Because Owning And Flying Your Beechcraft Can Be Done Safely AND For Less Money!
FTA System Tips & Tricks by Brian Manke


This narrative was written and contributed to by F33A Bonanza owner, Brian Manke, regarding his experiences and the solutions he developed to make his FTA AC system function more "pleasantly".

This narrative is long overdue based on some of the comments I have read over the past several months. I have also had several of you reach out to me looking for help and it's obvious that this information needs to be published. I know when I started down this journey I could not find any documentation. I hope this information helps several of you and saves you a lot of time so you don't have to go through what I went through to get our system working correctly. 

It's also important to understand our system was installed in 2011. A lot has happened since then and who knows what happened to our plane before we owned it. 

I bought our plane about 3 years ago and back in 2011 FTA installed their air conditioning system. My wife’s family lives in Boston and mine in Chicago so our plane does some cold weather flying. Our first trip into cold weather was a bone chilling event and we FROZE. I wasn't happy and the wife was MOST displeased! I knew this wasn’t correct and thus began a three year odyssey to correct the many, many problems with our climate control system.

Heat Related Items

1.  Co-pilot vent not screwed to air frame. This is that big round vent that is mounted to the side of the air frame and is a fresh air vent from the leading edge of the wing. Ours was only screwed to the carpeting. Not a single screw between the valve and the air frame. HUGE air leak!

2.  Rear Bulkhead vent deformed & obstructed. This is the 4” or so round hole at the top of your rear bulkhead that should be connected to the exhaust port on the back left had side of your plane just behind the back window. This helps the air flow throughout the cabin when you are using the heat. Mine was deformed and obstructed.

3.  Heater mixing valve cable not secured to valve. Simple as this must sound, the cable must be securely attached to the mixing valve below the battery in the engine compartment. The bushing had been lost on mine and the cable was wrapped around the arm. The system will modulate the valve on mild days. It can only modulate the heat if it has a direct connection to the valve. 

4.  Heater mixing travel maladjusted. Again simple sounding but the system has to be able to turn it ALL the way on or ALL the way off to work properly. Mine was not. The cable was incorrectly attached to the servo and was not getting enough travel to fully open or close the valve.

5.  Heater flap seals. Inside the heater valve are rubber flaps that seal the valve. If yours are original or damaged this will naturally significantly affect your heats performance. Gee Bee Aerospace has the flap seals.

6.  Servo arm frozen. There are two servos inside the cabin below the main cabin door. One moves the heat mixing valve in the cabin, the other the defroster valve on the firewall above the copilot rudders. The servos have an arm with a ball tie rod on the end. One of mine was frozen solid. Instead of moving the cable, it would bend the cable. It’s amazing the cable didn’t break. Periodically these should be inspected and lubricated.

7.  Rear heat servo not secured. There is a valve inside the passenger compartment just in front of the copilots pedals that controls the air flow to the back seat passengers. There is a black servo just above it. Our servo was not attached to firewall and therefore could not actuate the valve.

8.  Temperature Sensor Air Flow. Does your system not seem to know what the cabin temperature is? Do you need to turn it way up or way down to get it to react? When I was on the home stretch this was one of my final problems. I could not figure out why I needed to sometimes crank the heat either way up or way down to unreasonable temperatures to get it to react the way it should. This was especially noticeable on mild days. Behind the pilots seat is the temperature sensor in a little black plastic housing with a stainless steel screen on the front. Behind the screen is a fan to draw the air in from the cockpit. After drawing the air in, the air needs to go OUT. There should be holes on the bottom of the housing to exhaust the air and ensure a continuous flow of air across the temperature sensor to get a reasonably accurate cabin temperature. Our housing did not have any holes. So the air inside the housing was trapped. Words cannot describe how much better the system works with holes for the air to exit the housing after passing across the temperature sensor.

While you are there, carefully check the connections of the four little wires. One of mine was poorly done, fell apart as I was putting the interior back together. When did I discover the problem? AFTER I had the entire interior reinstalled and could not figure why the fan would not work. Back apart again. You don’t want that to happen to you. If your wiring is bad, the connector is available from Digi-Key. Instead of trying to crimp those tiny connectors, they sell pre-made leads. MUCH easier to work with.

Pre-made wires: ... W2/5962843

Bonus information - this the same style connector used for the Garmin GSB 15. So these leads work in the Garmin connector too. :)

Temperature sensor socket: ... 400/252497

Other Items

1.  Check the wiring over closely.
a. Definitely check the primary feed to the system at the circuit breakers. Mine was being fed with a single 18 gauge wire that was poorly tapped into the primary supply cable for the entire cabin electrical system. There is now a proper copper bus bar connecting the row of circuit breakers with an appropriate sized wire that is connected to the main power feed with a ring terminal and not a ring terminal cut into a spade terminal. When I had my EL panel redone, I added labeling for the previously unlabeled circuit breakers plus the ones I added as part of our COVID big G upgrade.
b. My tail section was a mess. Wires everywhere. Poorly secured. Poorly routed. Did not affect system performance but it looked terrible.
c. If your head unit is mounted to the pedestal – check the wiring behind the control unit. The elevator cables are RIGHT behind it. There is not a lot of extra room. In addition the weight moves up and down in this area. My AC wiring was hitting the elevator control cable and weight. It was not easy to find a solution to ensure they are out of the way.

2.  Front Round Black Vent Fix. Do your black vents rotate and point wherever they want? This is easily correctable. The round black plastic vents just snap into the duct. Carefully pry them out. Once out you’ll see the two rows and molded in pins where they pivot. Carefully pry it apart, and put a small nylon washer on each end and reassemble. Requires a delicate touch, but once reassembled the vent won’t move on its own.

3.  Other air leaks. It’s amazing what other people will do to make their lives easier….. I found the main landing gear boots on our plane had been ripped off and discarded by the tip tank installer. Another huge air leak. Original, dry rotted and shot window seals. Pilot vent window seals. Door seal. All of these leaks significantly decrease the heaters performance. Gee Bee Aerospace offers excellent silicone replacement seals.

4.  Duct work. My ducts were in ok shape but were definitely not ideal. The middle row vent was collapsing. It can be reformed by carefully heating it back up with a heat gun. Do not go to hot! And this requires a delicate touch. Once you get it back to where it should be – fabricate an aluminum support ring to put inside so it holds its shape when it gets hot. For missing pieces of plastic or reinforcement, JB Plastic Weld Putty is amazing stuff for filling and supporting brittle ducts. ... g=btalk-20

5.  Insulation. I discovered much of my insulation had been ripped out over the years. All of my ceiling insulation was missing. I insulated the plane with SoundEx. Wow is it quiet now and the climate control system is more effective.

The system now operates as it should (and expected) and more or less you just set it and forget it. With only one temperature sensor we make minor adjustments (seasons, night vs day) but for the most part it works almost as good as a modern car. Our heating system can now keep the cabin comfortable (wearing either a long sleeve T or light sweatshirt) down to zero degrees Fahrenheit at night. I am not sure how much better I can get it so I would be interested to hear how effective other peoples systems are.