PSI - Issue 14

Manu Jain et al. / Procedia Structural Integrity 14 (2019) 184–190 Manu Jain / Structural Integrity Procedia 00 (2018) 000–000

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component is obsolete or requires advance technology. The modification will have to be incorporated in the other units also. This should have the concurrence of the design group of the project. Overhauling Overhauling is required for the life extension of the Air Vehicle. After the repair / modification and overhauling the units undergo visual inspection, bench check and finally airborne units have to undergo mandatory Environmental Stress Screening (ESS) and it has to be qualified as per the Acceptance Test Procedure (ATP). Replacement If any unit does not pass the ATP or is Beyond Economical Repair (BER) then that unit has to be rejected and replaced. 5. Life extension of Indian UAVs Every UAV has a shelf life and operational life based on its design criteria, role envisaged, storage and environmental conditions. Indian services have deployed various configurations of UAVs for various objectives /applications under different operational environments. Each UAV is designed with a different design philosophy and structural materials, which calls for a wide range of life extension procedures and techniques. Retiring/discarding a UAV without full use of its life, maximizing performance and minimizing cost is not advisable. This will lead to wastage of resources and time. India believes in value, attaching the importance of the performance of the UAV to its cost. Indian services prefers to overhaul or extend the life of UAVs with minimum or limited resources available to meet the operational requirement of airworthiness of the UAVs. Aeronautical Development Establishment, Bengaluru has designed & developed various classes of UAV’s which have been inducted into the tri-services and utilized successfully. In this paper, a high speed UAV named Lakshya which is an Advanced Pilotless Target aircraft and a low speed UAV named Nishant which is a surveillance aircraft are considered. These UAVs have unique characteristics and operational environment, details of these is presented in table 1. 4.2.3. 4.2.4.

Table 1. Characteristics and operational environment of Lakshya and Nishant Operation/Function Lakshya

Nishant

Launch Mode/Phase

 Zero Length Launcher  Target firing practice  Gunnery practice  Scoring practice

 11m rail launch, Hydro Pneumatic Launcher

Mission/Work

 Surveillance  Border patrolling  Target acquisition

Material

 Mostly metal (aluminum, steel etc.)

 Mostly glass fiber reinforced composite, with metallic bulkheads

Recovery/Retrieval

 Parachute system  Sea recovery/Land recovery  10 years shelf life  10 sea dunking/Land recovery

 Parachute & Landing bag  Land recovery

Life

 10 years shelf life  15-20 landings

ADE’s Lakshya and Nishant UAVs have under gone life extensions to ensure that they can continue to be airworthy even after their use by date. ADE has followed the following criteria for life extension of UAVs  The number of UAVs in operation / usage or available in the squadron and criticality of their requirement  Operational & storage environment which is based on the location of the squadrons  Component availability and technology obsolescence  Reliability and safety of operations in extended life  Economical savings from maximizing the potential use of the UAVs and lower maintenance cost.