Training

Helicopter Training

By Alex de Voogt | August 1, 2004

Considering a Stuck Collective

Helicopter training includes emergency procedures that, at the recommendation of the manufacturer (or sometimes the flight school), are either practiced with student pilot or at least briefed to him or her. As a manufacturer writes the pilot's operating manual or a flight school drafts its curriculum, choices must be made. Which emergency procedures will be briefed and practiced, and which will be shelved?

The arguments for not briefing and practicing such a procedure should be strong ones. The arguments are rarely laid out in the manuals. On the contrary, the lists of emergency procedures are hardly ever argued on paper. This may explain the absence of a stuck-collective emergency procedure in helicopter training manuals.

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One may summarize the arguments against practicing or briefing an emergency procedure as follows. There is no point in briefing or practicing a procedure for an emergency that is hopeless. In other words, if there is nothing that can be done by the pilot or discussed that could help recover the aircraft from its predicament, why train on it. This school of thought says there is no conceivable procedure that one could follow to recover from a stuck cyclic, so why prepare for it.

The Safety of Practicing

Another argument is that the emergency procedure may not be safe to practice. Examples might be ditching or auto-rotating just outside the height-velocity diagram. Occasionally it is argued (again, rarely in writing) that such an emergency is too rare. Indeed, ditching is rare, but there is still a procedure to follow. A 180-deg. autorotation is perhaps even more rare, but there is a procedure for it that is practiced widely.

There is also a procedure to deal with a stuck collective that is safe to practice, although this emergency is a rare occurrence. To justify practice or briefing of this procedure, additional positive reasons must be considered. For instance, stuck pedal procedures are practiced in some schools because they add to the pilot's skill without endangering students, instructors or aircraft. More importantly, the pilot may not respond appropriately to this emergency without having practiced or briefed the emergency procedure. This is perhaps the most important reason for continuing the practice of autorotations despite its relatively rare occurrence and its proneness to accidents in practice. The same line of reasoning is applicable to the stuck collective procedure. It is an optional training that is safe and adds to the pilot's skill while the pilot is not likely to act appropriately without its training or briefing.

So far and to the best of my knowledge, the stuck collective procedure is not known or taught in helicopter flight schools.

A stuck collective means that, in the worst case, the collective gives the helicopter maximum continuous power against the will of the pilot. A mechanical failure may prevent the collective from being lowered or from operating at all so that the helicopter continues with its maximum power setting. If this happens, the helicopter continues to gain altitude at a steady rate if no further action is taken.

To stop the helicopter from continue rising, the pilot should neither chop the throttle, since he then can not lower collective for an autorotation, nor apply forward cyclic. Forward cyclic increases speed and may stop the climb, but at best it will bring the helicopter to the ground at dangerous and disastrous speed levels. Surprisingly, these are two answers often found when pilots are asked about the appropriate course of action.

The appropriate action is to apply aft cyclic and reduce speed below the maximum speed of climb. In a Robinson 22 training helicopter, reduce the speed to approximately 40 kt. This reduces, or even stops, the rate of climb since the helicopter requires more power at this low speed and out-of-ground effect. It is possible to reduce speed to a hover and then hope for a better rate of descent. Unfortunately, this could introduce a vortex ring state if rate of descent is too high. A recovery from this state is hindered by the stuck collective. Therefore, a reduction of speed to at least Effective Translational Lift or above is maintained to reduce or stop the climb.

Achieving a Rate of Descent

When the rate of climb is reduced, the throttle is used to invoke a rate of descent. A three percent reduction may already have the desired effect. Indeed, a five or seven percent reduction provides a considerable rate of descent in nearly all helicopters. Turbine helicopter pilots may have second thoughts when rolling off the throttle--but the risk still outweighs the option of a run-on landing at record speed.

With a reduced air speed and a throttle that is reduced only mildly, the pilot may have a flight condition in which all warning lights are still off, the final approach is at a near normal speed and the emergency of the stuck collective is not complicated by any other emergency or danger.

Finally, it is possible to bring the helicopter to a hover since the collective input is not likely to be higher than that used for the hover. Rolling off throttle during a hover sounds like a hover autorotation and without a collective it may appear to become an uncomfortable set down. However, a slow throttle movement will set the helicopter down without any yaw movement, completing a safe emergency procedure.

Ask your student pilots or fellow instructors for their actions in case of a stuck collective--then decide if a briefing or even a practice session is worth your while.

Alex de Voogt is a researcher at Leiden University, the Netherlands, whose research publications focus on the psychology of expertise and the history of helicopters. He has been flying Robinson 22 helicopters since 1997 and is completing his commercial pilot's license this summer after gaining his experience in the Robinson 22 and 44 in both the Netherlands and the United States.

In the field

Mountain Flying Self-Taught

A veteran of mountain flying around the world offers tips for breaking into that racket and enjoying the wonders of altitude safely

By William C. Dykes

Flying helicopters in the mountains is as close as you'll ever come to creating the sensation of pure, birdlike flight. It's the way you fly in your dreams. The helicopter releases you from bondage to the earth without holding you prisoner in the sky. You're not trapped in speed and tied to an airfield. You have freedom to interact with the mountains, not just whiz through them for a look. You can perch on their peaks, rest on their ridges, and alight in their alpine meadows.

Flitting from meadow to peak to ridge to savor the view is like engaging in a dreamlike slow-motion astral projection that strums the senses and tickles the mind into other worldly musings. You can tell right away that if it were easy, everybody would be doing it. It's not easy, but then neither is EMS, offshore, Ag, or corporate flying. Each discipline requires its own set of skills.

It is simple though, if you learn a few basic steps. There are some things you can do in the safety and comfort of your present job to prepare yourself for a mountain flying job. I guarantee that the diligent practice of these maneuvers and a little luck will make the difference between being laughed off the property and having a slim chance, if you can talk the chief pilot into giving you a check ride.

Learn to see the wind

As an airborne creature, you need to know how the wind behaves in the high country. For this course of instruction, you'll need a swift-running stream with lots of different sized rocks and boulders in it. A film or tape will do if you live in the flatlands. Sit down and study the water's behavior. After watching for a while, you'll notice that the water behaves in certain predictable ways when it meets and flows over and around the rocks. A good rocky stream will show you living, moving mountain waves, ridge burbles, williwaw channels, updrafts, downdrafts, and areas of violent turbulence. A body of air moving as a prevailing wind is a fluid, like the water in the stream, and behaves the same way as it slides over mountainous terrain. A couple of afternoons of serious streamside study will reveal most of what you need to know about mountain wind patterns. Convection plays a part, too. Air that is heated in big sloping troughs like canyons or river valleys during the day will flow up slope. When it is cooled in the mornings and evenings, it will flow down slope. All you have to know is the time of day and the prevailing wind, and when you look at the terrain surrounding your landing spot, you will be able to see the wind. The idea is to use the winds the same as the other birds that fly in the mountains, to climb in the updrafts, descend in the downdrafts, and stay away from places where the air boils and fumes.

Fly without moving the controls

You can practice high altitude, high gross weight landings in a parking lot by the sea, or anywhere else your job calls for you to land, regardless of the size of the area or the weight of the aircraft. The object is to make your approaches and landings without moving the controls. You will, of course, have to move them, all of them, at some point during the approach. But if you manage your approach path and power applications properly, you can move them so gradually and minutely that a casual observer will not be able to detect any motion. At first it takes a lot of extra planning and concentration. You have to think about the effect that moving one control will have on the others and feed in the compensation early, rather than waiting for physical or visual cues. You have to keep your rate of closure on short final in really positive control. If you get too slow, you'll either fall out of the air or have to yank in power to keep going. Too fast, and you'll need a big hairy flare to get stopped. Either extreme will call for a flurry of stick wiggling. Keeping the aircraft stable will give you more power for lift. Feeding the power in gradually will allow you to monitor the amount of torque necessary to terminate the approach. If you're getting close and you are nearing a red line or a pedal stop, you can tell it is time to use your escape plan and go around. Nothing spikes the power gauges like pumping the sticks and dancing on the pedals.

Flying without moving the controls is a little like trying to make your catsup and french fries run out at the same time. Nobody alive can do it every time, but if you practice it enough, it is not only easier on the aircraft, it feels good, too. Instead of squeezing black plastic from the cyclic grip out between your fingers at the end of an approach, you will be sitting there at a hover, relaxed and serene, holding the cyclic with no more pressure than you would hold an over ripe peach. There's a downside to developing this technique. When your passengers see the helicopter take off, cruise, approach, and land with no apparent movement of the controls, their suspicions will be confirmed. No wonder helicopter pilots don't make any money! Anybody could fly one of these things--there's nothing to it!

Land with a one-point reference. Every perfect landing place in the mountains is designed around a stump, a rock, or a manzanita bush. Therefore, you won't have the luxury that airplane drivers and helipad heroes enjoy, of scanning the horizon during landing, triangulating your position using an infinite number of points and plopping her down in the middle. Most of the time, to get your skids down flat and clear your tail rotor, you are going to have to land with a point as a reference.

One of everybody's least favorite memories from flight training is their first try at learning to hover. The classic mistake was to fixate on a point on the ground between your toes and thrash wildly about trying to keep the thing still. After you gyrated around out of control for a while, your instructor would tell you to look out a ways, and keep your eyes moving. Well, when you have to touch down in an exact relationship with that rock, stump, or manzanita bush, you'll have to concentrate on that point and make your moves in relation to it. Hovering with a point as a reference requires some mental discipline as well as practice. Don't worry about being herky-jerky on the controls. It's a little depressing to be able to hold a rock steady hover at six feet from some mark on the pavement, then flop around like a fish at six inches. Every landing surface you're using right now has pebbles, grass clumps, painted lines or footprints that you can fix your attention on while hovering. Of course your peripheral vision has to stay on the job, but all your position and movement cues should come from a close-in point. Try looking out a side window at the toe of your skid and placing it precisely behind a particular pebble or some such, for each landing. This chin bubble and side window practice will also take some of the sweat out of landings when the windshield is fogged or obscured by rain.

Land your tail rotor. Landing the nose is easy. Flight surgeons are still making pilots go through the drill of finding their nose with their eyes closed. Most pilots are not too terrified of flunking this maneuver, since they're more or less constantly paying their noses some kind of attention. They're either picking it, scratching it, or thumbing it at somebody all the time.

Given that manzanita bushes have an insatiable appetite for tail rotor blades, it makes good sense to know where your tail rotor is, even though you can't see it. You just have to pay some attention to it. Every third or fourth landing, try to place your tail rotor precisely over a crack in the pavement, or bare spot in the grass that's in your landing area. After a hundred or so tries, your tail boom will start to feel like an extension of your spine, and you could touch it with your eyes closed!

Know your aircraft

Just because you're flying in the mountains, you don't have to kiss the middle of the helicopter's performance charts goodbye forever. It's just that more often than not, you'll be operating out near one edge or the other. Knowing what the aircraft weighs and what it will do at that weight is a simple act of self-preservation. Everything weighs something. Cameras, lunches, handbags, the whole shooting match will be scraped up and weighed by the Feds if something happens, and it's going to be your fault if the pile is too heavy for the altitude and temperature. Do the calculations for every leg until it becomes a routine part of your thinking process. A helicopter pilot in the back country gets downright intimate with his machine. He'll eat in it, sleep in it, rest in its shade, talk to it and stroke it like a living creature. If your aircraft is just an ego extension, or a showcase for your haircut, it'll show.

There are a million little tricks to mountain flying that make the job easier and safer, but you won't be expected to know them right off the bat. You can learn them through trial and error, or by watching the older guys do it. Don't be too proud to ask--a new guy sticks out like a dog at a cat show anyway. Everybody knows a new guy can't long line, pump fuel out of drums, or build a campfire worth a damn, so don't try to impress anybody with anything but your control touch for the first six months.

Dress and Behavior

This is one of the good parts. Dress is optional, haircuts are optional and, if justified by skill and dependability, behavior is optional within the exercise of common courtesy.

I learned something about mountain pilots from an old carpenter. To him there was no such thing as an ordinary board. Each one was an individual whose age, grain, knots, and twists suited it for a particular place in the job at hand. Once in a while there'd be one so knotty and warped that it was only good for blocking or spacers, and every now and then he'd run across one that was so clear and straight it would make him shake his head and grunt with appreciation. He'd go through a flitch of floor joists one by one, and lay them out in the order and the position in which they'd be used, before he drove the first nail. They all looked pretty much the same to me, so I asked him why he took all the extra time to sort them out. He picked up the first one on the pile, a fresh, fragrant yellow pine two-by-ten. He cradled one end gently in his hard old hands as he squinted down its length, and said, "This fellow here has a bow in the middle there, and as it dries out and gets older, it'll try to get worse. If we put it out in the center with the bowed side up, gravity and the load it's carrying will keep it straight." Nearly to a man, most helicopter pilots who end up flying in the mountains for a living turn out to be pretty straight characters who are mild of manner and conservative flyers. There's something about the nature of the place and the concentration demanded by the work that tends to level out the rough spots in character and flying technique. Probably because of the maneuvers required in his day-to-day work, a mountain pilot gets the urge to "hot dog" about as often as the Frito-Lay delivery man gets the urge for a salty snack.

Everybody knows that qualifications are purely and only a function of supply and demand, so don't be too put off by "mountain time" snobbery. Everyone who's doing it today got started when there were no mountain pilots available and operators were looking for careful, thorough pilots who were considerate of their machines and weren't afraid of hard work. If you start right now, you'll be ready by next spring. Good Luck!'

William C. Dykes has more than 15,000 hr. total flying time, including more than 5,300 hr. in helicopter. He's conducted mountain-flying operations in Africa, Asia and North and South America.

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