Can India build world-class flight control actuators for military aircraft?

Every Tejas fighter now flying relies on five imported components to move its most critical control surfaces — four elevons and a rudder. As of 2024, those primary flight control actuators are made entirely by one American firm, Moog Inc. Import dependence for them stands at 100 per cent.

An electro-hydraulic actuator is the muscle of a fly-by-wire aircraft. It combines electric command, hydraulic power, servo valves and precision cylinders to convert a signal from the flight computer into exact movement of a control surface — hundreds of times a second, under pressure and temperature cycling that few materials survive. On the Tejas, hybrid electro-hydraulic actuators take orders from a quadruplex digital fly-by-wire computer, meaning any indigenous actuator must prove flawless compatibility with that computer before it can fly. This is why only a handful of nations — the United States, United Kingdom, France and Germany — build them at the front rank.

India has now crossed the first line. On 19 April 2024, the Aeronautical Development Agency handed HAL the first batch of indigenous secondary flight control actuators — the servo-valve-based units for the Tejas Mk 1A's leading-edge slats and airbrakes — after successful flight trials. Developed by ADA with Research Centre Imarat, Hyderabad, and CMTI, Bengaluru, these are cleared for integration and are being produced at HAL's Accessories Division, Lucknow. That is demonstrated capability, moving into limited production.

The harder half remains in testing. The primary actuators are the work of the DALIA programme — Development of Advanced Linear Actuators — led by the Vikram Sarabhai Space Centre and begun around 1998. Integration testing of the DALIA units began at HAL's Iron Bird facility in November 2024, validating them against the flight control computer. An HAL official has said the indigenous actuators outperform Moog units on several parameters at roughly one-fourth the cost.

Why the gap persists is a matter of sequence, not capacity. An original plan to fit all 13 indigenous actuators on the first Mk 1A was deferred; developmental testing and type certification of the primary units took a back seat, and ADA only restarted the software work to make the digital flight control computer compatible with them in May 2024.

Closing the gap now turns on certification. The primary actuators must complete developmental flight testing and clear CEMILAC airworthiness approval — the final, unforgiving step between a component that works on the test rig and one trusted to keep a pilot alive.