Saturday, December 30, 2023

 

DDPMAS 2021

 Indian Military Airworthiness and Certification Document

(DDPMAS 2021 Supersedes DDPMAS 2002)

 

Kanchan Biswas

Former Director (Aircraft), CEMILAC, DRDO

(+ 91 9448376835, kanchan.biswas@rediffmail.com)

 

Abstract

Indian Military Airworthiness procedural document DDPMAS has gone through its third edition in 2021. DDPMAS 2021 supersedes DDPMAS 2002 which had superseded the original document DDPMAS-75. Unlike its previous versions, the DDPMAS 2021 is in three volumes, namely, ‘DDPMAS Framework’, ‘IMTAR’ (Indian Military Technical Airworthiness Requirements) and ‘Forms and Formats’. While the Frameworks gives the overall military airworthiness policies and guidelines, the detail procedures are dealt in IMTAR. The third document, the ‘Forms and Format’ gives the forms and templates to be used during airworthiness evaluations. This paper briefly discusses the changes and improvements that have been made in the policies and approach in military airworthiness and certifications as indicated in DDPMAS Framework.

 

Keywords: DDPMAS, Airworthiness, IMTAR, Air System, Airborne Stores and MTC


1.       MILITARY AIRWORTHINESS IN INDIA

Military Aviation industry in India traces its roots to the pioneering efforts of late Seth Walchand Hirachand, who set up HAL (Hindustan Aircraft Limited) at Bangalore in association with the erstwhile princely State of Mysore in December 1940. HAL was set up for overhauling US Air Force aircraft. The Government of India became a shareholder in March 1941 and took over the Management in 1942. Though HAL had primary focus on meeting military aircraft requirements, it had also a limited role in civil aircraft production of transport aircraft and Helicopter under license for airlines and state governments [1].

Aircraft D&D (Design and Development) activities started with the HT-2 basic trainer aircraft project for the Indian Air Force in 1953. In the absence of any military airworthiness agency, certification and quality assurance activities were entrusted to DGCA. In view of the increased design and modification activities taken up in the country, Ministry of Defence, Govt of India formed ‘Directorate of Technical Development and Production (DTD&P(Air)) in the year 1958 within the premises of HAL, structured similar to the British Airworthiness Groups to look after the Military Aircraft Airworthiness & Certification aspects including Overseeing of inspection. Later in 1960, the Design and Inspection related functions were separated and entrusted to Chief Resident Engineer(CRE) and Chief Resident Inspector(CRI) respectively. In the year 1968, the CRE`s were brought under the functional and administrative control of DRDO reporting to Director of Aeronautics. In 1995, all the CREs were brought under one umbrella CEMILAC (Center for Military Airworthiness and Certification) to consolidate Military airworthiness and certification [1].


1.1 DDPMAS - 2021

The experiences of CREs in certifying a wide variety of aircraft and equipment were consolidated into a document called procedure for ‘Design Development and Production of Military Airborne Stores’. The document (Shot titles: DDPMAS-75) was issued on 30th October 1975 by the Ministry of Defence as a mandatory requirement to be followed by the Certification authorities, Quality Assurance Personnel, Users, Designers, Production Agencies and Private companies.

The document was reviewed and reissued on 17 May 2002 as DDPMAS-2002 superseding DDPMAS-75. DDPMAS 2002 had two volumes, wherein volume 2 was exclusively for Airborne Software certification [2]. The latest version DDPMAS 2021 was released on 03 Feb 2021 under signatures of Secretary Defence Production and secretary Defence R&D, Ministry of Defence, Gov. of India [3]. DDPMAS 2021 is a three tier document as shown in figure 1.  



                                       Figure.1 – Hierarchy of DDPMAS 2021 Documents

2. SALIENT FEATURES OF DDPMAS 2021

While the basic ethos and spirit of airworthiness assurance have remained the same, DDPMAS 2021 encompasses wider aerospace domain and is interactive with modern technological changes. The document is also more elaborative in application procedures for different aerospace products and airworthiness functions.  However, due to this elaborative nature, the document DDPMAS 2021 is more voluminous compared to its previous variants. Some of the salient features of DDPMAS-2021 are discussed below.

2.1 Similarity with CAR 21

DDPMAS 2021 shows significant alignment towards the civil certification procedure FAR 21 (Federal Aviation Regulation Part 21 equivalent to Indian Civil Aviation Regulation part 21) [4]. These include organization approvals viz. Design Organisation Approval (DOA), Production Organisation Approval (POA) and Maintenance Organization Approvals (MOA) under the Organization Approval Scheme. However, the privileges enjoyed by the approved orgnisations, their responsibilities and organization monitoring processes are at variance at some places as compared to CAR-21 procedures.

2.2 Air System

The terms ‘Aircraft’ as used in DDPMAS 75 and 2002 has been replaced by ‘Air System’ in the DDPMAS 2021. An air system may represent an Aircraft (manned, unmanned and rotary wing), an Aero Engine or an Air Launched Missile (ALM) for which MTC (Military Type certificate) may be issued.

2.3 Instruments of Technical Airworthiness Approval                                                                          

Only air systems are issued with MTC or Restricted MTC. All other items including the propeller and Air Armaments are considered ‘Air Borne Stores’ for which issue of type approval is recommended. Other approval categories include IMATSOA and LOTA.

1) IMATSOA – ‘Indian Military Aviation Technical Standard Order Approval’ will be issued for items having generalized specification like ‘Indian Military Aviation Technical Standard Order’ once they are found to meet the standard order. This clearance is similar to ‘TSO authorization’ in civil aviation airworthiness clearances. 

2)  LoTA – ‘Letter of Technical Approval’ is similar to the term ‘LoTA’ used by FAA for items which do not merit approvals under other categories of ‘Type Approval’ or ‘IMATSOA’. As per DDPMAS-2021, Airborne Stores such as materials, electronic modules and finished parts may be issued with LoTA.

3) TA/PC - Type Approvals (TA) are issued to Airborne Stores which are specific/custom designed for use in any Air System and which are not covered by the above two categories. An initial approval called ‘Provisional Clearance’ (PC) may be issued by one of the RCMAs (regional offices of CEMILAC). The PC on a later date is converted to TA by CEMILAC corporate office. 

4) BOI Clearance – Bought Out Items from abroad fall under this category.  

2.4 Airworthiness Certification Plan (ACP)

The concept of ACP has been brought in DDPMAS 21. ACP is a document that brings out the details towards compliance to the agreed TCB (Type Certification Basis) of an Air System. For an Airborne Store, the ACP shall indicate the details of compliance of TAB (Type Approval Basis). For both Air System and Airborne Stores, the ACP shall clearly bring out the level and stage of involvement of TAA and other stakeholders at various stages of the development phases.

 

2.5 Quality Assurance Plan (QAP)

QAP is a document that details the quality assurance related activities through all phases of the design & development, production and maintenance of the Air System and Airborne Stores with the involvement of DGAQA or the QA departments of the Main Contractor/User Services.

 

2.6 Mutual Recognition

DDPMAS-2021 proposes a concept of mutual recognitions with certification agencies of other countries in a unilateral, bilateral or multilateral mode for products taken under joint ventures or consortium, with distinct work packages, for application by the Indian User Services or Govt of India. This will help export of indigenously developed military air system/airborne stores. Further, when civil certified aircraft are bought for military use, CEMILAC certification can be utilized for any modifications/system adaptations carried out on these aircraft on a later date.  


2.7 Export of Indigenously developed Air System/Airborne Stores

CEMILAC may support certification of indigenously developed Air System/Airborne Stores for exports from India to another country. However, MoD approval will be necessary for the export of indigenously developed military products. The certification procedure will follow the routes of ‘Ab-Initio Development and Production of Air Systems & Airborne Stores’ to obtain approval from TAA (CEMILAC & DGAQA) to facilitate exports.


2.8 Use of Civil Certified Aircraft in Military Applications

An aircraft Type Certified by the Civil Certification agency of India or the country of origin may be inducted for Military service use. The air system shall be operated and maintained by the User Services as per the documentations provided by the OEM. The user services shall also comply with all Modifications and Service Bulletins issued by the OEM from time to time. Any Airworthiness Directives issued by the regulating agencies of the country shall also be complied with by the user Services.

Post Induction, however, for any Modification and System Integration/Upgrades, any of the following routes may be adopted:

a) If the OEM carries out the new system integration/Upgrade and the Civil Certification agency of the country of origin provides certification coverage and issue necessary Supplemental Type Certification (STC) /or equivalent for the modified aircraft, the same shall be accepted.

b) If there is no provision for the Civil Certification agency of the country of origin to provide coverage for the military modifications, either the Military Certification agency of the country of origin or the Indian TAA shall be involved in the certification of the modified aircraft. Necessary MoU shall be signed between the stakeholders in this regard. Mutual recognition of TAA with the military certification/QA agencies of other countries will help in expediting the certification activities.

c)   If the modification/Upgrade is carried out post induction of the Air System by any agency other than the OEM, Indian TAA shall provide airworthiness and certification coverage as per provisions of ‘Continuing and Continued Airworthiness Procedures’ given in DDPMAS – 2021.

 

2.9 Accepted Means of Compliance (AMC)

AMC represents the preferred means by which the Technical Airworthiness Authorities (TAA) expect the intended requirement / criteria to be met. In the IMTAR – 21, AMC for every airworthiness functions/activities have been indicated.  


3.       INDIAN MILITARY AVIATION

3.1 Airworthiness Functions

Airworthiness Functions span from the initial airworthiness till the aviation machine retires. However, the function and involvement of the stake holders vary depending on the operational state of the equipment. They can be broadly discussed under three headings:

a)     Initial Airworthiness - The Design and Development of a new Air System product/Airborne Store leading to issue of type certification or type approval.

b)     Continued Airworthiness – All airworthiness activities post initial certification, related to design modification/system upgrade, Defect and accident investigation and carrying out design improvement to avoid future recurrence, aircraft/airborne store life assessment and deviation assessment during the production phase fall under the gamut of continued airworthiness.

c)  Continuing Airworthiness – Carrying out Schedule maintenance, Daily Inspections and incorporating airworthiness directives, in-service technical instructions etc. are considered as continuing airworthiness activities.

The details of the airworthiness functions are shown in figure 2. 

Figure 2. Military Airworthiness Functions 

3.2 Indian Military Aviation-Stake Holders

Indian Military Aviation stake holder can be broadly divided into –

a)     a)  Indian Military Airworthiness Authorities (IMAA) as Regulators and

b)     b) The Regulatees (parties subjected to regulations) includes D&D, Production and Repair and Overhaul agencies.  

DRDO undertakes design & development of military aviation air systems and Airborne stores. The SHQs (Services Headquarters) carries out continuing airworthiness and operational airworthiness activities for military air systems and airborne stores. Thus, DRDO and SHQs fall under both categories of regulators and regulates. as they are involved in both regulatory as well as regulatees functions.

The details of airworthiness stake holders along with their functions are shown in figure 3.



                    Figure 3. Indian Military Aviation Stake Holders - Roles & Responsibilities 


3.3 Organisational Approvals

To ensure that, the organisations taking up design, development, production and maintenance of Air Systems/Airborne Stores, possesses the requisite capabilities and infrastructures to undertake such activities, organisational approval schemes are established. Three types of organisation approval schemes are provisioned.

a)     Design Organisation Approval Scheme (DOAS) - An organisation involved in or intended to take up design and development activities of military Air Systems and Airborne Stores shall be assessed for DO Approval. 

b)     Production Organisation Approval Scheme (POAS) -  An organisations involved in production of Air Systems and Airborne Stores shall be assessed through a POAS.  

c)   Maintenance Organisation Approval Scheme (MOAS) – An organisations involved in maintenance of Air Systems and Airborne Stores shall be assessed through MOAS.

The approval schemes are to ensure that the organizations taking up D&D, Production or maintenance activities possess requite infrastructure, manpower and capabilities to carry out necessary activities. The technical, infrastructure as well as the manpower requirements will vary according to the type of the organization. Further, within the design organisations, the approval may be for ASDO (Air System Design Organisation) and SDO (Store Design Organisation).

The approval scheme involves requisite initial assessment and necessary monitoring provisions to ascertain the continued capability of these organizations for their activities. CEMILAC may approve setting up of Airworthiness Groups in approved design and development organisations for progression of airworthiness certification on behalf of CEMILAC.


4. CONTENTS OF DDPMAS - 2021

The DDPMAS Framework document is divided into two parts with each part is further subdivided into number of chapters, as follows:

a)     Part I: Airworthiness Management Framework

1)     Chapter 1: Introduction to Indian Military Airworthiness

2)     Chapter 2: Indian Military Airworthiness Framework

3)     Chapter 3: Military Air System/Airborne Store Acquisition


b)    Part II: Procedure for Design, Development and Production of Military Air System and Airborne Stores.

1)     Chapter 1: Ab Initio Design, Development, Production and Certification of Military Air System & Airborne Stores.

2)     Chapter 2: License Production of Air System and Airborne Stores

3)     Chapter 3: Bought Out Air System & Airborne Stores

4)     Chapter 4: Continuing Airworthiness and Continued Airworthiness

5)     Chapter 5: Flight Testing of Air System and Airborne Stores

6)     Chapter 6: Unmanned Aircraft Systems

7)     Chapter 7: Air Launched Missiles (ALM).

8)     Chapter 8: Research Air Systems & Airborne Stores.

9)     Chapter 9: Civil Certified Military Aircraft

10)   Chapter 10: Export of Indigenous Air Systems & Airborne Stores.

11)   Chapter 11: Organisation Approvals

12)   Chapter 12: Indigenous Substitutions of Airborne Stores.

 

5. INDIAN DEFENCE ACQUISITION PROCEDURE

Indian Defence acquisition procedure have three categories, the details are shown below:

a)     Category ‘Buy’ – means outright purchase of Defence item. It has three sub categories, as follows:

1)       Buy Indian IDDM (Indigenous Designed and Developed & Manufactured)

2)       Buy Indian

3)       Buy Global

b)     Category ‘Buy and Make’ – Initial procurement of fully formed (FF) followed by indigenous production under TOT/License.

c)     Category ‘Make’ – Indigenous Design & Development and Production.

1)       Make – I: Funding by Government.

2)       Make – II: Funding by Industry.

The airworthiness (Design certification) procedure as per DDPMAS-2021 will be as shown in table 1.

  

Table 1. Design Certification Procedure for Defence Acquisition Models

  

DAP Acquisition Category

Equivalence in DDPMAS

            Make (Make–I, Make–II)

            Buy (Indian – IDDM)

Ab-initio design & development


Buy (Indian)

Buy & Make (Indian),

Buy & Make Strategic Partnership Model (SPM)

              

             Licensed Production

Buy (Global)

Bought-Out


 

5.1  Military Airworthiness & QA Procedure

Any product procured for use in military Airborne applications shall have an airworthiness certificate. For Airworthiness and QA coverage, the following shall apply:

a)     Products categorized as ab-initio design & developed shall go through airworthiness certification by CEMILAC and QA including inspection clearance & acceptance by DGAQA.

b)     Products categorized under licensed production categories shall undergo inspection and acceptance by DGAQA. Role of CEMILAC will be to provide continued airworthiness assurance including defining the production build standard.

c)      “Buy (Global)” as well as “Buy & Make” category of product may have initial airworthiness clearance from the country of origin. However, CEMILAC and DGAQA will accord continued airworthiness assurance coverage during production and in-service phase.

d)     For Bought-Out items, if any indigenous modification/upgrade is envisaged at a later stage for the product, CEMILAC & DGAQA may be called in to provide airworthiness and QA assurance.

e)     Continuing airworthiness of all category of product will be provided by the SHQ (Service Headquarters).


6. AIRWORTHINESS CLEARANCE OF AIR SYSTEM/AIRBORNE STORES

Development of Air Systems/Airborne Stores can be based on either user requirements or the requirements generated by a MC (Main Contractor) and approved by the user. Only organisations approved for design activities (or possessing requisite requirement for DO approval) can take up D&D of air system/airborne stores. The certification routes can either be: 

      a)  Concurrent Certification – Development and certification progressing concurrently.

b)     Certification commences at the end of all developmental activities. In this scheme, besides tests and analysis already carried out by the developer, some more tests or analyses or both may be asked for by CEMILAC.

Irrespective of the option exercised by the Main Contractor, certification by CEMILAC would be issued only on demonstrating the compliance to the User as well as the airworthiness requirements as stipulated by the TAA.


6.1  Ab-initio Design and Development of Air System


As per DDPMAS 2021, an Air System includes fixed or rotary wing Aircraft, Unmanned Aircraft, Air Launched Missiles and Aero Engines. An MTC (Military Type Certificate) or RMTC (Restricted Military Type Certificate) are issued for Air System. The block diagram showing design, development, testing and evaluation of a complete Air System leading to issue of initial airworthiness approval for concurrent certification procedure is shown in figure 4.




Figure 4. Flow Chart Showing Ab-Initio Design & Development of Air System


Feasibility study and finalization of qualitative requirements shall be done in consultation with development agencies and other Government organisations as requested by Ministry of Defence. Air Systems development shall generally be taken up based on Staff Qualitative requirements (SQR) from User Services. In some cases, Main Contractors may also take up Air System development without any specific requirements from User Services. However, these Air Systems/Airborne Stores shall have potential application in Indian Defence Services.

Air system development shall be taken up by any DA (Design Agency) who is approved under DOAS or in the process of approval for the same. The Air system shall be designed against necessary SQR and ACC (Acceptable Certification Criteria) viz., MIL, DEF STAN, FAR etc. and shall meet the CONOPS (concept of operations) planned by the user.    

During the prototype development phase, if felt necessary, a SCRB (System Certification Review Board) may be constituted by Head CEMILAC. While design evaluation is carried out by CEMILAC, test and evaluation is a combined activities of DA, TAA, User and Flight test agency. All test plans and schedules are prepared by DA and approved by CEMILAC. DGAQA approves the test reports. For flight tests, flight clearance certificates are approved by CEMILAC while Flight safety certification is issued by DGAQA. Flight test reports are released by the flight test agency.  

 

6.2  Ab-initio Design and Development of Airborne Stores 

Airborne Stores include all Parts & Appliances, Airborne General Stores, Propeller, Aero Materials, Air Armaments, Crew Personal Protection Equipment, Fuel Oil Lubricants (FOL), Parachutes etc., used in an Air System. Airborne stores are issued with Type approval/IMATSOA/LoTA.  Design and development of Airborne Stores could be taken up as part of development of an Air System, upgrade of an Air System, indigenous substitute or obsolescence management. The Airborne Store development can be taken up only by approved Design Agency (approved under DOAS). Airborne stores having valid airworthiness approvals only can be installed on any air system.

The design, development, testing and evaluation of a complete Airborne Stores leading to issue of initial airworthiness approval for concurrent certification procedure is shown in figure 5.  



         Figure 5. Flow Chart - Design, Development and Certification of Military Airborne Stores


During the prototype development phase, if felt necessary, a SCRB (System Certification Review Board) may be constituted by Head CEMILAC. While design evaluation is carried out by CEMILAC, test and evaluation are combined activities of DA, TAA, User and Flight test agency. All test plans and schedules are prepared by DA and approved by CEMILAC. DGAQA approves the test reports. For flight tests (if required), DFC (Developmental Flight Clearance) are approved by CEMILAC while Flight safety certification is cleared by DGAQA. Flight test reports are released by the flight test agency. 


6.2  Indigenisation of Airborne Stores

Development of airborne stores and TTGE as a replacement to the existing airborne stores/TTGE falls under the category ‘Indigenisation’. Substitution of an indigenously developed Airborne Store with another indigenous Airborne Store shall be treated as an ab-initio development. For the purpose of indigenous substitution, subassemblies shall also be treated as an Airborne Store and shall be handled using these procedure provisions. Indigenisation of complete Air Systems shall be treated as an ab-initio development.

The flow chart for indignisation process leading to airworthiness clearance is shown in figure 6.




Figure 6. Flow Chart – Indigenous Development Military Airborne Stores 


The Indigenous substitution process should ensure that the functionality, safety, and reliability of the indigenized Airborne Store is adequately verified and validated according to the applicable airworthiness standards. The Indigenisation Agency shall be responsible for all activities of development, prototyping and qualification testing. The Indigenization Agency shall also handle all the issues related to the Intellectual Property Rights (IPR). Airworthiness clearance from CEMILAC will depend on the type and criticality of the store (refer para 2 above).  On approval, the indigenized store will be listed as an alternate item in the Standard of Preparation (SOP) of the Air System/Airborne Store on which the indigenized store is to be used.

Post indigenous development any production deviations during the production phase shall be addressed through a Non-Conformance Review Process (NCRP). Modifications to the approved SOP shall be handled through a Configuration Change Process (CCP) with relevant stakeholders by the Indigenization Agency. 


If the conditions of clearance of the indigenously substituted Airborne Stores are not satisfied or the field performance as per the feedback provided by Users is not satisfactory, the clearance issued earlier may be withdrawn by LTCC after due investigation with the Indigenization Agency.

 

7. CONTINUED AND CONTINUING AIRWORTHINESS

An Air System is normally operated for a very long period of time spanning few decades. Hence, the product has to continue to stay airworthy at any given time over its entire operating life. An Air System or an Airborne Store is treated to be airworthy when, it is built as per provisions of the initial airworthiness certificate (or the type records) and operated & maintained as per the stipulated maintenance documents. Therefore, it is not only imperative to comply with the initial airworthiness requirements but also to ensure that all necessary provisions exist for ensuring airworthiness throughout the lifecycle of the product. This is achieved by ensuring airworthiness in operational scenario through the process of continuing and continued airworthiness.

 

7.1 Continued Airworthiness covers:

All those processes that need to be carried out to ensure that the conditions under which Initial Airworthiness Approvals was granted, continue to be fulfilled during the production and life time deployment phase. Further, to keep in pace with technological growth, the air-system must be kept competitive (in its usefulness and capabilities) through system upgrade and maintainable through a process of obsolescence management. All these activities fall under the purview of ‘Continued Airworthiness’.

As per DDPMAS 2021, the TAA have to provide airworthiness assurance during all these processes as part of the continued airworthiness. The various continued airworthiness activities those are carried out are discussed below.


7.1.1       Failure /Incidence Reporting

A formal mechanism to be established by the User Services and the Main Contractor for reporting any failure/incidents. A DI (Defect Investigation) Committee comprising of members from TAA, main contractor should study all reported cases with a view to establish the cause of the failure. The DI committee should recommend corrective/preventive actions, which may be in the form of improvements in design /manufacturing or maintenance process /revision of operating life. DI committee recommendation should be periodically reviewed and further actions and point of embodiment of the suggested improvements will be taken based on detailed technical analysis and approval by TAA.

 

 

7.1.2 Service Instructions

The Main Contractor shall, with CEMILAC approval wherever applicable, issue Servicing Instructions (SIs), Service Bulletins (SBs), Urgent Operating Notices (UONs), Special Technical Instructions (STIs) and other promulgation mechanisms to inform User Services about changes that impact servicing, maintenance and operations. Service HQs is required to ensure that these instructions are promulgated to all applicable field units.

  

 


7.1.3 LMC Activities 

The Air Systems and Airborne Stores may require to undergo changes to the Type design by way of modifications & upgrades, subsequent to the initial airworthiness approvals (MTC/RMTC for Air Systems & Provisional Clearance/Type Approval for Airborne Stores). To control the airworthiness of the process of changes, the Main Contractor shall establish means by which the design, testing and production processes are evaluated and controlled such that each product meets the airworthiness requirements. The airworthiness approval of these changes will be regulated by a ‘Local Modification Committee (LMC)’. The constitution and functioning of the LMC is discussed below.

a)       Ministry of Defence (MoD) may constitute Local Modification Committee (LMC) with financial powers specific to a Main Contractor/Programme. CE (A), may constitute an LMC without financial power if necessary.

b)      The LMC shall be chaired by CEMILAC with members from Design, Quality and Production of the main contractor and DGAQA and User rep. The LMC shall address the major modifications/upgrades carried out on in-service Air Systems and Airborne Stores.

c)       A Local Technical Committee (LTC) comprising of representatives from all the stakeholders shall be formed by chairman LMC to discuss technical aspects of the modification, in cases where adequate technical information on the proposed modification are not readily available. LTC shall recommend its proposal to LMC.

d)       The LMC will be responsible for technical approval of the mod, define its safety/criticality classification as well as the point of embodiment of the mod for line compliances during series production/overhaul as well as retro compliances on the flying aircraft.  

 


7.1.4       Obsolescence Management

The Main Contractor shall have an obsolescence management plan to monitor, mitigate and inform Services to stockpile stores/components or procure alternates for stores/components that may face obsolescence, in a timely manner. The Main Contractor shall obtain the approval of TAA for the proposed alternate stores/ components.


7.1.5       Life Extension

As the initial life prescribed by the manufacturer is usually low and conservative, there is always a scope of reassessment of life and accord life extension. Whenever anyAir System’ orAirborne Stores’ are to be exploited beyond its initial prescribed life, CEMILAC shall provide the life extension on progressive/incremental basis, based on study, analysis and additional testing as deemed necessary for life extension. The Main Contractor and the Services shall provide all requested information/documentation for the purpose. A ‘Lifing Committee’ under the chairmanship of CEMILAC with members from Main Contractor, DGAQA and the User Services shall be constituted for the said purpose.


7.2 Continuing Airworthiness

Throughout the exploitation phase, an Air System must remain in a condition of ‘safe for operation’. All the processes/activities that ensure that the Air System is in safe operating condition fall under the gamut of ‘Continuing Airworthiness’.  The continuing airworthiness may be ensured by:

a)   Periodic servicing and maintenance of the Air System & Airborne Stores by crew/organisations of User Services, or Main Contractor or by any third party other than the OEM/User services as per the OEMs manual.

b)     Periodic review of the reliability of the Air System & Airborne stores.                                   

To facilitate the continuing airworthiness, the contractor shall:

1)     Incorporate all servicing and maintenance requirement at the time of initial airworthiness certification.

2)     Provide necessary TTGEs (Tool, Testers and Ground Equipment) and calibration schedules.

3)     Provide technical publications with proper illustrations.

4)     Provide adequate training, training material with regular SOP updates and certify instructors for subsequent training of maintenance crew.

5)     Establish proper provisioning mechanisms and process for stocking and storage of all spares & material required for servicing and maintenance.

The service headquarters shall carry out adequate audits to ensure that the continuing airworthiness organization are carrying out activities properly.

 

8. FLIGHT TESTING

Flight test evaluation may often be required for air system and airborne store for the purpose of initial airworthiness certification. Flight test may also be required in certain cases for continued airworthiness evaluation of the air system/airborne store consequent upon major system integration/upgrade.

DDPMAS-2021 has elaborated flight test procedures for three different scenarios, as shown below:

a)       Flight Testing of Ab-initio Developed Aircraft & UAS

b)       Flight Testing of In-service Aircraft & UAS for Modifications/Upgrades Carried out by a Main Contractor

c)       Flight Testing of In-service Aircraft & UAS for Modifications Carried out by the User Services.

 

8.1 Flight Testing Procedure

While the level of risk and the quantum of effort required will vary depending on the complexity of product-design under evaluation, the basic tenet of flight testing remains the same. The general flight test procedure is described below:

 

8.1.1       Flight Test Platform

The Air System used for flight testing (prototype/In service air system) must be registered with an Indian Military tail number. If the platform has a civil tail number, then necessary concurrence from DGCA shall be obtained for undertaking flight testing activities.


8.1.2       Flight Testing Agencies

The flight test department of the Main Contractor/Services HQ authorized flight testing agency are responsible for carrying out the flight testing of Air Systems and Airborne Stores.

The test Pilot(s) and the Flight Test Engineer(s), shall be graduates of a recognized Test Pilot School or shall have undergone a suitable course on flight testing of UAS for undertaking developmental, experimental or production flight testing. Flight testing after production or overhaul may also be undertaken by a pilot who has undergone production flight test course at any recognised Test Pilot School and qualified on the particular aircraft/ UAS type.

Chief of Flight Test will decide the Flight test team and arrange for necessary briefing to the test crew. The test article will be handed over to the flight test team by DGAQA as per Form 1090 procedure. 


8.1.3       Airspace & Ground Space for Flight Testing

Flight testing shall be carried out in Airspace designated to undertake flight testing activities. The flight test agency is responsible for seeking the air space clearance, availability of the runway, radio communication frequency channel for communicating with the ATC etc., The test agency shall ensure availability and proper functioning of the facilities such as but not limited to, telemetry, serviceability of the runway/ship deck, the arrestor barrier system /arrestor recovery system, before undertaking flight testing.


8.1.4       Flight Test Documentations

Flight test documents shall include at the least the following:

a)     Flight Test Specification - The Flight Test Specification containing the flight test demonstration requirements shall be prepared by the Main Contractor in consultation with the flight test agency and approved by CEMILAC.

b)     Flight Test Plan - The Flight Test Plan for the planned block/phase/trial of flight testing capturing the objectives of the sorties planned for the block/phase/trial shall be prepared by the Flight Test Agency in consultation with the Main Contractor.

c)     Flight Test Schedule - A flight test schedule for each taxi or a sortie, capturing the details of the specific tests to be conducted, shall be prepared by the flight test agency.


8.1.5       Flight Test Instrumentation

Flight testing shall be carried out on an instrumented platform. Real time transmission of critical data to a ground monitoring/ control station through telemetry may be ensured by the Main Contractor. The overall instrumentation plan shall be prepared by the Main Contractor/flight test agency in consultation with CEMILAC.  The Main Contractor in consultation with the flight test agency is responsible for ensuring that the platform is adequately instrumented as per the agreed instrumentation plan including all On-board Flight Test Instrumentation LRUS. The instrumentation shall satisfactorily facilitate flight test validation of the systems being tested.


8.1.6       Flight Clearance

CEMILAC shall issue ‘Flight Clearance Certificates (FCC)’ for all Developmental Flight Trials of Air System and ‘Developmental Flight Clearance (DFC)’ for Airborne Stores to evaluate its design, functionality and integration aspects. The FCC/DFC shall be prepared by the Main Contractor in consultation with CEMILAC and shall be jointly approved by the Chief of Design of the Main Contractor and CEMILAC.  CEMILAC shall clear individual flights through the Flight Program Clearance Memo (FPCM) after ascertaining airworthiness of the aircraft or UAS. The FPCM shall be prepared by the Main Contractor and approved by CEMILAC. FPCM certifies the aircraft’s fitness as per the planned flying program. Flight data analysis for individual sorties and work done report including snag disposition details duly coordinated by DGAQA shall be completed before seeking clearance of the next sortie. However, in exceptional cases, if data analysis is not possible before next sortie, it must be completed by end of the day and next sortie may be cleared based on pilot debrief.

DGAQA shall issue Certificate of Safety of Flight through Form 1090 for undertaking flight testing for Air System/Airborne Store (Form 700 for aircraft already in service use). Flights shall be conducted by the flight test agency within the boundaries (flight envelope limits and other clearances) defined in FCC. Subject to the availability of the clearances through FPCM and Form 1090, the flight test agency may plan and execute the requisite number of flights as required to complete the planned tasks, within the scope of the FCC.


8.1.7 Withdrawal of Flight Clearance

If, as a result of an accident or any untoward incident, if CEMILAC considers that it would be prudent to restrict further trials pending investigation, CEMILAC shall advise Service Head Quarters, DGAQA and Main Contractor and may withdraw the current FCC temporarily.


8.1.8 Flight Test Report

Flight test reports after a block of flights or after completion of a milestone activity shall be prepared by the Main Contractor in consultation with flight test agency and forwarded to CEMILAC.

 

REFERENCES:

1.           Nagraj K, Kalyanam VK and Annamalai SP. Reference Book on Airworthiness and Certification of Military Fixed Wing Aircraft’. IDST-B REPORT No. IDST/CEMILAC/01 dated Mar 2005. CAPSI No. and Date: IDST /CEMILAC/02/CONT, Dated 23 July 03.

2.           Frame work and Procedure for Design, Development and Production of Military Air Systems and Airborne Stores. DDPMAS Version 1.0. Ministry of Defence, Gov. of India. February 2021.

3.   Procedure for Design, Development and Production of Military Aircraft and Airborne Stores, DDPMAS-2002 (Supersedes DDPMAS-75). Ministry of Defence Gov. of India. 17 May 2002.

4.   Civil Aviation Requirements, CAR-21. Certification Procedures for Aircraft and related Products and Parts. Issue II, Revision 5 dated 13 Sep 2018. Directorate of Civil Aviation, Govt. of India. 





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