On the dreaded 'D' date I completed a turn around inspection before departing the Gamghadi Helipad for VNNG in an AS350B2. Take-off time was 1240nst/0655utc. With 5 PAX, 70kg cargo & 280litres fuel. As there was local weather; rain showers & hilltops embedded in cloud I elected to fly following the Karnali River to overfly VNSK, then onto VNNG. I had completed a power assurance check earlier that day & the engine health was above par. Operations were normal during the flight & I was flying over the Karnali river at around 1,500’agl. At approximately 1306nst/0721utc the engine chip caution light came on. About 2 seconds later the engine oil pressure warning light came on, at this same instant the cockpit completely filled with smoke, so I had totally lost all visual reference! Then in the next 1 second a sudden & massive yaw to the right indicated that the engine had failed. Next the Nr low alarm rang as I was lowering the lever to enter autorotation. At this stage the smoke was so thick & heavy that I was unable to see the instrument panel, nor the ground outside. Visibility was IMC, completely zero inside. I screamed at the PAX to open their windows & I kicked in a bunch of left pedal to side slip the machine to force extra airflow through my window to force ventilate out the smoke away from my area so that I could see the panel & assess my autorotation options. Once visibility had partially returned sufficiently inside, I could see that the Ng was 0%.I then determined that my auto-glide profile would put me directly into the Karnali River, but just beyond my glide range was a suitable rice paddy for landing? So I elected to raise the collective to reduce Nr below the low red line in an attempt to extend the glide profile to my intended forced landing spot. At one time I attempted to return Nr into the green range, lowering the collective lever but it was clear to me that I would not make my selected landing spot. So I further reduced Nr to ensure I would reach my forced landing spot.Once established on this glide profile I gave a MAYDAY call stating; MAYDAY MAYDAY MAYDAY Helicopter 9IW engine failure going down 1 mile North of Munma Barracks.The smoke continued to hamper visibility, making judgement difficult. I was now around 100 meters from the pad & started my flare, then levelled as the aircraft came just over the rice paddy & I cushioned on. Due to the uneven ground (rice paddy levy wall) the skids collapsed during the ground slide & the tail-boom partially separated. The landing was slightly heavy due to Nr being low, but in my judgement without the Nr being reduced the glide range would have been insufficient to reach the rice field & we would have crashed into the boulders & raging monsoon flooded river below where survival would have been zero.
All PAX safe & uninjured, only injury was me....................................emotionally
Machine repaired & flying again
Just another day, another dollar, less tax
