[patrolpilot]

The last update of 4XXW SFMS, 190-00356-03 Rev. G, indicates that there are no autopilots authorized for LPV approaches (attached image). Not sure you could use the info posted for the 5XX SFMS if you didn't have one on board.

That said, Sandel had a software update that would allow my 3308 to do it. So, I purchased it, it wasn't cheap, and I had the avionics shop install it and do some hard-wire changes that it required. The update also provided the autopilot integration to fly it.

As a note, Sandel might have bit the dust in '20. They were walloped by everything that happened this year to include the wildfires in CA. They no longer are answering their phones or emails. I bought the annual DB update for the 3308's memory; yeah, it has a Jepp DB of US fixes in it. The shop had a problem with the date range of the software, and it would not load. At least the annual update is cheap. Anyway, my 400A actually does a heck of a job flying an LPV approach. Spot on. My airplane was just up to APC for a problem, it was the attitude indicator, not the autopilot, and the test pilot let it fly the approaches to minimums as part of his profile.

As a note, it is worth taking the airplane to APC in Tulsa. They ended up flying my airplane twice with their pilot and techs, and the tweaks were worth it. They have the equipment the I suspect no one else has. The airplane is flown through a test profile; in the Skymaster's case, there is a tech in the front with their pilot, and there is a tech in the back seat with the seat laid down, making adjustments to the box in the overhead. While they are doing this, there is a great place to eat 171' away; Evelyn's Soul Food. Jimmie Cricket! Tulsa is directly on our Victoria to St. Paul grandkid flight. Evelyn's will be a mandatory "fuel" stop north and southbound.

Me personally, I don't have a problem letting it fly one. My 400A is always in top shape, I know how to monitor a system and an approach, and my 20K hour plus background is heavy with both IFR and LNAV operations. Of course, look at the Terrain Proximity notes on the same attachment. You're not supposed to use it either. Right, that's one of the reasons you bought it and maintain the updates. Garmin is covering the butt.

The difference between the 400A and B is that the A uses chain/sprocket drives, and the B uses torque motors. The B flies the airplane with input pressure just like you would by hand. I'm not sure the C337 ever had any B installations.

I briefly considered going to the glass, but that means an autopilot change as well. With the STEC 55 being the only option, it's not for me. I've flown a bunch of different airplanes professionally since I retired from the airlines. I see a lot of inop STECs. The three STEC installations I've been flying this year are all inop (all 55s). I've talked to three shops this year about going to the glass, which means that I leave the 400A. All three have told me to plan on doubling the autopilot's cost to cover the installation labor. That is not out of line with what I've experienced with other installations I've had done over the last two years. I keep a spare, rebuilt attitude indicator on the shelf; that's the real key to the 400A. APC has prepped it, but I will take the airplane up there to adjust if it is put in use.

I've got a bunch of stuff to be done going into my annual in a couple of months, but I'm not going to go to glass in my airplane. Too much $$$ for an airframe that is working towards 50 years old, that's me. If everything craps out, or I feel the need for glass, I'm going to buy a used late-model Seneca V with all the bells and whistles; FIKI, radar, and airconditioned and be done with it.

What's weird is that in the late '70s, I flew a 337G, P337G, and a PA34-200T Seneca II professional during the same time period. The 337G was flown on a pipeline patrol from the TX/Mexico border into AL weekly. The P337G was flown in TX and Mexico, and the PA34 in TX, NM, CO, and Mexico. I liked all three. I guess I'm back to my roots.