engine failure

[Glory.]

wow.

Engine failure? The gear is splayed out but obviously it could have been worse.
http://www.liveleak.com/view?i=9114ba2dfd

[sky's the limit]

Sounds like it, you can hear the turbine winding down.

Well done to keep it upright, everyone walked away, the rest is why you pay insurance.

How's training going Glory???


stl

[kingeddie]

High power , right pedal turn in a 206 LTE my guess

[sky's the limit]

High power , right pedal turn in a 206 LTE my guess

Just listened to it on the desktop, not the laptop. I think you're right KE, the engine doesn't seem to waiver very much, big right turn too...

stl

[Glory.]

High power , right pedal turn in a 206 LTE my guess

Just listened to it on the desktop, not the laptop. I think you're right KE, the engine doesn't seem to waiver very much, big right turn too...

stl

Yea, actually thats what I orginally thought looking at the shadow and the fact that on the way down they were still turning, and my guess is the pilot was trying to get the camera man the best shot so, maybe he forgot which direction the wind was coming.

Trainings good STL, hands stink like Jet A, loving those 14 hour days, and enjoying the sunny bright weather in langley


I guess I could be flipping burgers. Haha but in all seriousness, its good. Learning curve like a cliff, but its good.

[kingeddie]

Looks like he is out of left pedal and he is lowering the collective to get some power off and ground show up uninvited as usual.

KE

[sky's the limit]

Looks like he is out of left pedal and he is lowering the collective to get some power off and ground show up uninvited as usual.

KE

Uninvited guests just aren't welcome, are they?

stl

[pileit]

Vortex ring state is my guess, look at how he is in a turn and then starts descending. If he would have got LTE it would probably have kicked.

By the shadow it looks like he backed into his down wash with partial power.

Again, just a guess.

Would be interesting to find the initial on this one as the video is excellent. Camera guys just don't give up do they, not even any swearing or praying to a deity. Or they are not smart enough to be scared.

Cheers

[GilletteNorth]

I was under the impression a helicopter had to be nearly stationary and descending for vortex ring state to occur. My only knowledge of it really comes from studying the accident in New York with that Canadian Forces Sea King accident years ago. I Googled the definition for vortex ring state and:

Vortex ring state, also known as settling with power is a hazardous condition encountered in helicopter flight. It occurs when the helicopter has three things occurring; a rate of descent greater than 300 feet per minute, an airspeed slower than effective translational lift, and the helicopter is using more than 20% of its available power.[citation needed] A helicopter typically induces a vortex ring state by descending into its own downwash. This condition can be corrected by moving the cyclic forward, which controls the pitch angle of the rotor blade, slightly pitching nose down, and establishing forward flight. The aircraft will fly into "clean air", and will be able to regain lift.

The helicopter appeared to be flying level along the highway while filming so I'd say... no, not a ring vortex accident. I also concede I may be totally wrong too though.

[The Mole]

Vortex ring and settling with power are not the same. vortex ring simply put is stalling the rotor system. Settling with power is to high of a decent rate to stop with available power. My 2 cents

[splitpin]

Vortex ring and settling with power are not the same.

Really???

http://en.wikipedia.org/wiki/Settling_with_power

http://www.cybercom.net/~copters/pilot/ ... tling.html

http://www.dynamicflight.com/aerodynami ... ing_power/

[sky's the limit]

VRS and Settling With Power aren't the same, although the terms are often confused and used interchangeably.

stl

[The Mole]

Hmmm you quoted wikipedia lol. When i get home ill change that. Just because it on the internet doesn't make it true.

Oh splitpin, take your credit card, go to chinook helicopters in abbotsford. Get K.O to take you out, and demonstrate the difference. Then you will understand.

[splitpin]

Hmmm you quoted wikipedia lol. When i get home ill change that. Just because it on the internet doesn't make it true.

Oh splitpin, take your credit card, go to chinook helicopters in abbotsford. Get K.O to take you out, and demonstrate the difference. Then you will understand.

Damned if I would ever pay for a helicopter ride! I've been surrounded by them for the last 45 years. Perhaps one of you so called gurus would explain to us exactly what happens to the airflow under the two different condition we are talking about here, and how each is induced and the cure. I'm not trying to get into a scap here, it's just that when I check the internet they all (not just the ones I posted) say the two problems are one and the same. Now we have two chaps that say the problems are different. Very confusing!!

More info here:http://www.dynamicflight.com/aerodynami ... ing_power/

And here:http://www.heli-chair.com/aerodynamics_104.html

And here:http://answers.yahoo.com/question/index ... 608AAVUT0m

And here:http://www.pilotfriend.com/training/fli ... et_pwr.htm

[sky's the limit]

I think you'll find that the two are very different indeed, and most of the websites you quote are American. Americans tend to use the terms interchangeably as you can see in those pieces you quoted, we do not in Canada. VRS and settling ARE different things. Our definition of "settling" here refers more to exceeding the power requirements due to high weight/low airspeed.

I get into "settling" frequently with production long line work, and its a function pwr demand/availability vs decent rate and is controllable, and even useful in certain applications. VRS is another matter entirely - the air recirculation of which you speak. The recoveries are similar of course, the severity of the situation is not.

I've got too much grass to go and cut, so I won't launch into this fully, but ask ANY of the "gurus" here in Canada what the differences are, and you'll get a very succinct reply.

stl

[splitpin]

I think you'll find that the two are very different indeed, and most of the websites you quote are American. Americans tend to use the terms interchangeably as you can see in those pieces you quoted, we do not in Canada.
stl

You should perhaps pass that thought to the T.S.B. of Canada.
The highlight is mine.


Air 2001




The Transportation Safety Board of Canada (TSB) investigated this occurrence for the purpose of advancing transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

Aviation Investigation Report
Collision With Terrain
Helimax Ltd.Hughes 369D
(500D) Helicopter C-GYTY
Baffin Island, Nunavut, 69º10' N 074º21' W
09 August 2001
Report Number A01Q0139

Summary
A Hughes 369D (500D) helicopter, C-GYTY, serial number 270078D, was being used to transport geological survey personnel and geological samples. The helicopter had picked up two passengers and one sample cache and was in a circling descent for landing at another cache. During the final approach, the helicopter struck the ground heavily, bounced, and tumbled. The pilot was fatally injured on impact. The passengers survived the impact, but later succumbed to their injuries. The helicopter was destroyed by impact forces and a post-impact fire. The sky was clear and winds were light and variable. The accident occurred at about 1700 eastern daylight time.

Ce rapport est également disponible en français.


Other Factual Information
The float-equipped Hughes 369D (500D) helicopter was proceeding along a traverse line to retrieve geological samples that had been placed at intervals along the line. While en route to the second cache location, the pilot made a radio transmission to personnel further along the traverse line. The helicopter was observed overflying the second cache site and, from an estimated altitude of 200 feet above ground, started a tight clockwise descending turn to land at the cache location. The helicopter flew a steep, descending, right turn through 270 degrees and continued the descent toward the cache. Ground personnel heard a brief, unintelligible radio transmission, believed to be from the pilot. Shortly thereafter, a large plume of smoke was seen to rise from the accident site.

The terrain was hilly and rock covered. The helicopter, in forward flight, at a high rate of descent, and in a 25-degree nose-down attitude, struck the ground just below the crest of a hill. On impact, the right float and skid tube dug into the surface, and the left float broke free from the helicopter. The belly of the helicopter was crushed, rupturing the internal fuel bladders. The helicopter bounced, tumbled, and came to rest facing the opposite direction to the line of flight, approximately 60 feet from the initial point of impact. There were high concentrations of fuel at both the initial impact point and the final resting point of the fuselage, with traces of fuel spills along the wreckage path. An intense, fuel-fed fire consumed most of the helicopter.

Rotor strike marks were found on the gravel and rock surface approximately 10 feet beyond the initial impact point. All five main rotor blades were within the vicinity of the wreckage area. Each main rotor blade ejected outwards from the body of the helicopter and broke in two or three pieces, suggesting that the rotor system was powered at the time of the accident. Most of the cabin area and main fuselage had burned away. There were no main rotor strikes evident on the tail boom or the fuselage. Damage to the tail boom and tail rotor components was due to impact forces. Other components were examined to the degree possible, and no indication of a pre-existing mechanical malfunction was found.

Various fuel samples were gathered from the fuel supply tank where the helicopter was based. All of the samples were clear and bright, with no trace of contamination. The engine (Rolls-Royce Allison 250-C20B) was examined at the TSB Engineering Branch; no pre-existing mechanical failures were found. An examination determined that the engine was delivering power at impact; however, the level of power could not be established.

The aircraft was certified, equipped, and maintained in accordance with existing regulations and approved procedures. The aircraft had flown a total of 7623 hours and had undergone its last 300-hour inspection at 7543 hours. There were no known mechanical deficiencies before the flight. Although precise data was not available, it was estimated that the aircraft was being operated within the prescribed limits for weight and centre of gravity. The pilot was sitting on the left side.

A helicopter can exhibit the descent profile and impact characteristics of this accident for a couple of reasons: vortex ring state or power turbine rpm (N2) droop. Vortex ring state, also commonly referred to as "settling with power", is a condition of flight where the airflow through the main rotor is re-circulated. The result of this condition is that, as power and pitch are increased, the rate of descent also increases. It is generally accepted that three conditions are required for the onset of vortex ring state: zero or near-zero airspeed, powered flight (induced airflow passing downward through the disk, with higher power settings being more critical), and a rate of descent between 300-600 feet per minute. Under these conditions, a helicopter may start to descend rapidly. If a pilot then applies more collective pitch to slow the descent, more rotor downwash is created, which intensifies the re-circulation and increases the rate of descent. To recover from vortex ring state, a helicopter must exit the disturbed column of air that is being produced, either by entering autorotation or by gaining clear undisturbed air by displacing the cyclic forward to regain airspeed. A significant amount of altitude may be lost during a recovery attempt, and recovery at low altitude may not be possible.

Power turbine rpm (N2) droop occurs when engine power is unable to increase as the rotor pitch is increased. When the helicopter is decelerated abruptly, or during a normal deceleration with a sudden updraft, it is possible for the main rotor rpm (NR) to exceed the normal governed speed. When this occurs, the N2 momentarily rises above the normal governed N2 speed. The magnitude of the effect is dependent on the rate of deceleration or the suddenness and intensity of the updraft. If the NR and N2 rise above the selected governed speed, fuel flow to the fuel control unit will automatically be reduced to bring the N2 back down to the selected governed speed.

If the collective is subsequently raised rapidly in an attempt to reduce high rotor speed or arrest a developing sink rate, the NR will decelerate quickly, and the N2 will also droop because the fuel control unit is still on a reduced fuel control schedule. Once below the normal N2 rpm, the governor will signal the fuel control to increase fuel flow; however, there will be a lag before increased fuel flow causes an increase in N2 and NR. During this period, low NR and N2 speed states can result. If the aircraft is close to the ground, it may not be possible to regain sufficient NR to arrest the descent rate. In the most extreme case, droop can be so great as to induce main rotor blade stall.

The pilot had approximately 7000 hours of flying experience on various helicopter types. An autopsy of the pilot did not reveal any physiological condition that may have affected his performance. Toxicology examination was negative for the presence of alcohol, medication, or illegal drugs.


Analysis
The brief radio transmission during the accident sequence suggests that the pilot was not incapacitated prior to impact. The tight descending turn to the right on approach suggests that he had not visually acquired the cache and was responding to verbal cues from the passengers. Had the pilot visually acquired the cache, he would likely have flown a left turn to allow him to keep the cache in sight during much of the manoeuvring and the approach to landing. During a right turn, the pilot's view of the approaching terrain and the cache would have been blocked by the passengers on his right and by the right side of the aircraft. This would have made it difficult to judge the requirement for speed and power adjustments.

The helicopter was developing a substantial amount of power at impact, and main rotor damage was consistent with powered flight. As the helicopter struck the ground without any apparent yaw, it is likely that the tail rotor components were functioning, and that the pilot had directional control. The imprint of the skid tubes at the initial impact point, the immediate rupture of the belly fuel tank and the presence of a large fuel spill all indicate a high rate of descent at impact. The nature of other fuel spills on the ground also suggests that the helicopter struck the ground at a low forward speed.

Light local wind conditions, the slow flight profile, and the rate of descent described in this report were all conducive to the development of a vortex ring state. During its final descent, the helicopter may have encountered a slight downwind as it parallelled a ridge line to the west of the landing area. A slight downwind would be hardly noticeable but would cause a decreased airspeed on final. Decreased airspeed would, in turn, increase the likelihood of vortex ring state developing during the final descent. If vortex ring state developed during the latter stages of the approach, chances of a successful recovery would have been significantly decreased, and the pilot may not have been able to arrest the helicopter's rate of descent.

The aircraft flight profile described immediately prior to the accident was that of a tight, descending and decelerating turn to landing. Large and rapid power changes were likely made during this manoeuvre, and droop on short final may have prevented the pilot from arresting the rate of descent.

The following TSB Engineering Branch reports were completed:

LP 062/2001 - Rolls-Royce Allison 250-C20B Engine Teardown
LP 063/2001 - Examination of Main Rotor Blade
LP 064/2001 - Main Rotor Pitch Housing

Findings as to Causes and Contributing Factors
The helicopter developed a high rate of descent on short final approach, and the pilot was not able to arrest the rate of descent prior to impact.
Findings as to Risk
The approach pattern flown (to the right) would have made it difficult to judge the requirement for speed and power adjustments.


Conditions necessary for the development of vortex ring state or N2 droop existed during the approach.
This report concludes the Transportation Safety Board's investigation into this occurrence. Consequently, the Board authorized the release of this report on

[sky's the limit]

Ok,

You obviously know more than I do.


I've trained at three different companies this year alone, on five types of machine, and EVERY discussion we have on the subject highlights the differences. I KNOW the difference when I fly every day...

What you're trying to tell me is that they are same thing, they are not. If you'd like an in machine demo, please feel free to stop by the Base and I'd be happy to show you the difference.

You can post as many links as you like, TC or otherwise, but it doesn't change the fact that they are two different phenomenon. In aviation, we can't even agree on the interpretation of regulations due to language, and this is a language issue, NOT a physical one.

If somebody else cares to take up the fight, please feel free, I'm obviously ill-equipped to continue this one....


stl
PS Just because the piece says "VRS, commonly referred to as settling with power," doesn't mean they are the same thing. One final time - they are NOT.

[splitpin]

Ok,

You obviously know more than I do.

No chance of that stl


I've trained at three different companies this year alone, on five types of machine, and EVERY discussion we have on the subject highlights the differences. I KNOW the difference when I fly every day...

What you're trying to tell me is that they are same thing, they are not. stl, I'm not trying to tell you anything! I am just confused as to why seven different links say one thing and you say another. I asked you to explain the causes, differences and cure earlier but so far that has not happened If you'd like an in machine demo, please feel free to stop by the Base and I'd be happy to show you the difference.

You can post as many links as you like, TC or otherwise, but it doesn't change the fact that they are two different phenomenon. All I have been asking is for an explanation of the differences, what's the big deal!!In aviation, we can't even agree on the interpretation of regulations due to language, and this is a language issue, NOT a physical one.

If somebody else cares to take up the fight, please feel free, I'm obviously ill-equipped to continue this one....

If I remember correctly Splitpin, you're a wrench no?
Now that's a charming comment stl. I would have expected better from you. I'd like to see your reaction if someone said something like that to you. Not good form.
stl
PS Just because the piece says "VRS, commonly referred to as settling with power," doesn't mean they are the same thing. One final time - they are NOT.

[sky's the limit]

There, I deleted my "charming comment."

You seem to be taking offense, I assure you I'm not intending to offend. However, if you look at some of the language you've used, it could be construed that way also. The beauty of the written word I suppose.



I DID explain the difference to you above.

VRS is the onset of air recirculation in a given set of conditions as you've confirmed with your postings and links. No argument there.

Settling With Power is not the same. Settling happens when you have inadequate power available for the weight of the machine and given decent rate/airsped. This is NOT recirculation of air, it is simply not having the margins of power available for what you're asking the machine to do. Can Settling lead to VRS? Absolutely, but not if you know how to avoid it, or play with it.

Settling, like VRS can be avoided with airspeed, in any direction, but with VRS you are trying to break the recirculation pattern, whereas with Settling you are simply trying to increase the efficiency of the disk. ie reach some sort of translational lift to give you the extra lift you need, and fly out. Settling is something that we can use to our advantage in some applications believe it or not, VRS is not something I care to experiment with.

Now, as to the numerous publications you're quoting.

As I said earlier, there is confusion of these terms, and this confusion can run right up to TC, the FAA, or any other governing body, much less the instructional folks who would rarely if ever, see either condition. But any pilot who's been flying in some areas of operation can tell you, what looks like a duck, and sounds like a duck, isn't necessarily a duck.

Just look at the Great LTE Debate.... Been going on for EVER. Talk to Bell, the FAA, or TC, and it's one thing, talk to any other manufacturer who produces a product with a properly designed and effective tail rotor, and it's another. VRS, SWP.... same issue on language, minus the politics.

Anyway, I do hope that helps. You'll have to pardon any shortness, it's been a bit of a frustrating week to say the least!

stl

[splitpin]

There, I deleted my "charming comment."
And I mine

You seem to be taking offense, I assure you I'm not intending to offend. However, if you look at some of the language you've used, it could be construed that way also. The beauty of the written word I suppose.
That's just the way crusty old farts talk stl. Deal with it



I DID explain the difference to you above.

VRS is the onset of air recirculation in a given set of conditions as you've confirmed with your postings and links. No argument there.

Settling With Power is not the same. Settling happens when you have inadequate power available for the weight of the machine and given decent rate/airsped. This is NOT recirculation of air, it is simply not having the margins of power available for what you're asking the machine to do. Can Settling lead to VRS? Absolutely, but not if you know how to avoid it, or play with it.

Settling, like VRS can be avoided with airspeed, in any direction, but with VRS you are trying to break the recirculation pattern, whereas with Settling you are simply trying to increase the efficiency of the disk. ie reach some sort of translational lift to give you the extra lift you need, and fly out. Settling is something that we can use to our advantage in some applications believe it or not, VRS is not something I care to experiment with.

Now, as to the numerous publications you're quoting.

As I said earlier, there is confusion of these terms, and this confusion can run right up to TC, the FAA, or any other governing body, much less the instructional folks who would rarely if ever, see either condition. But any pilot who's been flying in some areas of operation can tell you, what looks like a duck, and sounds like a duck, isn't necessarily a duck.

Just look at the Great LTE Debate.... Been going on for EVER. Talk to Bell, the FAA, or TC, and it's one thing, talk to any other manufacturer who produces a product with a properly designed and effective tail rotor, and it's another. VRS, SWP.... same issue on language, minus the politics.

Anyway, I do hope that helps. You'll have to pardon any shortness, it's been a bit of a frustrating week to say the least!

stl

Thank-You for you clear explanation stl. Now, about this LTE thing!!:laughbig:

[North Shore]

For us bolted wing guys, LTE = ?? Please?

[The Mole]

LTE=Loss of tail rotor effectiveness.... its complicated.



This a real simple example of SLP.

http://www.youtube.com/watch?v=qtT_eMVnWck

Nothing wrong with that aircraft. When it hit the ground. Wings still making lift, engines making power...

This is a real simple example VTR

http://www.youtube.com/watch?v=0vjeNQ9Z ... re=related turn your volume down, the music is really bad.

[sky's the limit]

Thank-You for you clear explanation stl. Now, about this LTE thing!!:laughbig:

You just HAD to go ahead and bring that up, didn't you???? I'll get you my opinion in a minute......!


stl

[North Shore]

LTE=Loss of tail rotor effectiveness.... its complicated

Tail no longer counteracts the torque of the main, and so we start an uncontrolled rotation in the direction of the main rotor blade? I guess if it continues, the main blade loses effectiveness, and as posted so eloquently earlier, the "ground shows up, uninvited as usual." More complicated than that?

[sky's the limit]

Close, but not quite.

Some tail rotors are not designed to be powerful enough for the helicopter they happen to be bolted on, and one manufacturer coined the term "loss of tail rotor effectiveness" many years ago to explain why their helicopters would start uncomanded spins to the right - the opposite direction of the main rotor. Torque, works in the opposite direction as the force applied, so in a North American helicopter where the right side blade is the advancing one, the machine will want to spin right, or against it. The tail rotor helps keep the nose left.

LTE is just the simple fact of not enough thrust from the tail rotor to counteract that torque force. The FAA, TC, and Bell Helicopter would have you believe otherwise, but it's just poor design. Other helicopters CAN encounter so called LTE, but you have to be in some pretty extreme conditions to see it.

I'm sure someone else can add more, I'm flying in the rain today and need to go dry off...

stl