Damage from Ingested Cowl Plugs?

techflight said:
Yes, I'm curious if the oil analysis can provide relatively definitive info on if I should be concerned about engine damage or not - if anyone has any additional insight here I would really appreciate it!
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Your best bet might be Blackstone, where you can write comments on the form when you send the sample in. Blackstone will reply specifically to your comments in the narrative that they provide with their report.
 
When I first got the Comanche it had to live outside for a month or so. Flew it one day, and the next day I went out and both sides of the engine compartment were filled with nesting material. Packed absolutely full of hay/straw/grass. Cowl plugs kept them out. I think I stuffed a blanket or something in it until I got cowl plugs.

MooneyDriver78 said:
I can’t imagine a bird nesting in a hot engine compartment, that’s a dumb bird and Darwin will hopefully prevent it from breeding.
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You realize the engine isn't hot when it sits overnight, right?
 
We get a letter every month from the airport manager in which he warns us to plug our cowls and any other openings this time of year because of bird nesting. He says they can get into your plane within a couple minutes after your parked this time of year. He also asks us to keep our hangar doors closed when out flying to keep the birds from nesting in the hangars. Says once they get in they won't leave and will find other ways into the hangars if they start to nest in one.
I have seen it myself, these planes are like magnets to birds for some reason.
Of course I use cowl plugs to keep the heat in during the winter.
To me it is no big deal and I am more than used to removing them since all the school planes I trained in used them for the same reason...birds! School planes sat out on the ramp 24/7 except during storms.

I need to get custom plugs made for my winter block off plates that I use during the winter.

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Birds suck and they absolutely get into an airplane and make a mess very quickly. I fly planes that have cowl plugs and pitot covers. Haven't forgotten them yet, but it is high on my list when I get to the plane to remove them. I do the final walk around just before I'm ready to get in and start.
 
TrueCourse said:
So take your pick. Bird bird nests or the risk of still-installed inlet plugs to cook your engine. Sometimes things that are designed to fix a problem end up creating problems. Professional pilots have left jet engine inlet covers installed during a layover and destroyed a perfectly good and expensive jet engine during an engine start. That is also a lack of a good preflight as well communication breakdown between two crew members. Again, if you can’t see inlet plugs, especially those painted red, you shouldn’t have been flying that day.
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Very much of a moot point. If you fail to remove the plugs from the cowl, that’s your fault. Bird nests vs. leaving the plugs installed is an obtuse comparison.
 
It seems that most folks vastly underestimate the amount of work required to remove a birds nest. I’ve seen people just stick their hand in the inlet and scoop around and call it good.

Reality is the cowling must be removed and possibly some of the inter- cylinder baffles. This is particularly true if the aircraft has been flown and the slipstream has packed it in. It does not take a real lot to obstruct the passages between the cooling fins which results in localized hot spots. Wire and compressed air may aid the clean-up.

If you own it you can ignore it. It’s your engine at risk!
 
R.L.Mauzy said:
I may be wrong but I'm pretty sure that any overheating concerns could be answered with a bore-scope. The discoloration of the cylinder walls, valves, or pistons etc would be fairly obvious. That and the oil analysis and a compression test should be able to solve that question in my mind.
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Thanks. I didn't ask about doing a borescope, but they are doing a compression test, oil analysis, and I will be reviewing the CHT data once the cable arrives. It sounds like that should be sufficient.
 
NoHeat said:
Your best bet might be Blackstone, where you can write comments on the form when you send the sample in. Blackstone will reply specifically to your comments in the narrative that they provide with their report.
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Thanks for the advice. They already sent it in unfortunately and not sure where, but it sounds like it should provide useful evidence regardless.
 
techflight said:
Thanks. I didn't ask about doing a borescope, but they are doing a compression test, oil analysis, and I will be reviewing the CHT data once the cable arrives. It sounds like that should be sufficient.
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Filterclear?
 
Randomskylane said:
Filterclear?
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Forgot to ask, just sent them a note but they didn't mention it so presumably it was fine. Compressions were all good. Everything should be fixed by the end of the day today and flying again tomorrow morning.
 
I put my control lock, pitot cover and cowl plugs in a vinyl bag that resides on the pilot's seat when in position. My first action when entering the plane/preflight is to place the cowl plugs/pitot cover then control lock inside before the bag leaves the seat.
 
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Cowl plugs to elimate birds nests have been highly effective over the years, but they are not infallible.
Consider this jaw dropping example of mine. Flew into Ann Arbor Michigan in the late afternoon. Was tied down in front of the FBO’s active hangar and ramp. Had cowl plugs installed. On arrival late morning the next day, there was an exceptionally large nest that required me to de-cowl and hose out the debris.

So before and during nesting season, always have a high index of suspicion even if using plugs. Before removing the plugs, my procedure is to open up the oil dipstick door, carefully look with a flashlight all the nooks and crannies that can be seen. Next, probably most importantly on my Archer, look and feel with your hand for any tiny debris on the lower rearward facing engine compartment shelf opening. If “anything” is there, a de-cowling is warranted. Also look at the ground below that shelf. These efforts have saved me several times.
 
robin ardoin said:
I put my control lock, pitot cover and cowl plugs in a vinyl bag that resides on the pilot's seat when in position. My first action when entering the plane/preflight is to place the cowl plugs/pitot cover then control lock before the bag leaves the seat.
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Those items were listed explicitly on our checklist.
 
Magman said:
It seems that most folks vastly underestimate the amount of work required to remove a birds nest. I’ve seen people just stick their hand in the inlet and scoop around and call it good.

Reality is the cowling must be removed and possibly some of the inter- cylinder baffles. This is particularly true if the aircraft has been flown and the slipstream has packed it in. It does not take a real lot to obstruct the passages between the cooling fins which results in localized hot spots. Wire and compressed air may aid the clean-up.

If you own it you can ignore it. It’s your engine at risk!
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Nah. You bring an air compressor out there with a nice blower wand and it gets rid of it pretty easy.
 
RyanB said:
Very much of a moot point. If you fail to remove the plugs from the cowl, that’s your fault. Bird nests vs. leaving the plugs installed is an obtuse comparison.
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It was a little bit of sarcasm, not to be taken seriously or critiqued as if it were.
 
Cap'n Jack said:
Cowl plugs? This time of year, they help to keep birds out of the engine compartment. I remember seeing birds fly into the air inlets of a plane that was parked for maybe 15 minutes with nesting material.

I'm sure determined birds will find other ways into the engine compartment, and other places in the plane, but the cowl plugs help a lot. In winter, I suppose they help retain engine heat during a short stop or preheat, but otherwise they probably don't do much.
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I guess this is really one of those, YMMV things. In thirty years, I've never used a cowl plug and I've seen evidence of birds nesting only once. But I've also never flown a plane that spent significant time on a ramp.
 
Lindberg said:
I guess this is really one of those, YMMV things. In thirty years, I've never used a cowl plug and I've seen evidence of birds nesting only once. But I've also never flown a plane that spent significant time on a ramp.
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Yes, probably YMMV, location, etc. I suspect hangared planes have fewer nests in them. It also depends on the bird species endemic to your airport because not all birds use cavities for nests. The size of the holes (cowling and other places) play a role since birds choose cavities big enough for them, but small enough to deter predators, so maybe your plane doesn't have "desirable" holes.

MooneyDriver78 said:
I can’t imagine a bird nesting in a hot engine compartment, that’s a dumb bird and Darwin will hopefully prevent it from breeding.
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It happened, and we were amazed when we saw the bird fly into the inlet several times with grass.

Remember Newton's law of heating and cooling. The engine is initially very hot compared to the air, and so it transfers heat to the air quickly at shutdown. Just a little airflow is sufficient to move the hot air out of the cowl and replace it with cooler air. The rate of cooling is proportional the the difference in temperature, so the engine loses a lot of heat at shutdown, and loses less heat later. There are other variables in Newtons law beyond the engine and ambient temperatures, but those are the most important ones.
 
Lindberg said:
In thirty years, I've never used a cowl plug and I've seen evidence of birds nesting only once.
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In my experience, it is very location specific and even on the same airport. Have actually watched birds start the nesting process on aircraft in between flights in some areas. And birds are not the only issue. In some areas other critters like tree frogs can ruin your day especially with turbine engines if you leave the inlets open with a few 135 operators even mandating inlet plugs during the festive frog season. Definitely a YMMV topic.
 
I have spent so many nights at my hangar that overlooks a empty grass lot that I have noticed the same routine the last couple hours of day light. I would say I see at least 3 different types of birds land in that field to eat and they move on and a different group of birds land and graze always around dusk. Lots of birds at our airport. WE have a county park with lots of wooded acres nearby.
 
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I think they can read numbers !

Visualize 20 F-100 aircraft parked outside. The flock determined “ 714” would

make a great home. No matter how much you cleaned and repositioned that

aircraft the nests would reappear.


There was a 172 that flew in from about 500 miles away. 3 live birds were in the

stab and vertical fin. My guess is they were born inside and grew so large the

couldn’t get out. The entire tail came off for removal and clean up!
 
We had a grill out at our airport a couple years ago before covid. Some of us stood around BSing and watched many birds go in and out of the rear horizontal stab of a 172. There a group of them going in and out. The airport manger was there and commented that he warned the owner about the bird problem ahead of time. He said birds do the most damage to small aircraft.

My plane sat in a open faced lean to hangar for a few years before I owned it. I found a lot of mud dabber nest during the first annual I helped with before I owned the plane. Then found even more as the year went on. I am hopping I got 80-90% of them out by now. Some would fall down and then I was able to vacuum them out in some cases months later. The plane only flew 9 hrs in 10 years before I bought it.
This was only about half of them during the first annual I helped with. I think the previous annuals were imaginary?
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I'm curious if this would count as an insurable occurence for OP. Just looking at the layout of the foam in the pic it could easily obstruct airflow to the rear cylinder. Not an A&P, but in my opinion pulling monitor data is a must and if CHTs went above redline I'd be reluctant to trust it.
 
No matter how much of a hurry I'm in I always do a "nothing stupid" check before starting up.

When I think I finished the pre-flight I say "let me make sure there's nothing stupid" and I do one last walk around to catch anything like chalks, tie downs, aileron clamps, pitot covers, cowl covers, tow bars, open baggage doors.

Also adds a bit of peace of mind on longer trips
 
Wanted to post what should hopefully be the final update here: the alternator belt has been replaced, which appears to have been the only problem. The aircraft has flown several hours since with no abnormalities. The compression test came back normal, and while the oil analysis will take several weeks I was able to pull the CHT data from the JPI EDM and the temps seem to have not risen above 370 degrees during the course of the flight in question (see below for the full data).
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Thank you to everyone who provided me with some insight on this!
 
You definitely lucked out, what's the status of the renter with the club?
 
I was snowmobile riding with a guy earlier this year. We stopped about 5 miles out to situate some gear. He made a comment that a mouse ran out when he started, 1st ride of the year.

We looked closer under the hood, another mouse ran out. After that we removed a nest that was partially hidden.
 
This reminds me of the time I flew to the beach with my dad. His wife drove 150 miles to the airport to pick us up IN SECOND GEAR. We found out after my dad burned his hand on the hood and asked her how the car drove
 
techflight said:
Wanted to post what should hopefully be the final update here: the alternator belt has been replaced, which appears to have been the only problem. The aircraft has flown several hours since with no abnormalities. The compression test came back normal, and while the oil analysis will take several weeks I was able to pull the CHT data from the JPI EDM and the temps seem to have not risen above 370 degrees during the course of the flight in question
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Great news to hear ... and a good lesson for all of us (not just those that rent) to be sure and do a proper preflight.
 
PaulS said:
You definitely lucked out, what's the status of the renter with the club?
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I would hope a swift kick in the knackers and telling him to pound sand if he wants to rent it again.
 
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