In a body blow to the government’s continual Atmanirbhar campaign, Indian Air Force (IAF)announced that Tejas, the Light Combat Aircraft (LCA) and Dhruv, the Advanced Light Helicopter (ALH) – both showpieces of indigenous aerospace prowess – would be benched for the 2025 Republic Day Parade fly past, an extremely popular and keenly awaited spectacle over Kartavya Path (erstwhile Rajpath). While the reason for the Tejas being kept away was an IAF policy decision to disallow single engine aircraft due to safety concerns, the Dhruv was kept away as it had been grounded after an India Coast Guard (ICG) Dhruv crashed at Porbandar Airport on January 5 this year. All three crew members perished during the accident and an investigation is ongoing. At the time of writing this, the final report of the defect investigation team, initially expected on March 3, is still awaited.This article looks at the chequered history of the Dhruv, the build up to the grounding, and suggests prescriptive action to render the Dhruv a reliable platform.
By Gp. Capt. AK Sachdev (Retd.):
The Dhruv Story
The Dhruv story is a cause for Indian pride as the helicopter is an indigenous aerospace success story. It has been used extensively, including at high altitude, and in many roles including transport of passengers and cargo, utility, reconnaissance, medical evacuation, and weaponized roles over land and sea.Designed by the Rotary Wing R&D Centre of Hindustan Aeronautics Limited (HAL), it is a twin-engine helicopter in the 5.5 ton plus category (i.e. the Maximum Take Off Weight or MTOW is 5500 kg). It first flew in 1992, entered military service in 2002, and received type certification from Directorate General of Civil Aviation (DGCA) for civil operations in 2004. Some reports claim that more than 400 Dhruvs have been produced but, according to HAL’s own website, the figure until June 2024 is 345 of which 313 were for Indian defence services (including ICG). Interpolating the production figures, another 15 could have been manufactured since June 2024 thus taking the total produced to around 360.
There are four military versions numbered Mk-I, Mk-II, Mk-III and Mk-IV, the last one being a 5.8 ton machine. While the first two are utility versions and use a Turbomeca (now Safran Helicopter Engines) TM333-2B2 powerplant, the latter two use the ARDIDEN 1H1 engine (developed in collaboration with Safran and named Shakti). The Mk-III is a utility role platform suitable for high altitude operations while the Mk-IV is essentially a Mk-III with weapon systems and mission sensors and is called Rudra while another version, the Light Combat Helicopter (LCH), or Prachand, is also based on the Dhruv design. The Sarang air display team of the Indian Air Force (IAF) also uses the Dhruv.
HAL’s Trials, Users’ Tribulations
The Porbandar airport accident was the third crash involving the Dhruv in four months. The Dhruv has flown more than 4,00,000 hours reportedly since induction but in the last 23 years, there have been 30crashes of which 13 were fatal, leading to loss of 39 valuable crew lives. Of these, four were in Ecuador and the rest in India, with IAF and Indian Army suffering the majority — a total of 20 accidents. Of these,thirteen were attributed to technical faults and that is a very high proportion. The remaining are either unsolved or have been pinned on human error but when one views the tenor and texture of the technical issues that surfaced with each successive crash (and averted accident), one is nudged into considering the possibility that even the crew who erred could have been operating in the presence of what air safety professionals term as hazards inherent to the helicopter’s design or its manufacturing process.
Understandably, the findings of military Courts of Inquiry are not revealed in their entirety to the public domain. However, DGCA is mandated to “issue Airworthiness Directives (ADs) in respect of any Indian civil registered aircraft,engine, propeller and appliance fitted to such aircraft to make good of any feature orcondition affecting safety of the aircraft. (sic)” ADs issued by DGCA consequent to each Dhruv accident/incident reveal an interesting tale of their own. DGCA’s official site has details of AD’s issued from July 2008 until July 2023 up to which date 39 Ads have been issued of which one has been superseded. Of the 38 current ones, 34 relate to Dhruv. Some more could have been issued before July 2008 and at least three more would definitely have been issued after July 2023 (after the accidents since then). This statistic is significant when juxtaposed to the fact that the civil Dhruvs are a handful in number.
The ADs and public domain reports from pilots who have flown and/or test flown the Dhruv point to one major problem being vibrations on the Integrated Dynamic System or IDS which comprises the Main Gear Box (MGB), upper controls and the rotor head. The IDS is a critical component that transfers the power produced by the engine to the rotors above it. A system built into the original design did not serve its purpose well and so another system was retrofitted to reduce the vibrations in the area occupied by the crew and passengers.
The failure to assault the root cause led to cascading events and destructive failures along the entire transmission system and the allied control systems. So, with successive accidents patch solutions were found e.g. when an accident revealed broken control rods, they were replaced with stronger, stainless steel ones (without addressing the MGB platform vibrations). As a result, the problem shifted upwards to the swashplate, a mechanical device that translates input via the helicopter flight controls into motion of the main rotor blades. HAL Chairman and Managing Director (CMD) DK Sunil reportedly attributed the Porbandar Airport Dhruv crash to “swashplate fracture”. Space constraints limit description of many such reports which underscore not just the quantitative but also the qualitative texture of the defects revealed by successive accidents.
Some experts feel that the swash plate (and the IDS) are not the problem as the January 5 accident is the first one in which the swash plate is the accused. Nonetheless, some of the problems are, as one pilot puts it, continuing “birthing pangs”. The Directorate General of Quality Assurance (DGQA) has the responsibility of quality assurance of the Dhruv from its birth, while Centre for Military Airworthiness and Certification (CEMILAC) is also required to be associated with design and development and subsequent military certification. A major systemic flaw is the fact that DGQA and HAL are both under the Department of Defence Production (DDP) and thus, are the responsibility of the same Secretary. One wonders how objective would the DGQA be in its quality assurance diligence and how many of its findings and recommendations would be accepted by the same Secretary who is responsible for HAL’s production figures.
There is also the constant refrain from crew that the corrective actions by HAL have been band-aid ones and have not addressed the major design problems. While the zealous rush to make the first Dhruv sale is understandable, the slew of accidents that afflicted the helicopter raises a question about the level of diligence applied by DGQA during the design process and CEMILAC and DGCA for the military and civil certification processes.
Concluding Remarks
More than 300 Dhruvs, military and civil, remain grounded since January 5 this year. Some critical and inescapable tasks that the Dhruv was being used for are now being carried out by the Army through hiring of civil helicopters. On February 11, HAL CMD told media that, “By March 3, we’ll determine if the fleet needs a full review or if this is a one-off glitch.” More significantly, he said, “No inherent flaw exists in the helicopter.” He also, by implication, hinted that training gaps or maintenance oversights were the possible causes. A committee was formed under the chairmanship of Air Marshal Vibhas Pande to investigate the January 5 accident but reports indicate that the Committee is to address maintenance practices of ICG.
These reports appear accurate as he was the Air Officer Commanding in Chief of IAF’s Maintenance Command. It may be mentioned here that the daily servicing of ICG Dhruvs is being carried out by HAL personnel. It would appear that HAL is carrying out its own investigation on the accident too. As at the time of writing, nine weeks have passed since the last accident and there is no clarity about the next steps. It is possible that the report is taking time as HAL realises that this time it may be difficult to gloss over the root causes of the accident as the matter is in the public domain — bare and exposed. However, HAL has demonstrated in the past that it has a strong lobby and may yet avert any finger being pointed at it.
The defence services have never been satisfied customers of HAL and are wary that the current investigation may also not address the core issues of design. It is not just the defence services that are unhappy. HAL has been trying to export the Dhruv too and has limited success, the most sordid saga being with Ecuador. In 2009, Ecuador purchased seven Dhruvs. Over the next six years, four had crashed and finally, in 2015, Ecudaor declared the helicopters unfit for operation and discontinued their use.
Inevitably, the Dhruv safety record debate tends to get entangled with the Atmanirbhar refrain. As a flagbearer of the indigenous aerospace industry, it cannot afford to be afflicted by recurring accidents that denounce HAL’s design, production and maintenance processes while raising questions about quality assurance and certification. Although it appears far fetched as yet, if the trend continues, Dhruv users could start window shopping for equivalent helicopters with a better safety record, even if they are not indigenous designs. Whether HAL’s robust lobby at the centre will ever let a foreign helicopter come into the Dhruv’s domain is doubtful.
Whether it is a military or a civil user, helicopter availability and serviceability figures are important but, when it comes to safety, and human lives are at stake, there is a limit to which users will endure disturbing occurrences, near misses, incidents and accidents. With three accidents in four months, perhaps it is time to pause and ponder and carry out a comprehensive fact finding and fact evaluating exercise encompassing all 30 accidents to reach long term solutions instead of patch remedies. If that means a long period of grounding while HAL goes back to the drawing board to address the strands that connect most of these accidents, so be it.
( Views expressed are personal)
