SR20 Exhaust AD

I am after your opinion on the Exhaust AD (SB 2X-78-07 R1) that was issued a long time ago which requires a pressurisation check every 100 hours.

What is amusing or disturbing is that, you either carry on with the 100 hour check or replace the heat exchanger with the new improved one which is supposed to be more reliable and then carry out the 100 hour inspection as before! Doesn’t make sense.

Am I right in thinking that, Cirrus has designed and now supplying parts that require inspection on regular basis as there is a potential for failure?

Hi Mo

I have owned my SR20 for almost 10 years and SB 2X-78-07 R1 is a bummer and there is not a solution I am aware of to make this go away.

I might be mistaken, but there was a failure which precipitated this 100 hour AD.

Considering the few ADs our airframe has - I guess I have come to accepting this as a shortcoming.


Fwiw , it did catch a leak in one of exhausts a year ago, small leak, but could have developed into something worse.

I don’t really think that is a logical conclusion. All exhaust systems are potential CO leaks. It is likely that the additional pressure test is an overly cautious reaction, but that often happens when you find a problem. Just an an abundance of caution.

True, but among Cirrus aircraft only the SR-20 has the repetitive AD with no possible termination. It would appear Cirrus does not have the engineering knowhow to build a proper heat exchanger no matter how much time and money they have to try. They have had years to figure something out.

I had to replace my heat exchanger because it failed visual inspection (it looked like it had a crack) even though it passed the pressure test. The AD is quite clear on the point, logic notwithstanding. Meanwhile, we’ve seen turbos with a hole in the exhaust big enough to stick your finger in, but that seems to be OK.

I’m sure there must be some sort of logic here.

Some sort of logic, twisted perhaps [^o)]

BTW, the TN’s have a blister that is a pressurized heating system. There is more pressure in the heater blister than in the tailpipe. In other words, even a crack in the heating section should not (in theory) be able to pass CO into the cabin. One of George Braly’s better ideas.

Thank you guys for sharing your though and your experience.

Roger, the problem we have is this: is this exhaust system prone to failure? if the answer is yes, then is there a guarantee that the pilot will survive the CO poisoning in flight or make it to the next inspection? Hypothetically the exhaust can fail during its flight right after inspection!!! And the pilot may not make it to the next maintenance/inspection.

I will be interested in finding out about the new design of Lycomming installation and its exhaust system in SR20!

For peace of mind you might consider having an emergency oxygen bottle, with full face mask, available for such an occasion. Also ensure your CO2 indicator is good.


Anything is possible. OTOH, we’ve been flying SR20’s since 1999. Not trying to trivialize this but in 18 years and millions of hours of operations it hasn’t been a problem.

It is clearly being inspected enough that you can just enjoy your plane. Install a CO detect and have fun flying your SR20.


When LOP… there is no CO…


Fly safe… FLY LOP