How serious is a cracked exhaust pipe?

poadeleted3

Pattern Altitude
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Mar 2, 2005
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I happened to see a Skyhawk at the airport recently with a crack in the exhaust pipe. It ran two or three inches from the end of the pipe, maybe halfway to the cowling. The operator mentioned they were going to have it fixed before it cracked all the way up to the cowl. I got to wondering if that is safe, or if it's a plane you wouldn't operate until it got fixed.
 
RUN AWAY!

Cracked pipes can cause fires, and can leak CO into the heat exchanger which proides the heat to the cabin.

I think that there are a few engine fires on the NTSB reports caused by cracked exhust pipes.
 
Joe, I wouldn't operate it.

Depending on the ventilation system, it can induce carbon monoxide in the cockpit. In addition, depending on where it is, the hot exhaust gasses can leak and cause damage.

This is particularly true on a turbocharged aircraft. On my aircraft, turbo inlet temperature redlines at 1725, and normally runs 1600 to 1620. An exhaust leak in the engine compartment can burn wiring and hoses, and may even damage engine mounts. If before the wastegate, it can also affect engine power.

From my perspective, a cracked exhaust is reason to ground the aircraft.
 
That piece of exhaust is just a short section to direct exhaust products away from the cowl. it probably isn't any airworthiness problem.

But it is an indicator, of attitude toward safe maintenance.

One muffler on a 172 has the carb heat muff, which delivers heated air to the carb for de-ice.

the other is the heat muff for the cabin, cracks in the muffler with in the heat muff will cause death to the cabin occupants, by delivering carbon monoxide into the cabin hot air duct.
 
Joe, out of curiousity, at which airport did you see this? If you don't feel comfortable stating it flat out, how about a hint, given that we locals know the airports you frequent. The little mom & pop op near the state pen? The FBO at the class D from which you sometimes rent? I'm hoping you don't say you saw it at my home field....
 
Joe Williams said:
I happened to see a Skyhawk at the airport recently with a crack in the exhaust pipe. It ran two or three inches from the end of the pipe, maybe halfway to the cowling. The operator mentioned they were going to have it fixed before it cracked all the way up to the cowl. I got to wondering if that is safe, or if it's a plane you wouldn't operate until it got fixed.

The question is, if it's cracking there, is there anywhere else that it could be cracked? Personally if they said that, I'd just say "Let me know when it's fixed and I'll rent it then." or something to that effect.
 
if it was cracked towards the end of the pipe, not near the dealio (technical term) for the cabin heat, i wouldnt worry about it too much, but make sure it is on the list of things to do and keep a close eye on it.

Found a crack on the exhaust of the towplane earlier this year right at the exit point of the cylinder. We had had the other half of the exhaust off the last year and replaced as it had worn through and the tow pilot got a little hot with blue flame shooting straight out into cowling. consequently i didnt get much flying in that day.
 
tonycondon said:
if it was cracked towards the end of the pipe, not near the dealio (technical term) for the cabin heat, i wouldnt worry about it too much, but make sure it is on the list of things to do and keep a close eye on it.

The problem is that you don't know when that crack is going to propagate up into the muff (don't want it happening in flight), nor do you know the condition of the rest of the pipe.

This is one where I play it safe and ground the aircraft.

(Turbo driver).
 
Joe Williams said:
I happened to see a Skyhawk at the airport recently with a crack in the exhaust pipe. It ran two or three inches from the end of the pipe, maybe halfway to the cowling. The operator mentioned they were going to have it fixed before it cracked all the way up to the cowl. I got to wondering if that is safe, or if it's a plane you wouldn't operate until it got fixed.

In and of itself, that crack I wouldn't worry about, I'd just stop drill it and drag a TIG out to it when I got a chance. Problem is, that unless a specific known accident caused the crack, and even then, you probably have more cracks and they could be in places that pose a greater hazard.

I wouldn't feel right until I at least did a complete inspection of the entire exaust and stop drilled the crack. In reality this would require about an hour.
 
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