What cleaner should be used to clean the inside of vaccum gyro horizons and altimeter
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What cleaner should be used to clean the inside of vaccum gyro horizons and altimeter
My friend has just boughts Cessna 150 and found out that the vaccum gyro horizon is not working properly. He opened it up and found out that inside of the instrument is covered up with a white powder. Looks like its a corrosion but I am not sure. If this is a corrosion why is it white? What cleaner sholud be used to get rid of this white stuff so that not damage the instrument?
Many thanks
Many thanks
IMHO your friend should take it to an appropriately approved 145 workshop to see if the unit is repairable. I would not advocate enthusiastic owners carrying out their own maintenance on critical instruments such as attitude indicators. Cleaning has to be carried out in accordance with the manufacturer's maintenance manual and using incorrect cleaning agents and techniques can seriously damage and affect the correct functioning of sensitive instruments.
Your friend opened up a flight instrument? I think you'll find that far exceeds his privileges. It would certainly exceed mine as a licenced engineer. Instrument inspection and repair requires specialised test procedures and equipment. The airworthiness certificate may well be invalidated by unauthorised work. How does he know the case isn't leaking when it's reinstalled in the aircraft? What if it fails when he needs it most?
I'd suggest the aircraft and instrument be passed to an AMO for proper rectification; the gyro horizon will most likely then be sent to a specialised repair shop.
To answer your question, aluminium alloy corrosion tends to be white or grey.
Edit: Ah, happybiker beat me to it.
I'd suggest the aircraft and instrument be passed to an AMO for proper rectification; the gyro horizon will most likely then be sent to a specialised repair shop.
To answer your question, aluminium alloy corrosion tends to be white or grey.
Edit: Ah, happybiker beat me to it.
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Unless it's registered as experimental your friend has just created himself a nice ornament.
It HAS to go to an overhaul facility to have work like this done on it. In fact, he doesn't even have the authority to remove it from the instrument panel, if his intention is to put it back there.
But you already knew all that.......
It HAS to go to an overhaul facility to have work like this done on it. In fact, he doesn't even have the authority to remove it from the instrument panel, if his intention is to put it back there.
But you already knew all that.......
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My friend has just boughts Cessna 150 and found out that the vaccum gyro horizon is not working properly. He opened it up and found out that inside of the instrument is covered up with a white powder. Looks like its a corrosion but I am not sure. If this is a corrosion why is it white? What cleaner sholud be used to get rid of this white stuff so that not damage the instrument?
Your friend isn't allowed to remove the instrument, open the instrument, or even open or separate the pitot-static system and attached lines behind the instruments. Your friend is operating illegally, and dangerously.
The work on the instrument needs to be done by the holder of a repair station certificate, which is certified to do that specific work. Beyond that, your friend needs to refrain from the misguided belief that he can or should work on his own airplane.
There's another general aspect to consider. Let's say that an unqualified owner has carried out some unauthorised and undocumented tasks and as a result there is a fatal accident. Once the cause is found, the investigators are going to go through the AMO's records and quite possibibly lay the blame on the last mechanic to have carried out inspection and/or maintenance in that particular area of the aircraft. His signature will be on the checksheet, which is a legal document. Once the lawyers get hold of that...
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14 CFR 43 Appendix A does allow for preventative maintenance. However, simply because a task is named therein, does not mean it's authorized. The task cannot involve complex disassembly or reassembly, and all pertinent current maintenance publications must be referenced, as well as all procedures performed in accordance with not only those standards and call-outs, but industry standards. The individual performing the work must be qualified to perform the work, and must use the appropriate tools, parts, etc, called for by the manufacturer.
Further, the person performing the work must be aware of any applicable AD's or specific inspections that must be performed, and the non-mechanic may not be qualified to perform those inspections. Many private pilots or owners are misguided and believe they can perform the work cited in Appendix A, when they cannot.
In this case, there is no question that the owner/operator/pilot may not do the work...it's not authorized and not with in the scope of what is allowed under appendix A, or under the privileges accorded the private pilot. Neither is it something a mechanic can generally carry out, without specific authorizationa and certification.
That the original poster asks what cleaners may be used indicates that the maintenance publications have not been referenced for the item in question, providing some reference as to how out of place this request is. That the original poster also stipulates to being a mechanic also throws the question in doubt, and leaves little doubt that the operation is inappropriate.
Further, the person performing the work must be aware of any applicable AD's or specific inspections that must be performed, and the non-mechanic may not be qualified to perform those inspections. Many private pilots or owners are misguided and believe they can perform the work cited in Appendix A, when they cannot.
In this case, there is no question that the owner/operator/pilot may not do the work...it's not authorized and not with in the scope of what is allowed under appendix A, or under the privileges accorded the private pilot. Neither is it something a mechanic can generally carry out, without specific authorizationa and certification.
That the original poster asks what cleaners may be used indicates that the maintenance publications have not been referenced for the item in question, providing some reference as to how out of place this request is. That the original poster also stipulates to being a mechanic also throws the question in doubt, and leaves little doubt that the operation is inappropriate.
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Thank you
My friend is very well aware of the FAA regulations. Thank you for answering my/his question.
But frankly I believe that those FAA rules are outdated. There are lot of types of work that can be done by the owners. Examples: to replace bulbs in the instruments, cleaning the glass, replacing instrumets filters, gaskets, the back with cracked/broken ports. Of course, if the mechanism is broken the instrument cannot be fixed in the field. Special test equipment is needed to make adgustments and tests. But minor problems can be and I think should be fixed in the field! Other examples: Navcomms - photocells repalcements, replacement of the displays that are replaceable you do not need a slder iron, some other monor problems with the radios that does not affect frequencies and power. There is a lot of problems that could be fixed by the aircraft owners in the field providing they have qualified technicians who have tools and service manuals. But the FAA does not allow this and the owners have to send avionics instruments with the minor problems to the shops. The repairs cost a lot of money to the operators no matter if its a minor problem or not. That is why in many cases the owners fly with the equipment not functioning properly. Does that help to solve the problem. I do not think so. It makes it worth.
But frankly I believe that those FAA rules are outdated. There are lot of types of work that can be done by the owners. Examples: to replace bulbs in the instruments, cleaning the glass, replacing instrumets filters, gaskets, the back with cracked/broken ports. Of course, if the mechanism is broken the instrument cannot be fixed in the field. Special test equipment is needed to make adgustments and tests. But minor problems can be and I think should be fixed in the field! Other examples: Navcomms - photocells repalcements, replacement of the displays that are replaceable you do not need a slder iron, some other monor problems with the radios that does not affect frequencies and power. There is a lot of problems that could be fixed by the aircraft owners in the field providing they have qualified technicians who have tools and service manuals. But the FAA does not allow this and the owners have to send avionics instruments with the minor problems to the shops. The repairs cost a lot of money to the operators no matter if its a minor problem or not. That is why in many cases the owners fly with the equipment not functioning properly. Does that help to solve the problem. I do not think so. It makes it worth.
Last edited by airflorida1; 13th Jul 2009 at 19:02.
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Your post is disjoined and difficult to read. However, most telling is the following:
You and your friend know the regulation well, but have elected not to follow it. You believe you know more than the FAA, you believe you know what's best. In addition to acting illegally, you have also acted foolishly, both destroying the value and utility of the instrument, and rendering it useless.
Perhaps most disturbing, you elect to do so and defend your actions in the process. What has been done is wrong. Until you are able to not only see this but admit it to yourself, there is little use carrying on any further conversation with you. One can only hope that your actions will garner the attention of an inspector who will be willing to see your certificates suspended in order to prevent harm to yourselves or others through your foolishness.
My friend is very well aware of the FAA regulations. Thank you for answering my/his question.
But frankly I believe that those FAA rules are outdated.
But frankly I believe that those FAA rules are outdated.
Perhaps most disturbing, you elect to do so and defend your actions in the process. What has been done is wrong. Until you are able to not only see this but admit it to yourself, there is little use carrying on any further conversation with you. One can only hope that your actions will garner the attention of an inspector who will be willing to see your certificates suspended in order to prevent harm to yourselves or others through your foolishness.
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I can see where you are coming from and it soooo tempting just to do a little DIY work on your plane. But the basic reason you and your friend are legally prevented from working thinks like avionics, instruments, flying controls, seats etc. is that you don't have the correct manuals, training, testing, equipment etc. to perform these tasks. That is why you have to send them off to specialised repair shops. There are hundreds of smoking holes in the ground because some clown has "fixed" something on their plane. Worse, one of these idiots may have "fixed" something and then let someone else fly it who has no knowledge of the work perfomed. By all means work under the supervision of a "tame" licenced engineer, but please, don't DIY.
If you can't afford to have things fixed properly, you can't afford to fly. But more importantly, the people on the ground beneath you and those whom share the sky with can't afford you flying either.
PM
If you can't afford to have things fixed properly, you can't afford to fly. But more importantly, the people on the ground beneath you and those whom share the sky with can't afford you flying either.
PM
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When I was working in an instrument calibration shop a while back, one of the jobs we often did was repair and calibration of vacuum gyros - both horizons and DGs. The mechanisms are more robust than the equivalent electrical instruments but it is much more difficult to set up the erection system. Typically, it would take a skilled, trained bench technician, equipped with all the proper tools and a RPY table, a couple of days to strip, clean, replace damaged bearings (you have corrosion in there, right?) and jewelled pivots, then reassemble, coarse adjust and calibrate the instrument. Each time you perform an adjustment you have to seal the case, run the gyro up to speed and check the erection rate and final attitude. If any adjustment is needed you have to re-open the case, adjusting and repeating the process over and over again until its back in specification.
So, you reckon this is too expensive? How much do you reckon your friendly neighbourhood bench technician is worth? Two dollars an hour? ten? fifty?
...and if you get disoriented at night like that Kennedy chap, how much does a funeral cost?
So, you reckon this is too expensive? How much do you reckon your friendly neighbourhood bench technician is worth? Two dollars an hour? ten? fifty?
...and if you get disoriented at night like that Kennedy chap, how much does a funeral cost?
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I worked with avionics manufacturers and in the avionics repair shops so I can and do repair all avionics on my cessna 182 airplane myself. I can fix any avionics on my plane. I have service manuals, toos, test panels and special test equipment. I never worked on instruments though that is why I asked the question about the instrument. I do some minor repairs on the instruments though too e. g. I change the bulbes in the instruments, replace instrumets filters etc. And no one will ever convince me that I cannot do this. Yes, I can! 
If you can not do this kind of job you MUST send your avionics and instruments to the repair shops. I am sorry for you that none of you cannot do this kind of work. For now I am just wasting my time explaning the things to people wo have no idea of what I am talking about 
If you can not do this kind of job you MUST send your avionics and instruments to the repair shops. I am sorry for you that none of you cannot do this kind of work. For now I am just wasting my time explaning the things to people wo have no idea of what I am talking about
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LEAFITOUT, you are wrong. I want to listen to sound advices and answers to my question, which in particular was how to remove the white powder-like stuff from inside the instrument. It was a technical question basically addressed to the technicians who worked with the instruments. I have never seen something like that in my practice. It was not concerned any legal issues or FAA rules.
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LEAFITOUT, you are wrong. I want to listen to sound advices and answers to my question, which in particular was how to remove the white powder-like stuff from inside the instrument. It was a technical question basically addressed to the technicians who worked with the instruments. I have never seen something like that in my practice. It was not concerned any legal issues or FAA rules.
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Just trying to think of accidents attributable to instrument failure...
Air India lost a 747 of the coast of Mumbai in 1978 (ADI/INS)
EMB 120 at Leeds in mid 90s (ADI)
Surely must be more...Air Florida, you cannot quote a PPRuNe thread as approved data.
I believe that, statistically, the vacuum pump is the most unreliable part of a GA aircraft's systems (BTW). This might help.
Air India lost a 747 of the coast of Mumbai in 1978 (ADI/INS)
EMB 120 at Leeds in mid 90s (ADI)
Surely must be more...Air Florida, you cannot quote a PPRuNe thread as approved data.
I believe that, statistically, the vacuum pump is the most unreliable part of a GA aircraft's systems (BTW). This might help.
Last edited by Bus429; 16th Jul 2009 at 14:53.