#264 

Thank you Davide!

Thanks for sharing Ian!

That's exactly how I took it! :)

Trent Friend thanks for the feedback!

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Thank you!

CHAOS45 interesting never heard of it!

@@HelicopterGround It is an electric pressure cooker that is simply amazing. Doesn't take long, makes tough cuts of meat tender. Nothing better in the world for things like london broil or stew beef or roasts.... but also pork shoulders. It's absolutely amazing. Plus it doesn't use much power and doesn't heat your house up. Google it and look at the stellar reviews. Here's a link to their page, but you can get it a little cheaper on ebay, offerup, or craigslist. instantpot.com/ ..... GET IT AND YOU WILL THANK AND YOU WILL BE THANKING ME SOON!

@@cshamm Thank You For the Wed Site Sir............JESUS is LORD

Thanks for commenting Jim!

Depends on the situation.

No way…NOT me. In my mind, your chances of surviving the G-R incident are greater certainly than the ‘boom chop’. With a severed tail, you’re DONE every time. It’s not THAT easy to get into a full Ground resonance situation IF you’re paying attention AND in control of the helo..or knowledgable about what it takes to stay out of G-R. I’ve had int onset brieflyonly a couple of times in the Schweizer 300. BOTH times were fixed different ways though; a FULL-down on the collective AND also picking it back up IF RPM’s are ‘near the top’. Both worked fine..

@@m118lr That's just it though. You've experienced the onset of GR a couple of times. I've never even come close to Low-G Mast Bumping. Its not about survivability, its about the likelihood of ever having to deal with it.

A-Star's are junk. Look how there's No frame from the top of the windscreen to the transmission mount. Not well built and not much room inside for the price. And the elastomeric dampers are inadequate for the weight of the blades, especailly if blade heat strips are added.

HARLEY D Enstrom Turbine Model.

Tim Morris they are a common platform in the rotorwing world though.

@@timmorris3056 : That's Why I Like HUGHES-500D, or the New MD-520N Helicopters.............JESUS is LORD

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@@HelicopterGround no problem i am a mechanical engineer with 10 years experience. Hit me up on my account if you are interested in having scientific input on your topics. I don't do youtube but i can call in

Throttle off.

@@HelicopterGround, please, I'm trying to understand. Isn't that what you did?

HI.!!.MR.KENNY.AND YOU TOO MAM.PLEASE APOLOGY ME.. FOR YOU DIDNOT ASK ME DIRECTLY..!!.WHEN GROUND RESONANCE APPEARED.. THE RIGHTFUL PROCEDURES ARE..IMMEDIATELY COLLECTIVE PITCH CONTROL LEVER LOWEST DOWNWARD..TRY CENTERRING THE CONTROL STICK(CYCLIC CONTROL STICK..SOME TYPES OF BIRDS..TOO MUCH LEAN BACKWARD OF THE CYCLIC STICK WHILE THE BIRD IS SEVERELY UP-DOWN BUMPING..MAY MAKING THE MAIN ROTER BLADES"S TIP HITTING TAIL ROTATING BLADES)..THROTTLE OR ENGINE CUT OFF..MASTER SWITCH CUT OF..FUEL SWITCH CUT OF..LEAVE OFF THAT HELL..!!.THESE ALL STEPS ARE RECOMMENDED..!!.(SOME DETAILS..PLEASE.ARE OMMITED).!!..**ABOUT "THE LIFT OFF"..IF DOING SO..WHILE THE BIRD IS SEVERELY BUMPING CONTINOUSLY..UP AND DOWN..NUMERROUS INHERENT BUMPING FORCES WOULD UNEVITABLE IMPOSE ALL THE BIRD STRUCTURES..LEADING TO SELF- DESTROYED IN PIECES OF BIRD..HIGHLY CHANCE OF FATALITY WOULD BE FACED..IF LIFTING IT OFF..THAT BIRD WOULD BE DESTROYED IN SHATTERED PIECES WHILE AIRBORNE AFTER LIFTING OFF THE GROUND..(TO CONTINUED..COFFEE BREAKE ..SIR.!!).NEW EDITION.!!..BEFORE ENDING..SIR.!.OWNING TO YOU..TRY UNDERSTAND THIS ACCIDENT.. I MYSELF APPRICIATE TO EVERYONE FOR TRY LEARNING THE UNKNOWN THINGS.!!.THE CHOPPER..HAVE MANY ADVANTAGES IN ITSELF..WHILE THE SHORTCOMINGS AVAILABLE INSIDER TOO!!..SUCH OF.. NEARLY EVERY TIMES OF CRASHING DOWN..PRETTY VERTICALLY DOWNED,,(HILL CRASHING IS EXCEPTION AL)..IF IMPACT ENERGY IS SO HARD ENOUGH TO DEFORME OR DESTROY FUEL TANK..THE TENDENCY OF IGNITION OF FIRE IS HIGHER IF THE FLYER DID NOT CUT THE ELECTICAL MASTER SWITCH OFF.!!..ALL TYPE OF CONTROLLING FLYING MACHINES ARE INCOMPARABLE MORE SOPHISTICATED CONTROL THAN DRIVING THE CAR..!!.FLYING IS THE SUCH. COMPLEXITY ISSUES BY IT OWN..ANYONE WHO CONTROLS IT..COMPLEX THINKING TO THAT ANYFLYER ..HIGHER RATE OF SURVIVABILITY THAT FLYER CERTAINLY WILL BE FACED...!!.SIR.!!.MAM.!!.YOU ARE INCLUDED.. ASKING PRETTY DEEP COMPLEX QUESTIONS..SHOWING OF YOUR SMARTNESS FOR TRY UNDERSTANDING THE UNKNOWN GROUND RESONANCE..EVEN THE SOME MEN DO NOT TRY TO KNOW THIS SOPHISTICATING ISSUES..!!.I DEEPLY APPRICIATED YOUR INTENTION TO UNDERSTAND THAT..!!. BYE.!.MAM.!!

@@tanintupmongkol5438 Hello there tanin! No more need to type in all CAPS to ask for an answer. We have the Absolute Best answer that works for Every situation including Ground Resonance, Works Every Time! Just go to your nearest city bus garage and buy a lifetime bus pass. You'll Never experience Ground Resonance with that Fool proof method!!! The fact is that helicopters are Very safe and Very useful, and no matter how many thousands of hours of flight experience a pilot has, there will always be an unknown variable to deal with in ANY peice of machinery. The best thing a pilot can do is to continue to train with high time instructors, continue to challenge their knowledge to the next level, and so on. The instructor here is Very well trained but there appeared to be an equipment malfunction, one of a thousand variables. He did the right thing and hung on till there was nothing left to hang on to. Turbine's don't spool up as quickly as standard piston engines so the lift off was out of the equation. So..... Our best advice to you 1) There's a Black Friday sale on bus passes for you, 2) NEVER trust your life in a Junk A-Star.... Happy Holidays!!!👍😁👍 Ontrac Air Service 52 years

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Please learn how to spell correctly.

@@humelakecabin sorry I am on my way out I am 62 and have forgot more than you ever know

Enstrom Turbine Model. Thanks for commenting!

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Don't know how often this happens... but helicopters with fully articulated main rotor systems are the most prone to ground resonance.

Clarence Watson yes some more than others!

Helicopters with fully articulated rotors (3 bladed or more) and its caused by pilot error

@ Most causes of helicopters suffering from Ground Resonance, is caused by improper maintenance or component failure in the rotor hub... most notably with varying quality &/or failure of the drag hinge components, causing the blades to predominantly lead or lag to one side of the rotor disk, resulting in an imbalance of its CG. This is why most cases of GR occurs during initial spin up. That's not pilot error.

@ I've witnessed it happen on run up.

Fully articulated is a type of rotor system.

It is one of the 3 main types of rotor systems on today’s helicopters. The term means that each individual blade can flap, lead/lag, and feather to account for un equal lift amounts in foreward flight. Usually only found on machines with more blades than two, such as an md500.

I can be lift off, it can also be roll off throttle depending on the situation.

Thanks Smitty!

@@HelicopterGround - Thank you for all you do in the aviation community! Great info here that I've had a tough time finding anywhere else.

Glad it came out for you ok Matt!

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Analysis The certified flight instructor (CFI) stated that the student smoothly lowered the collective and set the helicopter on the ground as he was rolling off the throttle. The helicopter then started to bounce (ground resonance) and the CFI reached down to make sure the collective was down and the throttle was off. The helicopter continued to "shake violently and ripped itself apart." The helicopter had a new design of elastomeric damper installed 91 flight hours before the accident. The new design dampers had been flight tested at the factory and approved by the Federal Aviation Administration prior to being put into service. The helicopter had experienced severe vibrations on two previous flights, one of which resulted in the chin bubble being broken. Inspection of the accident dampers, at the damper manufacturer's factory, determined the dampers were within manufacturer's specifications. After the accident flight the helicopter manufacturer recalled all the new design elastomeric dampers.

Probable Cause The National Transportation Safety Board determines the probable cause(s) of this accident to be: Ground resonance experienced by the pilots.

@@HelicopterGround Not looking to blame you, looking to learn. Fantastic that you shared the incident in the first place.

Yes. All survived.

Owner was pic.

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Depends on the situation. If rpm is low throttle off. If you are at operating at full rpm get it flying again.

Recovery is often possible if action is taken quickly. If sufficient rotor RPM exists, immediate takeoff can restore rotor balance by allowing the airframe to freely move and help damp the oscillation. If rotor RPM is very low during a ground resonance incident, complete shutdown may be sufficient.

As per the accident report. The elastomeric dampener failed. There was no recovery for that. Also the resonance started after rolling off the throttle. The recovery as per The Helicopter Flying Handbook at low rpm is not to increase throttle to try an fly again.

It can happen with a fully articulated system.

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They can be!

@@HelicopterGround They just are.

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No , " they " stated that the pilot ultimately became disoriented and lost spacial awareness.