Thoughts on the Mi-17 V5 Crash at Coonoor

An Indian Air Force helicopter with 14 persons onboard crashed into the hills near Coonoor, Tamil Nadu in southern India, around 12:20 PM (IST), Wednesday Dec 8, 2021. The Russian-made Mi-17 V5 helicopter ex- IAF’s 109 Helicopter Unit (109 HU) had taken off from Air Force Station, Sulur to the military cantonment at Wellington in The Nilgiris (Blue Mountains) when it crashed about ten miles short of destination.

It is an unprecedented loss of the highest ranking officer in Indian military. The crash takes away India’s first Chief of Defence Staff General Bipin Rawat, his wife Mrs Madhulika Rawat, four crew, the general’s defence advisor, staff officer, protocol officer and five personal security officers. IAF confirmed 13 deaths by Thursday evening. Lone survivor Group Captain Varun Singh, directing staff at Defence Services Staff College, was admitted to the military hospital at Wellington with grave injuries (he has since been shifted to Command Hospital Air Force, Bengaluru). Hope and pray he makes it.

A Mi-17 V5 helicopter at WGC helipad, Wellington, The Nilgiris, 2020 (representative pic by Kaypius)

I have vivid memories of a sortie I flew along that route many years back (1995) on a single-engine Chetak (Alouette) helicopter. Also, ironically, in 2020, I was witness to a safe, uneventful landing of a similar V5 from the same 109 HU at the Wellington Gymkhana Club (WGC) helipad. I subsequently used photos and videos captured of that beautiful flight to explain, with theory, experience & accident investigation, the nuances of helicopter performance. Though “performance” seems unrelated to the latest tragic crash, with a heavy heart, I write this piece to inform the lay reader nuances of weather, topography & flight rules for helicopter flying in the hills.

The location

Gen Rawat was headed for a guest lecture at the nearby Defence Services Staff College (DSSC) at Wellington. DSSC is a tri-service establishment that conducts the Staff Course for mid level officers. The Wellington cantonment also houses the Madras Regimental Centre, a military hospital (MH), the Wellington Gymkhana Club and support units. It is a beautiful town with salubrious weather year round, throbbing with the energy of young recruits from MRC & the “Owls” of DSSC. Homes and livelihoods at the one horse town are practically supported by the military, tourism & tea estates. The peace & calm is occasionally broken by a passing helicopter landing at WGC. Locals are used to helicopters that appear periodically overhead; so much that they remember accurately the route the choppers follow. On Dec 8, as per eyewitness accounts to this writer, the helicopter appeared to be flying lower and slower than usual. Fog or mist can also be seen in certain visuals that have appeared on open media. The regular beat of churning rotors suddenly ground to a horrible stop, chopping huge tree trunks & erupting into flames.

Flight Rules and Meteorological conditions

The fairway of golf course at Wellington Gymkhana Club (WGC), Coonoor in The Nilgiris has a helipad with unidirectional approach that’s usually used for airlifts ex-Sulur/Coimbatore. Military helicopters fly that route for VIP visits, logistics, medical evacuation, etc. It is a short climbing flight of less than 50 miles that would take a Mi-17 V5 about 30 mins along a predetermined route that military crew have been flying for decades. The helipad is approximately at an elevation of 6000 feet with hills and dense forests all around.

Such flights are undertaken under ‘Visual Flight Rules’ or VFR, which implies “see & avoid”. Most civil flights and fixed wing aircraft fly under IFR or Instrument Flight Rules. Most military helicopters operate VFR at low height, particularly in the hills where the departure or destination may not be equipped with modern navigation or landing aids.

The weather and visibility conditions that define ‘visual’ and ‘instrument’ meteorological conditions (VMC / IMC) are known to all pilots. An important distinction is in order. While you can abide by VFR or IFR in VMC, you cannot fly VFR in IMC. It is a simple geometrical problem of height vs terrain. You cannot avoid what you cannot see unless you fly at safety altitudes. IFR was impractical in the given location where the ill-fated helicopter was flying. ‘Continued VFR flight into IMC’ or ‘inadvertent IMC’ (IIMC) is one of the leading causes of helicopter accidents worldwide. Faith cannot move mountains in aviation.

Weather in the hills

Coonoor for the most part has lovely salubrious weather with clear visibility & sparkling clear skies. However, during winter season, low drifting clouds, fog & mist often roll in unannounced, reducing visibility that can push “see & avoid” VFR flights into peril. Also, technical issues, if any develops, can impose dangers due to hilly terrain and/or reduced performance. As such, the higher you climb, the lesser the margins for performance, abnormal situations or the room for error.

A VFR flight that encounters bad weather has one of three options:

  • Divert or force land before weather closes down
  • Deviate from flight path so as to avoid weather and continue flight keeping within VMC minima
  • Change to IFR flight plan in coordination with ATC

There are practical limits to options 1 & 2, especially in the hills or over ‘hostile terrain’. However, if the destination is a helipad like WGC with no IFR aids or published IFR procedures, option 3 is all but ruled out. Another danger is ‘scud running’ — descending to keep below clouds, thus getting trapped between lowering cloud ceiling and rising terrain.

Passengers disembark a Mi-17 V5 at the WGC helipad (2020 file pic by Kaypius)

The helicopter and crew

The Mi17V5 is a robust twin-engine helicopter with advanced glass cockpit, weather radar, moving map display, autopilot with flight director, etc. As compared to my generation of pilots who cut our teeth on VFR-only helicopters, sometimes getting lost and even descending to read the name of railway stations to reorient, aircrew today are trained for instrument flying and IFR like never before. Almost every helicopter pilot in the IAF today has a service-issue iPad with modern flight planning software and safety information. But the trap of VFR into IMC still lurks, particularly in the hills. Only RNAV / RNP-based low-level routes and ‘Point in Space’ approaches (with matching equipment and published procedures) can improve safety. We are still a miles away from that in India.

The Russian-made Mi-17 V5s were ordered in two tranches between 2011-2018, totalling 150, under the IAF’s Medium Lift Helicopter program. Since their induction, there have been five accidents (three fatal) in the V5 fleet, including one that was accidentally shot down by IAF’s own air defence during the Indo-Pak air skirmish on Feb 27, 2019. Contrary to speculation that arose soon after the crash, the track record of IAF V5s have been fairly safe & consistent, save for the odd crash enforced by human error. The IAF crew are trained & aircraft is well equipped to fly under Instrument Flight Rules (IFR). But IFR rules cannot be directly applied to such ‘VFR-only’ helipads, especially if they encounter instrument meteorological conditions. Sadly we don’t yet have a silver bullet for the deadly cocktail of bad weather and hills. Remember the Kobe Bryant S76B crash near Los Angeles in 2020?

Abnormal situations

IAF has not yet reported any reasons for the crash. It is a matter under investigation and nothing can be ruled out. However, any abnormal situation or failure can extract a heavy price in the hills. For example, an engine failure at high altitude may force the chopper to ‘drift down’, thereby reducing terrain clearance. At the other end, the crew may reach a physiological or helicopter performance ceiling when attempting climb to route safety altitudes. There is also no clear cut solution to an abnormal situation that may enforce a ‘land as soon as possible’ or ‘land immediately’ landing guidance. The helicopter pilot juggles around with far too many variables while flying in the hills. Often the best laid plans can fail.

Maintain calm, avoid speculation

The IAF has ordered a court of inquiry into the accident. No probable cause has been mentioned in the updates as of Dec 9. The helicopter was fitted with a CVR and FDR though it is not known whether the same has been retrieved intact from the wreckage. While we await the inquiry report, it would be proper to avoid speculating or fanning conspiracy theories. The tendency towards unregulated and unethical sharing of graphic videos and photos in the aftermath of any accident also needs to be curbed. It is immensely unkind to the victims and their families. This dark side was again on full display yesterday, as it was during past crashes (Suryakiran crash at Aero India 2019, Feb 2019 Mirage crash at HAL Bangalore, Budgam shootdown, etc).

My deepest condolences to the bereaved families. Blue skies.

(An edited version of this piece was first published as an op-ed by The Quint. You can access that here.)


©KP Sanjeev Kumar, 2021. All rights reserved.

About the Author

Kaypius (2019 picture by Sitam Moharana)

Kaypius is a former naval aviator, experimental test pilot & graduate of 61st Staff Course at DSSC, Wellington. He is dual ATP-rated on Bell 412 & AW139 helicopters and a synthetic flight instructor on ALH Dhruv. Over 90 of his articles have been published in magazines, journals and news media in India and abroad. He enjoys being ‘full-time aviator, part-time writer’ and blogs at He can be reached at or on Twitter @realkaypius. Views are personal.


19 thoughts on “Thoughts on the Mi-17 V5 Crash at Coonoor

  1. Balanced and informative, as always!
    Hope people are able to curb their personal prejudices and respect the grief of the bereaved. The time to speculate and/or criticise is certainly not now!

    1. Thank you for nicely explaining the constraints of flying a helicopter under difficult conditions. For a layman, you brought out the challenges the pilot must have faced.

  2. Very nicely worded article on MI-17V5 operations. The information shared about difficult mountain terrain flying under adverse Wx conditions very well analysed and articulated.

  3. Nice Insight Sir.
    V5 is a lovely bird sir and I have been onboard a lot of times.
    Appears like a CFIT with probable disorientation during the last phase in the clouds/fog.
    Just speculation sir…
    The COI team will do its job
    Saddened by the Loss of Precious Lives, It Hurts
    Sadgati to All
    Strength to the Family
    Blue Skies

  4. Hi Kaypius. As usual you take the cake. Well written as only I can expect you to have done so. Stay safe and happy landings. Sukhi

  5. An excellent analysis, particularly for those mediapersons who may be tempted to write articles or blog posts without being completely sure of the technicalities surrounding such events.

  6. Very very nicely articulated piece of explanation with great depth , & knowledge of helicopter flying. I am not only impressed, deeply moved by your writing.
    Wish you all the best for the years ahead.

  7. Lucid explanation of helo ops in mountainous terrain, with VFR/ IFR,only expert can articulate. GREAT BRO Being from your flock, albeit underwater tribe. As said let’s not speculate await the findings of COI.

  8. Perhaps this will be the most plausible scenario for this tragic crash.’Scud Running’ is truly a dangerous phenomenon.

  9. Article well worded to actually give an insite in actually fly condition s and the twilight condition between vfr and im.this is decided one of the factors .there must be many other added factors. Pilots also have to obey but u the pilot at that moment are infinal decision

  10. Very informative information about fly of Helicopter in hilly terrain with unusual weather conditions.Let us wait for enquiry report and should not believe in any sabotage.

  11. Sir,I have been always reading your articles which give in depth analysis without any speculations.Its a treat to read since,I was Helo controller onboard survey ships and always enjoyed and cherished Chetak flying operations from deck all my tenure in Navy.

  12. Very Informative. Is it not possible for the helicopter to climb to a safe altitude.. Say MSA then set course to the WGC helipad and descend VMC to make an approach? Is it necessary to fly the short route close to valley and terrain?

  13. The article has eased understanding of the situation for a layman. Though you have explained technology and regulations alongside it’s application in plain language, human behaviour in ‘high valued sorties’ is one aspect essential to understand the ecosystem well. Though it’s speculative, but I believe the core of the issue may be somewhere there.

  14. Nicely explained. A layman like myself can get the idea about limitations of a pilot while flying in hilly area. Let’s wait for the report of COI…

  15. A very well analysed and explained article by a thorough professional. It puts the whole issue in correct professional perspective. Hope the media and the so called experts stop speculating.

  16. One factor need deep tech investigation is a planned cyber attack by PLA to eliminate CDS Gen Bipin Rawat. He grid locked PLA in Aksai Chin & NE sector made formidable, but for the porous 3445 kms LOC/LAC & Xi s aggressive posturing made 600 small villages as small PLA Cantt with 100-150 Chinese settlements. Xi s plan to become No.1 world power & eliminate all this minor hurdles by eliminations( Wuhan scientists, Tianamen Sq, Uighurs, tennis player, Taiwan air chief, Tibetans, Mongolians+++others. Balance is history. Let’s wait till the C o I findings.
    We plan similar cyber attacks on their PLA leaders thru Sat int.
    Be safe. j j singh

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