Borescope

J

JOhnH

Touchdown! Greaser!
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The biggest problem I have with my A&P/IA is that he does not have a bore scope. Other than that, I really like, respect and trust him.

Would it be bad form to contact another A&P/IA and ask to have my engine bore-scoped and receive a written report, with pictures? Approximately, how much should I expect to pay for that?
 
Thinking back... I don't recall that any A&P or IA that worked on my airplane had a borescope (or at least didn't use it)...but I had a very simple aircraft (pa-28-140).

Is there something going on with your engine that makes you want to see pictures?
 
Bob Noel said:
Thinking back... I don't recall that any A&P or IA that worked on my airplane had a borescope (or at least didn't use it)...but I had a very simple aircraft (pa-28-140).

Is there something going on with your engine that makes you want to see pictures?
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Leakdown test at annual showed lower compression levels than in years past. Not too bad for a big bore Conti, but it was a change.
Oil analysis shows some metal for the first time. But the last two oil changes (at 25 hr deltas) were (1) not done and (2) lost in mail.

They want to do another leak-down test in 10 hours and another oil analysis in 25 hours. In the meantime, while I am trusting my life to this engine, I'd like to know a little more about what it looks like inside. I have had one in-flight catastrophic engine failure and survived a landing on a state highway. I'd prefer not to do that again.
 
JOhnH said:
Would it be bad form to contact another A&P/IA and ask to have my engine bore-scoped and receive a written report, with pictures?
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FWIW: I would think not but why not ask your APIA to recommend/find someone who can do the work and keep them in the loop. But a boroscope like a prop balance kit is one of those tools most mechanics don't own especially if talking about quality equipment. However, I used to arrange special services like that for my customers which lead to 2 people pitching in and helping me buy my 1st prop balance equipment as they got tired of taking their aircraft out of town for the checks. If you plan to boroscope on a regular basis perhaps approach your mechanic with a similar offer?
JOhnH said:
Approximately, how much should I expect to pay for that?
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In my experience, depends on the equipment and what procedure you want to follow especially if you want a report and pics. Regardless, I would have it done at your hangar as any discrepancy encountered in the check may ground your aircraft on the spot. I never scoped a recip but on the turbine side which have a number of boropscope requirements the costs on the low side were around $250-300 which should be in the ballpark for a recip following something like TCM SB03-3 with a commercial scope.
 
JOhnH said:
Leakdown test at annual showed lower compression levels than in years past. Not too bad for a big bore Conti, but it was a change.
Oil analysis shows some metal for the first time. But the last two oil changes (at 25 hr deltas) were (1) not done and (2) lost in mail.

They want to do another leak-down test in 10 hours and another oil analysis in 25 hours. In the meantime, while I am trusting my life to this engine, I'd like to know a little more about what it looks like inside. I have had one in-flight catastrophic engine failure and survived a landing on a state highway. I'd prefer not to do that again.
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I just heard back from my A&P. Turns out they now have a borescope.
 
Bell206 said:
FWIW: I would think not but why not ask your APIA to recommend/find someone who can do the work and keep them in the loop.
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Good suggestion. I did that and that is how I just found out he now has one. I don't know what kind or how much experience he has with it, but I'm glad he got one.
 
I bought one myself for $200 and the 2 A&P/IAs that I showed it to were impressed at the quality of the still-pictures I was able to take with it. It has an articulating head that allows you to see the piston tops, cylinder walls, and valves. I’ve also used it to look at a couple cam lobes on my IO-470 through the oil fill hole. It’s a worthwhile owner tool. I take it over to the shop during my annual, take the pics while the plugs are out, and give him a thumb drive with the files so he can look at them on his computer.

Below are pics I took from my neighbor’s V-tail Bo last week. Last pic is a closeup of the exhaust seat. Resolution is lower here so I could upload to POA, plus the pic is of my laptop screen taken with my phone.

B068625E-AF05-411C-A275-E7B72EC1C4D9.jpeg 5289B720-CC71-4539-82E3-424937A8992E.jpeg 8910C0DB-BAF5-423E-9073-BBD1700EDDAD.jpeg
 
I have two but never bother using for my engine. A compression test tells me what I want to know. If there is exhaust valve leakage I can't fly out I just pull that cylinder and fix because a continuously leaking exhaust valve WILL burn and get worse. I have used the scopes to check for airframe cracks inspection. In spite of what some say pulling a cylinder on a IO-520 is no big deal.
 
When the cylinder is leaking thru the valves, the borescope won't fix it..
Remove the cylinder disassemble the valves and take a good look.
 
Buy your A&P a scope and ask, but don't expect, them to take it off you bill. Seems there are many that run under 5 shop hours.

Pretty easy.
 
Ravioli said:
Buy your A&P a scope and ask, but don't expect, them to take it off you bill. Seems there are many that run under 5 shop hours.

Pretty easy.
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That actually crossed my mind before I found out he already bought one. I may have pushed him into it last year when I asked if he had one and when he said "no", I expressed an opinion that he should.
 
The Vividia is inexpensive and works fine. Can't understand any A&P that doesn't have and use one today. I have one (although not an A&P) and shoot a picture of all 12 of my exhaust valves every oil change. It's a predictive tool and even the engine manufacturers are coming around to the fact that a boroscope inspection tells a lot more about cylinder condition than the differential pressure test (although that test is still an FAA annual inspection requirement.) Read TCM's SB03-2. Its wording says the boroscope inspection "MUST BE USED" in conjunction with the differential pressure test. Sure, service bulletins aren't required for Pt 91 operations, but how could an A&P ignore this?
 
Lance F said:
but how could an A&P ignore this?
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Because most owners do not want to perform/pay for inspections/checks that are not required by Part 91. I played this game for a number of years until I switched to owner-assisted mx where the owners are more pro-active and involved. It is what it is.
 
Lance F said:
It's a predictive tool and even the engine manufacturers are coming around to the fact that a boroscope inspection tells a lot more about cylinder condition than the differential pressure test (although that test is still an FAA annual inspection requirement.)
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Just a bit of a sidetrack if you don't mind ...

I use a differential compression tester but I cannot find a reg that says it is mandatory. I know the AC's show it and TCM has their requirement but I can't find where the FAA has this as a requirement. Can you point me to it? Thanks!
 
Daleandee said:
I use a differential compression tester but I cannot find a reg that says it is mandatory. I know the AC's show it and TCM has their requirement but I can't find where the FAA has this as a requirement.
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Part 43, Appendix D, (d)(3):
https://www.ecfr.gov/cgi-bin/text-i...=true&node=pt14.1.43&rgn=div5#ap14.1.43_117.d
(3) Internal engine—for cylinder compression and for metal particles or foreign matter on screens and sump drain plugs. If there is weak cylinder compression, for improper internal condition and improper internal tolerances.
 
Bell206 said:
Because most owners do not want to perform/pay for inspections/checks that are not required by Part 91. I played this game for a number of years until I switched to owner-assisted mx where the owners are more pro-active and involved. It is what it is.
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I hear you. It is what it is. My comment was more towards the A&Ps that don't even own one. Seems an essential tool to me. When they were thousands of dollars, I can understand the objection. Now that they're a couple of hundred bucks, not so much. And during an annual since the plugs are out already for the differential pressure test, a boroscope inspection on one engine shouldn't take more than 30 minutes.
 
JOhnH said:
That actually crossed my mind before I found out he already bought one. I may have pushed him into it last year when I asked if he had one and when he said "no", I expressed an opinion that he should.
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This just in from the Ravioli talks out of both ends of his mouth department:

When there was a Lycoming AD that required a special tool to inspect the rod bushings or some what-not, the club's A&P charged us for the tool. I was livid. When the plane came back the tool wasn't in there, but it was on the invoice. I deducted the price of the tool when I paid the invoice. The President of the club paid the difference, since the mx was his cousin. ARGH!

Loved the planes, not the pains.
 
Lance F said:
Seems an essential tool to me.
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Define essential. I never owned a boroscope or even aircraft jacks but had access to both. However, I have owned several different prop balance kits. So it depends. Essential to me means I can’t perform my regular job but it doesn’t mean I need to purchase it regardless of the cost. As to tool quality vs cost that is for another discussion as if my name goes on it the quality side always wins.
Lance F said:
And during an annual since the plugs are out already for the differential pressure test, a boroscope inspection on one engine shouldn't take more than 30 minutes.
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Sure, but it can lead a “solution looking for a problem.” For example, if you have an engine with all 72+ compressions and no leakage but you decide to scope a cylinder and find some “discoloration” per the TCM SB the cylinder needs to come off regardless if there was no leakage which is required by Part 43 D to check internal cylinder condition.

But don’t get me wrong. Boroscopes have their place and as the owner if you want to follow the OEM recommendations more power to you. But your mechanic should also explain the pros/cons of that recommendation. However, every cylinder I’ve pulled required some sort of repair to correct the leakage so in my experience the boroscope would not have prevented the removal. Now I have heard of cases where certain individuals scoped their engines with a cheap boroscope whose digital color palette was a bit skewed resulting in cylinder removals for “discoloration” which was actually no issue. So as with most aviation stuff it depends…
 
455 Bravo Uniform said:
Vividia AbleScope VA-400 HD USB Borescope Endoscope with 180 Degree Articulating 8.5mm Diameter Probe and LED Lights
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I have the same one, it has a really good picture quality. Takes some practice finding your bearings when in the cylinder though. It takes me a bit to figure out how to put it where I need it.
 
Bell206 said:
(3) Internal engine—for cylinder compression and for metal particles or foreign matter on screens and sump drain plugs. If there is weak cylinder compression, for improper internal condition and improper internal tolerances.
Click to expand...

Thanks for the try but this does not state that a "differential compression test" is required which is my question. From this I take it that it could be a static, dynamic, differential, or even a "pull it through and feel the compressions" test. To clarity, I'm asking if the regulations anywhere state that it must be a differential test. I cannot find it anywhere other than the AC which is not a regulation.

I'm not arguing against the differential compression test as, to me, it is an excellent way to test a cylinder. It's just that I see many claiming that the differential test is mandatory but nobody cites the reg.
 
Daleandee said:
It's just that I see many claiming that the differential test is mandatory but nobody cites the reg.
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You're over thinking this. Part 43 requires a cylinder compression check. Full stop. If you can provide an acceptable reference per Part 43.13 that shows an alternate compression check other than a differential check then you'll have something. However trying to perform a compression check on an aircraft engine other than a differential check can get rather exciting.;)
 
Bell206 said:
You're over thinking this. Part 43 requires a cylinder compression check. Full stop. If you can provide an acceptable reference per Part 43.13 that shows an alternate compression check other than a differential check then you'll have something. However trying to perform a compression check on an aircraft engine other than a differential check can get rather exciting.;)
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Is there or isn't there a mandatory requirement for a differential compression test? If so please cite the reg. I'm not overthinking anything but it seems you're reading a requirement into the reg that just isn't there. So now you ask me to give a reference proving that a differential test is not required? o_O
 
Daleandee said:
Is there or isn't there a mandatory requirement for a differential compression test?
Click to expand...
No.
Daleandee said:
From this I take it that it could be a static, dynamic, differential, or even a "pull it through and feel the compressions" test.
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Let me try a different route. Yes it could be one of the above type tests if you had a reference per Part 43.13. While the differential test is the standard now some older aircraft had procedures for direct tests. However it falls to the mechanic which reference/test they use to perform the compression check. And if I recall correctly Rotax allows either direct or differential tests on their certified and uncertified engines.
 
Bell206 said:
And if I recall correctly Rotax allows either direct or differential tests on their certified and uncertified engines.
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Never did a direct compression test on my O-320. I think I'll do one next time I do a differential test
 
Tom-D said:
When the cylinder is leaking thru the valves, the borescope won't fix it..
Remove the cylinder disassemble the valves and take a good look.
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Yes, if flying a bit doesn't help.

I had a C-175 and fixing broken top rings was routine maintenance and it's really a simple job.
 
Bell206 said:
No.
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Thank you. I wasn't trying to prove myself right, just wanting to know what the answer really was ... that is why I asked the question.

Bell206 said:
However it falls to the mechanic which reference/test they use to perform the compression check. And if I recall correctly Rotax allows either direct or differential tests on their certified and uncertified engines.
Click to expand...

The differential compression test is, IMHO, the best tool currently available for learning the condition of a cylinder without disassembly. I use this test for my own airplane and it's easy to understand why this method the standard.

I have also learned that the "under 60/80 pull the cylinder rule" falls into the same wormhole ... but I digress.:D
 
Cylinder is leaking from the piston/rings and valves, which do you repair first.
 
Borescopes today are inexpensive for a decent articulation unit. The camera quality is pretty amazing for the price. We use one that hooks directly to our PC.
Vividia AbleScope VA-400 HD USB Borescope Endoscope with 180 Degree Articulating 8.5mm Diameter Probe and LED Lights
 
Tom-D said:
Cylinder is leaking from the piston/rings and valves, which do you repair first.
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Usually exhaust valve since once it starts leaking it will burn quickly. Worn cylinders and rings will just slowly get worse unless it a broken ring which can quickly score the cylinder and burn a hole in the piston which has happened to several times with a GO-300.
 
Snowmass said:
Usually exhaust valve since once it starts leaking it will burn quickly. Worn cylinders and rings will just slowly get worse unless it a broken ring which can quickly score the cylinder and burn a hole in the piston which has happened to several times with a GO-300.
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I'd get a cylinder. :)

really it's cheaper
 
Tom-D said:
I'd get a cylinder. :)

really it's cheaper
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Too black and white for me. Fact is an annual is an inspection not a cylinder changing exercise. A boroscope is an inspection tool, and I think an IA not using such an inspection tool for an annual inspection could be short changing a customer.
Fact is that exhaust valves showing stress can in some cases be inexpensively saved. These valves can be lapped in place and roto-coils are easily changed and cheap. These procedures are a whole lot cheaper than changing cylinders. Take a look next oil change, and the valve is better or it’s not. If it’s not, go ahead and replace it. I believe way too many cylinders are replaced “because” adding unnecessary costs to an already expensive endeavor.
 
Lance F said:
Too black and white for me. Fact is an annual is an inspection not a cylinder changing exercise. A boroscope is an inspection tool, and I think an IA not using such an inspection tool for an annual inspection could be short changing a customer.
Fact is that exhaust valves showing stress can in some cases be inexpensively saved. These valves can be lapped in place and roto-coils are easily changed and cheap. These procedures are a whole lot cheaper than changing cylinders. Take a look next oil change, and the valve is better or it’s not. If it’s not, go ahead and replace it. I believe way too many cylinders are replaced “because” adding unnecessary costs to an already expensive endeavor.
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when the cylinder / piston requires to be rebored and fit a new piston ring, it usually needs guide too.
the cost to rebore, and the parts, valves, springs, shipping and down time. it is cheaper to buy a new cylinder.
 
Tom-D said:
when the cylinder / piston requires to be rebored and fit a new piston ring, it usually needs guide too.
the cost to rebore, and the parts, valves, springs, shipping and down time. it is cheaper to buy a new cylinder.
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Not talking about any of this. Only using a boroscope to inspect for a funky looking exhaust valve. And depending on what you see inexpensively try to save the cylinder in place without dropping 2AMU and the risk of maintenance induced failure.
 
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