[Music] foreign let's talk about inspection fundamentals but before we get into details of inspections let's first talk about your mechanic certificate and interestingly enough the fa wants you to know what part of the Federal Aviation regulations applies to the issuance of mechanic certificates and the general rules that you'll operate under when you hold a mechanic certificate and ratings they want you to know that as a mechanic you're going to be certificated and operate under part 65. that's 14 CFR for code of federal regulations part 65. that's the part of the regulations that talks about issuing mechanic certificates and gives you your general operating rules you know that you've worked and studied very hard to get your mechanic certificate in ratings now what do you think would happen if someone tried to take the easy way and got caught cheating while taking an FAA mechanic test well the consequences are very significant the maximum penalty for cheating or other unauthorized conduct while taking an FAA mechanic test is ineligibility to receive any certificate or rating for one year and suspension or revocation of any certificate held and that means a person caught cheating on a mechanic test who also held a pilot certificate could have that pilot certificate suspended or revoked now the regulations require mechanic applicants to be able to read write speak and understand the English language but the regulations also have a provision that an individual who does not read write speak and understand the English language but is otherwise qualified May apply for a mechanic certificate if that person is employed outside the United States by a U.S air carrier so a mechanic employed by a U.S air carrier outside the United States who does not reach speak and write and understand English will have valid only outside the United States endorsed on his or her certificate when all your hard work is paid off and you've passed your knowledge and practical tests you'll be issued a temporary mechanic certificate that is good for a maximum of 120 days and the reason the FAA issues a temporary certificate is to allow them time to review your application and supplementary documents now you may be asked if they issue a temporary certificate so that a background investigation may be completed but no that's not the reason they issue a temporary certificate to a successful mechanic applicant to give them time to review the application and the supplementary documents now when you receive your actual mechanic certificate how long is it good for well the normal duration of a mechanic certificate with an airframe and or a power plant rating is forever unless it is surrendered suspended or revoked the duration of your mechanic certificate has nothing to do with your employment or how recently you exercise the privileges so when you've earned your mechanic certificate with an airframe and or a power plant rating it continues to be valid unless it is surrendered suspended or revoked now why would they suspend or revoke a certificate well one reason is for document fraud it's absolutely critical to the FAA and all other interested parties to be able to rely on the logbook records and the logbook entries that they are accurate and honest the FAA wants you to know that the maximum penalty for falsification alteration or fraudulent reproduction of any certificates log books reports or records is suspension or revocation of any certificate that you hold including any pilot certificate now once you've got your permanent certificate you're not completely Home Free as a mechanic you're not allowed to exercise the Privileges of your certificate unless within the preceding 24 months either the administrator has found you're able to do the work or you've served as a mechanic using your certificate in ratings for at least six months what that means is you have to keep your mechanic certificate current you have to work as a mechanic for at least six months out of the preceding 24 months or else have the administrator find that you're able to do the work in order to go ahead and exercise the Privileges of your mechanic certificate now that you've been issued a mechanic certificate do you think the FAA would want to know if you've changed your permanent mailing address you bet they would the FAA definitely wants to maintain a current mailing address for anyone holding a certificate issued under 14 CFR part 65. so if you move and change your permanent mailing address you have 30 days to notify the FAA of that change now one of the Privileges of holding a mechanic certificate is to perform or supervise maintenance on an aircraft the FAA may ask you what's included in the regulatory definition of Maintenance well maintenance means overhaul repair parts replacement inspection and preservation notice that preventive maintenance is not a part of the definition for maintenance preventive maintenance means simple or minor preservation operations and the replacement of small standard Parts not involving complex assembly for instance changing tires or replenishing hydraulic fluid would be examples of preventive maintenance so when you're performing maintenance you're involved with overhaul repair parts replacement inspection and preservation of aircraft now let's talk about 100 hour inspections let's assume that you're a mechanic with a power plant rating because you've got the power plant rating you can perform the 100 hour inspection required by the Federal Aviation regulations on a power plant or a propeller or any part of them and can release them for return to service because of the power plant rating you can do the 100 hour inspection whether the reg is required or not on the power plant the propeller and its component now let's assume that you have both the power plant and the airframe certificates if you have both power plant and airframe you can authorize the whole aircraft for return to service after a 100 hour inspection not just the power plant but the whole aircraft because you hold both certificates both the airframe and the power plant mechanic now you this does not apply to returning an aircraft to service after major repairs or major alterations because after major repairs or major alterations you need an ia's approval someone with an inspection authorization and we'll talk more about that a little bit later on now let's assume that you have someone working under you or someone that you're supervising who is not a Certified mechanic if somebody is working under you he is not authorized to actually perform a 100 hour inspection even if you've gone both airframe and power plant ratings you the mechanic must actually perform the inspection itself and then you can have the uncertified person working under your supervision help you fix whatever you found wrong but the mechanic himself has to actually perform the 100 hour inspection now you've finished the 100 hour inspection you're ready to return the aircraft after service you've got to make the proper entries in the aircraft maintenance record you've got to make the log book entries for that aircraft to be returned to service and the person who approves or disapproves either the whole aircraft or some item for return to service is the one who's responsible for making the entries in the maintenance records whether it's an annual 100 hour inspection Progressive inspection whatever whoever either approves or disapproves the aircraft for return to service is the one with the responsibility for making the entry in the aircraft logs now as a certificated mechanic you are allowed to perform 100 hour inspections on instruments you can inspect the instruments as part of a hundred hour inspection but you may not repair the instruments only in Instrument Repair Station can and we'll talk more about that later on also okay let's go on to annual inspections if you're going to do an annual inspection or for that matter even a hundred hour inspection you have to use a checklist and where do you find the checklist you find it in Far part 43. the checklist has to have at least the items that are listed in Far part 43 you can have a lot more on it if you want to but at a minimum it's got to have the items contained in Far part 43. now let's assume that while you're doing an annual inspection you find a defect that makes the aircraft unair worthy what do you have to do about it you have to provide a written notice of the defect to the owner you do not notify the FAA or anything like that but you do have to provide written notice to the owner of any defects you find that make the aircraft on air worthy when you provided discrepancy list to an aircraft owner or operator after an inspection it says in effect that except for these discrepancies the item inspected is airworthy and in most cases that item will be an aircraft okay let's assume the home the aircraft owner has gotten this list of discrepancies the aircraft was not approved for a return to service because of the discrepancies who can fix the problems any appropriately rated mechanic May correct the discrepancies it does not have to be the mechanic that found it in the first place it does not have to be someone with an inspection authorization it can be any appropriately rated mechanic to correct those discrepancies now let's assume that the mechanic the owner wants to use is located at a different airport he if he wants to fly the aircraft to a different airport in order to fix those discrepancies because it was not approved remember for return to service what does he have to obtain he has to obtain a special flight permit you have to get a special flight permit if you're going to fly an aircraft to another airport for maintenance if it was not approved for return to service after an annual inspection now what is a repair a repair and we're talking first of all about Minor repairs here repair is performed on an airframe means restoring that airframe to a condition for safe operation after damage or deterioration from time weather or whatever the person who is installing Parts on an aircraft is the one who is responsible for making sure that any materials used in the aircraft maintenance and repair are the proper type and conform to the right standard so whoever installs it the installing person or agency is the one responsible for making sure the right materials are used now a minor repair a working definition of a minor repair generally is one that can be accomplished without any welding without any riveting without any gluing a fairly simple repair that you can do without welding riveting or gluing on the aircraft now the FAA is going to pose you a number of hypothetical questions and they're going to say to you which of these are major repairs and which of these are minor repairs one of the things they'll ask you about is replacement of a damaged engine and mount okay you're going to replace a damaged engine mount and you're going to replace it with a new identical engine mount purchased from the aircraft manufacturer is that a major repair or a minor repair and the answer is it is a minor repair it is not an alteration because you're not changing anything you're using exactly the same part that was there before and it is a minor repair because you're simply replacing one part with another new part purchased from the aircraft manufacturer now if instead you were going to start welding or riveting or otherwise working on the engine mounts yourself to try and fix them that immediately becomes a major repair but simply replacement of a part that you bought from the manufacturer that you can just bolt on and you're not going to have to weld on and stuff like that that's a minor repair let's assume that they say to you that you've got a damaged vertical stabilizer you could say that this one is a little bit damaged we have a missing one here you've got a damaged vertical stabilizer and you replace it with a new identical stabilizer again purchased from the aircraft manufacturer is that a minor or major repair and is it a repair or an alteration well you're replacing it with an identical part so it's a repair it's not an alteration you have not changed the aircraft configuration and because you're replacing it with a part that you bought from the manufacturer it is a minor repair now if you fabricated a new stabilizer that would be a major repair because now you're into welding riveting and stuff like that and that becomes a major repair now let's assume that as a certificated mechanic you have done a minor alteration you can approve for return to service a minor alteration that you've done appropriate to the ratings that you hold in other words if you only if you only hold a power plant rating then it has to be in regard to power plants if you only hold an airframe rating then any alterations would have to be on the airframe only that applies to minor alterations but not to Major alterations major alterations and major repairs require the approval of an IA a person holding an inspection authorization now you have to make an entry in the aircraft permanent records in the log books when you make a minor repair on a certificated aircraft just like you have to sign it off after inspections you need an entry in the logs when you make a minor repair how about a major repair a major repair is any repair that if it's not done properly could affect the structural strength or the flight characteristics of the aircraft and this includes operations where you do welding riveting gluing and that type of thing now even if you've got a power plant rating you need to know that you are not allowed to do major repairs to a propeller even if you've got the necessary equipment available as a power plant mechanic you can do minor repairs on a propeller but you cannot do major repairs on a propeller for major repairs on a propeller the propeller has to go to a propeller shop so even though you've got the power plant rating that doesn't cover everything as far as propellers are concerned now what constitutes major repairs well how about fabric on fabric covered Parts this fabric definitely needs some attention paid to it the replacement of fabric on fabric covered Parts such as Wings fuselages stabilizers control surfaces is a major repair even if you don't do any other alteration or repair work on the aircraft replacement of fabric is a major repair because of its importance and significant against to the flight characteristics and safety of the aircraft now let's assume that you are repairing skin sheets on the aircraft and you're going to repair portions of skin sheets by making additional seams that would be classified as a major repair as soon as you're putting additional seams in the skin sheets that's classified as a major repair let's assume that you're overhauling a hydraulic pressure pump the overhaul of a hydraulic pressure pump by definition in the regulations is a major repair and is considered an appliance major repair because the hydraulic pressure pump is an appliance it's not the airframe it's not the power plant but it is an appliance that goes along with the aircraft and by regulatory definition it is a major repair let's talk now about major alterations something like for instance installing a turbine engine on a Cessna 172 that would certainly qualify as a major alteration a major alteration is a change in the basic design of an aircraft not listed in the manufacturer's specifications which could affect the structural strength or the flight characteristics of that aircraft let's take a look now in the figure pages in appendix 2 and when you get there take a look at figure 62. figure 62 that's actually part one of a three-part figure and let's take a look at what it is because the fa is going to ask you some questions about it notice that it's labeled area one in the upper left hand corner what this is is information about two different antenna installation kits you've got a dash 100 kit and a Dash 200 kit and this particular page area one gives you all of the different parts with their part numbers and the quantity that you need for the installation of those antenna kits two things that we want to take a look at because we're going to be talking about them later are the doublers there is a dash 101 doubler used in the dash 100 kit and there is a dash 102 doubler used in the dash 200 kit okay that is area one that gives us our parts information take a look at the next page notice at the top that it's labeled area 2. in area two here we've got General notes for the dash 100 installation below there on the same page we've got Area 3 which is the general notes for the dash 200 installation the next page is area 4 of this figure and area four of this figure is a drawing that shows you how to do the installation there is the area 4 over on the right hand side and what you're doing is you're installing a dumbler in order to install an antenna on the aircraft now how do we know for sure that what we're doing is installing an antenna because when you take a look at the previous page in area two and if you take a look at item seven in there it talks about retaining the antenna and installing the antenna so that's what these kits are designed to do now one of the questions the FAA might ask you about these figures is which doubler part numbers would you use in the dash 100 kit so take a look back at area one here's the dash 100 kit and how many of each different part you use in it and the same for the dash 200 kit and notice that when you're looking at the doublers the dash 101 doubler you use one of them in the dash 100 kit but as far as the dash 102 doubler is concerned you use one in the dash 200 kit but you do not use any of that doubler in the dash 100 kit so in the dash one 100 kit the doubler part number that you would use is the dash one zero one doubler take a look now at Area 3 on the next page because the fa might ask you which doublers require heat treatment before installation Area 3 is the general notes for the dash 200 kit and if you take a look at note number three in area three you'll notice that it says to heat treat the dash 102 which is the doubler for the dash 200 kit so the doubler that requires heat treatment before installation is the dash 102 doubler that goes in the dash 200 kit they may also ask you using only the information given which doubler is it possible to construct and install now when you're taking a look at the general notes for the dash 200 kit in Area 3 here take a look at the first cup couple of notes note number one says to do all bands iaw meaning in accordance with PS standing for process specifications 1000 and all holes in accordance with process specifications 1015. but they don't give us the process specifications so we do not have right here in the information given enough information in order to be able to construct this particular doubler let's take a look at the top of that same page in area two and see if we have enough information to construct the other doubler and when you take a look in area 2 which is the general notes for the dash 100 kit note number one says all bins should be plus or minus 0.5 degrees all holes should be plus or minus point zero zero three so there is specific detailed information there and you do have enough information to construct and install the dash 101 doubler based on the information given to you here in area two you do not have enough information for the dash 102 but you do have enough information for the dash 101. let's look again at the maintenance data figure Pages for those antenna installation kits and let's see if we can figure out how many parts you'd have to fabricate if you're going to construct and install one doubler you'll find the answer to that by looking at area one on the page labeled part one of three if you compare the list of parts of the dash 100 kit with the dash 200 kit you can see that they have exactly the same number of parts and the only difference as we discussed are the two doublers now as you look through the list of parts the rivets and the domed nut plates are standard Aviation Fasteners that you do not need to fabricate however the dash 103 clips and the dash 102 and dash 101 doublers are fabricated out of sheet stock to the dimensions that are shown on the page labeled part 3 of 3. so how many parts do you have to fabricate in the construction and installation of one doubler you'll need to make two clips and one doubler for a total of three parts with either the dash 100 or the dash 200 installation now in addition to going in the log book major repairs and major alterations also have to be entered on an FAA form 337 as well as in the log books it goes on this FAA form 337 major repairs and alterations so that there is a permanent separate record of major repairs and alterations that have been made to the aircraft let's assume that the repair or alteration major repair alteration was done to an aircraft engine and then it's going to go back in service how many copies the FAA will ask you of the FAA form 337 do you have to prepare if you've made a major repair to an aircraft engine well what you have to prepare is two copies of the 337 form that's minimum because the aircraft owner gets one of them for his maintenance records and the FAA gets a copy and the FEA keeps those copies in Oklahoma City so that you can find out you can get duplicates and find out all the major repairs and alterations that have been done on an aircraft two copies of the FAA form 337 have to be prepared now let's assume that you've completed work on an aircraft that requires a form 337. who should prepare the form well since you're the one who performed or supervised the work then you should prepare the form 337 the mechanic with the inspection authorization rating who approves the aircraft for return to service does not prepare the form 337 because he or she did not perform or supervise the work can the owner or operator of the aircraft does not prepare it either by regulation the person who performed or supervised the work is the one who prepares the form 337 and as a certificated mechanic without an inspection authorization rating what does it mean when you sign in the appropriate block on that form 337 by signing the form you are certifying that the work was done in accordance with the requirements of 14 CFR part 43 of the regulations the part that covers maintenance preventive maintenance rebuilding and alteration you are not approving the work for return to service since that's the ia's job and you are not just certifying that the maintenance information used was FAA approved data you are certifying that the work was done in accordance with the requirements of 14 CFR part 43. which by the way would include using the appropriate data now let's assume that you're filling out a form 337 for work you've done and you've run out of space in Section 8 for the work description what do you do well you need to attach one or more additional sheets of paper so you'll be able to complete that description of work and as you might guess the FAA has some requirements for what you put on any sheets you attach to a 337 just in case those additional sheets become detached they want you to include in addition to the description of the work the aircraft nationality and registration Mark and the date the work was completed but you do not need to include the make model and serial number of the aircraft now here's something to keep in mind form 337 is only authorized for use with U.S registered aircraft if a foreign Civil Air Authority requests the form as a record of work performed it may be provided and you can complete it the same way you would for a U.S registered aircraft but the foreign Authority should be notified on the form that it is not an official record and that it will not be recorded by the FAA aircraft registration branch in Oklahoma City Oklahoma put the other way form 337 is not authorized for use with other than U.S registered aircraft now whenever major repairs or alterations are approved for return to service the data used as a basis for the return to service must be FAA approved prior to being used for instance approved data would include things like airworthiness directives The Advisory circular on acceptable methods techniques and procedures FAA approved manufacturers instructions kits service handbooks type certificate data sheets aircraft specifications and so on now you might be asked if you could use data that has not yet been approved by the FAA as a basis for approving major repairs or alterations for return to service in other words can the data used in the major repairs and alterations be something that may be approved by the FAA after the fact and of course that is not acceptable you must use data that is already FAA approved prior to using it as the basis for approving major repairs or alterations for return to service now here's a guy who's busy at work trying to figure out the inspection interval on a part and sometimes the way it's written makes it kind of confusing on the FAA test for instance they might say to you that you need to check the thrust bearing nuts for tightness on new or newly overhauled engines and they're going to ask you how often they need to be checked and they give you the following information check it at the first 50 hour inspection after installation and then check it at each third 50 hour period and the question is how many hours do you have between the later inspections and the answer is a hundred and fifty hour intervals because if you're going to check it at each third 50 hour period Well 3 times 50 is 150 hours and so after the first inspection you're going to be checking it at 150 hour and a revolts or they might give you a different kind of question about valve mechanisms and they might say that you need to do a detailed inspection and adjustment of the valve mechanism and you do it at these intervals at the first 25 hours after the engine has been placed in service and later inspections will be done at each second 50 hour period and the question is what are the intervals for the valve mechanism inspections and the answer is 100 hour intervals you're supposed to do this one at each second 50 hour period and 2 times 50 is a hundred hours so you do this at 100 hour intervals let's talk about some requirements for maintenance records I'm sure you know the old saying the job isn't done until the paperwork is done and I'll bet you've already guessed that the FAA has something to say about the format you use for maintenance records what they say is you can use any format which provides continuity and includes the required information you do not have to use the format the manufacturer provides nor do you have to get permission from the supervising FAA flight standards district office to change away from the manufacturer's format you do have to make sure the format you use has the required information and provides record continuity in other words the entries are kept together and the format lends itself to the addition of new entries now now let's say that you've completed a 100 hour inspection on an airplane and there are separate maintenance records for the airframe the power plant and the propeller so where do you record the entry for the inspection you must record the completed 100 hour inspection in each of the separate records including individual records for each engine and each propeller if there's more than one now when you record satisfactorily completed inspections like that 100 hour or an annual you must include the aircraft total time in service for aircraft operated under part 91. but for part 91 aircraft you do not have to record the aircraft total time in service for maintenance preventive maintenance rebuilding or alteration aircraft total time and service is required to be included only in the inspection entry for part 91 aircraft what should the maintenance record look like that best describes the action taken on various situations for instance you have a control cable that shows approximately 20 percent wear on several of the individual outer wires at a fairlead and the question is what should the maintenance record entry look like what they're essentially asking you is do you have to do anything about it and if you do do anything about it what would the maintenance entry look like what would you have to do about it and how would you describe it in the aircraft log book well first of all if you've got 20 percent wear on individual outer wires that is acceptable until you get up to about 40 or 50 percent wear on individual wires you're okay so the way you would describe that in the log book is the where is within acceptable limits repair is not necessary you don't have to do anything about now let's take a look at a dent in a section of aluminum alloy tubing and see what the appropriate maintenance record entry would be let's assume that you have found a .125 inch dent in a straight section of half inch aluminum alloy tubing the first thing you need to determine is whether this Dent requires repair or not the accepted practice says that a dent less than 20 percent of the tube diameter is not objectionable unless it's in the heel of a Bend since this is a straight section of tubing the dent can go up to but not equal to 20 percent of the diameter you know the depth of this Dent .125 inches and you know the diameter of the tubing half inch or 0.5 then it becomes a simple math problem first divide the dent depth of 0.125 inches by the tubing diameter of 0.5 inches that gives you 0.25 to get the percentage multiply 0.25 by 100 and you get 25 percent so now you know that the dent exceeds the less than 20 percent limit and you will have to either replace the entire tube or repair it by cutting out the damage section and inserting a tube section of the same size of material using standard unions sleeves and Tube nuts your entry for such a repair might say dented section removed and replaced with identical new tubing flared to 37 degrees now be careful because you might see a choice that said dented section removed and replaced with identical new tubing flare to 45 degrees and of course that would not be acceptable since aircraft aluminum tubing must be flared to 37 degrees now let's assume that they say to you that the situation you've got is that you have a dent in a tubular steel structure that is dented at the cluster and what if anything do you have to do about it and how are you going to repair it well you do have to repair it and the entry would be welded a reinforcing plate over the dented area welding a reinforcing plate over the dented area or let's assume that they say to you that you had to replace some helicoils in a casting what the helicoils do is let you screw the bolts or nuts in without damaging the soft casting itself the maintenance entry that you would make for that would look like this eight quarter 20 inch standard helicoils were replaced the damaged inserts were extracted the tapped holes were gauged then new inserts installed and tangs removed tangs are the part of the Helicoil that you're holding on to with the insert tool and that's the type of Entry that you would make if you have to replace the helicoils you don't just say Helicoil is replaced they want more detailed in that they want information on exactly how the process was performed so that anyone who follows along in your tracks behind knows what was done now there are certain types of entries that not only would show up in the log books but they would also show up on FAA form 337 because they describe major repairs and alterations and here's one remove the right wing from the aircraft and remove skin from Outer six feet repaired Buckle Spar 49 inches from tip in accordance with figure eight and manufacturer structural repair manual number 28-1 if you saw an entry like that where it would go is it would not only go in the airframe log book not the engine but the airframe logbook but it also would need to be on form 337 which is what you're looking at here because that constitutes a major repair to the aircraft and on major repairs you have to do a form 337 as well as an entry in whichever is the appropriate log book and the appropriate log book for Wing repair is not not the engine log book it's the airframe logbook now when maintenance or alteration has been done and you're approving an aircraft for return to service there's a number of items that the person approving that aircraft for return to service has to enter in the maintenance record of the aircraft here's what has to be entered a description of the work performed or a reference to some kind of acceptable data the date of completion of the work not the date it was begun but the date the work was completed the name of the person who is performing the work if it's not the same person who's signing it off the signature of the person returning the aircraft for return to surface their certificate number and the kind of certificate that's held now when the work that's been performed on an aircraft has been completed and the authorized person signs the maintenance records for a maintenance or alterations that is a return to service for the work performed only it is not a return to service for the entire aircraft in other words the distinction they're drawing here is between routine maintenance or maintenance problems as opposed to an inspection like an annual inspection when an inspection is done the person says I've inspected this entire aircraft and it's okay for return to service if you've done some maintenance on the aircraft between inspections you haven't inspected the entire aircraft all you're certifying when you sign those long books is the repair or the alteration that I did is okay and okay for return to service but I didn't inspect the rest of the aircraft and I don't know what the rest of the aircraft is like so the maintenance records when you sign them off not for an inspection but just for maintenance or repair is a return for service only for the actual work performed not for the entire aircraft whoever does the work is responsible for making the entry but the aircraft owner is ultimately responsible for maintaining the required maintenance records for an airplane so the regulations really make two people responsible the mechanic is responsible for making the entries and the aircraft owner is responsible for maintaining the records and having them for a particular airplane so what are the records the owner must maintain and how long does the owner have to retain them for aircraft operating under part 91 records of all maintenance alterations preventive maintenance 100 hour annual and Progressive inspections must be retained for at least one year unless the work is repeated or superseded and those same records must be available and transferred with the aircraft when it's sold now you may be asked if you need to retain and transfer records of inspections performed in accordance with 14 CFR part 43 appendix d That's the 100 hour and annual inspections yes you have to retain those but that is not a complete or in this case correct answer you also must retain and transfer records of Maintenance per preventive maintenance and Progressive inspections you also may be asked if you need to retain and transfer records of the current status of applicable ads and the date and time when recurring ads are next due again that's not a complete answer and therefore in this case not a correct one and AD compliance will already be recorded in the maintenance and inspection records that you already have to retain now what if the maintenance records for an aircraft are lost or destroyed as you can imagine lost or destroyed maintenance records are a big problem the first thing you want to do in reconstructing them is to establish the total time and service of that airframe and you start by researching the records of repair facilities and individual mechanics that have been involved involved with that aircraft now the FAA may ask you if you have to establish the dates of all maintenance preventive maintenance and alterations or the dates and or times of all 100 hour annual or Progressive inspections no you do not need to do that because under part 91 you only have to retain records of those until the work is repeated or superseded by other work or for one year after the work is performed so in order to reconstruct lost or destroyed aircraft maintenance records you need to establish the total time and service of the airframe now let's talk about aircraft instruments for a minute you'll notice on air speed indicators that you have colored arcs on there the white Arc is the flap range the green Arc is the normal operating range the yellow Arc is the caution range the red line up here is the never exceed speed so the red line at the higher speed there is the never exceed speed the top of the green Arc is maximum normal operating speed the top of the white Arc is going to be the maximum operating speed with the flaps extended the bottom of the white Arc is the stalling speed with the flaps extended maximum gear extension speed is not marked on the airspeed indicator now for information regarding instrument range markings in other words where the arcs are going to go and so on for an airplane certificated in the normal category that information is given to you in F they are part 23 far part 23. now one of the things the fa will do they do not give you an actual airspeed indicator like this but they will give you speeds and they will ask you what would be the high end of the wide arc on an AirSpeed instrument if they give you the following table of air speeds first of all they'll say that normal operating speed is 260 knots never exceed speed is 293. Max gear operation speed is 174 and maximum flap extended speed is 139 and they ask you where the top of the white Arc should be located well normal operating speed is the top of the green never exceeds speed is that red line at the very high air speed maximum gear operation speed is not shown on the airspeed indicator and the maximum flap extended speed is the top of the wide Arc so the top of the white arc on that particular airspeed indicator should be 100 139 knots and every once in a while you actually have to paint an arc on an airspeed indicator to match an airplane if it if you don't have the right instrument and it needs correction in order to match the proper speeds maximum flap extended speed is the top of the wide Arc and on this airplane that would be 139 knots now a mechanic with an airframe rating can not perform minor repairs on an airspeed indicator even if you've got the necessary equipment available to you a mechanic cannot do any repairs on any of the aircraft instruments who do they want making repairs on aircraft instruments and FAA approved Instrument Repair Station and FAA approved Instrument Repair Station is who has to do it so remember that at a 100 hour inspection you can inspect the instruments but if there's anything wrong with them and if they need any repairs any work and FAA approved Instrument Repair Station is who has to do the work now to help you as you work on the maintenance of an aircraft there are some standards in regard to maintenance manuals the Air transport Association of America ATA and their specification number 100 established a standard for presenting technical information in maintenance manuals basically what that standard does is it divides the aircraft into systems and subsystems and gives numbers for them in order to simplify locating maintenance instructions for that particular aircraft so the system is standardized and no matter what particular airplane you're looking for you always know what set of numbers to go to to find out about a particular type of Maintenance information a particular system or subsystem the ATA manual standard specification number 100 now one of the ways the FAA keeps you abreast with what's happening maintenance wise with aircraft is aviation maintenance alerts that you can access on the faa's website which by the way is www.faa gov aviation maintenance alerts provide information about aircraft problems and suggested corrective actions they are suggested actions but they are not mandatory because aviation maintenance alerts are not like airworthiness directives now airworthiness directives are a whole different ball game airworthiness directives are issued by the Federal Aviation Administration and they are mandatory that means they must be complied with you don't have any option about it at all now the whole purpose behind airworthiness directives is to correct unsafe conditions in an aircraft or in a part this is the way the FAA notifies aircraft owners and as they say on the test other interested persons which usually means you the mechanic of unsafe conditions in either an aircraft or a part and prescribes the conditions under which the product may continue to be operated if they're going to allow it to be operated until you get a chance to fix it since airworthiness directives ads are used to correct different kinds of problems you might guess that they would tell you how quickly you must comply with the ad requirements and you'll find exactly that in a statement Under The Heading compliant for example you might read in ad and see a statement like this required within the next 25 hours time and service after the effective date of this ad unless already accomplished that would be the compliance statement because it's your instructions as to how quickly you must comply with this particular ad so what kind of actions might an ad require to correct the unsafe situation or allow the operator to continue using an aircraft until the problem is fixed the actions you may see required by an ad could take the form of an inspection parts replacement a design modification and or a change in the operating procedures for the aircraft NAD will not require overall changes in the content form and disposition of aircraft maintenance records but an ad may require conducting an inspection replacing Parts modifying the original design or changing the operating procedures now when are you as a mechanic responsible for checking ad compliance on an aircraft a mechanical is is responsible for checking ad compliance when he or she is performing an inspection that is required under part 91 part 125 or part 135. now do you have to check ad compliance anytime you return to service an aircraft or a portion of it for example after you've replaced a tire no you do not you only have to check ad compliance when you're performing an inspection that is required under part 91 125 or 135 such as a 100 hour or annual inspection now how long do 80 compliance records have to be kept they are not time limited they're required to be retained and then transferred with the aircraft when it's sold so the FAA is going to give you an airworthiness directive to read on the test and they're going to ask you some information about it first of all they're going to say that compliance with this ad is required as indicated unless it's already been accomplished and then there will be three different paragraphs of information about how an aircraft needs to be inspected paragraph one says as follows aircraft with less than 500 hours total time in service okay if the aircraft meets that less than 500 hours total time in service this is the inspection schedule inspect it in accordance with instructions below and they don't get into the actual inspection instructions all they're concerned about is do you know when it has to be inspected inspect at 500 hours total time or within the next 50 hours time and service after the effective date of the ad and repeat after each subsequent 200 hours in service so this is going to be a repetitive inspection required every 200 hours in service okay that's paragraph one let's take a look at paragraph two of the A.D this is for aircraft with 500 hours through 1 000 hours total time in service for those aircraft they have to be inspected within the next 50 hours time in service after the date of the ad and again it has to be repeated every 200 hours time in service paragraph three of the AED has to do with aircraft that have more than one thousand hours time and service they have to be inspected within the next 25 hours time in service after the effective date of the ad but again the inspections are repeated after each subsequent 200 hours in service what you notice when you look at these paragraphs is that regardless of when the original inspection has to be done and that's the purpose of the three different paragraphs is choosing when the original inspection has to be done in each case they have to be reinspected after each 200 hours in service and that is consistent in all three paragraphs the re-inspections are due every 200 hours in service okay what information do they give you about the aircraft itself they say to you that the aircraft has a total time and service of 468 hours that's what it has right now the airworthiness directives that we're just talking about was initially complied with when that aircraft had 454 hours in service and the question that they ask you is how many additional hours in service can be accumulated before the ad has to be complied with with again now the only issue here as far as which paragraph you're in has to do with when the aircraft has to be originally inspected and it already has been originally inspected at 454 hours time in service in all three paragraphs the repetitive inspection is due after how many hours in Service 200 hours time and service so if you take when the ad was done 454 hours and you add 200 hours time and service to that the next inspection is going to be due at 454 plus 200 or 654 hours time in service but they what they ask is how many hours are left before the next inspection is due and how many hours did they say the airplane has on it right now they said it has 468 hours on it right now so the next inspection is due at 6 54. it currently has 468 hours on it so the next inspection is due at 100 and 186 hours from now there are 186 hours to go now do not get caught on the test by saying that the next inspection is due in 200 hours the 200 hours is from the original when the original inspection was due but what they want to know is realizing that the aircraft has gone sometime past that inspection that it now has 468 hours in service the inspection was some period ago how many hours does it have left before it has has to be inspected again and the answer is in this case 186 hours left now let's assume that an airworthiness directive requires work on a propeller requires that a propeller be altered who's allowed to do it well if the alteration is a minor alteration a certificated power plant mechanic could perform that ad and approve the propeller for return to service but only if it is a minor alteration because even a power plant mechanic is not allowed to do major repair or alteration on a propeller that takes a propeller shock but he could do the minor alteration required by NAD Henry approve it for return to service now whoever complies with an airworthiness directive has to make an entry in the maintenance record of the equipment so that a mechanic coming along behind you knows that the 80 has been complied with and how that compliance was accomplished now let's talk about earworthiness certificates complying with aeds and doing all the other maintenance work on the aircraft is the way that the airworthiness certificates on the aircraft are kept valid the FAA wants you to know what part of the regulations covers the issuance of airworthiness certificates and that's covered in part 21 subpart h of the Federal Aviation regulations now they're going to throw a lot of different parts around Parts 23 and 25 of the regulations cover air more than a standard and part 39 covers airworthiness directives but in terms of the issuance of airworthiness certificates that's covered in part 21 of the Federal Aviation regulations now what happens if an aircraft is sold what happens to the air within a certificate well it simply transferred with the aircraft the airworthiness certificate goes with the aircraft NFL there where the aircraft is sold it simply is transferred along with the aircraft now what you see here is a sample of a type certificate data sheet but whether you work to find out information about the aircraft or the type certificate data sheets or whether you work with what's known as aircraft specifications depends on the date that the aircraft got its type certificate because the date is what determines what the document is called for instance prior to January 1st of 1958 the CAA issued documents known as aircraft specifications but after January 1st of 1958 they issued type certificate data sheets and for what kind of products do they issue type certificate data sheets well they issue type certificate data sheets for aircraft engines and propellers they do not issue them for appliances they only issue them for aircraft engines and propellers now what kind of information do those sheets give you the aircraft specification or the type certificate data sheet now what kind of information do those sheets give you the aircraft specification or the type certificate data sheet they reference among other things the required equipment that is needed to maintain the validity of the standard airworthiness certificate among other things they will tell you about whether a particular propeller can be used with the aircraft the suitability for use of a specific propeller with a propeller engine airplane combination so if you want to know whether you're allowed to use a particular propeller on an aircraft you would go to the aircraft specifications or the time certificate data sheets in order to see depending on the date the airplane was type certificated to see if that's allowed because what it will do is it will tell you about various alternative propellers that are allowed for that engine and airplane combination okay other types of information that you would find in the aircraft specifications or the type certificate data sheets is the placards whatever placards are required on an aircraft will be listed in those specifications or in the data sheets another item that would be found there is the location of the datum the location of the datum for the aircraft is very important when you're measuring in order to install or remove equipment and find out the effect on the weight and balance and that would be contained in the type certificate data sheet another thing that would be contained there is control surface movements that is also the type of information contained in the type certificate data sheet or if the plane is older in the aircraft specifications now you may see a designation code on a type certificate data sheet such as two pcsm well many aircraft specifications and some type certificate data sheets use codes like that to describe the general characteristics of that aircraft so what does two pcsm stand for well the 2p tells you that it is to place it has two seats the next letter is for cockpitter cabin design and the C means that it is a closed cockpit the third letter tells you the basic kind of aircraft and in this case the S tells us it's a c plane and the last letter the M is for the wing design and the MD codes to a monoplane instead of a biplane so a 2 pcsm is a two-place closed C monoplane or another way to spell fun now what if someone thinks they have an improvement for an aircraft like a bigger engine or something and they want to deviate from its original type design can they just do that no they cannot just do that unless they have proper authorization FAA form 337 supplemental type certificates and airworthiness directives are sometimes used as authorization to deviate from an aircraft's original type design how about a technical standard order no a technical standard order is not used for that it gives specifications for components or parts but it is not authorization to deviate from an aircraft's original type design but you can use an FAA form 337 supplemental type certificate or airworthiness directives to authorize you to deviate from the aircraft's original type design now sometimes you'll be working with supplemental type certificates supplemental type certificates are issued for a lot of things for instance to change the type of breaks that an aircraft has all sorts of things like this and they can be issued to more than one applicant even for the same design change several different types of breaks several different types of other things that can be done provided that each applicant shows compliance with the applicable airworthiness requirement the FAA doesn't care if there's 50 people with an STC or supplemental type certificate to put on new breaks or change this instrument or modify the interior whatever it may be as long as every one of them has complied with the appropriate airworthiness requirement now even if you've got an STC the regulation still require a approval of that aircraft after compliance with the STC because the installer has to make sure and someone has to inspect in order to make sure that that STC doesn't interact unfavorably with any other modifications in the aircraft and to make sure that the it was done properly and that the aircraft is still going to be air worthy stuff that's done with an STC is usually a major alteration and that is going to require approval from the appropriate person after the STC has been complied with now let's talk about technical standard orders or tsos what technical standard orders do is they set minimum performance standards they set environmental standards that equipment has to meet in order to be approved under the Tso and therefore you know if a piece of equipment is tso'd that it meets at least the minimum specs that are set forth in the technical standard order now even if something is manufactured in accordance with a technical standard order a TSO it still requires approval for installation in a particular aircraft all the TSO says is this particular item was manufactured to meet certain tolerances certain requirements certain minimum performance standards but if you're going to put it in any particular aircraft you're still going to have to have approval for that particular installation now one of the things the fa will be asking you on the test is what kinds of information and data constitute approved data and here's the type of things that would be approved data technical standard orders airworthiness certificates type certificate data sheets aircraft specifications and supplemental type certificates all of those cons Institute approved data it would not be a correct choice to say that all manufacturer's data is approved because it isn't all some of it is but some of it isn't so if they say all manufacturers data not necessarily also oddly enough it would not be a correct choice to say that advisory circular 4313-2a is approved data because advisory circulars are not mandatory and the FAA says it's not specific enough now another kind of type certificate has to do with propellers technical descriptions of propellers can be found in the propeller type certificate so just like airplanes have type certificates propellers have type certificates also that tell you all about the specs on that particular propeller the propeller type certificates now some aircraft are old and very old and didn't have much produced many of them produced and it's hard to find out information about them but that would be found in What's called the aircraft listing technical information about older aircraft models of which no more than 50 remain in service or a limited number were manufactured can be found in the aircraft listing so if they say to you on the test you've got older aircraft and there's no more than 50 in service where are you going to find the technical information about it the answer is in the aircraft listing let's talk about some different types of inspection that we might do first of all magnetic particle inspection what magnetic particle inspection is is a way of detecting cracks cracks that were basically invisible to the eye cracks and other defects in magnetic materials such as Iron and Steel now the drawback in a sense to Magnetic particle inspection is that it does not work with non-magnetic materials on those you've got to use some other type of inspection process but it will work on Iron and Steel and other magnetic materials so the fa will say to you what kind of Alloys can be inspected using the magnetic particle inspection procedure can iron Alloys be inspected that way sure they can because they're magnetic but you could not use magnetic particle inspection for copper aluminum aluminum or magnesium Alloys because copper aluminum and magnesium are not magnetic and you'd have to use a different inspection process okay what is the inspection process consist of what you do is you magnetize the part and then you apply ferromagnetic particles basically what you do is you apply magnetic particles to the part that you're going to inspect and you can do that either using a liquid medium or a powder medium either liquid or powder form and put it on the surface areas so you do need to know that you can use either a wet or a dry processed material as you're indicating medium that simply means that the magnetic particles that you're putting on the part can either be brushed on as a powder or you can put it on in a liquid medium either one is suitable for use for magnetic particle inspection okay so when you're doing the magnetic particle inspection what happens is the magnetic particles kind of line up and show the location of the defect and the approximate size and shape of it now with Magnetic particle inspection you use that primarily to detect flaws on or near the surface of the part that you're trying to take a look at because if the defect is very deep below the surface then the magnetization is not going to show as much of an effect the disturbance in the magnetization will will not have as much of an influence on the medium that you're using and it just simply is not going to show particularly well so magnetic particle inspection is used for Flaws or defects on or near the surface now there's two ways that you can do this magnetic particle inspection as far as applying the electricity and the magnetization to it is concerned you can either do continuous magnetic inspection or you can do what they call residual magnetization inspection with continuous magnetic particle inspection and that's what's used most often by the way you have the electric current and you have the magnetization going while you're checking it for the defects with residual magnetization inspection what happens is you remove the current and then you check and see with the residual that's left over what kind of flaws are being shown the continuous magnet genetic particle inspection is most often used because it's likely to reveal more than the residual method is the residual magnetization inspection usually is used only with Steels that have been heat treated for stressed applications now when you magnetize a part to do this magnetic particle inspection you need to magnetize it in two different directions both circular and longitudinal magnetization let's talk about what we mean there in circular magnetization basically the lines of magnetic force are going around the part this way essentially the defect is going to show up best when it is perpendicular to the magnetization so that if the magnetization is circular around the part like our bottom graphic shows the defects that are going to show up there are ones that are basically parallel to the long axis of the part on the other hand if longitudinal magnetization is done that's where the lines of magnetic force are lined up with the long axis of the part with longitudinal magnetization since the defects that show up best are perpendicular to the magnetization it's going to show up defects that are basically going around the circular part of that particular part so if you're going to do magnetic particle inspection you want to do both circular and longitudinal magnetization in order to show all the possible defects because otherwise you might miss some that weren't lined up with the way that you did it in particular you need to know that circular magnetization where the magnetization goes around the part like this is used to defect detect defects that are parallel to the long axis of the part this defect is parallel to the long axis of the part and it shows up with a circular magnetization sometimes the longitudinal magnetization like this will be done with a cable and continuous longitudinal magnetization with a cable will detect defects that are perpendicular to the long axis of the part this defect is perpendicular to the long axis of the part and that's what the longitudinal magnetization shows up and they want you to know that they consider that continuous longitudinal magnetization produces the greatest sensitivity in locating subsurface discontinuities in other words it's going to show up the defects the best now one of the things they'll ask is what type of magnetization would you use to detect a 45 degree crack in other words a crack that's running at a 45 degree angle and in that case either the circular or the longitudinal magnetization will work because they show up the defects that are basically 90 degrees to their type of magnetization but a 45 degree angle crack can be detected by either one of them either the circular or the longitudinal method now we're going to talk a little bit more about some of the cracks and so on but after you get done doing a magnetic particle inspection you have to demagnetize the part you have magnetized it to do the inspection you have to demagnetize it before you can reinstall it on the aircraft before you can use it again and they want you to know how to do that the way you demagnetize an item is by subjecting it to a decreasing alternating current energized coil not direct current but alternating current and to a decreasing current not to an increasing current a decreasing alternating current energized coil is how you demagnetize an item now we've been talking about using this magnetic particle inspection to find discontinuities what is a discontinuity it's an interruption in the normal physical structure or the configuration of a part it's something that isn't the way it's supposed to be but it may or may not affect the usefulness of a part depending on exactly what kind of discontinuity it is how substantial it is and where exactly it's located it may or may not affect the usefulness of that particular part now let's talk about fatigue cracks if you find fatigue cracks in a magnetic particle inspection you'll notice that they give sharp clear patterns they're found by the way in a highly stressed area of parts that have been in service never in parts that have not yet seen service because the fatigue rack basically means the stress of use has caused this crack now under magnetic particle inspection fatigue cracks are usually identified when a discontinuity is found in a highly stressed area of the part because by definition fatigue cracks are going to be found in the highly stressed areas and a fatigue crack causes the most buildup in the magnetic particle indicating medium over various other kinds of discontinuities and other kinds of cracks or problems now what is an inclusion inclusions are non-metallic materials that got trapped in the solidifying metal when the alloy was being created the pattern for an inclusion is a magnetic particle buildup that forms parallel lines a magnetic particle buildup that forms parallel lines now that's one way of inspecting parts to see if there's cracks and so on but it only works with what kind of materials magnetic materials Iron and Steel now let's assume that the part that you need to inspect and see if it has any problems or cracks is not made of iron or steel cannot be magnetized there is another non-destructive test that you can use in that case and that's called a Dye penetrant inspection the dye penetrant inspection will find defects that are open to the surface cracks and similar things in Parts made of any non-porous material and it does not have to be a material that can be magnetized because that's not the process you're using in this particular case so it would be an excellent test to use if you were looking for surface cracks and aluminum castings and forgings the dye penetrant inspection and the suitable developers that you use with it would find surface cracks in that and particularly appropriate with anything made of aluminum because aluminum you cannot use the magnetic particle inspection on one of the the drawbacks though to the die penetrant inspection is it will only detect defects that are open to the surface and this is the primary limitation of the dye penetrant method of inspection if the defect does not actually open up to the surface then the dye is not going to find it now one of the advantages of liquid penetrant inspections is the variety of materials that they can be used on the materials that you can use that inspection type on are ferrous metals non-ferrous metals and Plastics as long as they are non-porous Plastics you cannot use it it is not suitable for use on porous Plastics or on smooth unpainted wood which is also very porous because with those if the surface is porous instead of non-porous the dye is just going to go everywhere it's going to get absorbed by that surface now with the dye penetrant inspection basically what you're doing is a visual inspection of the part after you've processed it but the defects are made much more visible by the addition of the die the die can either be visible or fluorescent but essentially what you've done is process the part so that a dye makes any defects that may be there much more visible to you now what are the steps that you're going to take when you perform a Dye penetrant inspection first of all you thoroughly clean the metal surface then you apply the penetrant boy a lot of it here you apply the penetrant then you remove the penetrant with a remover emulsifier or cleaner and dry the part next what you do is apply the developer here we are spraying the developer on it will take it a little bit of time to set and then you inspect and you interpret the results that's the toughest part really on the die penetrant inspection is interpreting the results that you have and here we've got a crack that's shown up but we also have some other defects showing up over here that the dye penetrant inspection that the dye is bringing out now when you're preparing a part for the dye penetrant inspection you need to make sure it's clean and what you need to use is a volatile petroleum-based solvent a volatile petroleum-based solvent to make sure you get that part thoroughly clean otherwise the dye is going to collect with grease and so on and not going to give you the indications you're looking for after you've cleaned the part thoroughly and applied the penetrant the penetrant must cure for a period called the dwell time the time needed for that penetrant to get into any cracks the main determinant for the dwell time is the size and shape of the discontinuities you're looking for the length of this waiting time or dwell time does not depend on the size of the part or the type and density of the material the main determinant for the dwell time is the size and shape of the anticipated discontinuities now when you're using the developer to help find a crack the developer does not go into the crack because that's already filled with the dye penetrant what the developer does is acts as a blotter it pulls the dye out of the crack and makes it visible in the developer up on the surface so it's pulling the penetrant out of the crack it's acting as a blotter to give you that visible indication that you do have a crack in the material if the dye penetrant inspection indications are not good sharp and clear the probable cause is that the part was not thoroughly washed before the developer was applied you need to make sure that it's thoroughly washed before you put the developer on now when you're doing the dye penetrant inspection minute cracks finding minute cracks are going to require a longer than normal penetrating time as far as that dipenetrant is concerned now there's another type of non-destructive testing that you can use and that is called eddy current inspection any current inspection operates on the principal of determining how easily a material will accept an induced current and you either know from standard information how well it should be accepting it or you can compare it to a part that you know for sure is good and see if there's any differences and if it does not accept the current properly then you know that you've got some kind of problem for instance if the object has inter-granular corrosion it will not accept the current very well and that's going to show up as a very needle deflection on the meter and tell you that the material is defective so the eddy current inspection is most successful in detecting intergranular corrosion in non-ferrous metal non-ferrous metal because you're not able to use them magnetic particle inspection on it in this particular case the intergranular corrosion is pretty visible even on the surface but if it's not the eddy current inspection will find it before it even becomes visible now another non-destructive testing method is radiography in radiography what you're doing is using X and Gamma radiations to penetrate the material and to show the discontinuities to show any defects that are there and you can use it with either metal or non-metallic parts what happens is that the penetrating radiation is projected through the part to be inspected and then the processed film will show a shadow picture of the object now the principal advantage of this inspection method the radiographic inspection method is that little or no disassembly of the structure is required when you're doing it and you can do it to find deep-seated defects in parts or assemblies without having to take the assembly the structure apart for instance let's assume that you had a need to inspect a wing you needed to inspect the internal structure of a wing and you didn't want to disassemble the wing in order to do it radiographic inspection would be the most suitable method and it would show you whether you had defects or problems in the wing it would also be the most satisfactory way to determine the internal structural condition of a highly stressed cast aluminum alloy fitting so the radiographic inspection the real advantage of it is that you can see to the inside of things the internal structure of assemblies and parts without having to take it apart now there's three basic steps in the X-ray process the first one is the exposure to the radiation the second one is the processing of the film and the third one is the interpretation of the radiograph now as far as the exposure is concerned there are a lot of factors that are very essential and those factors are interdependent three of them show up on the FAA exam the material thickness and density the exposure distance in angle and the film characteristics are all factors essential factors on the radiographic exposure of the film but one of the things the fa will throw at you on the test while it's part of the radiography process doesn't have anything to do with the exposure and that's the processing of the film itself the film processing is important but it's not one of the factors as far as the exposure itself is concerned now there's another test which seems maybe a little bit low-tech after all the high-tech stuff we've been talking about and that's the metallic ring test let's assume you've made a bonded honeycomb repair using the Potted compound repair technique and you want to make sure the repair is sound what you do is you tap the bonded area after the repair is cured and what you're doing is listening you're listening to get a nice metallic ring and if you do that means you've got a good repair If instead you get a dull thud then you've got a problem now that we've covered all of the the different types of inspections let's assume that what you're doing is looking for surface cracks and aluminum castings or forgings what kinds of inspections would you use to find surface cracks well there's four that would be pretty good for you to use one would be dye penetrant inspection another would be eddy current inspection another would be ultrasonic inspection and of course there's always visual inspection what would not work would be a magnetic particle inspection and the reason that wouldn't work is we're talking about aluminum and aluminum cannot be magnetized and you would not use the ring test because remember the ring test is used to inspect a honeycomb composite and that covers what you need to know about inspection fundamentals [Music] foreign