Lost a cowl flap on a 182. Tips to prevent this in the future?

50kttailwind

50kttailwind

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50kttailwind
Sadly lost one flying recently. She’s a 65 H model and never even considered this possibility.

Luckily I found a replacement and the repair seems simple enough. I was horrified thinking I’d find damage somewhere, but it looks like the hinge came loose and away she went.

Cowl flap inspections will now go on the 25 hour oil change checklist. Can anything be done to really secure these? It appears they hang on by the pretty small hinge and that’s it. The remaining cowl flap is decent. There’s a tad bit of play/wobble in it but not bad.

Can a mechanic service both hinges to tighten them? Anything particular I should inspect other than visually and checking the cowl flap for movement?

Thanks as always!
 
You are NOT alone with the issue.

The rivets tear out of the lower cowl and the flap flops around hanging by the

control. For awhile.

The rivets loosen in the relatively thin metal and when torn out the holes are

now larger.

Sometimes the pin will wear the hinge until that fails but you may find that at

oil change time.

This is a task for someone that has sheet metal experience.

Not all A & P’s wear those hats.

ASSURE you wind up with a good repair or it may re- occur.

Some areas require blind rivets. Do not use commercial pop rivets.
 
50kttailwind said:
Can anything be done to really secure these?
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Unfortunately it seems to be a "feature" of 182s and especially the RH one. As a preventative measure I've applied a layer of silicon over the hinge area on new or clean serviceable hinge to reduce vibration. Another preventative measure is keep your prop balanced as this will affect wear at the cowl flaps as well as other items on the aircraft. But nothing beats a good check of the flaps on a regular basis and fixing them when needed.
 
First time??? This came loose about 30 min into a Two hour flight. Hear something weird once. Plane flying fine no issues. Continue on to land and see this. Btw also a 182H.
A92FA59C-12E1-456D-83F1-8DEDADDEE80B.jpeg
 
I had similar fun with this recently. The hinge wire fell out, which seems impossible. I’ll definitely try the silicone trick, thx
 
Inspect and/or replace the pins and/or hinges. That’s how you really prevent it in the future. Cheap insurance.
 
My event, the whole flap departed.

Inspection of the non failed flap showed that the pin had worn at each space to the next hinge section. Sort of like an exaggerated Tootsie roll. When the pin was drawn out, it fractured several places. We replaced the pins at annual as a preventive maintenance item, using the proper diameter of readily available SS rod.
 
The biggest problem I’ve seen is with the hinge itself. Vibration will cause the hinge to crack or the wire will wear out. This happens over time, so regular scrutiny may catch a failing hinge before the cowl flap departs the airplane.

As mentioned above, silicone on the hinge can help minimize the amount of vibration transmitted to it. A prop balance may also help keep vibration to a minimum.
 
50kttailwind said:
Sadly lost one flying recently. She’s a 65 H model and never even considered this possibility.

Luckily I found a replacement and the repair seems simple enough. I was horrified thinking I’d find damage somewhere, but it looks like the hinge came loose and away she went.

Cowl flap inspections will now go on the 25 hour oil change checklist. Can anything be done to really secure these? It appears they hang on by the pretty small hinge and that’s it. The remaining cowl flap is decent. There’s a tad bit of play/wobble in it but not bad.

Can a mechanic service both hinges to tighten them? Anything particular I should inspect other than visually and checking the cowl flap for movement?

Thanks as always!
Click to expand...
Install a hinge pin with a loop at the end, then safety wire it. BTDT.

Dave
 
My 182 had this after I made the offer, but before I had finished purchase. The seller and I worked through options. We ended up with the Horsham fixed cowl flaps at the sellers expense. I live in Phoenix so I felt the extra cooling would be a good thing.

Mine was also the right cowl flap and I understand it's due the the exhaust beating on it constantly.
 
This stuff can be blamed only on cheap annuals. Yes, vibration plays a big part, but mechanics should know that these things need checking. However, there are a lot of other things that need checking, and that takes time, especially stuff that requires the removal of inspection panels and some interior stuff, so the owner doesn't like spending the money. "If it ain't broke, don't fix it" seems to be the mantra. Or, if it's found, we get "Whaddya mean it's shot? It flew in here, didn't it? Leave it alone."

So it falls off, sometimes gets lost, and it's hard to find those things. New ones, if available, are expensive.

Cheap maintenance isn't cheap.
 
I agree with Dan that neglected maintenance is at fault.

But my belief is the the design is also flawed.

Multiple aircraft have the issue including some on a recurring basis.

Early replacement of the pin will minimize shaking and reduce component wear.

A hinge with more area to permit more rivets as well as a pin larger in length and

diameter might have helped longevity.
 
Magman said:
I agree with Dan that neglected maintenance is at fault.

But my belief is the the design is also flawed.
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There are plenty of places in any particular aircraft model that are weak. We're stuck with those defects unless someone comes up with an STC to beef it up significantly, or unless one buys a new 182, which will have an improved cowl flap setup.

Cessna (and the rest) never intended these airplanes to last for 50 or 60 years and 12,000 hours or more. GM and Ford and Chrysler didn't have that attitude either, and so we don't see unrestored 50- and 60-year-old cars on the road. But we expect our ancient airplanes to last forever, for some reason, even with walkaround annuals.
 
Some type of modification would be beneficial here; either as an STC or a

Minor Alteration. Perhaps the Type Clubs may assist.

Some of these aircraft are often used for Skydiving so they spend more time

with Cowl Flaps open at high power.


Many of these same types often have issues with the Carb Air Box as well.

Someone came up with a nice kit that alleviated the problem nicely.

IIRC the concerns with the “ Hockey Stick” have been addressed as well.


Cowl Flaps and hinges can be replaced even if pricey.

The Lower Cowl has a section where the hinge attaches.

Unfortunately, access to the back side is difficult as it is sort of sealed off.

My biggest worry is when you can’t attach the hinge with blind rivets to a

piece of “ Swiss Cheese”.
 
Dan Thomas said:
There are plenty of places in any particular aircraft model that are weak. We're stuck with those defects unless someone comes up with an STC to beef it up significantly, or unless one buys a new 182, which will have an improved cowl flap setup.

Cessna (and the rest) never intended these airplanes to last for 50 or 60 years and 12,000 hours or more. GM and Ford and Chrysler didn't have that attitude either, and so we don't see unrestored 50- and 60-year-old cars on the road. But we expect our ancient airplanes to last forever, for some reason, even with walkaround annuals.
Click to expand...

I can't agree more. Every aircraft design has a multitude of compromises in it. Cessna did not design aircraft for unlimited lives. They wanted it to perform a certain job to a certain degree, while being easy and cheap to manufacture. Notice ease of maintenance is missing? :)

Hopefully the OP gets this fixed well. The aircraft is talking, time to give it some love.
 
Magman said:
Many of these same types often have issues with the Carb Air Box as well.
IIRC the concerns with the “ Hockey Stick” have been addressed as well.
Click to expand...
Carb air boxes are famous trouble spots in Cessnas. They're attached to the carb, which is bolted to the engine, which vibrates violently around the crankshaft axis, which shakes that airbox mightily. The box's attachment to the carb is via a small flange, and a few rivets between that and the box, and it gets loose. Cheap annuals don't catch that, and so the looseness gets worse and worse until the rivet holes are torn out and now there's a real mess. If that looseness had been caught at annual the rivets could have been rebucked or replaced, and the box would go another few thousand hours. The same thing applies to the rest of the box, too. I used to find those boxes repaired with pulled rivets (like Cherrymax) which is one of the stupider things one can do. The stems in those rivets can escape and get sucked into the engine and cause cylinder scoring or worse. The same goes for small screws and nuts. Don't do it.

The hockey stick problem is mostly due to a maintenance error. The service manual tells you to torque those stab hinge bolts to 70-100
inch-pounds, but mechanics often think that the stab rotates around the bolts because they don't read that manual, and leave the bolts loose for the rotation. There are steel bushings inside nylon bushings in that hinge, and the steel is supposed to rotate in the nylon, and the steel is supposed to be clamped between the hockey stick and the internal bracket so it cannot shift and make the bolts wallow out the holes in the bracket and stick. That stick is too many thousands of dollars, and there are two of them. McFarlane has an STC'd stick splice to fix it for less money and hassle. But mechanics will wreck those too, if they leave the bolts loose again.

upload_2023-4-30_12-27-31.png
The airbox is mentioned as a 100-hour inspection item on the inspection checklist in the manual:

upload_2023-4-30_12-31-50.png

Many shops just use FAR43 Appendix D for reference for annuals. It does not have the detail required to force one to look at certain stuff. The manual's inspection checklists are far better. Even at that, Appendix D says to "check all systems." Fat chance.
 
Dan Thomas said:
Many shops just use FAR43 Appendix D for reference for annuals.
Click to expand...
You'll find the use of Appx D is driven more by the owner and is cost related. However, there are a number of shops especially a CRS that will only use OEM forms or they use a hybrid form that includes both. I prefer using both. Regardless of the form it still falls to the mechanic and the relation he has with the owner on how the form is "interpreted" as I've seen annuals/100hrs signed using either forms and you'd swear Blind Melon Chitlin did the inspection.
 
Sometimes the manufacturer gets things right but other times an STC comes about

because of a deficiency. With the 182 Series both are true!

The 182 - ( no suffix ) had no cowl flaps and I believe the induction filter mounted

directly on the air box.

Later models introduced cowl flaps and mounting the filter on the lower cowl and

utilized a flexible duct from the cowl to the air box. This duct could still

transmit some forces to the air box as the engine would shake though.


An STC was obtained that added “ straps” to the air box. This simple mod

will extend the life of the unit.
 
Seems like not a single annual goes by on our plane where we aren't doing something to repair the RH cowl flap attachments. Usually just a loose rivet, this year it will be the full piano hinge, which is the second time we've done that in 18 years of ownership. Pretty sure we haven't yet hit the point where we've paid more to keep it attached than what a replacement would cost, but it isn't cheap.
 
I think there's an STC to toss the moveable cowl flaps and install fixed flaps.
 
Dan Thomas said:
I think there's an STC to toss the moveable cowl flaps and install fixed flaps.
Click to expand...

I think that is only for the oldest 182 models, not sure exactly which. Fixed cowl flaps would definitely drop 2-3 knots of airspeed, at least.
 
50kttailwind said:
Sadly lost one flying recently. She’s a 65 H model and never even considered this possibility.

Luckily I found a replacement and the repair seems simple enough. I was horrified thinking I’d find damage somewhere, but it looks like the hinge came loose and away she went.

Cowl flap inspections will now go on the 25 hour oil change checklist. Can anything be done to really secure these? It appears they hang on by the pretty small hinge and that’s it. The remaining cowl flap is decent. There’s a tad bit of play/wobble in it but not bad.

Can a mechanic service both hinges to tighten them? Anything particular I should inspect other than visually and checking the cowl flap for movement?

Thanks as always!
Click to expand...
There have been plenty of posts on the Cessna Pilots Society forums about cowl flap wear prevention. One trick is referred to as the "RTV trick" linked below with excellent pictures and captions. It's all about preventing the vibration that destroys the hinge.
RTV Trick-rehash - Cessna Pilots Society (cessna-pilots.net)

If you're a Cessna owner/flyer, particularly a 182 owner, I'd suggest you join the forum. It's free.
 
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