Cairns Helicopter Crash

[Traveling Spanner’s]

Anybody know what happend?



Survivor tells of chopper 'death spiral'

A passenger on a helicopter that crashed near Cairns today says it went into a "death spiral" before it hit the ground.
The helicopter, which was on a charter flight, crashed at the site of a resort and residential development at False Cape shortly before 10.40am (AEST).
The pilot and two passengers were today being treated in Cairns Base Hospital, but a fourth man walked away without injury.
One of the passengers, identified only as Steve, told The Cairns Post online he was surprised to still be alive.
"Somehow I'm alive," he said.
"There was some turbulence and we got into a death spiral on the way down.
"We hit trees and I thought that was it."
A 45-year-old man has been taken to Cairns Base Hospital suffering from back and abdominal pain, as has the 40-year-old pilot, who has two broken ankles.
Another 40-year-old passenger is suffering from general abrasions, an Emergency Services Queensland spokeswoman said.
The crash occurred in rough terrain near the controversial Reef Cove Resort development, which local environmentalists want stopped.
A spokeswoman said the flight had not been authorised by the developers.
An investigation is under way.
AAP

[BigMike]

Pic and video:

http://www.cairns.com.au/article/2008/06/18/4696_local-news.html

http://www.cairns.com.au/images/uploadedfiles/editorial/pictures/2008/06/18/Cairns-WebUsual-CP18JUN08P454-CC102390-HELICOPTER.jpg


http://tools.cairns.com.au/images/gallery/2008/06/18/55815.jpg


http://tools.cairns.com.au/images/gallery/2008/06/18/55791.jpg


http://tools.cairns.com.au/images/gallery/2008/06/18/55771.jpg

[topendtorque]

couldn't pick up a rego there, don't know who owned it? anyone.

very lucky to get out those guys, looked like a fair way down.

[RobboRider]

It looks like VH-RYW. Not certain though. Owned by an ex-farmer now commercial pilot and leased to Heli-charters here in Cairns. At the time being used to inspect a partially completed resort development which has produced huge amount of protest and controversy.

Haven't much more to add than what's already posted. But the passenger mentioned turbulence on the local news.

I fly past that spot a lot and in strong south easter (which we have been having for a week or so) it is treacherous. It's in the lee of the hills of the cape with rolling wave turbulence that reaches out well past the cape. I always get clearance to track wide of the cape because of it.

Purely speculation but maybe they got into some overpowering downdraught or wave turbulance etc etc.

For the superstitious: The local aboriginal people are now saying the resort development and the cape are cursed. Has been a death in a excavator driver (big rock rolled on him.) A number of bad equipment accidents and bad weather causing lots of the retaining walls etc to wash away.

Maybe it wasn't turbulence at all:ooh:

[skid shoe]

Operator was Heli Charters - formerly Downunder Helicopters.
For those that know the crew there, the pilot was Steve P. Not the owner, Steve S.
I have no idea what went wrong but I suspect (pure guesswork) turbulence may have played a part as suggested by the pax. The crash site is at the foot of a small range of hills/mountains. Does any one know what the weather was like there today. Glad to hear there are no fatalities be it by good luck or good flying.:D:D Hope you're up and about again soon Steve.

[RobboRider]

Weather as per forecast here was 15/20 knots south easterly.

I wasn't flying or outside so I can't say if it really was - but if so it could have been pretty lumpy over the other side of the inlet.

[BigMike]

Survivors 'lucky' in Qld chopper crash

June 18, 2008 - 7:33PM

One of four survivors of a helicopter crash near Cairns on Wednesday thought he was going to die.

The Robinson R44 helicopter, chartered by environmentalists photographing a controversial resort development at False Cape, crashed shortly before 10.40am (AEST).

Of the four on board, the pilot was the most severely hurt, suffering two broken ankles. He had to be cut free from the wreckage.

Passenger Steve Nowakowski told reporters he was surprised to be alive.

He said the pilot warned of turbulence before the helicopter started a fast downward spiral.

"We went into a death roll and we just spiralled, near vertically, just straight down," Mr Nowakowski said.

"As soon as we hit the trees I thought it was all over, I thought that was it."

Passenger Mark Buttrose said it was calm on board as the helicopter descended.

"Everyone was pretty silent as it went down because we were concentrating on the pilot doing a good job and getting us down," he told Ten News.

The helicopter crashed through the trees and hit the ground.

All on board except the pilot escaped through an open door.

Mr Nowakowski said the whirring of the rotors was ominous.

"We hit the ground and then I realised I was alive, and I was waiting for the explosion," he said.

The Save False Cape group spokesman said his campaign against the resort development was now over.

"I've been to court, I've lost thousands of US dollars, I nearly lost my life," he said.

Witness Terry Spackman said it was hard to believe anyone could emerge from the crumpled wreckage.

Investigations into the cause of the crash have begun.

© 2008 AAP

[generalspecific]

interesting i wonder if the pop out floats popped in the impact or the trigger got pulled in an attempt to "yank the handle"...:confused:

[whack_job]

come on you bananas, this is an LTE accident all the way.

FFS

[imabell]

thats right, lte, lack of tertiary education.:E

[mickjoebill]

http://cairnspost.newspaperdirect.com/epaper/viewer.aspx

Here is a dramatic picture taken minutes after the event.
(Free one day trial to read all the story)

One still photographer, one cameraman on board as well as another (not small) adult passenger and pilot, add in floats video and camera kit.

Left hand front and rear doors can't be seen in any of the pictures so perhaps they were shooting on the pilots blind side.

Whilst we dont know what caused this accident others have found that a photo mission in gusty conditions with 4 on board can leave a R44 near the limit of operation or recovery.

Passenger is quoted saying "We were hovering getting really good pictures"
If true enough said.

The last thing on the photogrpahers mind is the direction of wind, he just wants the subject to appear in his field of view. indeed Steven Nowakowski told "CairnsBlog" that they gathered a great number of images and footage.
"My camera was totally destroyed, but I managed to rescue the memory card," Steven said.
Maybe he was in shock when he said that.

I wish them luck with their environmental campaign.

A side point, is it a good idea anyway to pop the foats in such conditions to "cushion" impact?



Mickjoebill

[Unhinged]

A side point, is it a good idea anyway to pop the foats in such conditions to "cushion" impact?

The pop-out floats inflate above and outside the skids, so on a vertical fall you'd still hit straight on the skids. A sideways impact would be much the same as there's no sideways support for the floats and they'd just push out of the way. You'd still end up with main contact on the skids in an impact of any magnitude.

[RobboRider]

Wee Man
If the wind was as forecast you'd be right. I don't know if it was. Wouldn't be the first time they got it wrong:bored:

I flew past the same spot on Saturday with forecasted 20 to 25 knots but I had 34 knots on the tail. Its hard to describe but that spot is behind the hills that form the downwind side/end of a wide valley that funnels the prevailling winds. There's a fair bit of a venturi effect down the valley so the forecasted area winds are often stronger in the valley.

As I said no evidence to say the winds were or were not as forecasted. Just speculating with some local knowledge.

[r44tropic]

the only reason i go via the leads is for pax comfort, has to be 25kts plus for that. it is bumpy mainly in two spots on the cape and next to the aerials about 2 minutes of flying. The Lee side of hills in prevailing winds have a few bumps and can have odd wind direction, same on all hills with valleys.

[topendtorque]

LTE;

Lack of Technical Education,

Lack of Training for the Environment,

or simply

Lackadasial Transient Enzyme.

[mickjoebill]

If one can image a "death spiral" would the reduction of the weight of one passenger make a difference in regaining control?


Would the reduction of weight of one passenger make any difference in loss of control due to LTE? (hypothetical question not necesarily related to this incident)



Mickjoebill

[JimBall]

LTE doesn't exist. It's an ar**-covering invention. The simple correct term is loss of control by a pilot failing to recognise the warning signs.

[imabell]

thank you jimball,

now if only we could convert the masses, but no, there will soon be plenty of "lack of technical education" experts, (thanks tet), to shoot the messenger.:rolleyes:

[topendtorque]

LTE another in line with Jimball's statement

Lousy Turnout of an Excuse.

[kflexer]

What is it called when your left pedal is on the bubble and you are still yawing right? with low airspeed, high gross weight and high density altitude? LTE
Keep them moving!

[EVG]

Have heard rumor that tail rotor GB was found long way from crash site and blades in fairly good condition, may have not been still attached. Now that would cause some LTE

[ascj]

me thinks that would be LTG then

[Ned-Air2Air]

LFTG - Loss of Farking Tailrotor Gearbox :eek::eek:

[Rotorhead412]

Thats a new one! A farking gearbox? Never new the robbys had them! Wheres the best place to find final reports for these accidents when there actually issued?

[topendtorque]

Wheres the best place to find final reports for these accidents when there actually issued?

We call it the crash comics, and you'll get to wait a farking long time.

It may well be a worth while comment that the TRFG has disappeared, by the look of one of the photographs. It could have been torn off when the remainder of the rear far'n end got snotted against yon tree as cann be seen by the bent metal.

This may have been very convenient as hard objects like that have been known to help cease rotation in a most uncompromising but helpful manner.

Had the FTRG departed whilst still above the flora, then almost certainly (given the Cof G displacement which would have happened as evidenced from photos of the farn heavyweight and layabout dispossesed pax) [see accompanying article] then the last thing that our illustrious pilot could have been attributed with might have been, "F' Never Seen That Before", as his soul sailed f'n skywards.

[Diatryma]

We call it the crash comics, and you'll get to wait a farking long time.

I hear the ATSB will not be investigating - so we may never know!

Di :yuk:

[topendtorque]

I hear the ATSB will not be investigating

It's a bit sad if they canner dream up an excuse to 'investigate', right on the pristine Barrier reef tropical holiday area.

Is this because of Kevin 07's razor gang policy? surely they're not acting only on a pain killer drug induced statement from the driver.

Let's assume for a second that here may have been a malfunction to the T/R drive shaft and our intrepid driver did not get the throttle off as you're supposed to thus giving the flight path as described by the onboard witness.

had there been any weaknesses in the Drive shaft system, for whatever reason, and given the desciptions of the wind, load and mission profile, there is every chance that such a weakness could have been exploited given the excess of power and pedal that could have being used.

BTW was it charter or A/W?


to digress, for a second, i see recently where the oz media gave 'Kevin 07' a real drubbing as a dork recently. The reason was that on his recent trip to Japan he stood up in front a learned audience and told them all in Japanese, "Hi, my name is Kevin and I come from Australia".

most of us can't wait to see if he gets invited to the States to see whether he has enough of a grasp of their lingo to pull the same stunt.

but as i've said before, don't blame me, I didn't vote for the c**khead

[Diatryma]

NEWSFLASH - ATSB now investigating!!!

200803809 (http://www.atsb.gov.au/publications/investigation_reports/2008/AAIR/aair200803809.aspx)

Still might be a while before we know more - but at least they are looking into it!

Di :O

[Brian Abraham]

What is it called when your left pedal is on the bubble and you are still yawing right? with low airspeed, high gross weight and high density altitude? LTE
kflexer - no its not (well it is, but only by the uneducated), if you do a search you will find Nick Lappos addresses this fallacy at length. If I remember correctly it was a term invented by Bell to avoid liability in the courts when explaining why 206's were crashing. The fact is the tail rotor is just too small to do what is asked of it at times. If you read page one you would have noted that JimBall in post #18 quite correctly said

LTE doesn't exist. It's an ar**-covering invention. The simple correct term is loss of control by a pilot failing to recognise the warning signs.

[Diatryma]

I admit to being one of the uneducated when it comes to these things.

I have heard of a similar incident where the pilot experienced a sudden jolt and severe shaking with both pedals going to the floor.

Does that sound like a so-called LTE event?

Just curious.

Di :)

[kflexer]

kflexer - no its not (well it is, but only by the uneducated), if you do a search you will find Nick Lappos addresses this fallacy at length. If I remember correctly it was a term invented by Bell to avoid liability in the courts when explaining why 206's were crashing. The fact is the tail rotor is just too small to do what is asked of it at times. If you read page one you would have noted that JimBall in post #18 quite correctly said
Quote:
LTE doesn't exist. It's an ar**-covering invention. The simple correct term is loss of control by a pilot failing to recognise the warning signs.
Today 10:35]

I agree with your simple correct term
"loss of control by a pilot failing to recognise the warning signs"
Flying too slow at a high density alt. and with a high power setting in a machine that has limited T/R authority to begin with could cause "LCBPFRWS" Its just easier to call it LTE loss of tail rotor effectiveness , It is always pilot induced and is always avoidable. It is not some mysterious aerodynamic force that happens when we least expect it, it is simply what happens if we fly our machines outside their capabilities. In pretty much every country I have worked in they call it LTE. You and Nick can call it whatever you want

[JimBall]

I have heard of a similar incident where the pilot experienced a sudden jolt and severe shaking with both pedals going to the floor.

Well if BOTH pedals "go to the floor", then you're talking about a mech failure in the pitch control of the TR. Given that the pedals are linked - when one is forward the other is aft - it would take a catastrophic failure of the linkage to cause both pedals to go forward at once.

[Brian Abraham]

kflexer - The following is what Nick Lappos has to say on LTE. (Nick was test pilot for Sikorsky and did the work on the 76 - among other things).

The real skinny on LTE is simple and quite easily stated:

All rotors lose thrust when operating in disturbed air, including tail rotors, main rotors and fantails. LTE sets in when there is so little thrust margin that the loss of the maybe 5 or 10% of the thrust is enough to kill you. With a really marginal design, that slight loss of thrust unleashes the massive main rotor torque, and the aircraft bites its pilot big time. I cut my teeth on the old AH-1G snake, with its way too small tail rotor, and had at least my share of 360 turns while trying to get over someplace to cut the throttle.

LTE only affects those helicopters that have too little tail rotor thrust margin. Period. It is really not LTE it is "Not Enough Tail Rotor".

LTE happens when the tail thrust is consumed by several possible upsetting factors, and when the remaining thrust, by marginal design, is simply inadequate. Yes, inadequate. These possible tail thrust reducers are:

1) main wash into the tail rotor, as illustrated in the LTE handouts that we've all seen.
2) using somewhat too much main rotor thrust (collective pitch) at the bottom of an approach, especially in critical tail thrust conditions. I can touch the left pedal stops on any helo by simply raising the collective pitch until main torque washes out all tail margin. One inch more collective and WATCH out! You get LTE, surprise, surprise.
3) terminating an approach with a critical wind condition, where the wind is a few knots more than your helo can stand.

I did a study on "LTE" accidents to support a regulatory change meeting I was attending, and , wow, it was some surprise to find that about 95% of all LTE accidents were restricted to one brand name, and all LTE accidents were experienced by helicopters with very little cross wind capability.

The cure for LTE is quite simple - get a helicopter with a bigger tail rotor, as proven by the certified crosswind capability. Don't get in one that has an LTE history, and don't buy the bull that LTE is a pilot error problem. Don't buy into the new certification rules that allow you to operate with a helo that has no crosswind capability. If you do, get a good helmet, and a good insurance agent.

BTW, the LTE study that I did was opposed by an engineering manager from that particular manufacturer because "LTE is a pilot error problem, plain and simple" I asked how so many bad pilots were flying his helos, and expressed our luck that so few of these dumbos were flying all the other brands.

In the fantail, sometimes I can feel the main rotor wash flow into the tail, the pedal moves a few percent the noise increases, and that is that.

The big tail surfaces on the fenestrons and fantails are because the fan doesn't respond to small yaws, so the aircraft will snake a bit, unless the vertical tail is big enouigh to keep the nose ahead of the tail. On regular tail rotors, the tail rotor responds strongly to change thrust when some sideslip develops, and the yaw stability to small disturbances is strong. In fact the tail rotor area is as powerful as a vertical fin that is about 4 to 8 times bigger than the tail rotor.

This is one of the reasons why the Fantail is able to snap turn, because the fan doesn't care where the wind is from, it keeps its thrust and bending closer to normal. Under big sideslips, a tail rotor is positively screaming from the big stresses it develops. With the same maneuvers, the Fantail is calm as can be.

[topendtorque]

ATSB now investigating!!!


excellent.
albeit more difficult after the time lapse. i note the occurrence report refers to chtr. that may engender some awkward questions, Below A500 ft, extra pax and doing what appears as A/W?

I think we should reiterate that there is a second way to avoid the described LTE, other than buying the right helicopter, simply put the collective down, cyclic forward and fly away. duh!

[gulliBell]

Unfortunately when said collective is installed in said not the right helicopter which is said to be so close to said flora when the said TRFG departs the scene (LTE or otherwise), and when being flown by said pilot with 77 hours on type and 311 hours total, the said result will always be bent metal. As evidenced by everything said previously. Enough said.

[Diatryma]

Well if BOTH pedals "go to the floor", then you're talking about a mech failure in the pitch control of the TR. Given that the pedals are linked - when one is forward the other is aft - it would take a catastrophic failure of the linkage to cause both pedals to go forward at once.

OK - and I imagine that would explain a sudden jolt and severe shaking.


and when being flown by said pilot with 77 hours on type and 311 hours total, the said result will always be bent metal

In the above scenario (catastrophic failure) - would it make any difference how many hours the pilot had - on type (even if more than twice stated amount) or otherwise?



when said collective is installed in said not the right helicopter

As Pauline Hanson would say .... "Please explain?"


Di :cool:

[Delta Torque]

Well, the effect has been documented on a couple of machines...

I believe the naming evolution was:

'H*ghes Tail Spin', then 'Tail Rotor Stall', then 'LTE', after it was discovered that the tail rotor blades were still producing lift, albeit not enough....

[topendtorque]

I have heard of a similar incident where the pilot experienced a sudden jolt and severe shaking with both pedals going to the floor


any suspicious looking ten tonne trucks around? one of 'em mighta got a bit close to said flying machine.

[Kangaroo corner]

These are fixed utility floats, not emergency pop outs.
They have no effect on cushioning the helicopter as the skids are underneath the floats.

4 pax on a hovering film job with turbulance! Thats a big no-no!

[topendtorque]

4 pax on a hovering film job with turbulance! Thats a big no-no!


and possibly difficult to pass off as charter.

especially if there is a lingering passenger liability claim in excess of the limited liabiltiy of charter coverage.

I know its cute to go for the chtr with its statuted limited passenger liability. But in reality I believe that CASA has a bit to answer for here as they have for the last few years been trying to push most of the airwork into a corner with the soiled washing and some blessed operators certificate type of system.

They also want to push everyone else up to charter (except parachutists IMHO) or indeed RPT where clearly the operation is only charter. This means that your average 311 hour pilot hasn't got a shmick as to which category that he is supposed to be flying in.

Once again though, that blighted simple single component which has caused more crashes than many other things, has reared its ugly head.

[ReverseFlight]

I read Brian Abraham's post with great interest. I have not read Nick Lappos's article on LTE but I get the drift that LTE is a design problem and not pilot error. Where can I find this article ?

I have done a lot of research on LTE and the literature seems to be divided into two camps: some say the tail rotor stalls in an LTE but others say it doesn't. Which is correct ?

If Brain cannot help, can Mr Lappos or anyone else enlighten me ? Thanks in advance.

[Diatryma]

AO-2008-043 (http://www.atsb.gov.au/publications/investigation_reports/2008/aair/ao-2008-043.aspx)

(Abstract)At 1026 Eastern Standard Time on 18 June 2008, a Robinson Helicopter Company R44 Clipper II helicopter, registered VH-RYW, departed Cairns Airport, Qld, to film a residential development site that was located in the vicinity of False Cape, about 10 km east of the airport. On board the helicopter were the pilot and three passengers.
The occupants of the helicopter reported that while conducting the second period of filming, there was a sudden and violent movement of the nose of the helicopter to the right, which continued into a rapid rotation of the helicopter. The pilot's reported attempt to reduce the rate of right yaw was unsuccessful, and he entered autorotation and attempted to reach a clear area. The helicopter subsequently collided with trees before impacting the ground, seriously injuring the pilot and front seat passenger.
This accident highlighted the risk of loss of tail rotor effectiveness associated with the conduct of aerial filming/photography and other similar flights involving high power, low forward airspeed and the action of adverse airflow on a helicopter.
The investigation also identified that the lack of the nomination of a search and rescue or scheduled reporting time for the flight, decreased the likelihood of a timely response in the case of an emergency.
In response to this accident, the helicopter manufacturer advised that it was considering a revision to the aerial survey and photography flights safety notice that was contained in the R44 Pilot's Operating Handbook. That revision would, if adopted, include a discussion of the risk of unanticipated right yaw associated with the conduct of those flights.


Di :ok:

[ReverseFlight]

Diatryma, thanks for the belated but nonetheless interesting response to my post over a year ago. I note the date of the report is Dec 2009 while the date of the last revision to the POH was Apr 2009. Is there going to be yet another revision to the last amendment before another R44 pilot bites the dust ?

http://www.robinsonheli.com/srvclib/rchsn34.pdf

[Brian Abraham]

RF, forgive me for I missed your long past request. A google of "loss tail rotor effectiveness" will throw up any number of hits. This may be of use
Helicopter Safety | Loss of Tail Rotor Effectiveness [LTE] (http://www.helicoptersafety.org/genericaccident.asp?Keyword=LTE)

[longrass]

I thought the owner was JQ, last time we spoke he was, is he still around?

[topendtorque]

RF, forgive me for I missed your long past request. A google of "loss tail rotor effectiveness" will throw up any number of hits. This may be of use
Helicopter Safety | Loss of Tail Rotor Effectiveness [LTE] (http://www.helicoptersafety.org/genericaccident.asp?Keyword=LTE)


There seems to be a bit of a Cool Kat ambience on this thread saying that - of course it was LTE - and I note that the famous OZ Army paper on either LTE or VRS of the tail rotor surfaced on the ATSB report. WHICH IMHO did NOT quantify either one or the other. That is a bit slack.

But there seems to be a certain smugness about the outcome as reported.

Even though I have a fairly strong feeling that it was statements on this thread which injected a certain amount of enthusiasm to ATSB to get off their butt and go look, so to speak.

Now, for the sake of newbies, and many others who do not usually delve into low level maneuvres reading these columns, it may be best if it was quantified.

There is no doubt that the hapless driver may have invoked the wrath of the VRS on his T/R given the data as presented. BUT, that is no reason to crash a perfectly serviceable helicopter, even from as low as fifty feet above the terrain when it is induced.

One also needs to be careful in examining the stated wind flow ( which from experience I can say is the usual doctor around those parts) but with the surface interference of yon great hill may have been somewhat changed?

I certainly challenged the author of the OZ Paper many years ago to demonstrate to me this massive nightmare inducing phobia - LTE - as reported in his paper, just after he had published it. Result, no show.

For his benefit I have been able to induce such circumstance a bare handful of times of many years trying, so it can be done, by god. That's for sure, but I never crashed a machine doing it, Eh.

However before I go further into the analysis which I will not tonight, let me just portray one fact from the investigation. "there was a sudden yaw to the right"

For everyone's sake and opportunity to contradict it, I will say that a "sudden yaw" can only emanate from one of two causes.
1) T/R drive from the engine has gone AWOL
2) VRS of the T/R.

Overpitching, will initially only produce a slowly increasing yaw. Agreed?
Cheers tet

[Brian Abraham]

There seems to be a bit of a Cool Kat ambience on this thread saying that - of course it was LTE
tot, remember who posted
LTE;

Lack of Technical Education,

Lack of Training for the Environment,

or simply

Lackadasial Transient Enzyme.
I made no judgement as I recall to the cause of this accident, but merely responded to comments re LTE.
that is no reason to crash a perfectly serviceable helicopter, even from as low as fifty feet above the terrain when it is induced
The only time I experienced LTE was with a 206 sling loading into a very difficult pad located in a deep saddle between two peaks. It was only dumb luck that the placed the drop off to my right and was able to let it turn right and lower collective and dive down the mountain face to regain airspeed. One of the hazards of no formal instruction and teaching yourself mountain flying. Needed more than 50 feet. Once again circumstances dictate outcome.
Overpitching, will initially only produce a slowly increasing yaw. Agreed?The one and only time I've seen it entered accidentally rotation was very rapid, so have to say don't agree. Once again circumstances enter the equation. The gunship chaps had plenty of practice at hovering autos recovering from this scenario.

[helmet fire]

The following is pulled from another thread fixated on LTE: B206 You tube crash (http://www.pprune.org/rotorheads/338822-206l-crash-youtube-post4329721.html#post4329721)


I have trawled the previous threads on the LTE issue and have posted the following summary for future reference. It is made up from the previous work of three authors, Nick Lappos, Arm out the Window and myself. Thanks/apologies to Nick and AOTW!

If you see the sections on recovery techniques and the contrasting symptoms, you might understand why the distinction is very important and why mis-labelling the issue is dangerous.

Here goes:

Loss of tail rotor control: You are not able to control the tail rotor pitch mechanism - it is a true emergency. This could be a stuck control (left pedal, right pedal, or centre) or it can be a total loss of thrust (broken drive shaft or gear box). It can occur on any helo, but is relatively rare. Part of the training on every helo.

Loss of tail rotor effectiveness (LTE): "Newly" discovered and named in the 80's after many accidents - in particular OH-58/B206 model, and is the cause of a significant percentage of those model's accidents. Although somewhat awkwardly named (as the tail rotor is still effectively working and must be providing thrust) LTE refers to what is thought to be an ingestion of main or tail rotor vorticey through the tail rotor which causes a rapid onset of yaw in the direction induced by torque that cannot be overcome by the application of full "power pedal". The yaw rotation is typically high and can build up quickly enough to fool most pilots into believing they have experienced a loss of tail rotor thrust.! It forces a loss of directional control while inside the normal envelope.

It is prevented by using very conservative flying techniques, and preparing recovery escape manoeuvres, or by re-designing the tail rotor to assure adequate thrust. The typical LTE involves an approach to a spot with moderate cross wind, and a loss of yaw control when the approach is terminated near the hover. Once entered, recovery is very difficult without descending, often ground contact is unavoidable.

Loss of Tail Rotor Authority (LTA): In this situation, the tail rotor does not produce enough thrust to counteract the torque/crosswind combination you require, your power pedal hits the stop, and around you go - though gently when compared to LTE or total loss of thrust. LTA can occur on almost any helicopter when operated outside its normal envelope, typically when the rotor rpm is abused, or when very high torque is demanded. It is a symptom of mishandling the RRPM or Torque, not a separate cause.

It is prevented by pre planning weight/DA/power demands and carefully managing RRPM. Typical LTA events involve a takeoff or landing when the helicopter hits its engine topping, and the rotor rpm droops below the green arc, and subsequent Torque reaction overcoming the reduced tail rotor thrust even at max (maximum power pedal applied) causing a loss of yaw control. Recovery often can be made by lowering collective to recover rpm without significant descent, so that ground contact is often avoidable.

[ShyTorque]

Loss of tail rotor control: You are not able to control the tail rotor pitch mechanism - it is a true emergency. This could be a stuck control (left pedal, right pedal, or centre) or it can be a total loss of thrust (broken drive shaft or gear box). It can occur on any helo, but is relatively rare. Part of the training on every helo.

No, I disagree. These emergencies are different and should be treated as such.

A tail rotor driveshaft is more straightforward to deal with; usually this requires the engines to be shut down for landing.

If you did that when the tail rotor has run away to high or full positive pitch, it could be a fatal mistake.

[helmet fire]

ummmm...
I was not detailing the recovery actions and insinuating they were the same. At least that is what I think you are getting at...was it??

The purpose was to distinguish LTA and LTE which are now so often mis-labelled that "LTE" has crept into our vernacular as the sole cause of all ills. It has now even crept into the accident reports - see the skycrane thread as another example. I am concerned about this ever increasing mistake as it also increases the chance of an incorrect diagnosis and thus reduces the possiblity of a successful selection of the appropriate recovery.

See the thread I linked above: and the video. Then read the amount of "It was LTE" comments that indicate exactly what I am talking about.

Reminds me of the VRS versus insufficient power issue as well....

[ShyTorque]

HF, I hate to argue but my concern is in your wording. The sentence that I re-quoted states that a tail rotor drive shaft failure involves a loss of tail rotor pitch control, obviously it doesn't.

I'm unhappy to see these two types of emergency incorrectly grouped together because it can cause confusion and the pilot's actions, as you agree, may need to be very different.

From experience gained in teaching tail rotor failures of all types and how pilots react to them, I have see many get it wrong at first attempt. I ran the RAF's Puma simulator programme for a while. Our unit (240 Puma OCU, later 27(R) Sqn) was tasked with using the simulator to investigate all types of tail rotor emergencies, to expand the advice given in the FRCs and to increase the knowledge of all Puma pilots through additional training. Not long afterwards a 33 Sqn Puma had a tail rotor pitch control spider failure over the sea. As it was he was able to reduce power and carry out a gradual spiral descent. Although the aircraft had no floats they all got out without injury and the airframe was recovered from the sea more or less intact. The experienced pilot stated afterwards that without the new simulator training he would almost certainly have incorrectly shut down the engines and tried to autorotate. The outcome might then have been very different because it's likely it would have resulted in a total loss of control.

I do think it's vitally important for all helicopter pilots to understand from the outset that there is a basic and important difference between drive shaft failure and tail rotor control failure. Obviously, the required actions may also differ markedly between aircraft types.

Here's a very useful document:

http://www.caa.co.uk/docs/33/CAPAP2003_01.PDF

:)

[Brian Abraham]

Simulator training can be of outstanding value, but the usual computer garbage in, garbage out needs to be kept in mind. A major simulator trainer providing training to the industry on a widely used Cat A aircraft was of the view that with the loss of tail rotor drive in the hover you could pull collective, spiral up to 1,000 feet or so, nose over and gain airspeed, and continue in side slipping flight to a suitable runway for an engine off auto. And you were able to do it in the sim. In real life? Not from what I saw of a Huey losing tail rotor drive in the hover, executed a 270° turn in a nanosecond before a rapid wind off of throttle and landing with no damage.

[ShyTorque]

Brian, I am aware of the limitations of simulators in that respect; indeed it's a whole separate topic in itself.

Obviously, no-one goes out flying and fails tail rotors deliberately to gain absolute data to put in a simulator programme! What is programmed into a simulator when insufficient data is available is a best guess by the programmer and is known as "off-model" simulation.

Despite this limitation, what simulator training can do is to make the pilot more aware of the different scenarios he might one day be faced with in the air. Before the RAF began using helicopter simulators (Puma was first, using the Helikopter Service facility in Stavanger), the information given was insufficient and incorrect. Certainly during my initial training, we only practiced the stuck pedal situation and engine offs, as per the t/r drive failure scenario. MOD thankfully realised this was inadequate because there are so many different variations on the tail rotor failure theme and made provision to expand the relevant training. There is some reference to this in the CAA document I have linked to; albeit the main mention is about the Army Lynx.

[helmet fire]

HF, I hate to argue but my concern is in your wording. The sentence that I re-quoted states that a tail rotor drive shaft failure involves a loss of tail rotor pitch control, obviously it doesn't.

We descend toward semantics here (and off thread topic a bit too), however I will attempt to clean it up for you ST, though I feel you are reading differently from the intent. Does this help ?:

Loss of tail rotor control: You are not able to affect yaw control using the yaw control pedals - it is a true emergency. This could be a stuck control (left pedal, right pedal, or centre) OR it can be a total loss of thrust (broken drive shaft or gear box) in which case the pedals move but the aircraft does not react in yaw to the input. It can occur on any conventional helo, but is relatively rare. Part of the training on every helo.

The Puma incident may need a little more info to explain it to us non Puma types. What is the consequence of the "tail rotor pitch control spider failure" and why did they ditch?

[ShyTorque]

HF, I'm not descending into semantics; there are three different types of tailrotor system failure, each with it's own issues. You have grouped them into just two types.

Re. the Puma ditching: The Puma has five tail rotor blades. Running through the length of the hollow tail rotor drive shaft, is a push/pull rod. At the opposite end of the rod from the servo is a five armed "spider" (although everyone knows most spiders really have eight "legs", French ones perhaps have only five). At the end of each leg is a pitch control link, attached to control horns, one for each blade. As the servo moves the rod, the spider moves with it (it's bolted on), push/pulling on the pitch control links.

In this incident, IIRC, something between the servo and the links broke, giving fixed pitch, somewhat less than that required to balance yaw in the cruise. The aircraft began to yaw away from the MRG torque, giving very similar symptoms to a tail rotor drive shaft failure.

An unwitting pilot might have mistaken the situation for a driveshaft failure, in which case he would probably have auto-rotated and shut down both engines. In previous years there had been little in the Puma FRCs or Pilots' Manual to suggest otherwise.

This would be incorrect because the tail rotor was still producing some positive (anti-torque) thrust. Devoid of main rotor thrust, the aircraft would then have begun yawing in the opposite direction, possibly meaning the pilot would have lost control.

The only correct action, as taken by this pilot, was to reduce collective sufficiently to control the yaw. He kept the aircraft under control but unfortunately he had insufficient torque to mantain level flight. He was able to fly in a descending turn to the surface, whereupon they did a relatively gentle ditching and escaped unhurt.

[topendtorque]

bin away a bit and have had a good look at the full ATSB report, which appears quite sound.

Very interesting photo of the T/R assy I must say when you blow it up. no rotation damage at all it seems just a major sideways swipe on one blade, as it was departing the rear end, by something hard and fast.

when I talked about fast rotation, I was slightly wrong in my description.
Having experienced T/R drive shaft failure in a zero airspeed very high power-on profile, I can say that the rotation is slow from the start but increasing in intensity very quickly, to the point where at the second rotation, one said to myself, "self, you'se agotta wind that there throttle off and you'se a gotta do it now, eh" things were becoming very blurred out from I can say.

I did chop the gas, I landed, from about sixty feet in a '47 3B1 with just a slight bend in the rear cross tube, and luckily the t/r gaurd tube had contacted a light bush which helped slow the spinning down. Holding off until the thing fell onto the ground was also a major player.

shy Torque I hear what you are saying with the training, i had not done any of it prior to my event as described, it had merely been told to me. I was lucky. The Cairns pilot, it appears, had also never done any training, not so lucky.

The drive shaft failure scenario did not fit this accident though. especially the bit about blurred vision from fast spinning which was not at all mentioned.

I have never experienced over pitching of the T/R but can only imagine that the commencement and accelaration of rotation would be very similar to the Drive failure.(without it being checked that is)

Which of course does not fit this scene either.

However i have tried countless times to get myself into T/R vortex ring state, and only succeeded on four or five times but have also inadvertantly picked up the condition a few other times whilst mustering in areas of extreme surface interference, where one can never really predict the exact wind direction and intensity.

I can say that on each occasion that the onset severity is entirely different. To descibe it, May i say that if one was fitted out with false teeth, and that if one was silly enough to leave one's mouth open then one may expect to leave one's false teeth - over there - where one was a milli second ago.

On each occasion I had the full left pedal in within a heart beat, but prior to that in nearly all occasions the rotation had stopped with the same snapping severity.

There is a simple reason for that, have a look at the conditions for VRS and where it ceases, also of course never forget that the speed of rotation will be such that no vortices will be able to keep up with it and will simply wash off.

The other times it stopped very quickly even before i had commenced flying away with collective down and cyclic forward simultaneously.

To sum up, what is shrieking from this accident, and it is fortunatethat the ATSB were convinced to investigate, is the Lack of standards. As it shrieks at us from elsewhere in these threads.

shy, what you did and what happens now are two different things, and in response the dispensation of the frivilous I will submit another explantion of LTE. Lack of Training for Emergencies.

No matter whatever this manufacturer or others, writes nothing will change until "standards" are applied by those resposible to do so.
cheers tet

[grumpytroll]

If you are doing research on LTE then the paper must be blank because according to a chap named Lappos, it doesn't exist. Sorry to break it to you old man. cheers anyhow:ok:

[topendtorque]

Well it's certainly not me that's doing research on LTE for sure. I've always been quite critical of the usage of the term and particularly worried that it has done nothing for the confidence of young punters more than erode their confidence as some sort of bogeyman that is going to smite them from the sky.

I'd lay even odds that some of the accidents due to the scare factor of this bogey man are nothing more than a lack of training and understanding of the various maladies as described by shy torque, a hundred years ago.

Would you agree?

Those maladies are all that I demonstrate and teach recovery of. If some damm helicopter comany was so dim as to design a machine that didn't have a big enough T/R to counter torque at full throttle, when pulling a big hook load say, and those drivers there-of are also so dimm as to not be aware of it and be careful of it, well that's their problem.

but to pontificate on a litany of figure drawings of vortices that are supposedly attacking the T/R from various disastrous regions and confuse those issues with the above design problem is sheer lunacy.

I'll tell you one thing again, when you hit VRS state with the T/R, it's violent, It remains for a fraction of a second, and then the ceasing of it is just as violent. Been there done that. But to be the font of all wisdom on it without one hour of mustering or by just flying around in straight lines holding your mouth right is dead wrong.

LTE is purely and simply a lack of training for emergencies, proven again in Cairns.

ATSB should step up to the plate and make some recommendations to the CASA standards people to sort it.

tet