Homegrown LUH Takes To The Skies

Yesterday, as Pakistan’s armed forces were celebrating their 51st ‘Youm-e-Difaa’ (National Defence Day), the Ministry of Defence-owned Hindustan Aeronautics Ltd (HAL) conducted the 15-minute-long maiden flight of its homegrown, multi-role, 3.15-tonne, single-engined Light Utility Helicopter (LUH), 440 of which are required for the three armed services of India (125 for the Air Force, 259 for the Army and 56 for the Navy) over the following decade.

Yesterday’s LUH maiden flight was the culmination of seven years of R & D, this being indicative of a longer-than envisaged R & D period for the prototype. The MoD, it may be recalled, had sanctioned Rs. 376 crores for developing the LUH and HAL’s Rotary Wing Research & Design Centre (RWR & DC) began working on this project in February 2009. The MoD had then specified a target date for each of the LUH’ R & D milestones: building a full-scale mock-up; the design freeze; maiden flight; and attainment of Initial Operational Clearance (IOC). Back then, HAL had promised to freeze the LUH’s design by late 2010; conduct the maiden flight of the first prototype by 2012; obtain the certificate of airworthiness and IOC clearance by 2014, and begin delivery of series-production models by 2015.

But, as expected, none of those targetted milestones were met. The LUH’s design was frozen in only 2013 and its sole full-scale mock-up for evaluation and assessment was ready only by February 2015. Only after that did work begin on building a ground test vehicle (GTV) for design validation and testing of all dynamic systems, and the three projected flying prototypes for flight-tests and airworthiness certification. As of now, the revised milestones call for the flight-tests and airworthiness certification processes to be completed by 2019 at best, with IOC being targetted for 2021. All-in-all, therefore, a delay of six (06) years.

Such delayed attainment of the specified R & D milestones have been witnessed in case of the homegrown, 5.8-tonne light combat helicopter (LCH), work on which had begun at HAL’s RWR & DC way back  on October 3, 2006 when the MoD sanctioned a sum of Rs.376.67 crores for HAL to design and develop the LCH over a 24-month period. Powered by twin Ardiden 1H (1,200shp TM333-2C2 Shakti) engines, the first LCH prototype—TD-1—completed its first ground-run on February 4, 2010 and its maiden flight was logged on March 29, 2010. 

Exactly a year later, the Indian Air Force (IAF) placed a production indent with HAL for procuring 64 LCHs.  Three months later, the LCH’s second prototype, TD-2, made its maiden flight on June 28, 2011.  The third prototype—TD-3—made its maiden flight on November 12, 2014, while the fourth and last prototype—TD-4—took to the skies on December 1, 2015.

The LCH was originally targetted in 2006 to achieve its IOC by 2013, but as of now, it has yet to complete its weapons-firing trials (due to delayed availability of the DRDO-developed HELINA IIR-guided ATGM) and its self-protection sensor suite (comprising radar warning receivers, laser warning receivers and missile approach warning system) has yet to be integrated with the airframe. IOC attainment now is not expected before the end of 2018. The estimated delay in milestone attainment is six (06) years as well.  

The LUH, powered by a single 750kW Turbomeca Ardiden 1U engine along with a HAL-developed main gearbox and a Turbomeca-designed transmission, will have a maximum all-up-weight of 3,150Kg, have a range of 350Km and service ceiling 6.5Km (21,300 feet), and a seating capacity of six passengers plus two pilots. The LUH, being multi-purpose, will carry out various roles such as armed reconnaissance, troop transport, CASEVAC, ferrying underslung cargo, search-and-rescue, and flying training.

Just like the 5.5-tonne Dhruv ALH and LCH, the LUH will contain an avionics suite developed by HALBIT Avionics Pvt Ltd (HALBIT), which was created in May 2007 by Israel’s Elbit Systems, HAL and MerlinHawk Associates Pvt Ltd. The suite will include an: integrated AMLCD-based glass cockpit, a chin-mounted ‘Compass’ lightweight FLIR turret licence-assembled by the MoD-owned Bharat Electronics Ltd, a HAL-developed multi-bandwidth software-defined radio, and the Colour ANVIS NVG night vision goggle. The self-protection sensor suite, supplied by Sweden’s SaabTech (and identical to those installed on the LCH and the ‘Rudra’ helicopter-gunship version of the Dhruv Mk.4 ALH), will be installed and integrated by HALBIT.

In addition, several force-multiplier options are on the table for incorporation, since a low-flying LUH will be especially vulnerable to threats such as difficult terrain, enemy fire and the intersection of utility wires in the flight path, and will therefore often be required to operate in a Degraded Visual Environment (DVE), adding to the already heavy workload and leaving flight crews to rely on NVGs to accomplish their mission. Factors limiting the pilots’ FOV include: complete darkness, poor weather conditions, brownouts, whiteouts and sandstorms. 

To overcome such shortcomings and limitations, Elbit Systems’ BrightNite solution is now available. BrightNite enables utility helicopters of all types to successfully perform DVE missions in more than 90% of night-flying situations, providing them with piloting capabilities of attack helicopters.

Lightweight and compact, BrightNite is a multi-spectral end-to-end panoramic piloting solution that delivers the essential data directly to both eyes of the pilot, enabling intuitive flight in a head-up, eyes-out orientation in pitch dark and other DVE conditions. For helicopters like the Rudra and LUH, this unique solution comprises a FLIR turret and highly sensitive Complementary Metal-Oxide Semiconductor (CMOS) sensors that present an ultra-wide field-of-regard intuitive image to a display system that projects into the ANVIS helmet-mounted NVG. The display is overlaid by a synthetic layer that follows the contours of the landscape and a third layer of 3-D conformal symbology, which displays hazards, mission-conformal symbology and tactical data. Multiple crew-members can simultaneously scan the entire field-of-regard, using a single sensor and the synthetic world, thereby enabling them to fly in common line-of-sight.

Like the Dhruv/Rudra and the LCH, the LUH too adheres to the following FAR/MILSPEC standards:

* US Army Aeronautical Design Standard-33E (ADS-33E)

* Flaw-Tolerant Rotor System: FAR/JAR 29.571, AM 29-28

* Crashworthy Fuel System: FAR/JAR 29.952, AM 29-35

* Flaw-Tolerant Drive Train with Over-Torque Certification: FAR/JAR 29.952, AM 29-28

* Turbine Burst Protection: FAR/JAR 29.901, AM 29-36

* Composite Spar Main & Tail Rotor Blades with lightning strike protection: FAR/JAR 1309(h), AM 29-40

* Engine Compartment Fire Protection: FAR/JAR 29.1193

* Redundant Hydraulics & Flaw Tolerant Flight Controls: FAR/JAR 29.571, AM 29-28

* Aircraft-Wide Bird Strike Protection: FAR/JAR 29.631, AM 29-40

* Crashworthiness Standard: NATO’s MIL-STD-1290

* Crashworthy Seats conforming to MIL-STD-1472B

* Cockpit Instrumentation Lighting Conforming to MIL-STD-85762A

* Avionics Databus: MIL-STD-1553B or ARINC-429

* Autopilot Accuracy: MIL-F-9490D

* Embedded MIL-STD-188-141B ALE Link Protection

* Embedded MIL-STD-188-110B data modem

When operating as an armed aeroscout platform for battlespace surveillance, the LUH will be armed with twin rocket pods housing 2.75-inch rockets supplied by Belgium’s FZ, and four Mistral ATAM air-to-air missiles from MBDA.

Series-production of the LUH will be undertaken at a greenfield facility set up by HAL at BiderehallaKaval, Gubbi Taluk, Tumakuru, about 70km from Bengaluru. The foundation stone for this facility was laid on January 3, 2016 by India’s Prime Minister Narendra Modi. 

For radically improving the LUH’s hot-and-high operating parameters and enhancing flight safety, an option that could well be utilised in future under the auspices of the US-India Defence Trade and Technology Initiative (DTTI), under which HAL will be required to form an industrial partnership with US-based AVX Aircraft Company for incorporating the latter’s patented modification kit into the LUH’s airframe.

With its unique blend of co-axial rotors and dual ducted-fans, the AVX  kit offers greater aerodynamic and fuel efficiency, speed, range, payload, improved hover-out-of-ground effect (HOGE), and the ability to operate in hotter temperatures and at higher altitudes than any of today’s conventional light helicopters. It also reduces brown-out conditions in the landing configuration since, thanks to the ducted-fans, the helicopter can use a 5-degree nose-down or even-level approach to the landing zone. This increases flight safety by giving the pilot a greatly improved view of the landing zone.