Sub Module: 7.18: Aircraft Troubleshooting Techniques

 EASA / SARI MODULE 7
SUB MODULE 7.18
AIRCRAFT DISASSEMBLY, INSPECTION, REAPIR AND ASSEMBLY TECHNIQUES

FAULT DIAGNOSIS - TROUBLE SHOOTING

Aircraft maintenance schedules have been developed so that the amount of time an aircraft spends on the ground for routine inspection and servicing is kept to a minimum. However, aircraft might also “grounded” by equipment defects; it is most important that these are rectified efficiently.

One of the factors governing maintenance efficiency is the initial fault diagnosis, generally known as Trouble Shooting. Unfortunately defect rectification is sometimes attempted without prior fault diagnosis, or after only a limited attempt to narrow the field of possible causes. Such rectification usually deteriorates into a succession of component changes aimed a eliminating the fault by trial and error. This type of approach causes unnecessary work, waste of aircraft spares and excessive delays before the aircraft can be returned to service. All of this can be avoided by the application of some logical thought before work commences.

There are five basic steps to be followed when diagnosing a fault: -

1. Information Collection - Obtain all the relevant information on the defect and the circumstances in which it occurred.
2. Initial Examination - Localize the cause of the defect as far as possible by visual examination and applied equipment knowledge.
3. Further Examination - Examine the remaining possible causes of the defect and using functional tests wherever possible, select the most likely causes. Consult the trouble shooting flow charts in the Aircraft Maintenance Manual.
4. Rectification - Commence rectification work. Always keep a concise record of the actions taken and their result.
5. Post Rectification Testing - When the defect is rectified, functionally test the whole system or mechanism to ensure that secondary defects have not arisen.

Each of the five steps will be considered in greater detail, but because of the diversity of possible faults only generalized information can be given. Not all the checks listed will be applicable in every case but nevertheless they should be considered before proceeding with rectification.

 1. Information collection

The aircraft Technical Log entry which places the aircraft unserviceable is clearly the starting point for gathering information about the defect. A check should also be made for previous occurrences of the same or associated defects and note taken of the rectification details. 

Verbal Investigation - The Technical Log entry will rarely be comprehensive enough to provide all the information required. Enquiries should be made of the personnel concerned to obtain the following information:

  • Did the fault become apparent in flight or on the ground? If during flight, obtain details of altitude, speed, attitude at which the defect occurred.
  • Did the fault occur during testing or normal operation? Was its onset sudden or did it develop gradually?
  • Did the onset of the defect appear to be connected with a certain action such as system selection? Did selection of equipment other than the defective item appear to affect its operation?
  • What action was taken when the fault developed? Were standby system selections made? What effect did such selections have on the equipment?
  • What subsequent action has been taken in attempting to rectify the fault, or make the aircraft safe?
  • Can functional testing be carried out without damage to the aircraft?

Document Investigation - A study of past Technical Log sector record pages will show if the defect has occurred previously. If so, an examination of the appropriate Maintenance Control Records will sometimes give relevant information.
Examples are:-

  • Where previous adjustments have been made or where a progressive increase in the rate of replenishment of systems has occurred. These could have been compensating for a deteriorating state of serviceability.
  • Where previous defects of a similar nature have occurred. These may indicate a defect in design or manufacture, or could point to an undiscovered source of stress applied to the defective item.
  • The Aircraft Maintenance Manual normally contains Trouble Shooting Flow Charts which can be of assistance in locating the cause of the defect. It should be noted that seemingly similar defects can arise from different causes. 

2. Initial examination

This will be very largely governed by the type of defect which is being examined, but it should always be started with definite objectives in view e.g.:

  • To become familiar with location, form and extent of the damage
  • To establish the practicability of functional checks
  • To find the cause and effects of the more obvious types of defects

In some cases, involving straightforward defects, not all the steps detailed under ‘INFORMATION COLLECTION’ need be followed. However, you should be aware that a defect is not always as straightforward as it may seem at first, and it is bad to come to hasty conclusions and undertake a rectification programme based on a superficial examination of the facts. In addition, damage occurring as a consequence of certain defects must also be looked for and rectified (e.g. hydraulic fluid damage to electrical cable insulation and titanium hot air ducting etc.). 

When applicable, check for overheating by examining casings and structures for discolouration and flaking paintwork. Having carried out a systematic initial examination it may not have been possible to definitely establish the precise nature of a defect and its secondary effects. Knowledge of the affected
system or mechanism and proper use of the various aircraft manuals will enable a possible cause or causes to be assumed. These assumptions however, should be proven wherever possible by further examination or functional testing before rectification starts.

3. Further examination

This examination is aimed at proving or disproving the initial theories formed of the cause and nature of the faults within a system or mechanism. The form of examination used will be governed by the type of system or mechanism in question, and by the type, location, and form of the defect requiring rectification.
For internal or functioning defects in systems it is necessary to know how each component operates when it is in a serviceable state, so that detailed comparisons can be made with the symptoms.
A thorough knowledge of the system or mechanism is therefore essential.

It might be possible to insert test equipment into the system or mechanism or carry out BITE checks. Disconnections in a system should be limited as far as is possible to prevent the creation of leaks.

4. Rectification

  • It is essential that a record is kept of all work carried out, especially when the work is long anddetailed. Records of work carried out should be designed to fulfil the following functions:
  •  Provide an effective method of cross referencing between separate entries relating to the one job.
  • Cover, in full and accurately, all the aspects of the rectification and associated work being undertaken. Include rigging and component adjustment.
  • Give precise details of component lives and serial numbers in order to maintain “Lifed- Component records”, and to help any possible later investigations.
  • State un-serviceability arising from the work, as the subject of separate defect entries in the aircraft log book.
  • Record mandatory checks and inspections that are required as a result of the rectification. These should be entered as the need becomes apparent.
  • Each trade responsibility should be dealt with separately, but each entry should refer to the originating task.

5. Post Rectification Testing.

A functional test carried out on the completion of rectification will prove in a practical sense the effectiveness and efficiency of the rectification that has been carried out. Functional tests should, as far as possible, emulate the circumstances under which the fault first occurred, and should test the system or mechanism in all its functional roles. It may be necessary to have the aircraft test flown to fully test the rectification of a system or mechanism.
All faults arising from functional tests or test flights must be entered in the appropriate log book for subsequent fault diagnosis and rectification.


EASA PART 66 MODULE 7 ESSAY QUESTION:

You just received a call from Maintenance Control Centre informing you about a defect on aircraft on which you have been deputed to work on. What general steps will you take to troubleshoot the fault?

(Note: Write Your answer in the comment section below)

Comments

  1. One of the factors in maintenance efficiency is the initial fault diagnosis, generally known as troubleshooting.

    Information collection: you should obtain all the relevant information concerning the defect and the circumstances in which it occurred. If you checked the aircraft before you should check the technical log book to see if the same problem has occurred or a new problem has arisen.

    Initial examination: first we should become familiar with location, form and extent of the damage and to see if the functional tests can be performed. You should find the cause of the defect and if it has any effect on other components.

    Further examination: examine the remaining possible causes of the defects and using functional check to select most probable causes.

    Rectification: commence rectification of the defect and and always keep a record of action taken and its result in the technical log book.

    Post rectification testing: after the rectification has been done check if the problem has been solved or if a new problem might have arisen because of the previous rectification.

    The examination and rectification should be done according to the relevant maintenance manual.

    ReplyDelete
  2. Following steps should be taken to diagnose the fault
    .Information Collection
    The starting point of information collection is the technical log book. In technical log book all the defects which are pending or occur during the flight is written. During information collection when you go for verbal and document investigation you will know about the further and specific defect which occur on the aircraft.
    .Initial examination
    In initial examination engineer must familiar with the location, form and extent of damage.To establish the par-actability of functional checks and to find the cause and effects of the more obvious types of defects.
    Further examination
    In further examination we in go detailed study of the defect that how this defect occurs what could be the reason causing this defect and what else can we do to remove this defect and that it will not face by the pilot in next flight operation.
    Rectification
    In rectification we will remove the defect or the system which will require to be change must be change but when we are performing this task all the data should be recorded.while recording we will give the precise details of the components which are changed on the aircraft and also written the next serviceability of that component.
    Post rectification testing
    A functional test must be carried out on the completion of rectification will prove in the effectiveness and efficiency of the rectification that is done on the aircraft.
    Appropriate procedures can be follow by concerning the AMM.

    ReplyDelete
  3. To sort out the fault in the aircraft while inspection to check that where is problem is called troubleshooting.
    It takes five steps which are
    INFORMATION COLLECTION
    In this we collect the information of the defect like intensity through pilot ,logbook act.
    INITIAL EXAMINATION
    In this step we check the causes of the defects why this happen also examine whether it occur first time or many times.
    FURTHUR EXAMINAMINATION
    In this we concern that what remaining possinlefault can occur and also functioning test also perform to check furthur fault and concern the troubleshooting flow chart for the regularity of the procedure.
    RECTIFICATION
    In this we check the fault that we examine in the furtur examine and keeps the record of this.
    POST RECTIFICATION
    When the defect is removed then we thoroughly function the whole system to check the accuracy of the parts .
    The whole procedure is done by proper pattern accordingly AMM.
    Subyal Ahmed.

    ReplyDelete
  4. Muhammad Hamza Ahmed

    Factors in which maintenance efficiency is the initial fault diagnosis, generally known as troubleshooting.

    Information Collection
    A Check should be made if the defect has been previously occured or the defect is new.
    before you check the aircraft you should check the technical log book to see if the same problem has occurred or a new problem has arisen

    Initial examination : in this examination we will do the practicability of functional checks and we will find the cause and effects of the more obvious types of defects and also we check the extent of the damage.


    Further Examination
    We will examine the remaining possible causes of the defects and using functional check to select most probable causes.
    That how does the damage occured then we will compare it then we will assume what could be the reason and lastly we will assume what else could be the reason of the damage
    Rectification: In rectification we will replace the damaged components
    POST RECTIFICATION TESTING
    A functional test carried out on the completion of rectification will prove in a practical sense the effectiveness and efficiency of the rectifiation been carried out.
    All faults arising from functional tests or test flights must be entered in the appropriate log book for subsequenr fault diagnosis and rectification.

    ReplyDelete
  5. Troubleshooting is done according to aircraft maintenance manual. The some procedures of troubleshooting are given below.
    .First we collect information about the defect.The technical log entry is enough for provide information and then find the cause of the object or more obvious types of defects sometimes defect occurs due to other equipment obvious defect at the time of work be careful not hasty conclusions and undertake a rectification program.The functional check can be performed without damage to aircraft.Before internal functioning defects first important thing we known how each component operates when it is serviceable condition.In rectification when components installed or removed must be written in log book in precise manner and detail component name, number and which work is done on aircraft. After the rectification functional test carried out.All fault occurred from functional tests or test flight must be entered in appropriate log book for diagnosis the rectification.
    All troubleshooting must be done according to AMM.

    ReplyDelete
  6. There are few trouble shooting techniques which has to be carried out when diagnosing a problem.

    There are 5 steps from which we can diagnose a problem through trouble shooting.

    COLLECTING INFORMATION ABOUT THE DEFECTS
    We havd to start the diagnosis from the point at which the aircraft became unserviceable, a check would be required to see if there were same defects before. We should note every detail in the technical log book.
    The techincal log entry would not be enough to provide us with all the information. We'll have to see if the problem arised during flight or did something tend to happen on the ground, if it happened during flight we'll take further flying information e.g altitude, speed etc. Secondly we'll have to check if something happened during testing or normal operation, we'll also have to check what corrective actions were taken when this problem arrived and that if functional test can be carried out or not.

    INITIAL EXAMINATION
    Initial examination should be done become familiar with location,form and extent of the damage, to establish the practicability of functional checks and to find cause and effects of more obvious types of defects. Not all steps should be followed under 'INFORMATION COLLECTION'.

    FURTHER EXAMINATION
    Further examination is aimed at proving or disproving the theories that were formed of the cause and nature of the faults within a system or mechanism. Form of examination will be governed by the type, location and form of the defect which requires rectification.

    RECTIFICATION
    We should keep record of all work espicially when it is long and has a lot of detail in it. Cross refrence method should be applied and precise detail of components should be given mainly of their lives and serial number. Trade responsibility should be dealt seprately but each entry should refer to the task.

    POST RECTIFICATION TESTING
    At last a post rectification testing should be carried out which will tell if we have the procedure we have done is correct or not.

    We should follow the required procedure given in the appropriate AMM

    ReplyDelete
  7. Generally all in inspection for any problem is done according to the Relevant AMM however the following steps should be Followed for any trouble shooting.

    Information collection:
    The initial step for trouble shooting is to collect all the possible data regarding the defect. The data can be collected from technical log book, pilot. The previous rectification carried out on the defect is mentioned in the technical log book also provide information about the current defect.

    Initial Examination:
    As the type of defect is known now we should localize the cause of defect by finding the location and from,extent of the defects. Finds if any need for functional test. And To find the cause and effects of more obvious types of defects.

    Further Examination:
    Examine the remaining possible causes of the defect or do functional Checks if needed. This Examination will prove the that the initial Examination was right or wrong.

    Rectification:
    As the detected component is know now the rectification commences and the component is replaced but it should be assured that a complete record of the work and their result should be kept.

    Post Rectification Testing:
    The whole system should be functional tested specially the component replaced which ensures that another defect is not arisen due to the previous rectification.

    All the Procedure regarding the inspection should be followed according to the Relevant AMM.




    ReplyDelete
  8. Trouble shooting is the process of analyzing and making corrective actions for the faults in the aircraft.

    STEPS FOR TROUBLE SHOOTING PROCESS:
    TO make any corrective actions for anything first we have to read about that actions which we have to take.So first step is the information collection in which we have to take information about that problem. The information should be taken verbally and by checking the documents.The second step is to take initial coreective actions and to questions with yourself about that problem that it will not have any impact on any other object or any other things. The third step will be the further examintaion. It will give us information about the type of the problem which is on the aircraft and it also gives us the information about the location of the default etc. We will also see the AMM for the corrective action of the defect.Next step is the rectification step in that step we will change the component which is defected and in last step we will do the functional check of that component which is changed.
    We will also consult the AMM when we are taking corrective actions.

    ReplyDelete
  9. Inspection procedures are made to make the aircraft ground time for maintenance minimum. That’s why preference should be given to the following procedures.
    Information collection:
    Information should be collected about the component that failed and also about the condition in which it failed, attitude, altitude and all the relevant conditions.
    The relevant person should be asked about the component wether it failed suddenly or it build up gradually?
    Did it fail to operate when relevant switch was activated or any other system had an effect on its operation when they were activated?.
    Initial Inspection:
    The defect should be localised to a specific area by implementing the equipment information or the experience.
    The extent of damage, location and cause should be inspected and known. The applicability of the functionality test should be accessed. The cause and the extent of the damage of the most probable defects. The rectification procedure should not be started on the first attempt because it is not that simple as it look. The situation must be accessed first.
    Further examination:
    Further examination involves the rectification of the residual defects left. There are some steps that should be done, that include what is the normal operating properties of a system and how it operates. Then to know, What could have caused it to work like it is working now, and to know how it should work normally. Then it should be compared. Then it should be known what else could have caused it, the thing that is not expected to interfere with the equipment normally.
    Rectification:
    Rectification involves the step to rectify the component, and all the step taken should be noted in a technical logbook.
    Post Rectification:
    Post rectification involves the complete functional test of the system or mechanical part that was defective.
    All the inspection procedures are written in the relevant AMM and should be consulted. Any slackness can result in a devastating event.

    ReplyDelete
  10. Trouble shooting it the systematic search for the source of a problem in order to solve it, and make the product operational again.
    As someone in on the specific aircraft as he recieved call from the maintenance control center informing about the defects on that aircraft. There are five method for diagnosing a fault in the aircraft.
    Information collection is the first method of diagnosing a fault in an aircraft as it is the starting point for collecting information from the pilots crew or tech log book it should be of verbal or by documents and the check should be made for the previous defects.
    Second step is the ini initial examination as it the method in which we visualise the defects and it examine it . In this step we should have to find the location to established the functional checks and also to find tha cause if the defect.
    Third step is the further examination of the defects as in step the examination has to be done to prove or disprove the initial theories to find the nature of the fault. In step de tak comparisons are made. In further examination we should consult the trouble shooting manual.
    Rectification is the process to rectify the fault occur in the aircraft. In this progress it is essential to keep the record of all the work carried out. It gives precise details of the component lives and serial numbers.
    Fifth and the last step for diagnosing aircraft fault is the post rectification testing as it is carried out at the completion of the rectification and will the efficiency and effectiveness of the rectification that has been carried out.
    Best safety precautions has to be taken by qualified maintenance personnel’s while trouble shooting of the aircraft after concerning the relevant maintenance manual.

    ReplyDelete
  11. Dignosing the problem and finding the errors and inspect these foult is the process called trouble shooting.

    We need to start the inspections by collecting all the information about the diffects we need to consult with the pilot and we need to check with the log book and also knowing what is the cause of diffect.we have to check that functional test will be performed or not .
    Then we have to examine that the following surface that what type of damage is occour then we need to check which type of damage is it and what is it's cause .
    We need to check that the damage is caused by the nature like lightning strike or bird strike or it is the machnism fault.
    Then we have to rectify by making record of every task giving all the details like serial numbers
    After doing this all we can functional test of all check-in all that all work is done properly or not .we need to clear all the things .
    We should be follow all the thing according to given maintanance manual.

    Zohaib

    ReplyDelete
  12. One of the factors governing maintenance efficiency is the initial fault diagnosis generally known as trouble shooting.

    There are five basic steps:
    1-Information collection:we should obtain the all reletive information on the defect and circumstances in which it occurred.If we checked the aircraft you should check the technical log book to see if the same problem has occurred and arisen the new problem.

    2-In initial examination :engineer must familiar with the location, form and extent of damage.To establish the par-actability of functional checks and to find the cause and effects.

    3-Further examination: we should examine detailed study of the defect that how this defect occurs what could be the reason causing this defect and what else can we do to remove this defect and that it will not face by the pilot in next flight operation.

    4-Rectification: In this we check the fault that we examine in the furtur examine and keeps the record of this.

    4-Post Rectification testing: When the defect is removed then we thoroughly function the whole system to check the accuracy of the parts.

    Examination and rectification should be done according to the AMM.

    ReplyDelete
  13. Trouble shooting One of the factors governing maintenance efficiency is the initial fault diagnosis.

    Information collection: Information collection is one the steps to be followed when diagnosing a fault.

    The starting point for gathering informatiob about the defect is technical log book entry.The aircraft technician should take a look at the technical log for previously made findings and rectification. AME should look into the log book and find out if the fault occured during the flight or when the aircraft was at the ground, if it happend during flight check for altitude ,speed , attitude details when the defect occured.
    Also AME should look into that if the fault occured during any testing or normal flight and if the fault occured all of a sudden or did it occured with the passage of time.

    Initial Examination: Initial examination is about to become familiar with location , type of defect and how much is the damage.And to find out cause of the obvious type of damages.
    Checks should be made on
    Fluid systems, Mechanisms including fluid system mechanical components,static Assemblies,Rotary Assemblies.

    Further Examination: This examination is usually aimed to testify the intial findings made about the cause and reason of the faults in system.
    The sequence of the examination should be as follows.
    Obtain physical performance data.what should and what does occur in the system or mechanism.
    What could cause the difference between how it should work and how it does work.
    What else could cause the difference between how it should work and how it actually works.

    Rectification: It is important to keep the record of all the previous work done, if the work is long and detailed.
    Following function should be made in rectification.
    Look into the details of work done and their separate entries on one type of work done.
    Proper details of components should be made and their seriel numbers. It cab help in ivestigation incase of any accident.
    Unserviceability can occur arising from the work it should be mentioned as a subject in the log book.
    Every type of rectification should be done separately , it should not be off the track from the orignal task.

    5.Post Rectification testing: After rectification and practical work done functional test is very important as it proves the efficiency of work done.


    If any fault or defect happens during the functional test it should be mentioned in log book appropriatly.

    ReplyDelete
  14. Most aircraft maintenance manuals have troubleshooting sections, which guide the technician through the logical and best faultfinding.

    more practical way of solving the problem is a follows:
    1. Information collection is first step - obtain all relevant information on defect and the situation in which it occurred. The more information we have more accurate the work. Read the aircraft technical logbook and history.

    2. Initial examination –confined to a small area of the defect as possible as visual examination and required tool for execution of defect.

    3. Further examination – examination of the remaining possible reasons of the defects and using functional test wherever possible. By following the trouble shooting flow chart in relevant AMM.

    4. Rectification – the execution of the defect always keep the concise record of the action taken and their result.

    5. Post Rectification Testing. The functional test of the whole system to confirm that there is no any other defect arisen.
    all action must be taken according to relevant AMM safety precautions.

    ReplyDelete

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