The Indian Coast Guard faced arguably its lowest point in history when the service lost its second Advanced Light Helicopter Mark III Maritime Role (ALH Mk3MR) in four months. CG 859 crashed at Porbandar airport at about 1215 hours on Jan 5, 2025 while on a routine training sortie. Videos shared by onlookers show the helicopter engulfed in flames on the runway shoulder. Three crew onboard — Comdt Saurabh, Dy Comdt SK Yadav and Pradhan Navik Manoj — were recovered from the wreckage and shifted to Government Hospital, Porbandar, but it was too late. All three crew members perished in the crash.
Unprecedented losses
On Sep 2, 2024 another ICG ALH, CG 863, had crashed into the sea off Porbandar while on a night medevac mission killing both pilots & one ACM(D). The board of inquiry (BoI) into that accident would perhaps have just concluded before CG 859 from the same squadron became a smouldering wreck at the same home base. ICG has now lost three of the 16 newly-inducted ALH Mk3 MR with a sobering loss of six lives. 835 Squadron (CG) Porbandar has been whittled down to two helicopters, with more than half the squadron’s flight crew wiped out in ALH crashes.
Though army and IAF have had more than their share of ALH losses, this tragic turn is unprecedented in ICG’s history. Indian Army’s 254 AA Sqn for instance lost two ALH Mk4 ‘Rudra’ in less than seven months in 2021 (both fatal). For the ICG, the latest crash makes it three hull losses of the ALH Mk3MR in less than two years. It is a damning statistic produced by the cruel intersection of design, execution and HFACS; definitely not something to be normalised.
Preliminary eyewitness accounts
A preliminary eyewitness account quoting HAL onsite team indicates that the helicopter completed one training sortie of about 90 minutes, did a ‘running change’ (crew changeover with rotors running) and left for the next training sortie in which it crashed. As per a report shared on social media, the helicopter apparently crashed nose-down from hover at 200 feet. This is at variance with other another version that the helicopter spun out of control and crashed left of the runway during a go-around. The BoI will have to seek out more eyewitnesses, including video footage if any, and corroborate these with cockpit voice recorder and flight data recorder (CVFDR) data to piece together the accident. Unlike service airfields where every takeoff and landing is video recorded, civil airports such as Porbandar run by Airports Authority of India (AAI) are not required to do so. However, air traffic controllers on duty will be able to give a more reliable account of the last moments of CG 859.
It is understood that the CVFDR has since been shifted to Bangalore for analysis. Decoding, analysing and making sense of this data could take anything from a few days to months, depending on the post-crash integrity of the ‘black box’ and investigation protocols involved. While the BoI investigates the circumstances that brought down CG 859, a few issues germane to ALH and its chequered history beg a revisit.
Control actuator issue
Fractured control rods in the flight control chain of the ALH have led to at least half a dozen crashes, some fatal. In some cases, the post-crash fire consumed the evidence while in some recent crashes, the retrieved broken rod provided telltale evidence. This author had explained the issue of ‘collective eye-end failure’ and ‘booster rod failure’ after a fatal army aviation ALH crash in Arunachal Pradesh (read here). Major failures in a helicopter’s flight control chain will almost always be catastrophic. Certification thus requires such a high level of reliability and redundancy of hydraulics and the entire flight control chain as to preclude a major failure in the entire life of the fleet. However, it took multiple accidents and copybook ditching of naval ALH Mk3MR IN 709 off Mumbai in Mar 2023 for HAL and military certification authority CEMILAC to confront the issue with the seriousness it deserved.
After IN 709 ditching and the fleetwide grounding that followed, HAL recalled all existing ALH control rods for load tests and subsequent replacement of legacy control rods with stainless steel ones. This approach suggests that the loads on legacy control rods were either outside design limits or the design/metallurgy of the component was suspect. However, HAL agreed to neither and, as per a news report of May 23 below, blamed the failure on maintenance error and called the new rods as “design improvement“. It is my reading that the services, HAL and CEMILAC have made peace with the control rod issue without going to the root of the problem. It will thus not be surprising if such catastrophic failure raises its head again. This “something broken, something fixed” approach of HAL is neither new nor surprising. Yet the services seem happy to go along.
An uneven playing field
One of the reasons for the inability of services to take HAL to task is the unequal playing field the PSU enjoys while dealing with its customers. Nowhere is it more prominent than in the access to data related to component failures and accidents. The services operate in silos and are loath to share their internal travails in the fleet with other users. While HAL has almost complete access to this data across services, individual users do not have access to a common repository of such data. This is a serious systemic flaw that needs to be plugged. The three service and ICG together operate over 330 ALH. It is incomprehensible why safety-critical information, data pertaining to failure rate of components & reasons thereof, and accident reports should not be easily accessible to ALL users on a common grid.
Performance Based Logistics (PBL)
This author had flagged serious concern about the PBL clause loading the dice against a fledgling service (ICG) grappling with its first major induction of a complex machine. It is not clear on what basis and for whose benefit the 75% aircraft availability and 45 hr/mo/ac figure was arrived at. The relentless pressure to maximise gains from the PBL contract by flying 45 hours per month should have been reviewed after CG 863 accident. From all accounts, the coast guard’s existing bench strength of pilots & maintainers have been hard put to deliver this quantum of flying. Also, the question begs answering whether HAL would have deputed the best of their support crew for four dispersed locations across India. Was there a case to throttle back on monthly flying task till at least the CG 863 accident report was reviewed and course corrections implemented? Now that tragedy has revisited Porbandar, maybe the authorities will pause to listen to whatever boots are left on the ground.
Major failures that go under the radar
The shocking failure rate of key components of the ALH across services also needs to be investigated by an independent agency with no affiliation to HAL. It is reliably learnt that between 12-14 main gear boxes, or Integrated Dynamic System (IDS) as it is known in the ALH, have had to be withdrawn from a newly-inducted fleet of 16 helicopters of the ICG alone. The other services have their own horror stories. In which part of the world would this be acceptable? Add to this, frequent instances of hydraulic failure, engine/MGB chip, MFD failure, engine failure and so on have become par for course. There have been at least three recent cases of ‘power loss’ (single engine failure) on ALH in as many months that have gone unreported in the largely lazy defence beat of Indian media. While individual services window-dress their statistics and hoard such information, the OEM gets a long rope to escape each time. HAL is not entirely to blame for this. Any OEM with a bottomline to protect will take the easier route if the customer allows them to. Watchdogs like CEMILAC, RCMA and DGQA are busy playing the proverbial ostrich while people die. It is a lamentable state of affairs that calls for an independent investigation and a holistic appraisal. Presently, the murder weapon and the evidence has been presented to the accused himself. It is akin to the police investigating police brutality, for want of a darker metaphor.
Design gaps that manifest as pilot error
A little-known and far less researched area of ALH is design gaps that may manifest as ‘pilot error’ or ‘maintenance error/shortfall’ (a term now replaced by ‘human error’ but i use it here intentionally). I give you just a few examples from the top of my head so that it may inform future design:
- Providing a trigger-guard on the ‘AFCS off’ switch that can be inadvertently operated by a pilot tightening his/her grip on the cyclic. In a stressful situation or in the incipient stages of spatial disorientation or inadvertent IMC, this can lead to a loss of control inflight (LOC-I).
- Integrating and enclosing upper controls inside the IDS thus hampering daily inspection of critical flight control components (maintenance).
- Designing lateral and longitudinal control rods that are capable of being installed wrongly (CG 855 crash at Kochi, 2024).
- A rotor and flight control design that brought a new term into ALH pilots’ lexicon — lateral cyclic control saturation.
- Four-bladed rotor system that became a nightmare for vibration control, leading to innumerable maintenance flights.
- Nuisance warnings generated by HTAWS that incentivises pilots to disable the system thus denying them the protection it was meant to provide.
In my experience, HAL has always resorted to band-aid fixes and additional warning/cautions rather than walking back a design, that too after much blood was spilt. Ego and pet peeves have often ruled over prudence and a long-term perspective on safety. Regulators and certification authorities have stepped in far too late, if at all. If the last gate of safety in HAL — the elite team of test pilots and test engineers in HAL Flight Operations — also start toeing the party line rather than going for ‘precision and excellence’ in flight testing, we are looking at a very bleak future.
Where is the incentive to improve?
Reproducing a paragraph from a blog i wrote in 2018 sounds apt for the occasion:
In my time with the industry, I have seen up close young, bright minds, eager to ‘make a dent in the universe’ like Steve Jobs. Working in aerospace design and development is a dream many young Indians will die for. But the entry barriers are huge, quality benchmarks are nebulous, you need chacha batija connections to get inside. Once you join a PSU like HAL, a safe, secure job awaits you. Unions protect the workers’ interests while middle and senior management run around like headless chicken. Test crew – all former military pilots – can’t look beyond their noses. Narrow parochial interests and hubris pervades all discussion.
Nothing has changed. This is where we have parked all our hopes for the future.
In a way, the services drawn into a deadly embrace with their tormentors, with undefined atma nirbharta goals and well-defined import-ban lists, have invited this misery upon themselves. Strategic partnership model for boosting Make in India and private sector participation in big-ticket aerospace and defence manufacturing in India is all but dead. All we have is a public sector behemoth with zero competition and orders on a platter for the foreseeable future. To expect world-class quality and commitment to safety in this scenario is to live in a fool’s paradise. This aspect was dwelt upon by none other than IAF Chief Air Chief Marshal AP Singh while speaking at a recent seminar (watch here).
Earlier (10-15 years ago), there was token resistance to the shenanigans of these sloth-laden PSUs and some hard talk was possible. Now there is none. One even felt a sliver of hope that the right-wing Modi government would be able to bring in competition or straighten out the inefficiencies of these PSUs. Even that has proven to be a pipe dream. Very soon, our forces will be taking dictation from PSUs on how to write specifications or dilute products. The Indian armed forces in general and the rotary wing in particular will ultimately pay the price in blood for this shameless charade where monopoly rules the roost in a monopsony.
If the long trail of blood and the latest crash of CG 859 does not shake our collective conscience, I do not know what will.
***************
© KP Sanjeev Kumar, 2025. All rights reserved.
Views expressed are personal, written with a view to raise awareness and contribute to flight safety. Feel free to debate and contribute to the discourse. Please avoid speculation and keep comments respectful of the deceased and their families. I can be reached at realkaypius@gmail.com.
Such frequent crashes are unacceptable. It appears we are not learning our lessons from the past accidents. Hope the urgent corrective actions are taken to ensure no more crashes
Kaypius, once again you are spot on with all that plagues the ALH-HAL world. It is so sad to continue loosing precious trained human lives for deficiencies of design/material/ workmanship ….. and above all the lackadaisical attitudes of both sides.
Kaypius, once again you are spot on with all that plagues the ALH-HAL world. It is so sad to continue loosing precious trained human lives for deficiencies of design/material/ workmanship ….. and above all the lackadaisical attitudes of both sides.
Very well written a really sad story of the HAL- services aviation journey where hiding facts has a long history. Really unfortunate
This is another Dhruv accident that should not have happened. From the eyewitness accounts of the helicopter crashing from a 200 ft hover it seems like a control / AFCS malfunction or failure that prevented the crew from recovering.
A series of many such failures over the lifetimes of numerous ALH helicopters would suggest a serious design flaw in its IDS ( Integrated Dynamic System) ,hydraulic systems in conjunction with AFCS etc .
Like was suggested in previous occasions a high level empowered committee of capable members with backgrounds of the Operation , Regulations and Industry must be formed and investigate in a holistic manner what happened, why it happened and what are the solutions that can help solve these problems and ensure greater safety and reliability of the Dhruv helicopter.
Like WESTLAND in 80 s when ONGC Epmloyees refused to fly in WESTLAND and the entire fleet was grounded, ONGC Employees are in for the same situation once again…for whom the new TRIAD of HAL-PHL-ONGC is being formed with DHRUV as AXIS…
TUMULTUOUS JOURNEY OF ALH/DHRUV HELICOPTER… THROUGH THE YEARS….
2002-2025
——————————–
Having done a little bit of research on ALH/DHRUV HELICOPTER ACCIDENTS …I am finding the data to be horendous and hearwrenchibg when viewed in totality. Viewing one odd accident points out only to local and specific issues and doesn’t show the SYSTEMIC MALAISE. One has to go through the history of accidents and the trend to arrive at wholistic figure.
In a few days, we will forget these 3 lives lost in Porbandar crash yesterday on 05 Jan 25 like we have done with earlier ones…and the world will move on. What will remain is grim SPIKE TREND in accidents and loss of valuable LIVES in DHRUV unless some DRASTIC measures are taken at highest level and the ACCOUNTABILITY is fixed at every stage. Otherwise, it will not only keep KILLING people…it will also KILL the HELICOPTER INDUSTRY in long run by scaring away the potential users.
What I am presenting are only WHATs (FACTS) drawn from information available in media , and I will leave HOW & WHY to your wisdom to analyze and draw lessons…..
DHRUVA THROUGH THE AGES……
2002-2025(23 YEARS)
30 – TOTAL ACCIDENTS
13 – FATALS
39 – LIVES LOST
——————————-
WHERE IT HAPPENED….
04 – ECUADOR GOVT.
26 – ACCIDENTS IN INDIA
11 – AIR FORCE
09 – ARMY
02 – BSF
01 – NAVY
03 – COAST GUARD
——————————–
BREAKDOWN YEAR WISE :-
>>>2002 – 2007(5 YEARS)
02 – TOTAL CRASHES
01 – FATAL
02 – LIVES LOST
>>>2008 – 2012(5 YEARS)
06 – TOTAL CRASHES
02 – FATAL
07 – LIVES LOST
>>>2013- 2017(5 YEARS)
08 – TOTAL CRASHES
04 – FATAL
15 – LIVES LOST
>>>2018 – 2022(5 YEARS)
07 – TOTAL CRASHES
03 – FATAL
08 – LIVES LOST
>>>2023 – 2025( 2 YEARS)
07 – TOTAL CRASHES
03 – FATAL
07- LIVES LOST
——————————-
ANSLYSIS :-
>> 03 YEARS – MAX GAP BETWEEN ANY 2 ACCIDENTS
>> 04 YEARS – NO ACCIDENTS (2008, 2006, 2020, 2016) REST 18 YEAES ACCIDENT EVERY YEAR.
>> 04 – MAX ACCIDENT IN ONE YEAR (2023)
>> 02 FATALS – EACH YEAR IN
2011, 2014, 2021,
>> 07 CRASHES (3 FATALS) – WORST PERIOD 2023-2025(2 YEARS)
>> 28 – MILITARY ACCIDENTS
9 – MAX BY AIR FORCE
>> 02 – CIVIL ACCIDENTS (BSF)/
PHL
>> 08 (03 FATALS) – ACCIDENT IN FIRST 10 YEARS(2002-2012)
>> 22(10 FATALS) – ACCIDENTS IN LAST 12 YEARS(2013-2025)
>> SURPRISINGLY, NUMBER OF ACCIDENTS & FATALS, BOTH INCREASED WITH TECH ADVANCEMENT & EXPERIENCE ON TYPE.
——————————–
NOTE :-
All these data are collected from open media sources in public domain. Since most of them are MILITARY Accidents, there is a likelihood of some errors here and there. However, broadly, these accidents have taken place for sure.
Commander MK Singh(Retd)
Indian Navy
Veteran Helicopter Pilot
Unfortunately, there doesnt seem to be any solution in sight, neither from the Armed Forces nor the civil customers, leave aside the OEM or the govt!
As has happened innumerable times, the fleet across would be grounded, some nut-bolts tightened, ac patted on its back & ‘ghoda-daud-ke-chal!
Frankly, the ball is (has) in the Armed Forces’ court now as far as Dhruv goes.
What surprises me is that HAL/ govt is happily continuing with this safety record which is totally unacceptable in civil flying; who will fly these machines (leave alone buying) with pathetic records?
Lastly, if this is the track-record of the 1st machine from HAL, dunno what will happen with machines that are in pipe-line!!!
Thanks for the wake up call. Please look at three successful government organisations :
Indian Navy (Surface Element)
Simulator Development Division, Indian Army.
ISRO
Please reflect on what makes them different. What makes them successful ?
Nothing has changed and sadly the death count has only increased.The Union govt continues to hear itself and echoes for showboating at little or no regard for human lives.And the agencies that use the product are sworn to secrecy with some privileged to be judge and the accused.This is crony capitalism at its worst.The author continues to challenge this fatal anomaly while getting lonelier
Good article
There is no doubt on PSUs competence and professionalism. They have best of brains…Sadly most of the time used for wrong reasons. Otherwise in same country when ISRO from carrying rocket on cycle, they have been able to put a CRAFT on MOON in second attempt while in the same period HAL has not been able to provide a stable helicopter on EARTH…that says it all…just one word…DISDAINFUL ATTITUDE towards ARMED FORCES whom PSUs consider a CAPTIVE MARKET and their COMMERCIAL SURVIVABALITY is at the cost of LIFE SURVIVABALITY of ARMED FORCES.
And here we ARMED FORCES are equally to be blamed…by ACCEPTING such sub-standard and dangerous product as WAR MACHINE from PSUs even at cost of losing highly trained manpower..
Just think…
ISRO’s remarkable success, both in India and globally, stands in stark contrast to the challenges faced by HAL, particularly in terms of long-term quality issues. While ISRO has consistently demonstrated excellence and innovation, HAL’s struggles can largely be attributed to the organizational culture, which seems to have been influenced by the practices of retired IAF personnel. It’s worth noting that while less than negligible % of ISRO’s workforce comprises of retired defence personnel, HAL, on the other hand, has a significant numbers of its technical staff drawn specifically from IAF retirees who typically join after completing 15 years of service.
This cultural influence, characterized by a “Chalta hai” and “Jugaad” mentality, has often led to promotions for mediocrity rather than meritocracy, hampering HAL’s potential for sustained excellence. Additionally, HAL’s reliance on the IAF as its primary customer, with the majority of its budget coming from IAF allocations, further entrenches this dynamic.
With respect to the ALH , there are significant concerns regarding its composite materials. Personally, I found limited data on effective firefighting measures for composite structures, even when professionals were tasked with developing a detailed plan. The solutions presented were not concrete, and the fundamental issue remains unaddressed: once composite materials catch fire, they tend to burn into pure char, posing severe risks to the crew inside the aircraft. Given that a substantial percentage of the ALH structure comprises composites, this is a critical safety concern that needs immediate and thorough attention.
Addressing these cultural and technical challenges is vital to ensure HAL’s ability to deliver world-class products and maintain its relevance in both domestic and international markets.
No one can improve, until he is willing to accept his flaws. Aviation sector boasts ‘Zero tolerance’ policy to ensure paramount flight safety.. Equally applicable to Defense Aviation sector, where attributability of even smallest incidents, high failure of spares and repetitive snags is being established. On contrary, whenever any mishap, lethal accident occurs, all stakeholders goes in eyewash mode, the investigation approach is mostly remote controlled in order to satiate all concerned so that ‘show must go on’. Overall, we must admit that we indians don’t want to come out of our comfort zone as an individual or an organization..deeply grabbed by ‘Ostrich effect..
Let’s come to ALH Dhruv Aircraft.. If u closely observe the recent pattern of accidents, the threshold point of failure was sudden stress/load on on cyclic/lateral controls while moving out of Hover..extensive study required to understand fatigue on flight controls during all flying profiles of ALH Dhruv..
Let’s hope, all ALH users, HAL,DGAQA and CEMILAC will sit together and conclude something meaningful.
Let’s remember,Armed forces run by Moral of it’s soldiers… but such accidents create doubts, skepticism in maintaners and aircrew’s Mind… Not a healthy sign for aviation.
MAINTENANCE/DESIGN ISSUES OF ALH/DHRUV – CIVIL PERSPECTIVE
Most of us are wondering regarding the actual state of Maintenace/Design issues in ALH/DHRUV. Since allmost all except couple of the accidents happened in MILITARY, the exact nature of defect/malfunction never came out in public and remains wrapped in veil of confidentiality which ofcourse is required for military hardware.
However, due to few DHRUVs being in Civil(Govt) since beginning there is a window to peep into what has been happening with ALH/DHRUV as regsrds to maintenanc/design esince beginning of Commercial Flights courtsey DGCA.
There has been over 30 AIRWORTHINESS DIRECTIVE issued since 2008 on ALH/DHRUV by DGCA based on INCIDENTS/ACCIDENTS of both, Civil & Militaty helicopters.
Here is the compilation of AIREORTHINESS DIRECTIVES on ALH/DHRUV…by DGCA…
DGCA AIRWORTHINESS DIRECTIVE – ALH DHRUV (2008-2023)
(SOURCE – DGCA WEBSITE)
1/7/08
1. AD 001- On one of the DHRUV helicopters, during inspection of IGB area, a crack was noticed. Since an unsafe condition has been identified that is likely to exist ordevelop on other aircraft of the same type design, this Airworthiness Directive is being issued for visual inspection and submit the compliance certificate to Certification and Airworthiness Group of RWR&DC, HAL, Bangalor
2. AD 002 – Crack was noticed at the bolt head of five bolt-blade fork (big) of two DHRUV helicopters.
3. AD 003 – Hydraulic System – 1 pressure and fluid loss was reported on one of the DHRUV helicopters. Likely cause of the leak was attributed to the rubbing of hydraulic hoses with LH TGB fairing.
4. AD -004 – On one of the DHRUV helicopter, there was an in flight warning for collective pitch anticipator (CPA) redundancy failure for engine-2. During check CPA connector was found to be loose. As a result of this, loss of CPA input to the FADEC has resulted and caused failure of CPA redundancy for engine-2.
5. AD 004 – On another DHRUV helicopter, there was a warning for CPA failure on both the FADEC when collective pitch was lowered after touch down. On investigation, it was observed that the CPA input to both FADEC was out of range. Further it was found that CPA moving end check nut was loose and tab washer used for locking the check nut was bent incorrectly. These factors had contributed to the CPA rigging disturbance and were the cause for the snag.
6. AD 004 – There was an in-flight power loss warning followed with large split in NG, TGT and torque parameters of the two engines. Investigations with diagnostic PC revealed that FADEC2 had logged CPA failure. On checking CPA circuit, one wire on the flying lead of CPA was found cut at about 4 inches from the connector due to sharp fold in the CPA flying lead.
2/3/09
7. AD 009 – Rotors Flight Control – Rotor Control – Marking on cyclic stick, trimming of L-angle of separator wall, provision of additional safety and modification of fork assembly.
1. To facilitate proper placement of rigging tool on cyclic stick during rigging, a marking on cyclic stick is provided.
2. Trimming of L-angle to clear interference with hydraulic tube bushes.
3. Added safety by introduction of split pin.
4. To increase clearance between FDR/CVR potentiometer as well as coll pick off fixed end and fork assembly by decreasing the lug width of fork assembly
8. AD 010 – Stabilizers – Vertical Stabilizer – Installation of web stiffener on front spar of fin torsion box assembly. To reinforce the front spar of fin torsion box assembly, as per board of inquiry recommendation.
9. AD 011 – During flight when HF transmission is on, amber light of tail rotor vibration warning system flickered. To rectify problem it was proposed by RWR&DC to replace the existing velocimeter Model No 7310 with velocimeter Model No. 8866-1 having improved EMI/EMC shielding.
16/02/10
10. AD 012R 1 – Rotor Drive (s) –Gearbox(es) – One time check for presence of water inMGB lubricating oil of Dhruv helicopter IDS assembly.
A case of water ingress into IDS assembly on one of Dhruv helicopter was noticed in 2006. Detailed investigation revealed that water ingress into Main Gear Box was through top cover (p/n: 201P620H 0000 207) of IDS. It was also observed that non-standard “O” ring was used, which resulted in improper sealing against water.
Usage of correct size “O” ring as per drawing was emphasised and as an improvement sealing of top cover using sealant was introduced as additional feature against water ingress.
A recent case of water ingress has come to notice on one of Dhruv helicopters. Preliminary investigation revealed existence of a connector on IDS inspection cover (p/n: 201P 636H 0006 201). This inspection cover, with connector on it, is not a standard part as per SOP. Further, the “O” ring of the top cover was found damaged. It is possible that IDS with such inspection cover and damaged “O” ring installed on top cover might have led to seepage of water into MGB of IDS.
The water presence in lube oil of IDS has very serious effects like corrosion.
11. AD 013R 1 – NAVIGATION – Dependent Position Determination – Design improvement in GPS antenna bracket.
1. On some of the Dhruv helicopters, incidents of GPS antenna along with bracket and connector breaking away from main structure during flights were reported.
2. Investigation by Failure Review Board attributed the failure ofsheet metal antenna bracket to its inherent strength deficiency. Replacement of existing GPS antenna bracket with machined bracket was recommended.
3. Part breaking away from aircraft during flight may cause injury to person or damage property on ground.
12. AD 015R 1- TAIL ROTOR DRIVE – Gearboxes – Installation of modified parts of AGB assembly to control the interfacing tolerance for avoiding low lube oil pressure.
Controlling of the interfacing tolerance of AGB assembly (P/N 201P 655H 0000 001) parts to avoid internal leakage and to overcome low lube oil pressure of ALH AGB assembly.
01/04/10
13. AD 016 – Cracks were reported on two TRA flange assemblies.
HYDRAULIC POWER – Main – Additional inspections of tail rotor actuator (TRA) flange assembly for crack.
20/08/10
14. AD 017R 1 – Collective eye end of UCS connecting rod were found broken on two Dhruv helicopter after their forced landings
ROTOR (S) – Rotor heads(s) – One time check on connecting rod assemblies (UCS) for crack detection.
15. AD 018 – Crack was noticed at threaded area of bolt-blade fork (big) on DHRUV helicopter.
Rotor (S) – Rotor BLADES – One time fluorescent dye penetrant CD check on bolt blade fork (big) – MRB.
16. AD 019 – Free play of approximately 5 mm was observed on TRA assembly during 1000 hours inspection. Based on detailed inspection and study, vendor has identified that “PINs”p/n 3101-010 used on TRA p/n 3101-000 from serial number 40 to 145 are not heat treated to the drawing requirement. Existence of this condition significantly reduces the fatigue life and may lead to loss of directional control.
HYDRAULIC POWER – Main – One time check on tail rotor actuator
2/11/10
17. AD 020 – Crack was found during inspection on LH side of horizontal stabilizer mounting bracket fitted on vertical fin spar and IGB rib.
STABILIZER – Vertical stabilizer – One time check for crack on IGB rib on fin torsion box assembly & tail boom assembly AFT
09/06/11
18. AD 021 – Engine oil leakage was reported by pilot after last flight. On inspection, rear bearing lubricating oil pipe (return line) found damaged.
AIR CONDITIONING – Distribution – One time check on interference of air conditioning tube with engine oil scavenge pipe and modification for introducing improved clearanc
19. AD 022 – . In some of Dhruv helicopters cracks were observed in IGB rib bottom and associated area of fin torsion box assembly
STABILIZERS – Vertical Stabilizer – Reinforcement of IGB bottom rib and strengthening ofIGB rib in fin torsion box assembly.
04/07/11
20. AD 023 – During a sortie on one of the military Dhruv helicopter, at hover, prior to take off, low rotor warning was observed. Helicopter carried out a safe precautionary landing. On further investigation, it was noticed that the fixed eye‐end of the collective pitch anticipator (CPA), p/n 34LL03C502W3290 was detached from the body of CPA. Such failure may affect handling qualities of helicopter adversely.
Engine Controls – Power Control – Inspection of collective pitch anticipaton.
02/09/11
21. AD 024 – In one of the civil Dhruv helicopter, it was observed that the elastomeric bush (p/n201P 636H 3000 201) was seating on the radius of TDS sleeve. This was due to the bearing flange assembly was done towards tail rotor side of TDS support bracket instead of towards FWD side of the helicopter. This wrong assembly may lead to gradual failure of the bearing leading to loss of tail drive power6
TAIL ROTOR DRIVE‐ Shafts – Check of elastomeric bush seating position on tail drive shaft assemblies (Seg.‐3 & Seg.‐4) in situ on the helicopter
U
27/02/12
22. AD 025 – The Alert Service Bulletin “One time torque check on mounting bolts of Main Rotor Blade” is issued on the basis of recommendation made in preliminary
investigation report on accident to BSF (Air Wing) Dhruv helicopte r VT-BSH (DW63) on 19-10-2011.
This AD, which prescribes/mandates action to be performed on to helicopters as stated above to restore an acceptable level of safety is hereby issued pursuant to CAR 21.3B. TC holder/ Operators are required to comply with the above stated AD within the
stipulated time.
23/07/12
23. AD 026 – During investigation of some of the incidents of Advanced Light Helicopteer (Dhruv) owned by defense forces, it was found that the collective eye-ends of connecting rod assembly were broken.
Since an unsafe condition has been identified which is likely to develop on other Advanced Light Helicopters of similar type design,this Airworthiness Directive is being issued for installation of improved steel eye-ends in place of existing titanium eye-ends to achieve higher fatigue strength.
24. AD 027 – In one of the civil Dhruv Helicopter, step marks at spline area of input flange of Intermediate Gear Box (IGB) was reported.
25. AD 028 – In one of the Military Dhruv Helicopter, Pilot observed physical travel of collective lever obstructed at corresponding torque of 72 percent. Defect
investigation revealed that the clip assembly connecting FDR/CVR
potentiometer to control rod was found displaced by approximately 20mm upward from its designated position.
Introduction of split pins in FDR/CVR potentiometer attachments of cyclic and directional channels.
21/03/13
26. AD 030 – In accordance with the para 3.3 (v) of GM 21.91 of CAR 21, this
modification is considered as mandatory Major Modification by the TC holder as an unsafe condition has been identified which exists in other Advanced Light Helicopter (ALH)-Dhruv
This Airworthiness Directive is issued
i. To provide visual inspection means for opening and closing of pilot door , co-pilot door, sliding door and hinged doors; and
ii. To provide door opening and locking instructions on clamshell door.
02/12/14
27. AD 031 – During 500 hrs servicing if a civil variant Advanced Light Helicopter (ALH) Dhruv, it is observed that the cylindrical roller at the input side of IGB was overheated and damaged. This damge us attributable to Oil starvation. The type of failure is considered critical as it may affect drive line from MGB to TGB.
19/02/15
28. AD 032 – In one of the ALH dent mark was observed on end plate RH side. Aldo dent and erosion on protection strip drlsminatoon was observed on TRB. It was found that one screw from TGB fairing RHS-Attachment came out and hit the TRB first then got embedded into plate. This type of failure is considered critical and it msy affect both TRB & End Plate.
17/10/16
29. AD 034 – During 500 inspection change in CT density was observed on collar region of some of the main rotor blades of Dhruv helicopters. This indicates onset of local delamination.
01/06/17
30. AD 035 – In one of the ALH restrictions of movement was observed in the longitudinal circuit on Main Rotor Actuator(MRA) and Tail Rotor Actuator (TRA). Restriction on movement of circuit would lead to reduced controllability of helicopter.This type of failure is considered critical and it may affect controllability of helucopter.
19-10-2011
31. AD 036. Multiple occurrences of abnormal sound/possible surge and power loss of TM333-2B2 engines installed on ALH Dhruv Civil Helicopters along with vibration and jerks in cockpit during flight.
02/02/21
32. AD 037 – On one of the Military(IAF) helicopter during flight, Hydraulic System-1 Low level warning light came on and helicopter made precautionary landing. On further inspection Crack was observed on the valve body lug of Main Rotor collective Actuator of system-2 and failure of the lug resulted in the leakage of the hydraulic oil from O-Ring interface.e
13/07/23
33. AD 039 – During a routine sortie, Indian Navy ALH MK-III helicopter ditched into water close to Mumbai coast on 08/03/23 where in control loss in the collective channel was noticed during the flight. Post incident inspection control rod body in the collective control circuit was found broken.
Just came here looking for TAHA sahab’s sugar coated justifications …
One aspect that is not factored in the article is that original Mk I type of ALH of Navy and Coast Guard, 8 nos. and 4 nos. respectively are flying even today after 15+ years of service without major accidents. Even in Army and Airforce there are helicopter of Mk I types flying at around 3000 flight hrs. Whatever recommendations are made further must meticulously examine these aspects, while reviewing what has been fixed and improved and what could have gone wrong unrealised in Mk III/ IV types, later.
1. Considering CG is one among the extensively utilizing ALH Mk-III, After a couple of years of utilization, wear & tear has started happening in different parts of machine, proving that the machine is not designed to be STURDY or upto the mark for a minimum years of span too. The same incident would have happened at other civilian or defense dispatchments too, after utilizing these many hours of aircraft.
2. And If wear and tear is concern for HAL, then why in-house service routine is being followed for accident prone Mk-III while other aircrafts are being sent to Bangalore etc. at HAL establishments.
3. Seems like with advancement in technology in aircrafts, safety is compromised.
4. MK-I is still safer either because it is not as advanced as Mk-III, Mk-IV or it has not being flown as same number of hours as MK-III.
5. Why in the whole fleet, controls rods/system is not extensively tested, if heard of stress testing. There is difference if you do good testing on new machine v/s used or old machine. If it is done, then why incidents of control system happening. This indicates clear fault in aircraft testing module itself.
6. Even with 863, similar control failure is being suspected now because pilots were very much experienced and they were already acting at the site of mission. But no action is being observed from either CG or HAL side on that incident till now inferring like HAL has wrapped up that incident putting fault on others instead of analyzing it deeply(just like most of the times).
7. Everyone here should keep in mind that these accidents are not to be taken lightly(not even 1) just because they have not happened in your neighborhood. These had killed ‘Gems of country’ in aircraft, their families support, their squadron’s confidence on machine, money spent on aircraft/ trainings and reputation of service as well as country.