Preflighted a C172M, Water in Tail.

[Bryce Salmi]

I went to preflight a C172M this morning here in the Los Angeles area where we've been getting a lot of rain over the past week with more to come. Prior to starting the preflight I rocked the wings from the right wingtip to dislodge any water in the fuel tanks. Hearing the expected sloshing in the wings I quickly noticed that there was a sloshing from the tail section that was unexpected. Investigating more showed quite a bit of water stuck in the tail.

I cancelled my flight since this IMHO serious affected weight and balance. Anyone else experience this? Plane owners know it's there so likely getting looked at and fixed. I'd imagine let alone from the immediate concerns of w&b a longer term corrosion issue could be at play too!

 

[Kevin Holbrook]

Birds nest in tail blocking aft-most drain hole.
Vertical stabilizer is probably full of nests and bird crap too.
Ask me how I know…

 

[Dan Thomas]

Shoddy maintenance. There are drain holes in the belly to prevent water accumulation, and the mechanic should be under that belly at least once a year to see that they're open, and every 100-hour/annual inspection requires a check of the structure and all systems, meaning that the mechanic should be into that tail and making sure water hasn't been accumulating and corrosion not happening. Water leaves stains in the dust. I have found plenty of such evidence in some airplanes, along with the accumulated sludge and mud that forms from dust that blows in there and engine oil that wicks through the belly seams. That stuff plugs drains.

That water can cause rusting of the control cables, leaving them prone to failure. I really can't understand why flight schools and FBOs don't do a better job; that sort of neglect can cost them the entire airplane, maybe an accident with big lawsuit, stuff that sinks the company and leaves the owners broke. It's false economy to shortcut the maintenance.

 

[Bryce Salmi]

Good to know! This plane recently came out of its annual so quite surprising. Would be interesting to find out how a plugged drain was missed in that. It really hasn't rained as hard or long as it has this past week here in SoCal for a very long time. Luckily it seems to have been caught quite early, within a few days of the rain. After this experience I'm definitely going to shake the tail section more often after rain!

 

[Magman]

I agree with preceding comments and would like to congratulate OP on find.

My thought is that the owner could add “checking drain holes” to the

Preventative Maintenance list.

This can be EXTREMELY serious.

Bonanza owner reported that the controls became “ stiff” at altitude in winter.

Sure enough; the water in the tail cone was deep and the ice interfered

with the controls.

Even more amazing is how the owner addressed the situation.

Any guesses?

 

[Grum.Man]

I once looked at a Luscombe with “no damage history”. Started our pre purchase inspection only to discover about 5 gallons of water in the tail. The guy confessed to replacing some damaged belly skins before he repainted the plane. He never added the drain holes.

 

[RyanB]

This plane recently came out of its annual so quite surprising. Would be interesting to find out how a plugged drain was missed in that.

The annual is only as good as the mechanic who performed it. It really shouldn’t be surprising, there’s some crappy mechanics out there. I’d imagine a great number of those who routinely look at the same flight school aircraft, become somewhat complacent during their inspections as well.

 

[Magman]

So; if a drain hole is plugged or missing, how many folks would NOT WANT

the IA to designate the aircraft as Airworthy?

Assuming the area is absolutely dry.

 

[Gary Ward]

I went to preflight a C172M this morning here in the Los Angeles area where we've been getting a lot of rain over the past week with more to come. Prior to starting the preflight I rocked the wings from the right wingtip to dislodge any water in the fuel tanks. Hearing the expected sloshing in the wings I quickly noticed that there was a sloshing from the tail section that was unexpected. Investigating more showed quite a bit of water stuck in the tail.

I cancelled my flight since this IMHO serious affected weight and balance. Anyone else experience this? Plane owners know it's there so likely getting looked at and fixed. I'd imagine let alone from the immediate concerns of w&b a longer term corrosion issue could be at play too!

Yes there are small holes for drainage. Mine were mostly blocked by aluminum chips from when they built the plane. I was able to get some out with a shop vac accessing through the inspection hole in the side of the fuselage. But not all of them and some were stuck to the floor from age.

When my plane was at the avionics shop and they were installing a pitch servo they pointed out a frayed trim cable to me. So I got a pair of trim cables from McFarlane. My AP/IA climbed back into my fuselage to replace them with me helping. It is a tight fit back there and uncomfortable. He brought a pad from a outdoor glider off his porch so he had some padding to lay on and to protect my plane and him. When we were done with the trim cables install I fed him a shop vac hose and scuff pad. He knocked loose the chips and dirt and vacuumed it out for me. Really no good way of doing it without removing the interior and climbing back there that I know about.
Then a couple years later Garmin issued a SB and the avionics shop had to get back in there again. Luckly they did not have to remove much the interior to get in there. When we did the trim cables it was stripped bare back there. Then I reinstalled the package shelf with all the proper hardware.

I asked him(Avionic tech) to take a couple pictures of what he did. It shows how clean it is back there now.

 

[RyanShort1]

Shoddy maintenance. There are drain holes in the belly to prevent water accumulation, and the mechanic should be under that belly at least once a year to see that they're open, and every 100-hour/annual inspection requires a check of the structure and all systems, meaning that the mechanic should be into that tail and making sure water hasn't been accumulating and corrosion not happening. Water leaves stains in the dust. I have found plenty of such evidence in some airplanes, along with the accumulated sludge and mud that forms from dust that blows in there and engine oil that wicks through the belly seams. That stuff plugs drains.

That water can cause rusting of the control cables, leaving them prone to failure. I really can't understand why flight schools and FBOs don't do a better job; that sort of neglect can cost them the entire airplane, maybe an accident with big lawsuit, stuff that sinks the company and leaves the owners broke. It's false economy to shortcut the maintenance.

You realize that often there is high turnover in flight school maintenance departments… for the same reason we don’t have experienced airline captains that love GA teaching our students. This is the violence inherent in the system - that students don’t want to, or can’t afford, to pay for higher quality instructors and maintenance personnel in what is already a very expensive proposition, and the rookies often don’t know what they don’t know!

 

[Magman]

Lately folks have suggested a rope around legs to help get me out.

ref #9 pix

 

[PaulS]

Yes there are small holes for drainage. Mine were mostly blocked by aluminum chips from when they built the plane. I was able to get some out with a shop vac accessing through the inspection hole in the side of the fuselage. But not all of them and some were stuck to the floor from age.

When my plane was at the avionics shop and they were installing a pitch servo they pointed out a frayed trim cable to me. So I got a pair of trim cables from McFarlane. My AP/IA climbed back into my fuselage to replace them with me helping. It is a tight fit back there and uncomfortable. He brought a pad from a outdoor glider off his porch so he had some padding to lay on and to protect my plane and him. When we were done with the trim cables install I fed him a shop vac hose and scuff pad. He knocked loose the chips and dirt and vacuumed it out for me. Really no good way of doing it without removing the interior and climbing back there that I know about.
Then a couple years later Garmin issued a SB and the avionics shop had to get back in there again.

I asked him to take a couple pictures of what he did. It shows how clean it is back there now.

Hmmm, not doing that job if you're fat.

 

[Jim K]

Hmmm, not doing that job if you're fat.

Watching my a&p crawl into the front baggage of my Lance (I could've closed the door), I concluded that a&p might not be a profession for me.

 

[Dan Thomas]

I agree with preceding comments and would like to congratulate OP on find.

My thought is that the owner could add “checking drain holes” to the

Preventative Maintenance list.

This can be EXTREMELY serious.

Bonanza owner reported that the controls became “ stiff” at altitude in winter.

Sure enough; the water in the tail cone was deep and the ice interfered

with the controls.

Even more amazing is how the owner addressed the situation.

Any guesses?

It can cause serious CG issues, too. A friend bought an airplane and flew it home. Couldn't get it trimmed. Seemed awful tail-heavy. He found a bunch of water back there.

 

[Dan Thomas]

My AP/IA climbed back into my fuselage to replace them with me helping. It is a tight fit back there and uncomfortable. He brought a pad from a outdoor glider off his porch so he had some padding to lay on and to protect my plane and him. When we were done with the trim cables install I fed him a shop vac hose and scuff pad. He knocked loose the chips and dirt and vacuumed it out for me. Really no good way of doing it without removing the interior and climbing back there that I know about.

I asked him to take a couple pictures of what he did. It shows how clean it is back there now.

We were in there every 200 hour inspection. The airplanes got about 800 hours a year on them. I had a piece of plywood I laid on that baggage shelf to carry my weight to the bulkhead without kinking that light aluminum angle under the front edge of the shelf. Easy to wreck that.

Far 43 Appendix D lists the MINIMUM stuff to be done on an annual, and this sort of thing is there:

Appendix D to Part 43 - Scope and Detail of Items (as Applicable to the Particular Aircraft) To Be Included in Annual and 100-Hour Inspections
(a) Each person performing an annual or 100-hour inspection shall, before that inspection, remove or open all necessary inspection plates, access doors, fairing, and cowling. He shall thoroughly clean the aircraft and aircraft engine.

Each person performing an annual or 100-hour inspection shall inspect (where applicable) the following components of the cabin and cockpit group:

(1) Generally - for uncleanliness and loose equipment that might foul the controls.

(5) Flight and engine controls - for improper installation and improper operation.

((7) All systems - for improper installation, poor general condition, apparent and obvious defects, and insecurity of attachment.

(b) Each person performing an annual or 100-hour inspection shall inspect (where applicable) the following components of the fuselage and hull group:

Systems and components - for improper installation, apparent defects, and unsatisfactory operation.

(g) Each person performing an annual or 100-hour inspection shall inspect (where applicable) all components and systems that make up the complete empennage assembly for poor general condition, fabric or skin deterioration, distortion, evidence of failure, insecure attachment, improper component installation, and improper component operation.

Now, I know that this sort of thing is regularly flouted. I found way too much stuff that had been in bad shape for years in places like the tailcone. How does one inspect, for instance, the flight controls back there without getting in there? You can peek though the access hole on the RH side of the tailcone but you can't reach the cables where they pass under the pulleys under that baggage shelf unless you pull the plastic interior out, and you can't check the bulkheads for cracking with that plastic in the way. They do crack, especially the one that carries that light angle. And the pulley bearings seize as the grease in them hardens, and then the cable starts to grind over them and get worn. There are pulleys under the cabin floor and in the aft doorposts that almost never get checked. I have freed them all up and the owners are amazed at the ease and precision of the controls after that.

As I said, it's false economy to ignore that stuff. Seized pulleys wreck both themselves and the cable, an expense that could have been avoided with five minutes effort and some light oil. Bulkheads develop small, repairable cracks that turn into big cracks that require component replacement. Plugged rain holes cause internal corrosion that can trash a lot of structure and the cables, too. Whatever excuse an school or FBO comes up with really doesn't justify such stuff, and it always hurts a lot more in the end.

 

[Gary Ward]

We were in there every 200 hour inspection. The airplanes got about 800 hours a year on them. I had a piece of plywood I laid on that baggage shelf to carry my weight to the bulkhead without kinking that light aluminum angle under the front edge of the shelf. Easy to wreck that.

Far 43 Appendix D lists the MINIMUM stuff to be done on an annual, and this sort of thing is there:

Appendix D to Part 43 - Scope and Detail of Items (as Applicable to the Particular Aircraft) To Be Included in Annual and 100-Hour Inspections
(a) Each person performing an annual or 100-hour inspection shall, before that inspection, remove or open all necessary inspection plates, access doors, fairing, and cowling. He shall thoroughly clean the aircraft and aircraft engine.

Each person performing an annual or 100-hour inspection shall inspect (where applicable) the following components of the cabin and cockpit group:

(1) Generally - for uncleanliness and loose equipment that might foul the controls.

(5) Flight and engine controls - for improper installation and improper operation.

((7) All systems - for improper installation, poor general condition, apparent and obvious defects, and insecurity of attachment.

(b) Each person performing an annual or 100-hour inspection shall inspect (where applicable) the following components of the fuselage and hull group:

Systems and components - for improper installation, apparent defects, and unsatisfactory operation.

(g) Each person performing an annual or 100-hour inspection shall inspect (where applicable) all components and systems that make up the complete empennage assembly for poor general condition, fabric or skin deterioration, distortion, evidence of failure, insecure attachment, improper component installation, and improper component operation.

Now, I know that this sort of thing is regularly flouted. I found way too much stuff that had been in bad shape for years in places like the tailcone. How does one inspect, for instance, the flight controls back there without getting in there? You can peek though the access hole on the RH side of the tailcone but you can't reach the cables where they pass under the pulleys under that baggage shelf unless you pull the plastic interior out, and you can't check the bulkheads for cracking with that plastic in the way. They do crack, especially the one that carries that light angle. And the pulley bearings seize as the grease in them hardens, and then the cable starts to grind over them and get worn. There are pulleys under the cabin floor and in the aft doorposts that almost never get checked. I have freed them all up and the owners are amazed at the ease and precision of the controls after that.

As I said, it's false economy to ignore that stuff. Seized pulleys wreck both themselves and the cable, an expense that could have been avoided with five minutes effort and some light oil. Bulkheads develop small, repairable cracks that turn into big cracks that require component replacement. Plugged rain holes cause internal corrosion that can trash a lot of structure and the cables, too. Whatever excuse an school or FBO comes up with really doesn't justify such stuff, and it always hurts a lot more in the end.

I edited my post above. When we replaced the trim cables and vacuumed it out I had the whole package shelf out and all plastic out of the back. Over the years all the wrong hardware was reinstalled. I got all new proper length and style hardware to re install the package shelf. I am picky like that.

I was really bummed and aggravated when the avionics shop said they need to get back into my plane to install that teflon cable guide that keep the cable off the connector when they go slack for the rudders.

I took the plane over there thinking they can remove all that crap and I will re install it in my shop when their done. To my surprise they only had to remove the back plastic wall to get it there. Ryan is who installed my AP and was the guy who got in there to do the SB work. The only thing I did before taking the plane back to avionics shop was to remove the back seat to make it easier on them. I was very happy that Ryan is a smaller guy and did not bend my package shelf. They did it while I waited and watched.

No way my AP mechanic would have fit in there to replace trim cables with the package shelf in place.
Before with all the missing shelf hardware I bet Ryan would have bent that shelf. It is pretty solid with the right hardware in place.

 

[Bryce Salmi]

Wow thanks for the info all! I had a chance to investigate more and realized the drain holes people were talking about absolutely had greasy dirt clogging them. With ease I poked through the hole and water instantly started flowing out. This stream lasted 5 minutes easily.

Before I touched anything, you can clearly see the plugged holes.

 

[Dave Anderson]

I bet you'll be adding that to your preflight checklist real soon!

 

[bflynn]

So; if a drain hole is plugged or missing, how many folks would NOT WANT

the IA to designate the aircraft as Airworthy?

Assuming the area is absolutely dry.

Well, no, just unplug it.

Not sure how a certificated airplane would ever be missing a drain hole. Seems like big legal territory there.

 

[Bell206]

Not sure how a certificated airplane would ever be missing a drain hole.

FYI: it can be the #1 thing missing after skin repairs in my experience as the drains holes are not always listed in the repair references.

 

[Daleandee]

When my plane was at the avionics shop and they were installing a pitch servo they pointed out a frayed trim cable to me. So I got a pair of trim cables from McFarlane. My AP/IA climbed back into my fuselage to replace them with me helping. It is a tight fit back there and uncomfortable. He brought a pad from a outdoor glider off his porch so he had some padding to lay on and to protect my plane and him.

To boldly go where no one has gone before! Been there myself:

 

[Getonit]

Let's not beat the maintenance guys up too much on this one. My old 152 would hold a little water and the interior was clean. I think surface tension of the water and the way the hole was made prevented it from draining properly. I have a vague recollection that it was listed in the POH to insert something in the holes. Occasionally I would get a little bit of water.

 

[Gary Ward]

Let's not beat the maintenance guys up too much on this one. My old 152 would hold a little water and the interior was clean. I think surface tension of the water and the way the hole was made prevented it from draining properly. I have a vague recollection that it was listed in the POH to insert something in the holes. Occasionally I would get a little bit of water.

Yup I see water dripping out of my plane after flying in the rain. I think you want to see water dripping after flying in the rain?

 

[Magman]

Many folks are not aware of what an Annual Inspection really is.

in the “ inspection Authorization Information Guide “ the feds state that “servicing

is not part on an Inspection but may be a convenient time to accomplish it”.

Hence, aircraft can have the Shimmy Damper or a Struts or lube items that were

not accomplished.

Prior to the Annual; Owners should get a firm understanding of what is to be

accomplished and by whom.

IA is Inspection Authorization and INSPECTION is their focus.

“ IA’s don’t really work, they just make work for other people”.

There are many tasks that an A & P or even the Owner can accomplish.

Having the IA do non- inspection tasks can be more costly and even slow the

process down.

The product of an Annual Inspection will likely be a List of items that need to

be accomplished in order for the aircraft to be deemed Airworthy.

There many also be a listing of recommended actions.

My practice is to have “ Mental Handcuffs” that do not permit me to do

any corrective actions until the “look phase “ is complete.

Then parts may need to be ordered and the List addressed.

It will be the Owner or an A & P doing the Corrective Action.

It’s also possible the IA may take that hat off and reveal the A& P hat

before starting on the List.

So I would write up the plugged drain hole to be accomplished.

It may be possible to clean one hole out but it can slow the whole

process down if it grows in scope.

As Dan said in #15, this can well happen.

I’ll cite some examples in next post.