I made some primary improvements to my airplane; gear door removal, cargo pack, and air conditioner.

They went beyond the G5s, looking for any approvals for the airplane, but it failed when you got to the autopilot supplements. Things change, and this was a year ago; I doubt it given what goes into an STC and the remaining number of airframes and their age, but maybe there is hope. The best-case scenario for my airplane they could find was to keep the Sandel 3308, purchase the WAAS software ($,$$$), and buy spares. This far outweighed the only replacement autopilot option; the STEC 55.

I'm not a fan of the 55; I've flown too many airplanes with it, and there is something, at least one feature, that is always out. My avionics guy is not a fan of it (said he would not install one), and the guys at APC will tell you that to keep it right, it takes more maintenance than a 400A (of course, there are more flight profile features). There is also a good Cessna Owners Association article about keeping the 400A as the replacement options are less desirable. Of course, many 400s are in bad shape because no one seems to want to spend money on autopilot maintenance or keep them tuned up (the problem with the 55s I've flow and the manufacture is an hour flight away). Any autopilot needs regular maintenance.

Personally, I'm okay with steam gauges, especially with an iPad with ForeFlight. Of my 22K flight hours, only about 25% of them are behind glass. I flew the B737-200, 300, 500, 700, and 800 and never had a problem jumping from one to the other. I even had a single day where I flew four different models, steam to glass and back. For the money, I'd rather have a weather radar in my Skymaster than spend the money on the typical glass installation. Also, Garmin's planned obsolescence (which the others follow) bugs me for the money that goes into the glass. I once was the Aviation Director of a large corporate flight department. I cannot picture going before the board of directors to ask for money for the airframe on the cycle that Garmin runs; the equipment and installation cost vs. airframe value; I would have been replaced. My CFO (wife) is very lenient, but she would croak if I truly explained that last statement.

Just to add to this it is the only option that will allow you to entirely remove all the analog gauges and your vac system. Lots of folks use the lateral/ (and ILS vertical) guidance outputs from newer systems, including G500/E5/EFD1000/G5 etc.

Thanks guys. I'm happy to hear there's options with the IFCS.

I guess I'll have to think about whether it's worth the extra money for the g500 txi vs a pair of g5's. And also whether it's worth removing the analog gauges and vacuum system.

Cheers
DD

That is the question, Dan. I'm not sure how I would have gone if mine had the ICFS. It's a lot of money into an old airframe with part availability issues and prices for those parts what they are.

I have a P337 with IFCS 400. I went with a G500txi PFD and G5 as backup. Have a GAD43e and GMU out in the wing. I keep the Vacuum System only because it runs the boots for de-ice. The system is fully couple to the A/P will fly with GPSS and will fly approach through GS capture.

I had Carpenter Avionics do an overhaul on the AP last summer. It works great!. If you need I have the manual for the adjustments on the IFSC 400, full service Manual. There are quite a few things you can manage on your own with intercept angles, scalloping on altitude and turn rates. All meant to be done in the air. I looked at a new AP, but 25K to give me the same functions I have already, albeit more accurate, but seems a bit out of line.

That's good to know, thanks.
Did you have to keep your old attitude gyro for the AP? My understanding is that the g500 or g5 can control the AP, but the original gyro attitude indicator must still be connected for it to work properly.

for the benefit of the group, anyone who needs the IFSC Manual I have put it on my google drive, and the link is below.

https://drive.google.com/file/d/1Y68...ew?usp=sharing

With the Gad43e installed you can remove ALL mechanical gyros. So that is the system I have. This does require both the 500txi and the G5 as you need a backup to the 500 as PFD. I can tell you the system works great.

https://drive.google.com/file/d/1M9V...ew?usp=sharing

https://drive.google.com/file/d/1s5B...ew?usp=sharing

Thanks!

DD

Very nice!

GPSS options with 400A
 

Hello everyone. Quick basic question. I have a '65 C337. When I purchased my plane, it came with a Nav400, IN A BOX. I was advised, from a hangar neighbor, that Autopilot Central is the place to have the 400 bench checked/repaired. My question is what instruments drives the Nav 400? The AI, HG or turn coordinator? The reason I'm asking is I'm sure that those instruments have been changed from the originals. So I'm looking at pricing replacement instruments? I don't want to spend the money to install a $30,000 S-tec in a plane that I paid $22,500 for! Actually after buying a overhauled Cont IO-360C and six rebuilt cylinders for the other engine I'm in for over $40,000. But still If I wanted a $70,000 aircraft I'd buy a newer C337, that's better equipped, in that price range.
Thanks in advance!
Regards,
BILLS

So it all depends on where you are based. I am pretty happy with the work done at Carpenter Avionics. Based in the Nashville area at Smyrna. Good work,fair price. They got all of the components working together correctly. Best if you can take the plane to whomever, lots of moving parts....

The attitude and heading indicator. I dig the part numbers out in a bit.

A great deal also is dependent on the features you autopilot has. Two axis? Alt hold? Auto trim? Do you have a slaved DG? Is there a flight director? I can give the name of a guy in MI that is kind of an autopilot whisperer.

What Frank said about features. On the AQI site, see the ARC instruments. You will need to get into the Avionics installation and parts manuals to figure out what you have in the box.

GPSS options with 400A
 

Patrol Pilot. Thanks for the reply. I have the original equipment list. I'll check it to see if lists the instruments. Also check the part numbers of the instrument in the box of autopilot parts. But I think there is only an AI.
Regards, BILLS

The Nav-O-Matic 400 (Straight 400) had two versions that I am aware of. There was an early model with a little different control head and then the current unit used up to about 1969 I think. It seems the change from the early 400 to the latest 400 was about 1968. Attached are a couple cut sheets of the systems

If someone needs other info on the Nav-O-Matic 400 I have a couple files about these units. Service and Parts manuals and user manuals

Nav-o-matic 400
 

Herb. Thanks for the pictures. I think I have the system on Fig 3-1. But I'll have to go to the airport to check. I may need the manuals you have. I did download the schematics for the head and computer, from you in the past.
Regards, BILLS

Navomatic (STRAIGHT) 400
 

Herb.
Thanks for sending me the thread. I checked the autopilot I have and found I have both types shown in the pictures. The one that was installed in my C337 is FIG 2-1 but the other system I have is FIG 3-1. I contacted Autopilot Central (Tulsa)and Mayday (Michigan) they both say that getting those OLD navomatic (straight) 400 can be difficult to fix and or find the parts. It seams that my 400 requires a DG and a AI. The AI I have is the old type pictured. I was hoping to get a more modern AI that shows more details and color coded (blue/brown). Autopilot Central is quoting about $10,000 to get my system working/installed with a DAC converter.
The other shop is NOT sure about the overall costs? I have contacted tha Nashville shop yet. But will if the other shops can't help!
regards, BILLS

Navomatic 400 (Straight)
 

Herb.
Hello again. I'm looking for 1965 Navomatic autopilot manual. Probably the install manual as I'm trying to determine the DG and AI that are required for the 1965 year 400 Navomatic. I downloaded the manual that you had, but it only shows Chapter 3 and Fig 3-1. My 400 is the one with only one trim light on the control head. If you have Chapter 2 and Fig 2-1 I'd appreciate it.
Thanks.
Regards,
Bill Story bstory@pa.rr.com

Navomatic 400 (STRAIGHT)
 

TO Herb.
Thank you for the manuals. You won't belief it but I have those on CD. What I don't have is the manual you sent me a while back. I don't know what manual it was but the title was Section 3, with a Fig 3-1. BUT I need the Section two of that manual. That's the pre-1966 model. Any chance you have that one? Also while researching Cessna manuals, I learned that according to the Electronics parts manual the original 1965 C337 lists only the Navomatic 200 and 300. The manual states that the 400 was installed starting with serial number 240+. I think that's a 1966 337A. My 1965 serial number is 200. I've asked one of the avionics shops that I'm working with if I can install the 400. So far no answer. I cannot belief that there are no 1965 C337 with 400's installed. Maybe owners of the 1965 models can let me know if they have a 400 installed???
Again many thanks for your assistance!!
Regards, BILLS

That is a lot of money ($10K) to get the 400 up to speed. The only thing you can do is compare it to the purchase price of a STEC 55 along with the labor to install it against just how bad you want an autopilot.

The avionics shop has not called to bring my airplane yet for the fellow who asked about my installation and the paperwork. I hate bugging the guy as a sole operator; he is always up behind a panel.

I did a very short flight Friday in LIFR to go work with a guy on a High-Performance endorsement. KVCT-KPKV is a short 17nm flight that requires a climb from SL to 3K, a course reversal, and then the LPV approach. The 400A flew it smoothly and to perfection. I attached the 3D View of my track and the approach plate.

Navomatic 400
 

TO Patrol pilot.
Thanks for your reply. Yes you are correct, about spending $10K to get my old straight 400 working. But as I stated in an earlier thread, my plane is NOT worth, to me, dumping $30K plus for a new autopilot(S-tek 30). But an investment of LESS THAN $10K would be worth it. I fly long trips in my C337 and at 68 years old the trips are very tiring! With me doing ALL the grunt work I'm hoping to be under $10K? The other reason to invest $10K is I'm currently training for an instrument rating. I just wish, as many other C337 owners, to have one of the New autopilots that single Cessnas and Pipers have as options.
Regards.
Bill Story

Maybe this is the one

Navomatic 400
 

TO: Herb.
No sir, that's the one you sent me before. That is for 1968 C337. I take it you don't have section 2?
Thanks for your continued assistance.
Regards.
BILLS

Per a 1968 Navomatic 400 repair manual:

Computer-Amplifier part number 30520-0014 (14 volt) or 30520-0028 (28 volt)
Control Unit [dial unit on the pedestal] 30510-1114 (14V) or 30510-1128 (28V)
Gyro-Attitude Indicator 30475-0100 (Type G-519A)
Directional Gyro 30370-0100 (Type G 520A)

Above for an "AF-520A".
Herb's pictures for "AF-520 B&C".
Hope this helps some. I see a firm called AQI that sells them and overhauls. Maybe there are others...

I hear you, Bill; I will be 67 this year, but at any age, having an autopilot, even a basic wing leveler, is worth a lot in a single-pilot operation. It gives you time to do many things, including watching for traffic and other tasks on any flight.

My vote would be for Autopilots Central. They run a schedule and seem to stick with the expected finish date. My work was supposed to be done at noon on a Friday (their normal end of week closing time), but everybody stayed until 5 pm to make sure I got out. They did this for me without over-time shop hour charges.

I see that you are in NE PA, so Tulsa is a long flight. My thoughts or at least a question for any shop working on a 400 is, "are you going to tune it to the airplane on a check flight?" Two shops in Texas were honest with me by saying: we are going to pull everything out and send it to APC, and your airplane will sit here while APC goes through your gyros and boxes. What we won't be able to do is tweak it inflight when we put it back together."

As in a post I made concerning my autopilot work at APC, twice as much was found after the test flight as were found at the bench. This lead to some small components being replaced. I wanted to fly the flight with the two technicians but was smart enough to let their pilot do it as I figured he had seen it all. It was a smart move as, after the first flight, he told me all that they do on the flight (about an hour's worth of flying), and he showed me his kneeboard with notes; a lot was going on that I would have never thought to look at, let alone understand. The pilot was a Cessna guy, and he said he probably flew the acceptance flight in my airplane as it rolled out.

In that other topic, I also relayed how it takes two technicians in flight, one in the right rear overhead of the airplane, one upfront, to do what they do. These two fellows have a couple of unique "boxes" that they have made over the years of 400 work that help them fine-tune the beast.

When looking at other shops and their bids on your work, ask them if the actual 400 bench setup and testing will be done in-house and will they be accomplishing the inflight adjustments. The first will unnecessarily increase the downtime on your airplane if sent off, and the latter will not provide a finished product.

I had found a complete Cessna bench setup for sale, the same boxes on the APC bench (not the inflight boxes), and offered to buy it for my shop. The guy that works on my airplane didn't want it as he said there was more to it than that. He said, "it's too late to acquire the knowledge that an outfit like APC has." At least APC is training the young guys.

With the certain schedule that APC maintains, I bought a round trip ticket on United from Tulsa to Victoria, TX, and back. It was the cost of one night's hotel and meals. In that my wife and I go to St. Paul twice a year to see family; with a stop in TUL, we are going to plan an overnight on the early fall flight so that APC can keep the 400 tuned up. I spoke with the boss; he thought it a great idea as too often so many are letting their 400s go. He felt the 400 is better than the alternative.

My freshly overhauled AI was bad; still, in warranty, I found a replacement in TUL (Porter-Strait Instrument Company) and returned mine for warranty as I would like one on the shelf as a failure ends 90% of my flying. APC suggested that when returned, I send it to them to adjust the nulls as it will not come from the instrument shop ready to slide into the Skymaster and it's 400. It's not a complete 400 tuneup, but it will keep me going until I get back to TUL. I still haven't received the AI back, but when it does, I will slap a label on it and send it to TUL. I have a T&B on the shelf that needs O/H; I will send it to PSIC as well; I liked how they worked with APC and the help they offered to get my airplane out of the shop!

Yep, $10K is probably worth it all considered!

Navomatic 400
 

TO: Patrol Pilot.
Thanks for the reply.
A hangar neighbor suggested Autopilot Central, as he had them do some component work for him. So I contacted them. Randy the old mechanic said "we no longer work on the 400!" Yep, that's what he said, he mentioned that they WOULD work on it but basically if I needed parts I'd be screwed?? So I contacted Mayday Avionics in Grand Rapids, MI. Suggested by a SOAPA member. The main tech there called me and said he had a lot of experience with the 400s. He also said that they have an electronic engineering company that makes several problem components in the amplifier, ie, transistors and resistors, that are the usual replacement parts needed. I'll have to ask about the test flight. As I said earlier, that shop is much closer. I haven't decided which shop I'll be going to. Have to ask more questions to each shop before making my choice.
Thanks for your assistance.
Regards, BILLS
PS: I live in NW Pennsylvania, between Erie and Pittsburgh.

Navomatic 400
 

wslade2 .
Thanks for the reply. Is the AF-520A the amplifier? The reason I'm asking is if that number is for the amplifier? Because my number is CA-520A?
Thanks, BILLS
PS: Do you have the SECTION 2 manual? The Section 3, which Herb sent to me is for 1968 model year, mine is a 1965.

Ahhh... the straight 400, no A or B.

I am trying to attach a PDF file of a few salient pages from the manual to see if this helps find the parts you need.

Handwritten on the front of the manual is "1968 AF-520A" which I surmise represents the straight Nav-o-matic 400 model this manual is for. You will see the Amplifier is "CA-520A", the number you have on your amplifier.

Hopefully, if I am successful, there is a PDF file attached to my post.

Also, here is a listing of the proper actuator numbers.

Attached is another PDF

Navomatic (straight) 400
 

wslade2.
Thanks, that is part of the manual I was looking for. I'd assume the avionics shop will have the rest for when I send them my components.
TO ALL: Many thanks to you guys' help!! Many think I'm crazy trying to get an an OLD straight 400 autopilot back in my airplane? But I always enjoyed flying(Civil Air Patrol's airplanes) with at least a single axis autopilot on long trips.
Any other thoughts or help from my fellow SOAPA members would great.
Regards.
BILLS

Our Skymaster is at Mayday right now. We have a Bendix FCS810 that has been intermittent. They told us when to drop it off and started working on it the next business day. As you mentioned, we had a FET fail and their electronic company is making some replacements. They've been great to work with.

Bill

Navomatic (STRAIGHT) 400
 

Patrol Pilot.
Thanks for the reply.
I have a straight 400. The earliest model. NO A or B. I do have another 400 which I'm trying to determine which one it is? I'm sending the pictures and serial numbers to Mayday Avionics, hopefully they can figure this out. I have a dual knob DG I'm hoping that will work with the second 400?? Who know!