GFA330
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Corrosion On Aircraft

Wed Feb 28, 2007 4:56 pm

How common is that corossion is found on commercial acft ?
Is this a sign that the aircraft is nearing the end of it's life ?

Hope somebody with some engineering back ground can shed some light on this.

txs
 
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jetmech
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Corrosion On Aircraft

Wed Feb 28, 2007 5:33 pm

Quoting GFA330 (Thread starter):

G'day GFA330,

Many factors are involved in corrosion forming in commercial aircraft. Significant factors include the environment the aircraft is flown in, spillage of any corrosive cargo, and age. Generally speaking, older aircraft will have more corrosion than newer ones.

"D" checks are usually where comprehensive corrosion checks are performed. Newer aircraft in for their first "D" check may have little or no corrosion, whilst older aircraft in for their third or fourth "D" check may have much more corrosion. Corrosion checks usually become more thorough as the aircraft ages and the rectification of this corrosion can add many weeks to the length of a "D" check.

Corrosion is not really a problem if it is caught in time and rectified. When corrosion is found, it is usually removed by grinding with a sandpaper wheel on a die grinder. It is essential to remove all the corrosion and smoothly blend the area where it has been removed into the surrounding structure. Measurements of the blend-out are then taken and compared with the limits in the Structural Repair Manual (SRM).

If the blend-out is within the SRM limits, the area is treated with iridite. Iridite is a two part chemical process that firstly cleans the aluminium by acid etching the surface. A special chemical layer is then applied to this surface which forms a protective layer on the bare aluminium. When dry, the surface is primed and painted. There are other chemical corrosion protection kits for magnesium alloys. I'm not to sure about titanium alloys.

If the corrosion is outside the SRM limits, you generally have two choices. If it is particularly severe, the easiest option is to generally replace the damaged structure with a new component. The SRM may also suggest repairs to re-inforce parts of the structure when it may be difficult and time-consuming to replace structure. In the end, it is the cost and time to inspect for and repair corrosion damaged structure that may signify the "economical" end of an airliners life.

Regards, JetMech
JetMech split the back of his pants. He can feel the wind in his hair :shock: .
 
SEPilot
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Corrosion On Aircraft

Wed Feb 28, 2007 9:03 pm

My experience is with light aircraft, and corrosion is second only to damage as a reason for ending a light aircraft's life. From an engineering perspective corrosion presents two problems: first, of course by reducing the effective thickness of the metal, and second by creating stress concentration points that can lead to cracks. This is particulary important for structural members like wing spars, where a seemingly insignificant amount of corrosion may in fact be a big deal because of the likelyhood that it can induce a crack.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
BAE146QT
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RE: Corrosion On Aircraft

Wed Feb 28, 2007 10:53 pm

This would be a good time to mention Aloha Airlines flight 243, which is an interesting study of a high-time and high-cycle airliner operating in a more-than-usually hostile environment.
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A/c train
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 2:19 am

Corrosion protection is only as good as the mechanic applying it, as jet mech says, you must remove ALL corrosion first, it is no good leaving a bit to keep within limtis because your problem will only come back.
Iridite is a strange trade name? ive known and have only ever used Alocrom 1200 to reprotect, this has 2 parts and is a 50:50 mix, you should neutralise with water after application then clean the area.
Most common areas for corrosion on pax a/c will be the floor structure under toilets and galleys, any dissimilar metal contact such as behind steel anchor nuts are a favourite, steel with aluminium placed in an electrolyte equals corrosion.
If you take a screw out of a floorboard and white dust comes out with it, this generally means your going to lift the boards up to find a whole load of overtime coming your way. Boeing generally have repair schemes In accordance with the SRM for most floor structure, but airbus generally have a 'Meccano' assembly, unbolt corroded structure, place new piece in, drill off new piece and hi lok or bolt it in.
Most aircraft flying round will have corrosion on them, the extent depends on the age and QUALITY of maintenance carried out.
best regds
a/c
 
ZKNZA
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 3:21 am

Quoting JetMech (Reply 1):

Many factors are involved in corrosion forming in commercial aircraft. Significant factors include the environment the aircraft is flown in, spillage of any corrosive cargo, and age. Generally speaking, older aircraft will have more corrosion than newer ones.

"D" checks are usually where comprehensive corrosion checks are performed. Newer aircraft in for their first "D" check may have little or no corrosion, whilst older aircraft in for their third or fourth "D" check may have much more corrosion. Corrosion checks usually become more thorough as the aircraft ages and the rectification of this corrosion can add many weeks to the length of a "D" check.

Corrosion is not really a problem if it is caught in time and rectified. When corrosion is found, it is usually removed by grinding with a sandpaper wheel on a die grinder. It is essential to remove all the corrosion and smoothly blend the area where it has been removed into the surrounding structure. Measurements of the blend-out are then taken and compared with the limits in the Structural Repair Manual (SRM).

If the blend-out is within the SRM limits, the area is treated with iridite. Iridite is a two part chemical process that firstly cleans the aluminium by acid etching the surface. A special chemical layer is then applied to this surface which forms a protective layer on the bare aluminium. When dry, the surface is primed and painted. There are other chemical corrosion protection kits for magnesium alloys. I'm not to sure about titanium alloys.

If the corrosion is outside the SRM limits, you generally have two choices. If it is particularly severe, the easiest option is to generally replace the damaged structure with a new component. The SRM may also suggest repairs to re-inforce parts of the structure when it may be difficult and time-consuming to replace structure. In the end, it is the cost and time to inspect for and repair corrosion damaged structure that may signify the "economical" end of an airliners life.

Regards, JetMech

Very well said JetMech,another thing that can prevent the onset of corrosion, is by applying a corrosion prevention compound to the airframe.The amount and frequency it is applied, is up to individual operators and what enviroment the aircraft is flying in.I know that Air NZ applies a huge amount of CP to their aircraft due to the operating enviroment that they fly in, consequently Air NZ aircraft are usually corrosion free.
 
Dougloid
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 3:38 am

Guys, I'm guessing y'all have never done a tank and plank job, because where the bad stuff is, is inside of fuel tanks.

See, where there's entrained water in fuel, bacteria live at the interface, eat the fuel and crap in the water....which is corrosive indeed. Biocides are used to some effect but not always effective.

Matter of fact, I proved this again the other day when the power went out...Pulled a kerosene lamp down off the shelf to get it ready and refill it and it stank. The fuel, which is colorless (I use mineral spirits because it's cheap) had turned a piss yellow, there was a little disk of crap in the bottom of the glass and it smelled awful.

Cleaning the lamp out with anhydrous isopropyl cleaned it all out....had the lamp been metal it would have rotted the bottom out of it.
If you believe in coincidence, you haven't looked close enough-Joe Leaphorn
 
FredT
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 5:19 am

Poor maintenance, especially as in poorly performed repairs, are a surefire way to corrode an aircraft to the scrap heap in little time as well.  Sad

Rgds,
/Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
EMBQA
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 6:10 am

Quoting GFA330 (Thread starter):
How common is that corossion is found on commercial acft ?
Is this a sign that the aircraft is nearing the end of it's life ?

Corrosion is very-very common in aircraft, but that is why airlines and airplanes have routine inspections and checks. To look for and repair defective areas. Corrosion prone areas include: entry areas, galley under floor, under lavs areas and under cargo areas. many of these areas will get a special treatment of CPC (Corrosion Preventitve Compound) to help extend the life in these areas.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
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jetmech
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 7:08 am

Quoting A/c train (Reply 4):
Iridite is a strange trade name? ive known and have only ever used Alocrom 1200 to reprotect, this has 2 parts and is a 50:50 mix, you should neutralise with water after application then clean the area.

I'm not sure of the actual name of the chemicals, but we used to call it an iridite kit for whatever reason, and I did get the details of the process a bit wrong. The first chemical to be applied to the bare aluminium is the cleaning chemical. You then use scotchbrite to scrub the surface thoroughly. Scotchbrite is the tradename for the polymer based scouring pads used to clean pots and pans.

Once you have scrubbed thoroughly, you rinse with water as you mentioned. I used to then repeat the cleaning process once or twice more to get the surface as clean as possible. Once the surface is clean, you spray the etching / protective chemical on, usually while the surface is still wet from the last rinse. You are meant to leave the etch / protective chemical on until you get a light golden brown colour. You then rinse the excess off with water which leaves the surface ready for primer and paint.

Quoting ZKNZA (Reply 5):
is by applying a corrosion prevention compound to the airframe

Yep, I completely forgot about that. We used to use a two part spray on chemical process made by the Ardrox company. The first coat was light Ardrox which was a light water repellent oil. Once this was dry, we would apply heavy Ardrox which used to spray out as a light to medium foam. During my later days at my first employer, Boeing began to use a one part CPC, which appeared bright red on the surface like a mix of blood and tomato sauce! The worst thing after a day spent CPC spraying was all the excess CPC chemicals that fell on you. You would try to wash your hair when you got home but you would find that all the CPC had completely water proofed your hair!

Regards, JetMech
JetMech split the back of his pants. He can feel the wind in his hair :shock: .
 
Mr Spaceman
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 1:10 pm

Hi guys.

Quoting GFA330 (Thread starter):
How common is that corossion is found on commercial acft ?

Also, I'd like to ask how common it is to find corossion inside the engines (both piston & jet) of aircraft.

After taking some shots of this Challenger bizjet, I looked in the rear section of one of the engines and was surprised to see a patch of rust. At least it looked like rust at first because of the colour. Then I believed that it was a stain from some kind of liquid.

In the case of a jet engine, can areas of rust appear in the exhaust nozzle if the aircraft has just sat around for a while & the engines haven't been started? If the answer is yes, how big of a concern would it be & would it need to be fixed or would the hot jet exhaust just burn it away after the next engine startup?

http://img.photobucket.com/albums/v373/Thud/EngineRust.jpg

http://img.photobucket.com/albums/v373/Thud/BlueWhite601Challenger.jpg

Thanks,

Chris  Smile
"Just a minute while I re-invent myself"
 
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HAWK21M
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 3:32 pm

http://www.corrosion-doctors.org/Modules/Modules.htm

http://www.engr.ku.edu/~rhale/ae510/corrosion.pdf

On Freighters the Lack of Galley & minimum use of the Toilets help the Area below these unit to be less prone to corrosion that normally would be present on Commercial Aircraft due water seepage thru the Rubber mats & Mylar sheets over time.
Its Important as mentioned above,that during corrosion removal,all traces should be removed & then the surface treated with a Corrosion preventive compound to avoid the corrosion comming back up again.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
PurdueAv2003
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 5:00 pm

Quoting Mr Spaceman (Reply 10):
Also, I'd like to ask how common it is to find corossion inside the engines (both piston & jet) of aircraft.

I don't have enough experience with turbine engines, but I do know that piston engines can be prone to corrosion on the cylinder walls if the engine sits unused for a long period of time. If you are going to have a piston aircraft sit unused for an extended period of time, you need to accomplish certain preservations steps (i.e. use preservation oil and desicant plugs) to protect the engine.

Being a structures type, I have seen some significant corrosion damage. I saw a 737 not too long ago that had a good portion of the bear strap around the aft cargo door just flake away. Anyone that knows the door cutout repairs for the 737 will tell you that they are not fun. You almost expect that the aircraft will list to the right with the amount of weight you are adding!  wideeyed 
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Dougloid
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 11:14 pm

Quoting EMBQA (Reply 8):
Corrosion is very-very common in aircraft, but that is why airlines and airplanes have routine inspections and checks. To look for and repair defective areas. Corrosion prone areas include: entry areas, galley under floor, under lavs areas and under cargo areas. many of these areas will get a special treatment of CPC (Corrosion Preventitve Compound) to help extend the life in these areas.

Back in the day Garrett was outfitting B727s for rich Arabs on a regular basis. They got a couple from Qantas, and I gotta tell you-the Aussies had about tbe best damn anti corrosion program around. EVERYTHING had a good thick coat of LPS on it.

As far as engine corrosion I did my share of repairs to the same on Garretts which used a magnesium engine case. What we'd have to do is wire brush the paint and corroded metal off, treat with Dow-19 (buffered chromic acid solution) prime and paint. Sometimes we'd rebuild the metal surface with DEVCON which is the best damn epoxy stuff around.
If you believe in coincidence, you haven't looked close enough-Joe Leaphorn
 
Dougloid
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RE: Corrosion On Aircraft

Thu Mar 01, 2007 11:24 pm

Forgot to mention one of the worst I ever saw, it was a 707-138B that belonged to Frederick B. Ayer in New York and had been leased to Bouraq for the Hajj run in Indonesia. Well, Bouraq hadn't paid their fuel bill so Shell deadlined the aircraft and it sat on the ramp in Indonesia for a couple years. Anyway, something got worked out and a crew brought it back to the states. It hit the coast 75 miles off course and got the people at Vanedberg up in arms.

It sat on the ramp for a few weeks so I got on board thru the door behind the nose gear. The upstairs crapper had leaked and corroded all the radios underneath it. The rest of the airplane smelled like a barn. It still had the sextant and the port hadn't been plugged. That's part of why they hit the coast 75 miles off course.

Speaking of smell, the worst airplane I ever was on was a Jetstar that belonged to Coca Cola, then got sold to Ferdie and Imelda Marcos. It sat on the ramp for a couple years in the Phillipines, but before it got closed up, the cabin crew all took dumps in the chemical toilet.

It got bought by Tiger Air and the crew flew it to Los Angeles with a case of Ozium-every fifteen minutes they'd spary a can in the cabin and then retreat to the cockpit. Tiger Air ended up selling it to somebody who had to tear out all the interior because the smell had soaked into the vinyl and insulation and couldn't be removed.
If you believe in coincidence, you haven't looked close enough-Joe Leaphorn
 
miamiair
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RE: Corrosion On Aircraft

Fri Mar 02, 2007 1:55 am

Quoting JetMech (Reply 9):
The first chemical to be applied to the bare aluminium is the cleaning chemical.

Alumiprep-33

Alodine 1200 or 1201 is the conversion coating.

Quoting Dougloid (Reply 14):
Speaking of smell,

Air Zaire DC-10-30 comes to mind in a flash.

Then again, any DC-8 or 707 that was used to haul livestock without the use of the plastic sheeting. That did wonders for job security... The exfoliated corrosion had a nasty smell...
Molon Labe - Proud member of SMASH
 
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HAWK21M
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RE: Corrosion On Aircraft

Fri Mar 02, 2007 5:03 pm

Anyone use LPS3 + Danitrol.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Dalmd88
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RE: Corrosion On Aircraft

Sat Mar 03, 2007 2:28 am

Dl a few years ago switched to Cor-Ban made by Zip-Chem Products. It is a lot easier to apply than the old brown stuff we used to use. I can't recall the proper name for the old stuff. Cor-Ban comes in an aerosol can that can be directed into the toughest spots.

As for the original question about corrosion. Yes, it is out there. I worked structures for 8 years in DL heavy check. Spent a lot of time on MD88, 727 and 737 classics. Number one spot to find it on any airplane is under the lav and galley. I didn't do much work in these areas. Most of my time was bagbins and wings. I think the worse place I consistantly saw a lot was in the back end of the 737. Between the lav valve and the out flow valve there is a lot of mositure behind the aft bulkhead. Sometimes it seemed that everything we touched in that area just turned to dust.

The MD88 bagbins also get quite a bit of work. The door thresholds are usually pretty beat as well as most of the belly frames aft of the aft bin door. Both of these items usually occured by the second overhaul and could be saved by blending out the corrosion. By the third overhaul they were either repaired or just outright replaced. The cargo tie down tracks and seat tracks in the cabin are another spot. The seat tracks I think ususally were saved, but we found it cheaper to just replace the cargo tracks. Why waste three shifts grinding only to find it out of limits when it can be replaced in four hours.

We never really found much corrosion in the wing tanks. Most of the tank work I did was leak related.
 
Mr Spaceman
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RE: Corrosion On Aircraft

Sat Mar 03, 2007 10:19 pm

Hi guys.

Quoting PurdueAv2003 (Reply 12):
Quoting Mr Spaceman (Reply 10):
Also, I'd like to ask how common it is to find corossion inside the engines (both piston & jet) of aircraft.

I don't have enough experience with turbine engines, but I do know that piston engines can be prone to corrosion on the cylinder walls if the engine sits unused for a long period of time.

>> PurdueAv2003, Thanks for your reply & your answer. I've seen how car engines can get eaten away by corrosion when the car's been abandoned in a junk yard. That's a complete mess.

Regarding turbine engines, does anyone know what the discolouration in the tailpipe of the jet engine in my photo above is likey caused from? If it's not a rusty spot of corrosion then what would that brown stuff be in there?

Thanks,

Chris.  Smile
"Just a minute while I re-invent myself"
 
2H4
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RE: Corrosion On Aircraft

Sat Mar 03, 2007 11:17 pm



Have you engineers/techs ever used a corrosion inhibitor called Boeshield T-9? If so, any thoughts or opinions on the stuff?


2H4


Intentionally Left Blank
 
miamiair
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RE: Corrosion On Aircraft

Sun Mar 04, 2007 8:36 am

Quoting 2H4 (Reply 19):
Have you engineers/techs ever used a corrosion inhibitor called Boeshield T-9? If so, any thoughts or opinions on the stuff?

Replaced LPS-3.
Molon Labe - Proud member of SMASH
 
Panman
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RE: Corrosion On Aircraft

Mon Mar 05, 2007 3:04 pm

Just a minor correction to Jetmech's post.

It's not only on D checks that comprehensive corrosion detection is done. Where I work, we are not certified to do D checks, only up to C. We do an extensive CPCP programme on the B757. Our fleet includes the B757 that is the world leader in terms of cycles - oh and it's just turned 24 years old (date of build was 1 March 1983). I'm not sure where they send them for the D check's though.

I have seen some 2-3 year old A320's come in and have to have every single seat track under the wet areas changed - have yet to see a B757 that bad.
 
MD11Engineer
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RE: Corrosion On Aircraft

Mon Mar 05, 2007 3:37 pm

Quoting Dougloid (Reply 6):
Guys, I'm guessing y'all have never done a tank and plank job, because where the bad stuff is, is inside of fuel tanks.

See, where there's entrained water in fuel, bacteria live at the interface, eat the fuel and crap in the water....which is corrosive indeed. Biocides are used to some effect but not always effective.

I have never encountered corrosion inside fuel tanks on modern jets, though I have to say at the same time that I have never found water in the fuel samples taken during weekly checks either. I assume that noadays the water scavenging systems are so good that if a plane is regularly used (the fuel not standing in the tank for a prolonged time, like aircraft in storage), there is not enough water to promte corrosion.

Quoting Dougloid (Reply 13):
Back in the day Garrett was outfitting B727s for rich Arabs on a regular basis. They got a couple from Qantas, and I gotta tell you-the Aussies had about tbe best damn anti corrosion program around. EVERYTHING had a good thick coat of LPS on it.



Quoting HAWK21M (Reply 16):
Anyone use LPS3 + Danitrol.
regds
MEL

Personally I don't like LPS3 too much, because it will stay sticky and attract dirt. I prefer Dinitrol AV-8, AV-30 etc., because after a few days the surface becomes dry enough to touch (with the protective coating still being elastic to follow movements of the metal, similar to a layer of wax), so that dust and dirt will not stick on it.

Jan
Je Suis Charlie et je suis Ahmet aussi
 
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HAWK21M
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RE: Corrosion On Aircraft

Mon Mar 05, 2007 9:47 pm

Quoting MD11Engineer (Reply 22):
Personally I don't like LPS3 too much, because it will stay sticky and attract dirt. I prefer Dinitrol AV-8, AV-30 etc., because after a few days the surface becomes dry enough to touch (with the protective coating still being elastic to follow movements of the metal, similar to a layer of wax), so that dust and dirt will not stick on it.

True LPS3 has the Sticky coat unlike Dinitrol.But can a 2nd coat of Dinitrol over 1st coat of LPS3 be used.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Dougloid
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RE: Corrosion On Aircraft

Mon Mar 05, 2007 11:18 pm

Quoting MD11Engineer (Reply 22):
have never encountered corrosion inside fuel tanks on modern jets, though I have to say at the same time that I have never found water in the fuel samples taken during weekly checks either. I assume that noadays the water scavenging systems are so good that if a plane is regularly used (the fuel not standing in the tank for a prolonged time, like aircraft in storage), there is not enough water to promte corrosion.

Kind of depends on how new the aircraft is and where it's being operated and who's supplying the fuel and how long it sits on the ramp between trips, right?

Never say never....I've been in on a few tank and plank inspections and I've seen the stuff. Seen a few aircraft scrapped because the wing planks were corroded past serviceable limits too.
If you believe in coincidence, you haven't looked close enough-Joe Leaphorn
 
Venus6971
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RE: Corrosion On Aircraft

Tue Mar 06, 2007 12:30 am

Nobody has talked about stress as form of corrision. As the older airplanes go through more pressure cycles the constant inflating and deflating of the fuselage has its toll on a acft and the main wing spars that flex everytime you have airflow over the wing. NDI on older airframes such as eddy current and others will spell doom for an acft faster than old fashion rust you find around the lavs.
I would help you but it is not in the contract
 
Dougloid
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RE: Corrosion On Aircraft

Tue Mar 06, 2007 5:51 am

Quoting Venus6971 (Reply 25):
Nobody has talked about stress as form of corrision. As the older airplanes go through more pressure cycles the constant inflating and deflating of the fuselage has its toll on a acft and the main wing spars that flex everytime you have airflow over the wing. NDI on older airframes such as eddy current and others will spell doom for an acft faster than old fashion rust you find around the lavs

That would be more properly characterized as fatigue, no?
If you believe in coincidence, you haven't looked close enough-Joe Leaphorn
 
A/c train
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RE: Corrosion On Aircraft

Wed Mar 07, 2007 1:36 am

PANMAN, You must be a monarch boy ?
 
Panman
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RE: Corrosion On Aircraft

Thu Mar 08, 2007 2:10 pm

Quoting A/c train (Reply 27):
PANMAN, You must be a monarch boy ?

Good guess - indeed I am.

paNMan
 
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HAWK21M
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RE: Corrosion On Aircraft

Thu Mar 08, 2007 8:31 pm

Quoting Panman (Reply 21):
have seen some 2-3 year old A320's come in and have to have every single seat track under the wet areas changed -

Interesting.Is it Material related or the Carpet a contributing factor retaining moisture.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Panman
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RE: Corrosion On Aircraft

Sun Mar 11, 2007 6:56 am

Quoting HAWK21M (Reply 29):
Interesting.Is it Material related or the Carpet a contributing factor retaining moisture

I think it's material because the 757's use the same carpet.

PANman
 
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HAWK21M
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RE: Corrosion On Aircraft

Sun Mar 11, 2007 2:16 pm

Quoting Panman (Reply 30):
I think it's material because the 757's use the same carpet

Did Airbus reccomend any Change in Material of track.Was any remedy suggested.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Panman
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RE: Corrosion On Aircraft

Mon Mar 12, 2007 6:33 am

All we do is change the seat track for one of the same spec. I don't know if R&D is in communication with Airbus about it.

panmaN
 
greasespot
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RE: Corrosion On Aircraft

Mon Mar 12, 2007 8:07 am

Quoting PurdueAv2003 (Reply 12):
I don't have enough experience with turbine engines

Turbine engines have terrible corrosion. It was very rare that on every heavy engine visit we did not have to scrap one or more disks due to corrosion. This usually occured on the HPC module in most cases. I know on the JT8D there is AD 2003-12-07 that mandates a 7 year corrosion inspection and NICAD re plating on the date regardless of the cycles or hours on the disk.

GS
Sometimes all you can do is look them in the eye and ask " how much did your mom drink when she was pregnant with you?"
 
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HAWK21M
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RE: Corrosion On Aircraft

Mon Mar 12, 2007 11:36 am

Quoting Panman (Reply 32):
All we do is change the seat track for one of the same spec. I don't know if R&D is in communication with Airbus about it

If its a common problem I'm sure there would be an Alt P/N on the way.Were the Aircraft of one particular operator or Different operators.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Dougloid
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RE: Corrosion On Aircraft

Mon Mar 12, 2007 9:27 pm

Quoting Greasespot (Reply 33):
Quoting PurdueAv2003 (Reply 12):
I don't have enough experience with turbine engines

Turbine engines have terrible corrosion. It was very rare that on every heavy engine visit we did not have to scrap one or more disks due to corrosion. This usually occured on the HPC module in most cases. I know on the JT8D there is AD 2003-12-07 that mandates a 7 year corrosion inspection and NICAD re plating on the date regardless of the cycles or hours on the disk.

Greasy, that sounds kind of type and manufacturer specific. We never did that on Garretts as the wheels were solid Inconel and the impellers were solid titanium.

Matter of fact, the slickest repair I ever saw was one I worked on that had taken a seagull and actually bent one of the impeller blades. It still ran but sounded funny. It's a titanium forging and it takes a lot to bend a blade-only one I ever saw. We sent the impeller to Garrett and they sliced the blade down and welded a new chunk on and reprofiled it-you could hardly tell it had been repaired.

How's the academy going?
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