People tend to think that a helicopter drops from the sky like a stone when the engine fails. But that is not the case. When the engine fails, a light flashes in the cockpit and an acoustic warning signal sounds at the same time. The pilot has just seconds to turn the rotor blades to a horizontal position so that the rotation speed isn’t affected by air resistance or drag, otherwise the helicopter really would just plummet.
As there is no more boost, the helicopter falls at around 30 feet (10 m) per second. The forward speed must be around 60 knots (70 mph). This is slowed down about 100 feet (30 m) above ground by adjusting the nose of the helicopter flare. At 10 feet (3 m) above the ground, the blades are engaged again, thus breaking the fall, and the machine can touch down gently.
Every helicopter pilot has to prove he has mastered this procedure during the flying test. The minimum altitude for a so-called autorotation is 300 feet (100 m). Below that it becomes more difficult and dangerous. It requires a free, level area, large enough to allow the helicopter to slide forward another 16 feet (5 m). That’s the purpose of the sled-like skids on the helicopter.
Our Jet Ranger Bell 206 had to be flown from Ethiopia to Cameroon. I had taken off in Addis Ababa with two passengers and a lot of fuel in jerry cans. One of the passengers was a mechanic from a Swiss helicopter company who had just attained his helicopter pilot’s license. He had taken leave and was helping me with the maintenance of the helicopter. In return he was gaining experience and especially flying hours with me.
As we flew over the Chad desert it was once again time to refuel from our jerry cans. To do so I had to land. As I descended from 10,000 feet (3,000 m) altitude I could see a dried-up riverbed in the distance, surrounded by small trees and scrub. Nearby were a few small settlements. Hunger and drought were everywhere. “If I have to land, then I’ll come down among these abandoned people and find out how they are doing,” I thought.
I extended my approach and came down near the villages. My reserves were getting less and less. The gauge fell to five gallons as I turned left and prepared to land. That was a mistake. As I banked, the fuel shifted in the tank and for a moment the pump sucked in air. That was enough to extinguish the fire in the engine. I had enough fuel in the tank to come out of the turn but at that moment the engine failed. I found myself at about 100 feet (30 m) altitude above trees and scrub. Luckily, I had already performed several hundred autorotations, enough not to panic.
In a matter of seconds, I pulled the helicopter through the trees in a full stop autorotation, as there was no room to maneuver. The helicopter reacted to the sharp braking with a jerk, the tail went up slightly and then down again. My young co-pilot’s eyes were on stalks. “Now I’ve seen the impossible,” he gasped.
It was only when we inspected the helicopter that we noticed the true extent of our miraculous preservation. Just two inches (5 cm) from the delicate tail rotor was a little broken sapling stem, about one inch (3 cm) thick. Judging by our trail in the sand, the helicopter must have touched down on the left of this stem. Then, as a result of the hard stop, the tail rose, swept over the stem and finally – without touching the sapling – came down on the other side of it. Had the tail rotor even brushed against the stem it would have smashed into smithereens. That was truly angelic precision!
Repairing a damaged tail rotor in this desolate place would have been hard enough. Worse still, if we had lost the tail rotor the helicopter would have immediately spun on its axis and gone totally out of control. It could have been a write-off. We had plenty of reasons to be thankful!