Schiff Aero A/C

[KenFlo]

When we were looking for a 690B we wanted one with AC.  We live and fly mostly in the South and AC is a wife requirement.  The plane we purchased did not have Freon Air, only the air cycle machine, but the plane was everything we wanted except AC so we thought we would give the air cycle machine a chance.  On our first flight to Montgomery, AL it was a 85 degree day and muggy.  Wife was not happy with the air cycle machine so we decided to go with the Schiff Aero system.  So, after several weeks at TN80 I am now flying again and have AC. 
  We are very happy so far with the results.  The plane gets full pressurization differential now at 25K and above (it didn't before), cabin is very cool, and time between a heat soaked cabin and cool is only a few minutes.  One of the best features is the ground cooling with an extension cord plugged into a pig tail in the baggage compartment.  The AC runs in the cabin automatically when it is plugged in and requires no cabin access by the ground crew.  I have a yellow construction grade cord in the baggage compartment so the ground guys plug it in for me after they tow it out of the hangar.  When we arrive to fly, cabin is nice and cool.
  I still have a few minor tweaks required and have to go back to TN80 next week, but initial impressions are very favorable.  Its expensive, but wife is happy....

[Adam Frisch]

Nice report! I've always seen the Schiff system as an impressive alternative that thinks outside the box - was surprised they weren't more common. Maybe it's the price. Or maybe it's because Eagle Creek sold most of the Commanders and they had their own system. In any case, happy you like yours. Let us know how it holds up!

[donv]

Good to hear that it's working well for you. I can imagine that AC would be important in the south, and the standard ACM, while okay in cooler climates, might not be up to it.

[Bruce Byerly]

I hope it continues to well for you Ken.

To be frank, I have had mixed results and given the iron skillet like reliability of the original system, have a hard time understanding the interest in changing a model 690A/B. Not sure what the cost is these days but maybe you can share.  Of course I appreciate the benefit of Freon AC and the pre-cooling via 115 is neat.

Adam - just fwiw, no single shop sold most of the planes nor does anyone else have an alternative that you or anyone else can’t get for a 690.  Keith products builds the AC system.  It’s now about $53,000 in parts as I understand.

Cheers guys 

[donv]

The Keith system is really effective, with the dual blowers. It's hard to imagine a more effective system, really, although the 110v cooling does look like a nice feature.

[Adam Frisch]

No, they seem to make the most sense for Jetprops. There was the 840 I looked at that had had 13 overhauls of the Sundstrand in as many years... That's a shocking number and bill to deal with. But apparently the trick with Sundstrand is to be religious with oil changes and never use Max Flow.

I'm glad I have the Fairchild in mine. Although the ground blower is prone to failure.

[donv]

I think that, other than the oil and Max Flow, the big factor is operating in very hot and humid environments. The 840 you're thinking of, I believe, was in Central America for many years. My airplane has spent it's entire life in Germany, New England, California, and now the pacific northwest, so no real issues-- and I have freon, which makes the ECU's life even easier.

If I were based in a hot and humid environment with a Jetprop, I think the Schiff system might well be worth it.

[KenFlo]

Another benefit of the Schiff system is the cabin pressurization.  After several flights above FL250, I have cabin differential of 5.1.  All clean air not using much bleed air at all.  Engines seem to do better at altitude even when today was  +16 ISA.  All in all the system seems to be the right choice. 
You certainly could not make a very strong financial business case to install the system, but I couldn’t make a strong business case to buy the plane in the first place.....I just wanted it. 😀

[donv]

Fair point about the economic analysis!

I think the Jetprop with the Sundstand puts out more air than the 690s do, or tend to have fewer cabin leaks, so differential is less of an issue (not the case with the Enviro, though). I've flown plenty of 690s that wouldn't make 5 psi, so I see your point.

[donv]

I just saw a second Commander come into Aero Air to get the Schiff system removed. And on this one, it was installed fairly recently!

I've been hearing nothing but terrible things about the Schiff system these days.

[Adam Frisch]

Yeah, me too. On paper, it looks like a great system. Not sure what's missing - performance or service?

[donv]

Reliability and service, from what I understand. Of course, if the system was reliable the service would be less important.

[CMech]

I was reading the comments in the environmental and pressurization section and noticed there were some on the Schiff CCU System. I was a little surprised at some of the issues other owners were having with the system and that some were removing them to install the Enviro System, I would guess.  We had the Schiff CCU System installed on the TC980 in 2006 after continuously having to change the Sunstrand cooling turbine about every 200-300 hours or so. The plane  is operated in South Texas which is pretty hard on the turbine. The owner has been very pleased with the Schiff CCU System. The increased engine performance, because of the very low bleed-air extraction, is slowly paying for the system because of the higher airspeeds we have experienced since it was installed. More miles flown between 150hr inspections. We have about 2,000 hours on this CCU turbine now and have had almost zero issues with the system. Most pressurization issues have been airframe related. Usually bad seals, boots and ducts. The scheduled maintenance is about all we do to it, along with some of the improvement updates. The Freon system has been working extremely well also. We’re still using the original compressor and drive motor. The 110-volt power supply for the system works great when there is no GPU available. This has been our experience with the Schiff system.

[donv]

Wow! Not many people have positive things to say about the Schiff system, so I'm glad it's working for you. I have heard their support is terrible or at best nonexistent, but you never know.

Of course, I'm a big fan of the Sundstrand, and probably the only one you will meet, so I shouldn't talk.

[AC90TC]

The 840 airframe I fly has a PS CCU in it since 2014, we don't have quite as many hours as CMech, we are not far off and I would echo his sentiments. I've always been able to call Peter and his techs anytime for support and maintenance at his facility. Our setup has been relatively trouble free since we started having him be the only one to service the unit (usually fly around 80 hours a year). FWIW.

Nate