Learning To Fly Approaches In The Helicopter
So you can fly a helicopter straight and level now. You have experienced the thrill of finally learning to hover, and you have lived through picking the helicopter up off the ground and putting it back down. Things should start getting easier from this point on right? Not so fast.
I am sure that I have mentioned it previously somewhere, but one thing that always astounded me was how every new maneuver with the helicopter seemed just as difficult to learn as all the previous maneuvers. Seriously, how hard could it really be to learn approaches while flying helicopters? Well I was about to find out.
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When you first start learning approaches in a helicopter you will almost certainly be in a wide open area with no other traffic around and you will start with straight in approaches from 500' above the ground and into the wind. So, with the help of your instructor all you need to do is manage the helicopter's descent from 500' agl to a fixed spot on the ground out in front of you. A good standard rate of descent is about 800 feet per minute.
Fix Your LZ On Your Helicopter’s Windscreen:
Here is how you are going to learn approaches. You are going to get a visual fix on your "spot" or landing zone on the ground then you are going to focus on where that spot is located in your field of view on your windscreen (that would be your windshield in a car). Now it will be difficult for me to set here and tell you exactly where that spot is going to be on your windscreen. That will depend on the type of helicopter you are flying, and how far out you are from your LZ. We have already established that you are at 500' agl.
In the MD500 and Bell 407 we have a horizontal cross member that separates our lower and upper windscreen, we then have a vertical strip separating the left and right windscreen. A pretty standard approach would put my LZ somewhere near the center of the windscreen, above the horizontal strip. I am kind of stating the obvious here. Of course the LZ should be somewhere in the middle of your windscreen or you have a problem, right? Continuing....
You are going to learn to do approaches simply by holding the LZ in the same spot in your windscreen. That sounds pretty simple right? Let's look at it from a slightly different perspective. You are flying along at 500' agl and you pick out a LZ, but you continue to fly toward it while maintaining your altitude at 500'. Obviously the location of that LZ in your windscreen is going to very rapidly start moving down your windscreen right up to the point that you fly directly over the top of it.
Conversely if you pick an LZ out in the distance and get it fixed in your windscreen, but you descend rapidly way before reaching it, then you most certainly watched it move upwards on your windscreen.
elow is Cockpit view of Bell 407 on patrol.
Finally, let’s pick out the LZ, mentally note where it appears on the windscreen and start a gradual descent toward it. If after a few moments that LZ begins to move up on the windscreen you are descending too rapidly and you will arrive at the ground short of your LZ. If on the other hand the LZ begins to move down on your windscreen, you are not descending rapidly enough and you will overshoot your LZ if you don't fix the descent.
Keep Practicing Those Approaches:
I can pretty much guarantee that your first few approaches will not even be close, and will likely involve many go-arounds. In fact your first 10 or 20 approaches may not even be close. The only way to improve is to do them over and over and over again. You may do 10-15 approaches and notice very little improvement, if any at all. As with learning to hover in the helicopter, it can be a very humbling and exhausting experience. I can remember cursing myself under my breath and feeling like I disappointed my CFI with another screwed up approach.
Eventually however things will begin to click. The more in tune you become with the helicopter, the more relaxed you will be, and the easier it will be to hold that LZ in the same spot on your windscreen. To clear up any confusion, there is no "correct" spot for the LZ to be on your windscreen. This will vary depending on your altitude that you begin your approach, and the distance from which you begin your approach. Regardless of where the LZ appears on your windscreen, if you hold the LZ in that spot and don't let it move, you will fly directly to that spot, or at least within a few feet of it.
Even once you learn to fly a smooth approach, without over compensating with the collective, there will always be fine tuning. I can remember flying pretty good approaches but I would always, always, end up about 10 feet short of my spot. More fine tuning, such as looking past your LZ about 10' will start to bring your approaches closer to where you want them. Your CFI will assist you in fine tuning your approaches.
After a couple of years of flying you will look back and wonder what was so difficult about learning approaches. You will be able to fly a near perfect, no hover approach to landing and put the skids within an inch of where you wanted them, all while perfectly relaxed.
FLYING HELICOPTER APPROACHES TO A HOVER:
Now that you can do an approach, the next problem is that you have to do something with the helicopter once you reach the bottom of the approach/descent. You have to either, put it on the ground, bring it to a hover, or initiate a go around by adding power and climbing out.
In the first part of this article I focused simply on keeping the LZ in the same spot on the windscreen. I never even mentioned the term power management. But one uses power management (via the collective & cyclic) to keep that LZ in the same spot and fly a smooth approach. But what happens at the bottom of the approach when you want to bring the helicopter into a hover?
Flying the approach requires one power setting (set with the collective) but hovering requires a completely different power setting, I.E. more power. So now you must learn to smoothly transition from an approach power setting to a hover power setting. As you near the bottom of the approach you will begin to add power. You will slowly start pulling up on the collective, while adding left pedal (to compensate for the additional torque) and start coming back with the cyclic to arrest your forward movement. Coordinate all three of the controls and you come to a nice relaxed hover at the bottom of your approach. Get behind on any one of them and bad things start to happen real quickly.
For me I can tell you that the hardest thing for me to master while doing approaches to a hover, was getting in enough left pedal. Don't get in enough left pedal and the nose starts to come around to the right on you (in American helicopters) very quickly. Letting the helicopter spin is a bad thing. Even after telling myself repeatedly that I need to put in more left pedal at the bottom of the next approach, here would come the nose turning to the right. Damn it! This is definitely one of those times you have to be thinking and reacting out ahead of the helicopter. In other words, if you let the nose come to the right at all, you are re-acting behind the helicopter. Not good. You need to be anticipating and be out in front of the helicopter mentally. But some of this just comes with practice and experience.
Eventually, like all other areas of helicopter flight, you will master all of the dynamic forces working on the helicopter as you transition from a smooth approach to a stable 2-3 foot hover while not allowing the nose to come around one bit. It will become so natural you will eventually do it many times a day with little conscious thought.
FLYING THE HELICOPTER TO A NO HOVER LANDING:
When would you ever want to land without hovering first? How about off field in a dusty environment. The quicker you get the helicopter on the ground the less dust you stir up. That's just one example. Eventually you will become so proficient at your approaches and landings, that many of your landings will be a version of a no hover landing anyway. A run on landing is another type of no hover landing, but it is more of an emergency procedure which can be used in situations such as a stuck tail rotor.
In a perfect no hover landing you are going to completely arrest all forward and vertical airspeed at exactly the same time the helicopter skids touch the ground. Initially the hardest part of a no hover landing is just that; keeping the helicopter going toward the ground, and not stopping at a hover. Why is this difficult you ask? There are two reasons.
HELICOPTER GROUND EFFECT:
The first reason is ground effect. If you have flown a nice slow smooth approach then you necessarily added some power at the bottom of the descent to keep the helicopter from smacking the ground. But now you are in “ground effect” and quickly discover that the helicopter takes less power to hover in ground effect and essentially does not want to land. Now this may not be the approved FAA terminology to explain this, but that is essentially what happens.
The second reason I think is more psychological on the pilot's part. When you first begin to practice no hover landings it seems virtually impossible to descend through ground effect and land without first coming to a hover. No matter how many times your CFI coaches you "ride it all the way to the ground", you will inevitably stop at a hover. With much practice however, you will learn to coax the helicopter through ground effect and into a nice no hover landing.
MORE ABOUT LEARNING TO LAND IN A HELICOPTER:
When you are first learning to fly helicopters it is likely that you will do some of your training “off field” in open areas, (Off field is a term meaning you’re landing away from airport-air field, thus you are doing an “off field” landing.) It is almost certain that some of your first landings will be on hard packed dirt or grass.
While learning to fly helicopters it is not uncommon to go out and practice landings, approaches to landings, no hover landings etc. off field, then come back to the airport or base and struggle with landing on the concrete pad. This is sort of the same phenomenon as the no hover landing. Again, I think it is twofold, part ground effect and part psychological.
There is a difference in the amount of lift in ground effect over concrete or asphalt, vs. grass or dirt. The harder the surface the greater the ground effect is going to be, (The correct way to explain this is the harder the surface, the less power it takes to hover in ground effect). There is also a psychological aspect in that you know you get a slightly softer landing on grass, so it is a bit easier to coax the helicopter through ground effect when landing on a perceived softer surface.
Now get back to the base and try to put it down on the concrete pad and the damn thing just refuses to land, or you end up bouncing it all over the pad. The same can be true when transitioning to a different aircraft. Basically everyone in our unit experienced the same thing when we transitioned into the Bell 407 with hydraulics. I can't tell you how many times I heard experienced pilots say that their worst landing was the one back at the airport. But sometimes the best or easiest way to land on a hard surface is a no hover landing.
This is a good time to remind you that I am not a certified flight instructor and that the purpose of these articles are not to instruct, but to simply give you an idea what to expect when you start your own helicopter flying lessons.