On 17th December 2017, an old faithful workhorse of the Indian Air Force, the Mi-8 ‘Pratap’ helicopter (NATO code Hip) will retire after 45 years in service of the nation. It’s a poignant moment in IAF’s history. The old must make way for the new.
But the Mi-8 is not fading away anytime soon from the collective memory of our air warriors. Almost all of them must have spent some time inside it – either as crew or as passenger availing a drop, somewhere on the mainland, hills, or the Islands. Thousands of civilians in distress have been rescued by the ubiquitous Mi-8 which remains one of the world’s most produced helicopters.
Why should a naval aviator like me write a requiem for this wonderful machine from the IAF stable, having spent only a few hundred hours behind its controls? Allow me to explain with a small anecdote.
No Love at First Sight-
I still remember the first time I set my eyes on the Mi-8. She appeared all bulky, sooty and greasy, with a long slender tail and a main rotor which felt like it could use a little more revolutions per minute (RPM). She neither had the majesty of a naval Seaking nor the fine lines of western-origin aircraft. But my friends from the IAF extolled the helicopter without offering an adequate or compelling justification.
For them, it was simply “a beautiful machine to fly”. Once when an IAF Mi-8 made an enroute halt at the naval airbase, I hopped across to see it. Then Sqn Ldr MR Anand (Andy) proudly showed us around the aircraft. A newly installed GPS set appeared to be the only modern equipment in the cockpit. I went back, hardly impressed.
As luck would have it, I got my chance to fly the Mi-8 and discover the intricacies of the aircraft for myself.
An Affair to Remember-
July 2001. I was deputed from the navy for the rigorous Flight Test Course (24 FTC) at the AF Test Pilots School (AFTPS), Bangalore. I had a modest log book total, most of it on powerful helicopters flown at sea level where they perform like Virat Kohli in heat. I was not used to power deficits or minding a ‘twitchometer’ called the rotor RPM gauge. The single pilot, anti-submarine Kamov-28 ‘Helix’ that I had last flown packed a powerful punch and handled without a care at sea level. Between the lone pilot and a Tactical Coordinator (TACCO), all missions could be flown within a narrow airspace extending from sea level to a thousand feet.
Welcome to the World of Flight Engineers and Flight Gunners!
When I strapped up in the Mi-8 cockpit for the first time, I was quite enamoured with the luxury of space. Also, now I had an engineer and ‘cabin crew’. The Flight Engineer (FE) started up the helicopter while the Flight Gunner looked after the cargo cabin. No need to memorise any checks or procedures; the FE took care of everything and simply asked you to roll open throttle for taxy when ready. It felt good. The IAF pilots sure are a happy lot, I mused.
Handle with Care!
Alas, my joy was short lived. Soon as I raised collective to pick-up Z-2454 from Runway 27 of Bangalore’s HAL Airport, I realized the Mi-8 was an altogether different beast. Unlike modern turboshaft engines where the rotor RPM inched upward or held steady on applying power due to a collective pitch anticipation mechanism, in the Mi-8 the collective lever and rotor speed seemed to move in opposite directions.
The Mi-8 weighs-in almost same as the Mi-17 but has under-powered engines. Also, the rotor speed governing system is such that rotor RPM droop or overshoot is quite common when loaded. The helicopter had to be caressed into the air, all the while keeping a devil’s eye out for that small black needle called NR (Rotor RPM). After all, a helicopter’s rotor RPM is like heartbeat. Without that you are dead.
Smooth Ride Guaranteed
One can tell if the IAF helicopter pilot sharing your cockpit is an ex-Mi8 guy or just another helicopter pilot. The IAF helicopter pilots I know got their smoothness and finesse in flying on the Mi-8. The Mi-8 autopilot actuators needed a little foreplay every now and then. The FE would ask the pilot to maintain attitude while he trimmed the actuators with a rotary knob.
Initially, I refused to believe that the aircraft even hadan autopilot, being utterly spoilt on the Kv-28’s autopilot and flight director that were well ahead of its time. But in the hands of experienced pilots, the Mi-8 would melt into a gentle giant; the low frequency whirring of rotors punctuated by the pilot’s ‘click click’ on the trim release button.
Mi-8 in the Hands of a ‘Naval Dope’!
The learning curve on the Mi-8 was very steep at the AFTPS. Within a couple of sorties, we were up there testing the copter’s hover performance at scary ‘m/σ’ combinations (a non-dimensional parameter ‘mass upon density ratio’ used in flight test computations). Imagine the flight engineer’s horror while approaching a free-air hover with a loaded Mi-8 at 10000 feet, close to the helicopter’s hover ceiling, both engines screaming at max power and a ‘sea level pilot’ on the controls.
On many occasions, the rotor threatened to call it a day. Then there was the climb and descent performance phase where the helicopter had to be flown through a ‘sawtooth’ climb & descent profile, alternating between high-power climbs and steep autorotations. Mishandle the controls during either phase and the rotor RPM would wash off faster than the colour from the FE’s cheeks.
Enough is Enough!
My FE who was blessed with a ‘peace posting’ to salubrious Bangalore after spending many years in frontline hadn’t signed up for this. But he quietly endured the trauma inflicted on him through precipitate manoeuvres by a wannabe test pilot at the controls of a Mi-8 teetering on the edge of disaster.
On the third day of flight tests, after I had taken the aircraft into the ‘dead man’s curve’ a few times, the FE decided enough was enough. He took up position next to the entrance of the helicopter with a grave look on his face; hands tightly clasping the screwdriver all FEs use for opening cowlings during preflight external checks. Somehow, it looked like a weapon to me.
A Warning to Remember-
I walked to the helicopter with a student test engineer, test cards and an elaborate test schedule guaranteed to give goose bumps to any but the most seasoned pilot. I was about to board for the sortie when the FE put his hand across the entrance and stopped me. With a quavering voice, he made an almost inaudible but desperate request: ‘Sir, zara rotor RPM ka dhyan rakhna. Hamaare baal bachhe hain‘ (Sir, please mind the rotor RPM. We have children and families at home).
Well, I could tell him a thing or two about what a torrid time I was having myself, but I let it be. I shrugged my shoulders, held his hands and replied with an equally sombre face “Warrant Officer saab, mere bhi hain. Koshish toh kar raha hoon” (I also have a family. Believe me, I am trying like hell).
A Stepping Stone for Many-
And then began a wondrous journey of three years with the IAF where I flew the entire Mi family: Mi-8, Mi-17, Mi-171V, the gigantic Mi-26 and the gunship Mi-35. But I never forgot my flight engineer’s advice. Whether you fly-by-wire or fly-by-wife, while flying helicopters always mind the rotor RPM! My best lessons in engine handling were learnt on the Mi-8.
I know the current crop of pilots who grew up with glass cockpits and FADECs must be finding this funny. They will perhaps never know how it feels to roll up throttles and pour AVCAT into turboshaft engines while a Ko-50 kerosene heater kept you warm at sub-zero temperatures. The days of pilots having complete manual control over main engines are all but over. They don’t trust pilots with those things anymore.
Dual-redundant FADECs, digital four-axis autopilots and flight directors have turned flying into a push & play of buttons and knobs, all in the name of safety and expediency.
Au Revoir, Mi-8. A New Era Begins-
As the Mi-8 flies into the sunset this Sunday, it marks a culmination of sorts of an era of helicopter flying in the IAF that demanded utmost care and smoothness of hand. When the 112 HU at AFS Yelahanka bids goodbye to the Mi-8 on 17th December, many eyes will turn misty. A whole generation of pilots who graduated onto bigger, more modern helicopters after cutting their teeth on the Mi-8 will miss the patience and forgiveness of the ‘beautiful machine’ who let rookies make all their mistakes but returned them to the ground safely, each and every time.