In the late 80s, a naval Chetak (Alouette III) operating on a patrol mission over Gulf of Mannar (Operation Tasha) deviated from laid down profile. Flights ex-Naval Air Station Ramnad (now INS Parundu) those days presented many opportunities for ‘cowboy flying’. The low-time pilot dipped low over a highway and tailed a mofussil bus running that route. Couple of ‘joyride’ passengers onboard that ill-fated flight enjoyed the thrills of low flying as surprised travelers from the bus looked on.
Nobody noticed when a high-tension (HT) line running along the road turned sharply across at one point. The cables went through the Chetak like a hot knife through butter, decapitating the crew before electrocution and fire consumed the rest. In one grisly moment, it was all over.
Since the accident was primarily caused due unauthorised low flying, it was easy to miss the elephant in the room – unmarked wires and the ever-present risk of wirestrike for helicopters and small aircraft that fly around at lower strata.
30 years later, we are no safer as revealed by a string of wirestrike accidents, both in civil aviation and military. Our fatalistic attitude ignores this risk like it doesn’t exist. 21st August 2019 reminded us once again that the problem is alive and kicking. Sadly, the crew in this case aren’t.
The puff of smoke seen in picture above sent three onboard Heritage Aviation’s AS350B3 to blue skies forever. The helicopter was operating for flood relief, saving lives, when it reportedly flew into wires. Small helicopters like this operate single-pilot, have little to NIL automation or exotic Terrain Awareness Systems (TAWS, HTAWS for helicopters). They fly on Eyeball Mk II (meaning pilot’s eyes), relying on an intimate knowledge of terrain & topography. It is not an all-season fix because you can sometimes be deployed to unfamiliar or disaster-hit areas at short notice. The holes in cheese then align, like it did for this helicopter.
More aviation-friendly countries have marker balls on such cables. In India, we let the pilots eyeball it. Not surprisingly, this can end badly for many in a country with over 2.5 lac kms of powerlines (& counting). Here, anybody can string a wire or lay a cable across roads, valleys, houses at will. There are ad-hoc ziplines and ‘apple transportation ropeways’ across valleys in hilly states of Himachal Pradesh & Uttarakhand. Do they have an official sanction, even when they run across known heli-corridors? I would imagine this is another ‘wink wink’ arrangement. Sadly, it has taken lives. On 23rd Aug 19, two days after the Heritage Aviation crash, a Bell 407 crashed in the same geographical area. Crew escaped with injuries. Eyewitness accounts again point towards wire strike (pictures from media, source unknown).
Marker balls are hollow, fluorescent fittings placed on cables to improve their visibility. Installing these marker balls in situ requires helicopter support; a delicate & specialised task. See a video here.
It would be too much to expect in countries such as ours with a low density of helicopters that all power lines are marked. However, those that run across known ‘kopter routes’ need to be marked.
Let me explain with a ‘striking’ example.
There are published ‘Kilo Routes’ for helicopter traffic flying in / out of Mumbai. These VFR-only routes have been put in place to deconflict helicopters that primarily operate to Juhu, Mahalakshmi Race Course (MLRC), Dhirubhai Ambani Knowledge Centre (DAKC), Reliance Corporate Park (RCP), etc from fixed-wing traffic to Santacruz. There are published height restrictions (500/700 feet till 15 Nm) that are to be diligently followed. Most of these ‘Kopter Routes’ have HT/LT cables criss-crossing at several places. None of them are marked. In fact, if a crew without intimate knowledge of these obstacles were to diligently follow the published track and height for, say, a Kilo-19 arrival from northbound Radial 330, they will fly full-tilt into either the All India Radio lattice masts / wires about 9 Nm north of Mumbai, or into HT cables near Goregaon/Malad creek.
Recent wirestrike accidents should wake up authorities to this reality. Flying under ‘Special VFR’ dispensation is allowed ex-Juhu all the way down to 1 kilometre visibility. Actual in-flight situation can be far worse. VFR means ‘see & be seen, hear & be heard’. What you cannot see, you cannot avoid. And if you stick to published heights, you are doomed at some point. The whole thing hinges on pilot discretion, alertness and ability to maintain visual separation from obstacles. Regulations that throttle helicopter flying have glossed over the reality that we are poorly regulated & non-compliant when it comes to hazards posed by powerlines. As helicopter and e-VTOL numbers grow, so will conflict and accidents.
Optional equipment such as wire cutters & Wire Strike Protection Systems (WSPS) are also available for a premium. But these are not standard fit for policy makers & penny pinchers on either side. To avoid these death traps, it is common practice to overfly pylons or towers. This healthy airmanship practice is seldom possible in mountains or narrow corridors such as Mumbai’s Kopter routes. Also, terrain in most cases masks wires until it’s too late.
In Australia, 180 wirestrike accidents were reported between 2000-2010. ATSB research found that 63% of pilots were aware of the position of wires before they struck it. They even have a powerline safety program. Do we even have a database of wirestrike accidents? If yes, what does the data tell us? If not, are we waiting for a minister or VIP to fly into wires? Wait, that already happened! But we blamed it on the crew, restrung the wires & got on with life! Read here.
Even today, helicopters routinely operate to temporary & permanent helipads that hardly take into account the possibility of a wirestrike in the takeoff or landing path should a critical power unit fail.
Many have died. Maybe the power ministry and aviation ministry should talk to each other. It’s not the 80s anymore. Electricity has reached far flung areas; so have helicopters. The conflict is only bound to increase. Add to this, the hazard posed by unmarked ziplines or ropeways strung by farmers to ship their farm produce across valleys.
This morning (27th Aug 2019), early reports are coming in of a Cessna Citation 560XL VT-AVV crash at Aligarh airport. The light aircraft’s landing gear reportedly snagged wires that were not shifted after runway extension. If this is the situation outside a greenfield airport, spare a thought for helicopters that operate from dispersed sites, temporary helipads and disaster-hit areas.
It’s a clear & present danger.
©KP Sanjeev Kumar, 2019. All rights reserved. I can be reached at firstname.lastname@example.org. Pictures from open source.