4. FSTD Maintenance - Scheduled


This section of the manual is dedicated to establishing a comprehensive guideline for the maintenance of an FSTD. The guidelines provided herein are designed to meet and exceed the standards set forth by regulatory authorities to form a maintenance protocol ensuring that an FSTD can consistently provide an accurate and ensure the highest standards of training by maintained with increased reliability.

On a broad range, maintenance in ACAT is planned in two main categories as listed below,

    1. Scheduled Maintenance
    2. Unscheduled Maintenance


Scheduled Maintenance is a systematic approach to ensure devices are consistently operational and functioning at their optimal capacity thus reducing the breakdown or interruptions and prolonging device operational efficacy. The scheduled maintenance is further categorised into,

    1. Preventive Maintenance
    2. Pre-flight Check
    3. Qualification test Guide
    4. Objective Evaluation
    5. Subjective Evaluation
    6. Database update & Backup


  1. Preventive maintenance program forms the basis of our scheduled maintenance. It is a list of tasks derived from the maintenance advisory issued by the specific device TDM and tailored by ACAT engineers accumulated experience. It also includes checks for safety-related aspects of the training device, ensuring comprehensive maintenance on safety equipment and systems of an FSTD.
  2. A task list for preventive maintenance is formulated, detailing the frequency of each task as per the manufacturer's instructions for the training device. This list is further enhanced with additional maintenance items specific to the device, derived from our accumulated experience. It also includes checks for safety-related aspects of the training device, ensuring comprehensive maintenance coverage. The tasks will be specific to FSTD model and TDM.
  3. A Preventive Maintenance Workbook shall be maintained to record and document all the maintenance activities carried out in an FSTD and shall be specific to each FSTD.
  4. All the Preventive Maintenance Tasks (PMT) shall be accompanied with a procedure or work instructions guiding to accomplish a specific task. Each task shall be identified by an ID and may be a tentative time and workforce required for optimal execution.
  5. Any engineering personnel executing a PMT shall be authorised by the Technical Manager in prior for the category as per the section 8 of this document.
  6. The workbook shall be logged with following details,
    1. Task ID
    2. Task Description
    3. Initials / signature of the engineering personnel performing task.
    4. Date of the task performed.
    5. Remarks (optional)


  1. The Technical Manager (TM) or an assigned delegate shall establish a preventive maintenance plan for each training device and say shall be informed to scheduling for maintenance slot booking.
  2. PMTs are typically carried out during maintenance periods. If additional time is required, the scheduling shall be informed in prior, and an additional time shall be scheduled for maintenance.
  3. The engineering personnel performing these tasks, shall ensure that each step is completed thoroughly and conduct checks for the serviceability of the FSTD. Upon completion of maintenance tasks, the details are documented and signed off in the PMT Workbook.
  4. A designated Engineering personnel may review the completed preventive maintenance checklists if required. This review process is to confirm that all tasks were executed as planned, with the reviewer providing a final sign-off on the tasks.
  5. Weekly servicing tasks should be completed within two days of their due date. For monthly and longer servicing cycles, tasks should be finished within 10% of the allotted cycle time. Examples as below,
    1. Monthly = 3 days (28*10%)
    2. Quarterly = 9 days (92*10%)
    3. Half yearly = 18 days (180*10%)
    4. Yearly = 37 days (364*10%)
    5. Biennial = 73 days (728*10%)
    6. Triennial = 109 days (1092*10%)
    7. Quadrennial = 146 days (1456*10%)
    8. Quinquennial = 180 days (1820*10%)
  6. any instance where preventive maintenance tasks are not completed within the scheduled time, they are promptly rescheduled for the next available maintenance slot to ensures that the maintenance do not lag and FSTD remains in optimal working condition.
  7. If next available maintenance slot is not with in tolerance timeline or the task are not completed for any other reasons, that specific preventive task shall be considered as a corrective maintenance and tracked as in section 4.2 of this document. Any incomplete PMT shall be informed to TM or TM delegate.
  8. Regular analysis and adjustments shall be made to the PMT activities based on their effectiveness. Any changes or updates to the maintenance procedures are reflected in the corresponding forms and documents, which are kept up-to-date and under revision control as per section document management of this document.

A diagram of a work flow Description automatically generated


  1. Prior to every 24-hour operational period of an FSTD, engineering personnel must conduct a functional pre-flight check (PFC).On completion of PFC, it shall be recorded in a manner that is retrievable. No user shall be allowed for any type of training, check or evaluation without an engineering personnel completing PFC.
  2. Each successful PFC must be recorded by the engineering personnel conducting the functional check and any discrepancy found during the check shall be treated a corrective maintenance as mentioned in section 4.2 unscheduled maintenance of this document unless it satisfies the conditions overlayed in point 3 of this para 4.1.2.
  3. It shall not be considered as an unscheduled or corrective maintenance if the action taken to resolve the discrepancy satisfies the below conditions,
      1. If the discrepancy is rectified within the check period.
      2. If the discrepancy resolution does not need any part replacement.
      3. If the discrepancy is not affecting any QPS or safety features and equipment of an FSTD.
  4. PFC checklist is integrated as a part of daily maintenance task and considered as a routine scheduled maintenance. A dedicated PMT work instruction or procedure shall be accommodated for the checks that need to perform during the PFC.


Qualification Test Guide is a detailed specification and benchmark that an FSTD must meet to maintain its qualification status. It serves as a comprehensive guide for evaluating the performance and accuracy of an FSTD. The QTG is pivotal in ensuring that the simulator meets the specific standards and criteria set by regulatory authorities.

"It is a process of evaluating an FSTD performance to prove that it is capable enough to replicate the certification characteristics of a specific type of aircraft accurately, ensuring that all applicable regulatory requirements have been met."

These tests are used not only for initial qualification of the simulator but also for periodic recurrent evaluation, ensuring ongoing compliance with evolving standards and technological advancements. QTG is a fundamental tool in an FSTD's lifecycle, guiding the maintenance of high-quality standards in simulation training by providing a structured framework for performance evaluation and certification.

QTG can be classified into FOUR main categories.

    1. Validation Data Roadmap
    2. Objective Test Evaluation
    3. Subjective Test Evaluation
    4. Statement of compliance


Validation Data Roadmap (VDR) is a guide for Validation Source Data provided by the aircraft manufacturer to the TDM and authority. This data is specific to the aircraft model and overlays an overall guidance with the rationales and recommendations on the tests to be executed on an FSTD to evaluate the flight characteristics through the usage of Validation Source Data.

The MQTG shall be accompanied by the VDR guidelines over the appropriate flight test data that to be utilized in the QTG to ensures that the evaluation criteria are met in assessing the FSTD. The VDR includes rationales and statements from the TDM which support the alignment of FSTD results with actual flight test data.


Objective tests are a quantitative assessment of an FSTD to demonstrate that the performance and handling qualities an FSTD are complying within the prescribed limits with the help of tests performed through software tool. It is a process of creating objective evidence to compare with the Flight Manufacturer Data to evaluate an FSTD characteristics. These tests will be overlayed by the regulatory authorities specific to the Qualification Performance Standards.

    1. These tests must be conducted at least once every 12 months. The tests shall be divided into four parts, evenly distributed over each quarter of the year.
    2. The Master QTG binders must be maintained in their original condition throughout lifetime of the device.
    3. Alterations or removal of tests shall not be done without a prior approval from the qualifying authority.
    4. All modifications, regardless of their complexity, must be recorded in the MQTG Revision History to have a comprehensive log, detailing the date of change, the reason for it, and any pages added or removed.
    5. The Technical Manager is responsible for overseeing the tracking and updating of the MQTG.


  1. Each quarter test list will be further organised in a best possible way to include at least one test from each aircraft profile/system,to ensure that each quarter all the FSTD characteristics will be evaluated and early addressing over any degradation or variation.
  2. "For instance, if a test labelled 1.C comprises four subsets ranging from 1.C.1 to 1.C.4, it will be divided such that each quarter addresses one subset of 1.C. This distribution is strategically planned to facilitate timely detection of any variations or anomalies in an FSTD's."

  3. The Objective test are specific to an FSTD QPS level and applicable based on the initial evaluation. Each FSTD shall accompanied with its own FSTD test plans for the recurrent QTG runs.
  4. A work book shall be maintained to record the test status and validation details shall be maintained. This record must contain the test schedules for all the four quarters. This record must contain the validation status and the details of all the validating personnel.
  5. Once the test plan for the year is finalised, it shall be published to all the team members of the Engineering department and the test must be conducted at least once with in that listed quarter and the validated results should be saved.
  6. If additional time is required for the objective test to be completed, it shall be informed to the scheduling department for booking the slot as maintenance time.
  7. The tests shall be validated and approved only by the authorised personnel as decided by the TM and the validation must be done on the same pertaining quarter.
  8. On validation two scenarios may rise PASS or FAIL, further proceedings shall be done according to the validation results as follows,
    1. 1) PASS
      1. If the test pass in the validation, document it by logging in the test record mentioning its validation status, signature of the person validating along with the date of validation.
      2. The hard copy and the soft copy of the results shall be documented in respective binder and repository of the specific quarter.
      3. The validation status of the result shall be logged in first page either on hard copy or soft copy, but both copies must be identical.
      4. All the PASS results shall be further validated by QTG supervisor with in one subsequent quarter and after the end of FSTD year, random 10% of results shall be validated by TM. Same shall be documented in the workbook with date and signature.
      2) FAIL
      1. If the test FAILs, the validation or due to unforeseen circumstances or any test left unaccomplished with in the timeframe will be considered as a corrective maintenance as per section 4.2 of this document.
      2. The QTG Caretaker shall then decide to log a DR may be in consideration with the senior engineering personnel for final decision.
      3. The Failed test results must be documented, and the workbook should be logged with the info of FAILED status, DR details, signature of the person validating along with the date.
      4. The test validation status shall be logged either in soft or hard copy, but both copies must be identical.
      5. From this point the failed test will be considered as a corrective maintenance and followed in the Discrepancy Management system. No re-run results are required to be stored.
      6. When a QTG is failed, it shall be considered as MMI in consideration with HoT as described in the section 4.2.1.a of this manual, unless the deviated condition is not affecting the QPS of the device and its performance and handling qualities.


  1. Subjective tests are a qualitative assessment done by a type rated pilot based on his/her experience and expert judgement on the FSTD performance over various manoeuvres and handlings. In this assessment various flight system's normal and abnormal behaviours in various flight profiles will be tested.
  2. All systems of an FSTD including motion response, visual scene quality, sound feel, the aircraft replication including cockpit environment and the instructor station capability for approved training to be conducted shall be subjectively assessed. All the subjective test should be conduted at least once in every 12 months by a type rated pilot.
  3. Atleast one DGCA approved training must be conducted in every 12 months, if not performed, a writtern statement must be obtained on the performance & handling qualities of the FSTD from a qualified pilot who has flown the type aircraft on preceding 12 months.


  1. A subjective test checklist shall be established to conduct the assessments all the applicable test every 12 months by a pilot. Any revisions or changes to this list shall be logged in the document control tracker. These tests are specific to the FSTD QPS, and the checklist may listed only with applicable test for that QPS.
  2. A yearly plan shall be established and informed to the scheduling for blocking the slots and pilot availablity for the assessment.
  3. The assessment shall be conducted with an engineering personnel who will responsible only for techical assistance. A training log shall be accompanied for the assessment.
  4. During the flyout any open DR pending which are required to have more piloting insights may be checked. Any dicrepancy observed during the flyout shall be recorded and DR must be logged and treated as a corrective maintenance.
  5. The evaluation pilot and engineering personnel should document the assessment with date and signature along with their identifications.
  6. The subject test check may preferably conducted on last month of the quarter, so any discrepancy recorded during the quarter or any failing objective test can be assessed subjectively over the effect on handling and performance characteristics.



To be in similarity to the real-world changes, FTSD database shall be updated periodically or on requirement basis. The data bases include,

1 Navigation database User 28 days
(with minimum 3 airports)
2 PERF database User Requirement Basis
3 GSD Database In-house 180 Days or certified
airport changes
4 Terrain database In-house Requirement or certified
airport changes
5 AMI Data User Requirement Basis

These databases will be updated in best feasible way and except NavDB, any update to these databases shall be documented.


  1. The visual database shall be updated to maintain the simulator visuals, reflecting the changes made to the aerodromes over time.
  2. With compliance to OC 15/2014 any permanent changes to the real-world scenario in a certified airport, it shall be reflected in the FTSD visual scene as per below points.
    1. For a new airport runway, a runway extension, a new airport taxiway, a taxiway extension, or a runway/taxiway closure - within 90 days from the implementation.
    2. For a new or modified approach light system - within 45 days of the activation of the new or modified approach light system.
    3. For other facility or structural changes on the airport (e.g., new terminal, relocation of Air Traffic Control Tower) - within 180 days of the opening of the new or changed facility or structure.
    4. Any delay in update shall be informed to authority in prior and without a written extension grant from the DGCA, FSTD shall not be used for DGCA accredited training.
    5. INTEGRATION OF VISUAL UPDATES shall be carried out in as per TDM guidelines.


  1. All servers must have atleast one set of backup on all software aspect post Initial evaluation and a set of backups for the main computers pre and post every software load update.
  2. Servers which are critical and predicted to have frequent failures may be scheduled to have a periodical back up to endure continual operation.
  3. The backup procedure and process will be carried out as advised by the TDM or as decided by the TM. All backups shall be documented by the engineering personnel who completes the backup in a work book or a dedicated electronic establishment.