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What a way to go -


tradford

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Having the opportunity recently to get some stick time in an astar, i can say that the whole "if you can fly a robbie, you can fly anything" is like saying "the future shortage of pilots in inevitable", its just a sales pitch. Ive flown 44's with hydraulics, so i dont know why hovering is such a challenge in an astar. But just like a 22, give it 5 lessons or so and you'll get better at it. I was actually told i have the robbie shuffle where i am inputting too much into the cyclic. When the real pic does it, his hands barely move the cyclic.

 

That saying about the R-22, like the pilot shortage, is true, just misleading. Yes you can fly anything, but it doesn't say you'll be able to fly them well!

:lol:

 

I've only had one opportunity to land on a dolly,...and I passed it up! Oh' well?

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Having more than a few hours in Astars and dolly landings, I’ll offer this; I never, and I mean NEVER, “scooch” the machine while on the dolly. “Scooch” meaning; getting the helicopter light in the skids and using the pedals to move the helicopter a few inches while the skids remain in contact with the dolly surface. IF, I believe I need to reposition the helicopter on the dolly, I will pick it back up, reposition, and set it back down. Scooching IS how bad things happen. Additionally, I preach, stow your ego with dolly landings. That is, upon the set down, as long as you are completely on the dolly and not near the edges, don’t worry about it. It doesn’t have to be perfectly straight and the more you dilly-dally around to make it look pretty, the higher the probability of a problem…….

 

Astar flight controls are sensitive to input. Over-controlling is common. Pilots just need to get that fact out of their heads and fly the machine……

 

Lastly, regarding dolly op’s, my goal is, when setting down, the lateral centerline of my cyclic is at the front edge of the dolly. This guarantees the springs won’t be hanging off the back. I use this technique regardless of dolly size (which I operate on 3 different sizes)……. With 206’s, I place the skid tips at the front edge…..

Edited by Spike
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If that orange line seen over the vehicle is the entire dolly, it's the shortest dolly I've ever seen. Far too short to use without some serious preparation and planning. I'm not saying I could land on that dolly, but I know how I would safely attempt it...

 

First, the Astar lands fine. It will keep you very busy keeping it still over the ground the last foot or so, but quick control response to various pitch, roll and yaw excursions will hold position for a satisfactory touchdown. (Yes, a little forward on the cyclic makes it easier if everything gets snaky at the bottom). Never ever feel for the deck, because you can't reliably feel the difference between the spring contact and the induced turbulence. I've bounced a skid heel, or I thought I had done so with a foot of air underneath. The actual landing from that height is memorable.

 

Point is, how it feels will fool you. Fly it until the collective bottoms and plan gradual control input to maintain a stationary position with quick small corrections. Every landing is a slope, and you never know the direction of slope until you latch the collective.

 

You can't see the heels, but you can position them pretty accurately if you have a lateral reference. If nothing else, I'd put the aft end of the dolly on the pavement edge or a paint line to get that reference. CHOCK the dolly!!!

 

When positioning for landing, the heels will seem to be almost immediately under the pilot seat back at a 5 foot hover, but it's better to land forward than too far aft- most of the aircraft weight sits on the aft end of the skid. Having seen about a million autorotations to the ground with most using the stinger to level, I think one might be able to three-point an Astar without damaging the airframe, the stinger and tail boom are durable if you don't impact load them.

 

Every Astar landing is a slope. Even after skid contact, your control movements are small, slow and reversible in the event you wish to abort, just like slope training. You could load and offload with a toe in or 1 skid in an Astar,.. fly it just like that every landing.

Edited by Wally
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Apparently, the pilot made a comment to the tower; “They didn’t chock my cart. It was like a skateboard out here,” …. The word "was" is significant...

 

This will, and has already, started a debate about the usefulness of dollies….

 

 

The cart is not the problem here, decision making was.

 

preliminary information - NTSB Identification: WPR16FA029

 

"According to friends and flight instructors who had flown with the pilot, he had previously owned a Bell 407, and the accident flight was the first he had flown in the AS350 series without a professional pilot present."

 

 

https://youtu.be/Re2UCTP6KI4

Edited by iChris
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That’s a small dolly for an Astar private owner although; the right door has large windows. I’ve operated an Astar off a dolly with only the “upper” window and it definitely restricted the view of the dolly. However and again, dollies shouldn’t be in the discussion. Decision making #1. Skill level #2, Helmets #3. Private owners #4………

 

And, when I mentioned the word “was” as significant, it begged the question. Did the ground crew correct the chock problem and the accident was a result thereafter?

 

To wit, I’ve landed there many times and they are pretty good with ramp service….

Edited by Spike
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Having the opportunity recently to get some stick time in an astar, i can say that the whole "if you can fly a robbie, you can fly anything" is like saying "the future shortage of pilots in inevitable", its just a sales pitch.

 

Ive flown 44's with hydraulics, so i dont know why hovering is such a challenge in an astar. But just like a 22, give it 5 lessons or so and you'll get better at it.

 

I was actually told i have the robbie shuffle where i am inputting too much into the cyclic. When the real pic does it, his hands barely move the cyclic.

 

 

Helicopters in general share some of the same common characteristics. Though each make and model may share common characteristics, each has its own unique characteristics which differentiate it from all others. However, the same basic piloting skill set is transferable between different makes and models. We augment our current knowledge and skills through repetition, practice. Meaning we make greater by adding to and increasing our skill set.

 

There is no real issue to hovering an AS-350 and landing on a properly designed cart. There is no need to end up in an accident as seen in the above post. Your only challenges are to making up your mind that, you’re going to have to learn some new stuff by finding someone to teach you the right stuff.

 

A few of those unique characteristics are were you are seated as a pilot in the AS-350. You’re seated farther inboard than you may be use to and you don’t have that big open chin bubble below your feet (like in the Bell). Consequently, the view below your feet is restricted. As you reach 4-5 feet from the cart, the cart disappears below you. So it’s imperative that you line up with some type of reference as you approach the cart and move forward and downward toward you landing point. In addition, since you won’t be able to see the skids, you’ll have to rely fully on your references. In one of the videos above, they used flags as references at the front corners of the dolly.

 

The front of the skids maybe in a place you’re not use to. You’re all most seating in front of the skids and you can’t see the cart so it looks like you’re too far forward. If you’re fooled by that, you’ll in up with the rear end of the skids hanging off the rear end of the dolly (the steel springs used to prevent ground resonance hanging off too). Those steel springs can also cause problems, if you’re sloppy with aft movement of the helicopter and hook them on the dolly.

 

You’re going to have to learn to land those skids just were you want them without actually seeing the ground below you. You’ll have to fly it all the way down to the cart, you can’t be sloppy with the collective and cyclic anymore. In that second accident video (Post #21) you’ll see the helicopter skip left off the dolly which is characteristic of too rapid of a collective decrease for the amount of right cyclic applied. As stated in a post above, it’s like landing on a right slope (right skid low).

 

In the case of the two-bladed vs. the fully articulated rotor system there is a significant difference in control responsiveness; moreover, roll acceleration. In order for the two-bladed system to develop a control moment the rotor must first develop thrust, zero thrust, zero control moment. The fully articulated system can develop control moments without developing thrust.

 

The two-bladed rotor is hinged at the center of the mast; the blades of the fully articulated rotor are attached to the rotor hub at some distance. This offset hinging allows centrifugal force to produce control moments. Centrifugal force is independent of thrust; therefore, the fully articulated rotor can produce control moments even though it is not producing thrust. The additional development of thrust just increases the magnitude of the control moment that much more.

 

Therefore, with respect to the AS-350, unnecessary cyclic movement i.e. over controlling results in amplified changes in fuselage attitude, thus the reason for your quote: “I was actually told I have the Robbie-Shuffle, where I am inputting too much into the cyclic. When the real pic does it, his hands barely move the cyclic.”

Edited by iChris
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As to the difficulty of hovering the Astar, it comes from the rotor down wash affecting the tail rotor. When OGE the main rotor wake misses the tail rotor completely which is why it's so strong in an OGE hover and a good long lining ship. When it's IGE the wake can be in and out of the tail rotor based on wind since there's an overlap. The tail rotor can obtain translational lift all by itself causing the thrust to vary. They made it better in the B3 when they installed the trailing edge tab on the blade.

 

Very little wind gusting or changing directions in a hover can really wobble the ship around and the transition into ground effect with these wakes are why this ship takes a moment to control before setting it all the way down. And why the helicopter is most controllable while hovering with a slight tail wind.

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As to the difficulty of hovering the Astar, it comes from the rotor down wash affecting the tail rotor. When OGE the main rotor wake misses the tail rotor completely which is why it's so strong in an OGE hover and a good long lining ship.

 

When it's IGE the wake can be in and out of the tail rotor based on wind since there's an overlap. The tail rotor can obtain translational lift all by itself causing the thrust to vary. They made it better in the B3 when they installed the trailing edge tab on the blade.

 

Very little wind gusting or changing directions in a hover can really wobble the ship around and the transition into ground effect with these wakes are why this ship takes a moment to control before setting it all the way down. And why the helicopter is most controllable while hovering with a slight tail wind.

 

You’ve just described some of the same characteristics that effect all single rotor helicopters in a hover with a conventional tail rotor, not just the AS-350. In fact, all helicopters have their own respective degree of piloting difficulty in a hover due to these characteristics.

 

Remember yours and others first attempt to hover a helicopter. Why did it take us more than a few hours to learn to hover? Nothing that we were familiar with prior to helicopters had that type of control response and sensitivity. The problem, helicopters are inherently unstable, period.

 

In fact, the helicopter is said to possess positive static - negative dynamic stability. Meaning it has oscillatory motion, which is a characteristic of positive static stability; however, the amplitude of the oscillations increase as time passes, indicating negative dynamic stability.

 

Although some degree of stability is necessary for good flying qualities, pilots can learn to fly unstable aircraft. There is no real issue to hovering an AS-350. Helicopters in general share some of the same characteristics. However, the same basic piloting skills remain the same.

 

The AS-350 is no more difficult to master in a hover than any other helicopter. Technically, the helicopters behavior with respect to hovering is defined by its dynamic stability. Dynamic stability refers to the movement of an object with respect to time. In this case, we’re referring to the forces that cause the movement of the helicopter as it hovers with respect to time. We can categorize these forces under two categories, aerodynamic forces and inertia forces.

 

The aerodynamic forces including the ones you’ve mentioned, main/tail rotor lift forces, rotor downwash, wind, rotor vortex, ground effects and their interactions with the airframe, tail boom, and tail rotor. Modifications are sometimes added like the tail boom strake to unloading the tail rotor and reduce torque requirements by reducing unwanted lift created by the rotor downwash along the tail boom. Enhancements to the tail rotor blade to increase the lift coefficient i.e. thrust. The inertia forces are these mainly related to the aircraft’s mass, rotor inertia, and centrifugal forces. Inertia forces effect rotor response, pitch and roll rates, pitch and roll acceleration, yaw rates, and yaw-roll coupling.

 

Transitioning from a counter clockwise to a clockwise rotor rotation, will take some practice. We’re still dealing with an inherently unstable aircraft with the same aerodynamic and inertia forces that define the aircraft’s dynamic stability. However, this time, we’ll have to learn to handle these aerodynamic and inertial forces coming at us from a different direction. Right skid low vs. left skid low, opposite torque reaction and yaw-roll coupling, etc.

 

Eventually the pilot puts all this together and can hover over a spot with precision under almost any condition, in any helicopter. Based on practice and experience, the pilot learns to analyze and resolve the inherent instabilities of a hovering helicopter. This all works just as it did during that most difficult period when you first learned to hover; however, due to your additional knowledge and experience, it all fits together much faster.

 

There’s really no technical grounds for this myth that the AS-350 is more difficult to master in a hover. There’s so many pilots out there that do it with precision day after day. Yes, it will take practice and a little bit of your time.

Edited by iChris
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