Loose PA-28R 180 exhaust pipe
Answered By AOPA
Good afternoon

i’m contemplating purchasing a 1968 Piper Arrow and during the initial walk around, one of the two exhaust pipes , the rear one, was loose. My purchasing partner and I denied going for a flight for now, for other reasons but taking into account the somewhat light attitude of the owner : “ if something was wrong, my mechanic would have told me” attitude is a loose exhaust a concern on such a model?

thank in advance

E from Laval Qc
5 Replies
AOPA Staff Answer
Hi Emile,

First and foremost, if you don't like something with an aircraft during the walk around, don't fly it (which is the decision you made). I have several hundred hours on arrows (mostly newer ones, but with several thousand hours on the airframe), and I always checked the exhausts (as I was taught), and there shouldn't be any play in the exhaust. At our school we found cracked exhausts, loose exhausts, etc. They were training aircraft that were flying constantly and frankly weren't treated as nicely as a privately owned aircraft.

A loose exhaust should be checked by a mechanic and shouldn't be accepted by a pilot during a walkaround. It could just be a loose exhaust, or it could be an indicator of other damage. At any rate, it should be checked and fixed/cleared by a mechanic prior to you taking it on a flight. If the current owner is unwilling to do this it may be an indicator of how the aircraft is taken care of as a whole, and it may be time to find another airplane to purchase.
You should wonder what else has been pencil whipped.  I say, "run"!
10K hour CFI.  (Owner of 7 aircraft, the current one in the 23rd year).
Good afternoon Emile,

As an A&P mechanic and 1967 Arrow owner, I can speak with some experience about the Arrow exhaust.  I have replaced both forward & rear mufflers in my airplane over my 18 years of ownership due to hairline crack(s), usually in a weld or wear at the muffler heat muff clamping area.  There should be no appreciable movement of the exhaust pipe on the right side of the airplane cowling.  All 4 cylinders attach with 2 nuts/lockwashers/washers/gaskets to each cylinder.  Cylinders 1 & 2 route through the forward muffler and 3 & 4 route through the rear muffler.  The left end of the exhaust pipes (cyl 2 & 4) attach to the mufflers with a tension clamp & bolt with a tapered pin for alignment.  The right end of the exhaust pipes (cyl 1 & 3) attach to the mufflers with a slip-joint into the muffler.  When tight, the tension clamp arrangement and cylinder flanges will prevent any real movement of each muffler.  The heat muff clamps around both mufflers as a unit.  Any looseness is probably due to one of several factors.  1- the cylinder attach nuts may be loose, allowing the whole exhaust system to move and leak (very bad).  2- There may be a crack in the exhaust pipes or mufflers (very bad)  3- The hole in the muffler for the tension clamp taper pin may be worn or the taper pin itself may be worn (not too bad, but replace the clamp & hardware and check the hole size).  4- if the muffler is new, the slip fit of the right side muffler may not have heated up enough to bind to the right exhaust stacks, and the muffler may slightly wiggle (ever-so-slightly;  this will stop as the engine acquires run time and heating cycles).  If the muffler is loose, something is definitely wrong.  Should you decide to purchase the airplane, anticipate replacing the mufflers, and possibly, more exhaust components.  The big question is "What else is not right with this airplane that the mechanic didn't mention?"  Remember, almost nothing is un-fixable, given enough money, parts and time.

I hope this helps with your decision.

Thanks for your educated and generous response.

the owner did have his mechanic solder in a worned pin hole, drill a new hole and install a new pin to the rear exhaust pipe before our test flight over the weekend (as in your number 3 diagnosis). The pipe had regained its expected stiffness.

Thanks  again 
Québec, Canada
Thank you Hoss for your assistance, wise, and quick response to my inquiry..
Despite  my late return your help was very useful at the time.

Thanks again

Québec Canada