FAA Small Unmanned Aircraft Registration

1. Registration Begins from 21 Dec 2015

         The Aviation Rulemaking Committee's (ARC) Unmanned Aircraft System Registration Task Force (RTF) constituted by the Federal Aviation Administration (FAA) released the Task Force Recommendation Final Report on 21 Nov 2015. [Ref 1]. 

         Based on the RTF report, FAA has introduced statutory requirement that all small Unmanned Aircraft System (sUAS) weighing more than 0.55 pounds (250 grams) and less than 55 pounds (approx. 25 kilograms), including payloads such as on-board cameras, must be registered if it is to be operated outdoor in the National Air Space (NAS). The registry is live from the day on December 21. Registration is free for the first 30 days (up to 19 Feb 2016) and then $5.

       

2. What the Registration Mean 

           The registration could be web based or paper based. In preparation for registering online, each owner must provide his or her name, home address and e-mail address. Owners wishing to Register themselves as sUAS operator must be at least 13 years of age. Information on US citizenship or residence status is not asked. Upon completion of registration, the web application will generate a Certificate of Aircraft Registration/Proof of Ownership that will include a unique identification number for the UAS owner, which must be marked on the aircraft. 

          Owners using model aircraft or sUAS for hobby or recreation will only have to register once and may use the same identification number for all their model aircraft. The registration is valid for three years. Owners of any other UAS purchased after December 21 must register before the first flight outdoor. The same rule apply for model aircraft assembled from purchased kits. The registration is for each operator and not for each small UAS they possess.  

          The above statute indicates that a model aircraft or sUAS need not be registered at the Point of Sale (POS), however the operator must register himself if he wants to fly the aircraft.

3. Operating Rules

        Operator must mark his registration number or the serial number on all the aircraft he wishes to operate. If he has provided the aircraft serial number during registration process, he may display the same number on the aircraft. FAA has partnered with several industry associations to educate the public about using unmanned aircraft and model aircraft safely and responsively. The general operating and flight safety rules are:

    a)  Flight altitude limited to 400 feet above ground level (AGL).
    b)  Visual flight rules: Keep your unmanned aircraft always in sight. 
    c)  Never fly near manned aircraft, especially near airports.
    d) Never fly over group of people, stadium or sporting events. 
    e) Never fly near emergency response/evacuation efforts. 

4. FAA Rule Making Effort

           Department of Transportation (DoT), FAA's Federal Register Vol. 80 Sl. No. 35, No. 9544  'Operation and Certification of small UAS' was released on 23 Feb 2015 as notice to public for rule making (NPRM) [Ref 2]. The above proposed rule addresses operation of UAS, certification of their operator, registration and display of the registration marking on the aircraft.  

          The proposed rule would also find that airworthiness certification of sUAS is not required. The proposed rule would also prohibit model aircraft from endangering the safety of the National Air Space. 

5.  ARC UAS Registration Task Force (RTF) Recommendation

          FAA charted the UAS Registration Task Force of Aviation Rulemaking Committee to provide recommendation to FAA "On Registration Requirement and Process for small UAS including those used for commercial purposes, and all model aircraft". The stated objectives of the Task Force was to develop recommendations which ultimately would contribute to an enforceable rule imposed by FAA.

        The task force was comprised of individuals from a diverse group of aviation and non aviation perspectives (25 different groups from industry, commercial and business sectors, aircraft operators, aircraft pilots, academia, regulatory as well as government officials). The task forces met to discuss the three main objectives as the terms of reference set forth by FAA during 03 to 05 November 2015.  From these discussions, the task force developed high level recommendations for sUAS registration requirements that addresses the questions posed by FAA.

5.1 Min Weight UAS that Need to be Registered

         The safety of non-flying public and other users of the NAS was central to the task force's determination of what category of sUAS be excluded form the registration requirements. The formula considered was a standard aviation risk assessment formula used in consideration in manned aircraft. It was noted from a United Kingdom Ministry of Defence 2010 study that an object with kinetic energy level of 80 Joules (approximately 59 foot pound) has a 30% probability of being lethal when striking a person on the head. 

       The terminal velocity of an object falling from a height 400 feet can be estimated assuming that the net acceleration of the body will be due to acceleration due to gravity reduced by the body drag. The drag force acting on the body during the fall of the body will be a function of shape and velocity of the body at the instant. The task force considered a typical sUAS of projected area of 0.02 m >2 and and drag coefficient of 0.3. Solving for mass and velocity for a body to impact with a Kinetic Energy of 80 Joules, works out weight 250 grams and velocity of 25 m/sec or approximately 57 miles/hour. 

       The probability of such a lethal occurrences per UAS flight hours were estimated by the task force assuming the MTBF of UAS as 100 hours and population density of 10000 people per square miles. The probability of a catastrophic event was found to be 4.7 x 10 E-8 or less than 1 ground fatality for every 20,000,000 flight hours of UAS. 

        Considering that the acceptable risk levels for commercial air transportation are on the order of 1 x 10 E-9 and therefore this risk level of 4.7 x 10 E -8 seem acceptable to the task force. 

6. The UAS Certification 

In summary, it can be concluded that 

a) Unmanned aircraft weighing less than 250 gms requires neither certification of the product nor  registration of the operator. 

b) Unmanned aircraft weighing above 250 gms but less than 25 Kg needs no product certification but the operator who wishes to fly these aircraft must get himself registered with FAA.  

c) Unmanned aircraft weighing above 25 Kgs will be treated like manned aircraft as far as their airworthiness certification is concerned.

References:

1) http://www.faa/uas/publications/media/RTFARCFinalReport_11-21-15.pdf: "Unmanned Aircraft System (UAS) Registration Task Forces (RTF) Aviation Rulemaking Committee (ARC) -Task Force Recommendation Final Report"; November 21, 2015.

2) 80 Federal Register 9544 dated 23 Feb 2015, "Operation and Certification of Small UAS"; DoT, FAA.

Phases of Aircraft Certification

1.  Certification

           Certification is defined as a process which provides possibility of making certain that any aircraft whether civil or military has acceptable levels of safety for a given future utilization within the defined flight load spectrum for a specified period.

2.   Phases of Certification of an Aircraft

          Certification is normally carried out in four levels as shown in figure -1 below:

Figure -1: Aircraft Certification Phases

a) Level 1: Requirement Finalization - The requirement of the aircraft or the technical specification, the design standards (like FAR, Mil etc) and the materials to be used (existing approved materials or new materials to be developed) are decided in this phase. 

b)  Equipment (LRU) and Component Qualification 

c)  System level Qualification and 

d) Aircraft level functionality and operability assessment.  

3.  LRU Qualification 

     The LRU development and Qualification is carried out in phases as follows:

a) Development of F-F-F Model (Form, Fit and Function) - It is a model unit and used for checking the installation, functioning and access for maintenance. 

b) Prototype Model - Based on the F-F-F model experience, a prototype model is built with the engineering material to check proper functioning in full environment. 

c) SOFT Model - SOFT (Safety of flight test) model is an model which is subjected to all those exposures which are felt in each flight, SOFT is a subset of QT and soft cleared items can be released for developmental flight tests. In parallel full QT are carried out on other models. 

d) Qualification Test  (QT) Model - The QT model is subjected to qualification tests as follows;

     - Functional test on test rig

     - Structural test as proof of structural integrity

     - System Integration and ground evaluation 

     - Environmental test 

     - Flight and ground test 

     - Endurance test for life cycle environment. 

4.  System Level Certification 

Aircraft consists of many systems like Airframe Structure, Mechanical, Electrical, Powerplant, Avionics etc. The configuration design is based on the aerodynamics considerations. The system level certification will consists of evaluation of the system: 

  - System level functional requirements and all environment

  -  System safety an hazard requirement as per airworthiness standards

  - System Reliability (Redundancy or Fault tolerance) requirements 

  -  Maintainability requirements and 

  -  Specified life 

System evaluations go in phases

 - Design evaluation as per airworthiness requirement

 - Functional evaluation on system integration rig/box

 - Performance evaluation on aircraft at ground test

 - Performance evaluation on aircraft during flight.

5. Aircraft Level Evaluation 

Aircraft level tests to verify each system functioning at various stages:  

  - System evaluation during engine ground run (EGR)

  - System evaluation during Low speed Taxi Test (LSTT) (speed limited to 50 knots) 

  - System evaluation during High Speed Taxi Test (HSTT) (speed limited below to Vrotation speed)

  - Flight test evaluation 

6. Flight Test and Evaluation 

The principal purpose of flight testing is to determine if the complex machine designed can safely accomplish the designated task with the pilot workload kept within the human limitations and natural instinct of human being.

The flight test include handling quality assessment and evaluation of airworthiness performance requirements as well mission performance requirements. The flight tests are also to establish the operational boundary of the aircraft, aero-elastic and other boundaries. The all weather assessment will involve tests and evaluations under various airport altitude and ambient conditions. 

However there are some hazardous tests like determination of stall and spin behaviours, engine relight in air, safety assessment during simulated failures etc. which are normally carried out only after gathering enough data on the aircraft behaviour through flight tests. 

Military aircraft needs to go through weapon firing trials. 

7. Certification 

Based on the satisfactory tests and evaluation aircraft is issued with 

  - Type Certification (Civil Aircraft) 

  - Induction to service (Military aircraft). 

Associated activity during certification stage is the preparation of ODM (Operational Data Manual) , AFM (Aircraft Flight Manual) and MM (Maintenance manuals).  

DDPMAS - Indian Military Airworthiness and Certification Document?

1.  DDPMAS

            ‘Procedure for Design, Development and Production of Military Aircraft and Airborne Stores’ (DDPMAS) is a document released by Secretary, Defence Production, Ministry of Defence, Government of India on 30^th October 1975. The document was issued to define the procedure to be followed by various agencies involved in the design, development and production of military aircraft and airborne stores. The document was reviewed and reissued in 2002 as DDPMAS-2002.

2. Contents of DDPMAS

            The document is divided into five sections as follows:

           Section I:      Definitions

           Section II:     Process of Development

           Section III:    Design, Development and Production of Aircraft, Aero Engines and

                                Major Airborne Equipment

                                Chapter 1: Prototype and Development Phase

                                Chapter 2: Pre-Production, Production and In-service Phase

                                Chapter 3: License Projects

                                Chapter 4: Bought –out Aircraft

           Section IV:    Design, Development and Production of Airborne Equipment, Raw Material and AGS Parts. 

           Section V:     Procedure for Flight Testing of Experimental and Prototype Equipment.

3. Omissions and Exclusions

1)  Design, Development and Production of Airborne electronic equipment /stores are   excluded from the scope of DDPMAS and will be carried out as per DDPIL-2000  Procedures. Installation of such equipment on military aircraft would follow JSG: 755:2001 and procedures stipulated in DDPMAS -2002.

2)      DDPMAS – 2002 is not applicable to UAV and missiles unless they are carried on manned aircraft.

4. DDPMAS -2002

            DDPMAS -2002 was issued to incorporate various organizational changes in the Ministry of Defence, e.g. DTD&P (Air) renamed as DGAQA; airworthiness functions changed from Directorate of Aeronautics (through CREs) to CEMILAC (through RCMAs). In addition to Air Force, the Army and Navy came in a big way in aviation wing, thus the terms ASR was replaced by ASR/NSQR/GSQR and CSDO by CSDO/NSDO/MAG (AVN) etc. In addition to these changes, the regulatory bodies also added certain additional requirements over and above DDPMAS-1975 requirements.  

5. Changes Incorporated in DDPMAS 2002

1) General content - General content of DDPMAS -2002 is similar to DDPMAS -75; however certain changes have been incorporated. 

2)    ‘Section – V: Procedure for Flight Testing of Experimental and Prototype Equipment’ has been made in two chapters as, ‘Chapter -1: Development Flight Testing’ and Chapter -2: Flight Testing by User Services’.

3)    Annexures: DDPMAS -2002 has added five more annexures compared to DDPMAS -75 (all of them added in Section 3, Chapter-1). Two annexures have been split in to two     parts. The new annexures added are shown below:
     1)    Annexure –R: Declaration of Design and Performance
     2)    Annexure –S: Request For change in configuration
     3)    Annexure –T: Hardware/Software Delivery Note
    4)    Annexure –U: Responsibilities of CEMILAC
   5)    Annexure –V: Requirement to be submitted by Developing Agency for             clearance of Airborne Equipment imported from abroad.  
 6)    Annexure – G is split into two annexures as ‘G1: Certificate o Flight Trials –          Aircraft’ and ‘G2: Certificate of flight trials – Helicopters’.
 7)  Annexure – K (annexure J in DDPMAS-75) split into two; ‘K(i): Local                   Modification Committee -Details of Modification Proposed’ and ‘K(ii): Advance        Modification Information’.

6. Changes Related to the Procedure for Ab-initio Development

            Section – III, Chapter -1: ‘Prototype and Development Phase’ has been substantially changed, the discussion on the changes are shown below:

    1) Progression of certification – A new para (para 3) has been added indicating two certification routes viz., ‘certification commences after completion of all design activities’ and ‘concurrent certification approach’ could be followed. However, DDPMAS 2002 supports the concurrent certification approach only.

2)    New Concepts brought in – Formation of ‘Airworthiness Group’, ‘Configuration Control’, ‘Technical Reviews’ and ‘Bought out Items’. Necessary details however has not been provided.

3)    Design Standard of Preparation – A new para (para 17) added in addition to the     original para of ‘Design Standard of Prototype Aircraft’ appearing at Para 68. Both the     paragraphs discussing ‘Design Standard of Prototype Aircraft’ create contradictions and        confusion.  

  

4)    Certificate of Design – In DDPMAS -75, ‘Certificate of Design’ (COD) was part of the   Type Record (Para 18(a)). In DDPMAS -2002, in addition to the above requirement,  ‘COD’ has been made a requirement from the vendor before issue of first flight    clearance. CEMILAC participates in Design Reviews, evaluates Design Reports, approved test schedules, participates in test and verification trials and finally accepts test reports. So, the requirement of ‘COD’ for each system for issue of flight clearance  does not appear justified. 

5)     Section III, Chap – 2: describes the activities to be performed during ‘Pre-Production   and Production Phase’. What is ‘Pre-Production’ phase and what are the activities to be     performed during this phase has not made clear.

7.  Discussion on the Changes of DDPMAS-2002 from DDPMAS-75

   a) Annexures – Though five annexures have been added, the annexures are not sequentially arranged in the text.

    b)    Declaration of Design and Performance (DDP) – DDP concept has been introduced in DDPMAS-2002 under configuration control. The DDP route is followed in Civil Aviation Procedures. An aircraft development house accepts equipment (parts & appliances) for installation on prototype aircraft on the basis of the DDP issued by  equipment developer, who is a DOA (Design Organisation Approval) holder from Civil Aviation Authority. As and when the prototype aircraft is certified by the CAA, the equipment also gets certified and only then, the equipment manufacture can issue  ‘Airworthiness Release Certificate’ for the equipment. As CEMILAC itself is certifying the LRU (parts and appliances), DDP may not be applicable. 

   c)    Design Approval of Firm and Airworthiness Group – The design approval of firm is to be carried out as per CEMILAC/5342/1 dated Jun 1999. The document does not indicate any privilege or delegated authority to the approved organization. The procedure for approval of airworthiness group is to be carried out as per CEMILAC/TC/03 dated Sep 2000.  

  d)    Bought Out Item – Appendix ‘V’ to DDPMAS – 2002 includes information to be   provided by vendors on bought out items. It is understood that ‘RCMA’ is to clear the BOI for installation on Prototype aircraft based on the annexure –‘V’ checklist and DGAQA is to comment on the QA process of manufacture. 

                 For ‘Of the shelf’ items, the procurement should be supported by ‘Authorized Release Certificates’ or ‘DDP’ from the vendor or ‘TSO Authorisation’ for TSO items.During prototype development stage only a very limited quantities are procured and the supplier may not provide the QTR, FMEA, MTBF/MTBR, Reliability/maintainability reports. Requirements for these documents will lead to great bottleneck and delay to aircraft design and development project. The appendix ‘V’ is abnormally big and does not provide any value addition to safety and airworthiness of the aircraft or aero-engine being developed. 

8.  The Document DDPMAS

    a)    Purpose of DDPMAS - The purpose of DDPMAS as indicated in its ‘foreword’ and ‘preface’, is to evolve an optimum coordination among various agencies involved in the design, development and production of military aircraft and airborne stores. The document was written with concurrent engineering concept with the assumption that the design and manufacturing house (HAL), the regulatory bodies (Chief Resident Engineer and Chief Resident Inspector) and user (Air Force Liaison Office) are co- located.

  b)    Certification Procedure Document – DDPMAS is not a certification procedural documents like CAR 21 (DGCA), FAA order 8110.4c, ‘Type Certification Procedures‘ or USAF Policy Directive AFPD-62-6:’USAF Airworthiness (Jun 2010)’ and USAF Instruction AFI 62-601: ‘USAF Airworthiness (May 2011)’. DDPMAS does not define the procedure, responsibilities and delegated authorities vested on approved design and production houses.

 c)    Development of Electronics Item - Development of electronic items is not covered under DDPMAS documents. An extract of DDPIL may be included to give a general overview of the concept and to appreciate whether it significantly differs from development concepts of other airborne equipment.

  d)    Approval of Design Organisations - ‘Design Organisation Approval’ (DOA) is an important step toward design and airworthiness control. The DOA recognizes the   capability of the firm and define responsibilities of the design signatories and delegates necessary authority to them. The Design Assurance System (DAS) of the DOA carries out control and supervision over design and design changes.The airworthiness authorities monitor the functioning of the DAS and accepts the design and test reports by the authorized signatories. The ‘Design Approval’ (DA) by CEMILAC is similar to  DOA and the ‘Airworthiness Group’ of CEMILAC DA is similar to DAS of DOA as per CAR (Civil Aviation Requirement). If the above design approval procedure is followed no separate approval will be required for airworthiness Group.  

  e)    Approval of Quality Management System – In the lines of the Production   Organisation Approval (POA) in CAR, DGAQA confers Approval of Firms Quality Management System (AFQMS). Here, AFQMS does not delegate any authority to the  firm and DGAQA resorts to spot check to detect quality deficiency. DGAQA have restricted the AFQMS limited to Government and Public Sector Undertakings only.

   9.  General Comment  

   a)    It is essential to have a separate document bought out by CEMILAC detailing the procedure for design certification starting from the establishment of certification basis to the culmination of issuance of type certification.

   b)    A separate document should be brought out by DGAQA detailing the procedure for Quality Assurances through AFQMS during manufacture of the prototype as well as series production.

    c)    The procedural documents released by both CEMILAC and DGAQA should clearly define the responsibilities and authorities delegated to the approved signatories so as to cater for situations where the vendors and regulatory bodies are not co-located.

  d)    The procedural documents should be made available in the electronic media so that it become accessible to the vendors, development houses and the users.    

  

Airworthy Materials.? What are they?

Airworthy Material ..!

There is nothing like airworthy material either by definition or by name. However, the aircraft design have to meet the safety and airworthiness requirements, therefore the aerospace designer chooses materials with due care to meet the material property behaviour, process of manufacturing  and qualification.  

Design Structural Weight 

Structural weight is an extremely sensitive issue in aircraft design. Increase in structural weight in air frame, aero engines or guided weapons have snowballing effect. An extra kg of weight may cause an extra kg of fuel burn for each flight and thus reduce range or payload, for an aero engine, over weight by one kg may cause a loss of as high as 30 hp engine power and 1 kg extra weight for an guided weapon may require additional 6- 7 kg of propellant to be burnt. Aerospace designers therefore choose material with higher specific strength (UTS/Density)  and specific stiffness (Young's modulus/density). 

Scatter in Material Property

Scatter in material property is unavoidable and the designers have to use the minimum of the test values while estimating the specific strength or specific stiffness. The effect of this scatter on short term property (static strength or UTS) is usually low. For example UTS of duralumin may be 40-44 kg/mm^2, the designer is required to use 40 kg/mm^2 for his analysis.

The scatter in the dynamic properties like LCF, and HCF (low cycle and high cycle fatigue) are usually high. This is reflected in the upper and lower bound of the S-N curve shown in the figure. The scatter or the width of the band is usually due to reasons which are both internal and external to the test specimen or the components. The external factors include dimensional accuracy, surface finish and presence of any stress concentration. The internal factors which give rise to the high scatter bandwidth are the presence of unwanted impurity element that provide nucleation points for initiation of crack and help in crack propagation. 

Aerospace Grade Material  

 Aerospace metallurgists have devised methods for controlling these impurities to ppm (parts per million) level. Residual gases (O, H, N, Ar, He), non metallic S, P and metalloids impurities of Pb, Bi, Sb, As, Ag, Cu, Ti, Te are controlled to extremely low levels ( 0.3 ppm) where their deleterious effects are tolerable. These activities are normally not done for general engineering material processing. The trace elements in the general engineering materials are up to 500 ppm (0.05%). SAE Aerospace Material Specification (AMS) indicate the level of controlling the trace elements and impurities.

Bandwidth of S-N Curve

Bandwidth of S-N curve is significantly lower for Aerospace Materials compared to the General Engineering materials due to the improved metallurgical processing. Thus for the same deign fatigue life, an aerospace material can be stressed to much higher level compared to an general engineering material as shown in the figure. This gives the aerospace grade material an extra advantage to reduce the structural weights of the stressed components.    

Categorisation of Parts

As per the airworthiness standard Def Stan 00 970, a part can be categorised into different grades taking cognizance of the strength and stiffness requirement of the part as shown below: 

Grade A

A part shall be graded as 'A' if the deformation or failure of the part would result in one or more of the following:

  - Structural Collapse

  - Loss of Control

  - Failure of Motive power

  - Inability to operate or unintentional operation of any system or equipment essential to the     safety or operational function of the aeroplane.

  - Incapacitating injury to any occupant

  - Unacceptable unserviceability or maintainability. 

Grade B

All other parts not covered under category 'A'. 

Selection of Material Based on Component Grade 

For grade 'A' Components 

Material conforming to aerospace grades

For grade 'B' Components 

They may be manufactured by aerospace grade material or less controlled material like general engineering grades or proprietary material at the discretion of the designer. 

Reference: 

For details please see: 

Balram Gupta, et al., 'Aerospace Materials with general Metallurgy for Engineers', Volume I, AR&DB, 1996, Printed by S Chand & CompanyLtd, New Delhi. 

Unification of Military and Civil Aircraft Certification Procedure

Unification of Military and Civil Aircraft Certification Procedures

Airworthiness and Type Certification 

‘Airworthiness’ is defined as the demonstrated capability of an aircraft to satisfactorily fulfill the mission requirements with acceptable level of safety and reliability. Airworthiness does not guarantee an ‘absolute safety’ rather an ‘acceptable level’ of safety which is decided as mutually agreed among designer, manufacturer and the user on one side and the state or regulator on the other side. The foundation for this is the acceptability from safety consideration on one hand and the practicability form the point of technical feasibility and cost of compliance towards design and manufacture. The ‘Type Certification’ on the other hand is a legal declaration by a competent authority that the product has been designed, developed, evaluated and productionised in such a manner that its quality, reliability and integrity meets or exceeds the specified requirements.

Flight Safety and Risk Threshold

         ‘Safety’ of any flight would depend primarily upon, whether we are operating below or above the ‘Risk Threshold’. The basic tenet of flight safety is to ensure that the chances of achieving the tasks should be optimal while risks are minimal. The ‘flight safety directorate’ is to ensure that in peace time high level of risks is avoided. This is because the accidents have very deleterious effects on the morale of the flier. During the war time, however, task achievement is paramount and high degree of risk may have to be taken. Safety levels are quantified as ‘Casualties per Ton Kilometer of transportation (CTK)’ for civil aircraft while for military aircraft; it is ‘Accidents Rate’ per 10,000 hours of flight.

Military and Civil Aircraft Design Procedures

           While, commercial aircraft has a single mission of safe and comfortable ferrying of passenger and cargo, the military aircraft have to perform far more varied and different missions with each requiring different design requirements to be satisfied. Further, commercial aircraft uses only proven technologies, military aircraft design, to get an edge over the contemporaries, exploits latest but not fully qualified ‘developments in technologies’.  The new technologies also get certified along with the military aircraft certification. An aircraft design is a ‘trade off’ amongst diversified requirements. The ‘trade off criteria’ is different for commercial and military aircraft. For example: while performance and stealth are high priority for combat fleet, flying qualities and safety is most desirable for commercial aircraft.

     

         To maintain international safety of air transportation, ICAO has imposed that every member country should have a Civil Aviation Authority (CAA) empowered by the statutory rules of the country to impose regulations to maintain air safety. Certification is to be accorded by these CAAs only (for example: FAA (in USA) and EASA (European countries)) on compliance to the regulations. The military aircraft being ‘state owned’ undergoes government ‘self certification’ as per Mil–Std 516B (USA), JAP-100 (UK), DDPMAS -2002 (India).

System Safety: Military and Civil Aircraft

       System safety of military aircraft design is as per Mil-Std-882 while for civil aircraft FAR 25.1309 and SAE-ARP 4761 are followed. Mil 882 uses improbable (<10^-7) and ARP 4761 considers extremely remote (< 10^-9) as the limiting values. This is because military aircraft design accepts a higher risk for mission accomplishment. However both the designs follow the basic tenet of airworthiness, i.e. there should exist an inverse relation between the probability of occurrence of an event and the degree of hazard inherent in its effect. 

Inter-Operability of Civil and Military aircraft in the International/National Air Space

         The commercial aircraft need to comply with ICAO requirements of communication, navigation and surveillance (CNS) and Air Traffic Management (ATM). The latest ICAO decision mandated use of GNSS (Global Navigation Satellite System) and ADS-B (Automatic Dependence Surveillance Broadcast). With airspace becoming congested, dedicated airspace for military operation has become an issue. Therefore, optimum utilization of airspace has become essential. Further, when military aircraft flies in the national air space, it would share the airspace with national and international traffic, therefore, the military aircraft also is required to comply with the same requirement of CNS, ATM and TCAS. Thus for the interoperability of the two aircraft a common frame of rules are to be formulated.   The concept ‘Performance Based certification’ (PBC) has been proposed by Euro Control for the military systems to meet civil CNS/ATM requirement so as to fly in common air space.

Civil Certification of Military Aircraft

        Airbus military A400M Transport aircraft has been type certified by EASA following CS-25 and Initial Operational Clearance accorded on compliance to the additional military requirement indicated by the French Air Force. Lockheed martin has notified FAA for type certification of L-382J Hercules (civil variant of C-130J Super Hercules) to be marketed as LM-100J. In India Advanced Light Helicopter, Dhruv designed to meet UK MOD Def-Stan-00-970 was type certified by military airworthiness authority CEMILAC, DRDO. The same helicopter was later accorded type certification for civil use by DGCA, Min of Civil Aviation, Gov. of India, based on the tests earlier conducted. US military operates FAA certified aircraft as military commercial derivative aircraft (MCDA). FAA has released an Advisory Circular AC–20-169 and created a Military Certification Office to provide certification and continued airworthiness of MCDA. Sweden has also harmonized civil and military certification procedure considering cost of testing and certification of the same product more than once to satisfy two different authorities and applications.

        

Unified Procedure – Recommendation

         For criticality of application of military combat aircraft, it is recommended to continue the military certification of combat aircraft. However, considering the enormous cost and effort required for certification, it is advisable to have unified certification for the transport category aircraft for use in civil and military application. A unified approach is recommended for the certification of non combat aircraft as follows:

a)      Design and Production Organisation approval (DOA and POA) to be accorded following             international norms as per ICAO Airworthiness Manual. The design codes to be followed are as         per appropriate FAR category.

b)      The basic aircraft (green aircraft) can be certified on compliance to FAR requirements. The                 additional military staff requirements are to be marked as ‘Critical Review Item’ (CRI).

c)      While worldwide, the civil certification authorities have wider expertise in aircraft certification           and therefore, are entrusted for military aircraft certification also. In India, DGCA are not                   considered to possess requisite manpower and expertise to take up aircraft certification.                       Considering the availability of manpower and other infrastructure, CEMILAC, DRDO is                     recommended to take up the certification activity. 

d)      However, ICAO recognises only DGCA and not CEMILAC. Thus the type certification for civil         application has to be endorsed by DGCA. Thus it is required to have a close co-ordination                   between CEMILAC and DGAQA at all stages of aircraft certification. 

e)      It is recommended to from an apex organisation (Aerospace Commission) for overseeing these       two organisations and provides directions so that duplication of certification effort is avoided.  

f)       The apex organisation will give direction towards acceptance of all CRIs based on the military           compliance and accord operational clearance for service induction of the aircraft.

g )    To provide interoperability in the national airspace, performance based certification and                      unification of CNS/ATM to be implemented. 

Conclusion
        Certification is a costly and time consuming activity. Besides it is a specialised and a different task compared to design and manufacturing. Safety is a concern for both civil and military authorities. It therefore does not make sense to spend time and effort to certify the same aircraft twice just to satisfy two different regulatory autheirites.