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Extreme Trimming

Philipp Dejakom is an avid helicopter pilot. He flies a wide range of missions - and sometimes they're quite the adventure. Especially when he's hovering over impassable terrain, cuttings vegetation back from power line routes with a suspended saw.

Blue skies surround Peiting in Upper Bavaria. There's a bit of wind. Perfect flying conditions for Philipp Dejakom. Sat in the helicopter cockpit, the pilot leans right out into the bulge of the bubble door. His gaze is directed downwards towards the suspended saw, making short work of branches up to 25 centimetres thick roughly 30 metres below him. His face is a picture of concentration and all his senses are sharpened. Which way is the wind blowing? How are the helicopter and the tool behaving? Together, experience and intuition allow the pilot to judge which direction the stick should move in to pass the machine closely by a power line and to cautiously raise and lower the eight-metre-long saw. His only support: The copilot, keeping an eye on the instruments, and a man on the ground with a microphone to keep them abreast of the situation. This is no stunt, but rather an economical method of keeping power line routes clear of branches and thereby preventing power outages.

A dream becomes reality
Philipp was inspired to become a pilot after a flight in a helicopter during his teenage years. In 1998 he realised that dream by completing his studies in California. It was cheaper to study in California than in his home country of Austria, and the region offered more adventure to boot. He returned from the USA, acquired an Austrian pilot's licence and there was no stopping him.

Philipp Dejakom flies with and without external loads – be it for rescue operations, supplying mountain lodges or carrying construction materials into the mountains for cable car systems. He loves the variety and the thrills. That meant there was only a moment's hesitation when his employer was on the lookout for an experienced pilot they could trust to perform tricky manoeuvres while strapped to a saw weighing around 500 kilograms. "On the first flight, things were very tense, but it got easier as we got into the routine," reflects Philipp Dejakom, 40, with a smile. To date, he has accumulated over 6000 flight hours, roughly 400 of which have been spent trimming trees.

And yet despite all his experience, he cannot allow his concentration to lapse during a flight. Although the electricity is switched off along the stretch of line being worked on, sawing through a cable would entail a large delay in the work and additional costs for the client – most often energy companies from Germany, Austria and Switzerland. In addition, an entangled saw would place the pilots in mortal danger and would need to be jettisoned in a matter of seconds using a pull handle. Fortunately, Philipp Dejakom has been spared this situation thus far. A little luck is needed as well.

The checks before the start
Every flight is painstakingly planned in advance and the weather conditions are monitored for days. Yet Philipp Dejakom is the one who makes the fi nal decision on whether to fly, from his position at the site. A good pilot knows their limit. If the fog is too heavy or the crosswind is too strong, it's too dangerous to fly. Nevertheless, no wind at all is hardly cause for celebration, says Philipp Dejakom: "The trees sway to and fro because of the downdraught from the rotor. That makes the sawing harder." In contrast, headwinds, rain or even light snow are less disruptive. The helicopter, a SA 315 B Lama, is exceptionally sturdy and manoeuvrable. Provided that the technology plays ball – as it's certainly put through its paces as well.

Naturally, that includes the saw, where ten carbide circular saw blades with a diameter of 55 centimetres are placed in a row. It is crucial to accurately set the torque and ensure the blades have enough bite. The saw is driven by a 48 hp two-stroke engine. The saw is secured to the bottom of the helicopter using six metres of screwed-together aluminium pipe – known as the sling – and a hook. A cable inside the pipe controls the saw and provides additional protection. Almost 30 litres of fuel are located in the pipe above the saw – enough for around two hours. If everything works without a hitch, Philipp Dejakom can cut a path through a forest up to four kilometres long in that time. In comparison, five foresters with handheld saws and ladders would need two weeks and cost twice as much to do so.

By the time the saw needs refuelling and the saw blades need retightening, the pilot is in urgent need of a break as well. Maintaining this unnatural posture and constantly staring downwards are extremely physically draining. There is a risk that their concentration will lapse as well. An extra effort is required on Philipp Dejakom's part to refocus all his attention for the delicate moment when he lands the helicopter. With a substantial amount of finesse, he brings the saw to a standstill on the transport trailer. He carefully presses the pitch downwards and lowers the tool piece by piece until the person on the ground can hook it into its bracket. Philipp Dejakom flies backwards in a wide arc and cautiously lays down the sling. Then he lands. Shuts down the rotors. Removes his helmet. Takes a deep breath. And then? "I have something to drink and enjoy a good stretch."

Responsible for the content of this press release: VOLLMER WERKE Maschinenfabrik GmbH


VOLLMER WERKE Maschinenfabrik GmbH
Ehinger Str. 34
88400 Biberach (Riss)

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