it, or frost control, where a large barrel of oil is lit to provide smoke that will indicate the level of an inversion. You then fly with your rotors just above the smoke to bring the warm air down and prevent frost on crops, so, unlike Chapter 3, this chapter won't be boring! Note: Some of this is dangerous! Don’t try any of it without training! 176 Operational Flying External Slung Loads A helicopter can go where cranes are impractical or more expensive, or you might not be able to get a load inside the machine (maybe you wouldn’t want it there anyway, if it’s a dead animal or explosives), so you try and lift it. In theory, you can lift anything, provided the payload is available; I've even been asked to quote for lowering 800 feet of unrolled telephone cable down a mine shaft, because the drum it was rolled on wouldn’t take the weight. However, more common tasks are logging, placing air conditioning or ventilation equipment on the roofs of tall buildings, pulling cows out of bogs, picking up water to put out forest fires (water bucketing), dropping solution over forests (top dressing) or moving seismic equipment about. In fact, many tasks done with a helicopter are really extensions of load slinging, and, in remote areas, this will be a major part of your bread and butter – really specialised stuff will be found as subheadings below. A typical length is 25 feet, but can be up to 200, so don’t forget to include the line as part of the payload – it will be heavy (try about a pound a foot). If you get involved with the airconditioning-type loads on top of buildings, you will need a permit from the local authority, who will also need a lot of advanced notice. Check also for any bye-laws, the local environmental people, police and fire services (who may charge you for extra crews). Logging, officially, is removing felled and bucked logs from areas where all trees have been felled. It is very fast, with lots happening at once, and there will be a smaller helicopter to carry the used chokers every 75 minutes or so (chokers are lanyards with the equivalent of a slip knot which tightens as the load is taken up, making it more secure). It is not an operation based on finesse, as the machines are continually using full power cycles and undergo a lot of twisting, etc. If you’re planning to buy a helicopter that has been used on logging, inspect it very carefully! Selective logging is removing wood from where trees are standing, and is considerably more dangerous, at least to workers on the ground, because the downwash could dislodge all sorts of things. Cedar salvage involves moving loads of cut cedar blocks, which should all be of a similar length for best stability. Logs will be taken from high ground first so there is less risk of anything falling on workers below and you can see what’s going on better. They |