View Full Version : PHOENIX "rescue" No thanks!
Unregistered_
4th Jun 2019, 22:21
This is horrific and hard to watch. Google The Phoenix Fire Department stretcher spin. Jun 04, 2019
Not sure if the 'lookers on' have a tag line or not, I couldn't see one, but if so, it's totally ineffective.
Looks to me like relatively flat ground to the pilots ahead and left. I don't get it.
Winching should be an absolute last resort tool.
This "rescue" demonstration does our industry no good at all. The stretcher is even referred to as being "removed from the mountain in a "screamer suit"".
This is no good at all. Get professional or get out.
I assume you mean this one (http://www.abc15.com/news/region-phoenix-metro/north-phoenix/video-injured-hiker-rescued-from-piestewa-peak-by-helicopter) - I have to confess I was expecting to find you had exaggerated it but I was wrong!! What on earth would cause that to happen?
Cheers
TeeS
krautland
5th Jun 2019, 01:07
Press conference. Lady says "it got on social media and there were a lot of comments that showed people didn't understand what happened."
Yes. That is exaaaactly the problem.
https://youtu.be/Y3ViHPnxuk8?t=278
havick
5th Jun 2019, 02:02
They’re just getting a jump on the rest of the industry. Carving out a new niche of training up commercial space tourists. This is their G force trainer.
jokes aside, looking at the video either the weak link broke or they attached it tag line to the hook itself rather than the stretcher? Either way I’m not sure why you would persist rather than stop the spin first on the ground and regroup.
Unregistered_
5th Jun 2019, 02:09
First off, winching is the last option. If there is no other way of getting them out, winch.
Secondly if you have to winch, make it as low as you can, and if you do ALWAYS have a tag line and someone on the end of it who knows whats expected of them.
Never ever do a stretcher winch without a tag line.
I've seen quite a few similar videos from the US that don't seem to follow any of these guidelines.
Vertical Freedom
5th Jun 2019, 05:08
I can see my breakfast sprayed all of over this topic........I bet the poor old Lady was talking to GOD on the great white phone during this event :yuk:
Words from the Technical crew member - 'It happens sometimes but when it does we are trained to deal with'! Not from the video evidence - they took forever to sort the problem out.
I'm with you Havick, they should have stopped as soon as the line broke and put the stretcher back on the ground to reset.
Not the first time someone on the ground has made a mess of using the hi-line/tag line though.
ShyTorque
5th Jun 2019, 07:54
Surely a spin rate as high as that could have resulted in brain injuries or the patient throwing up and choking. What on earth was the crew doing (we know what they weren't doing..)?
SnowFella
5th Jun 2019, 08:59
Makes you wonder what kind of G loading that rate of spin would cause?
Flunked out at maths but just from a wild arse guess it would be well into the redout zone.
nomorehelosforme
5th Jun 2019, 10:30
This looks terrifying, my questions would be, who is making the decisions and surely there must be radio contact between ground crew and the aircraft? Surely someone(apart from the patient) must be screaming STOP, STOP! As mentioned by others surely they should have just gone back to point A set the stretcher down and started again? I have zero experience of winching but this just looks awfully wrong to me!
The winch-operator/technical crew member in the door should have directed the pilot to descend and also winched out to increase the distance between the stretcher and the downwash - maybe they don't talk to each other much!
A simple 5 -10 knot hover taxi would also have minimised the spin.
dogsridewith
5th Jun 2019, 10:50
Just on ABC TV. Lateral motion brought the spin rate down substantially. At max spin, a return to ground would have risked a nasty contact between stretcher and surface features?
Just on ABC TV. Lateral motion brought the spin rate down substantially. At max spin, a return to ground would have risked a nasty contact between stretcher and surface features?
Hence the need to winch out as well - the further the stretcher from the helicopter, the less the effect of the downwash - the crew chief said the rate of rotation reduced when they winched out but then they winched in again and it span faster!
With reduced spin rate the chances of one of the ground party being able to control the stretcher are increased - no need to actually put it on the ground.
They should have put the stretcher back down as soon as it was apparent that the tag line/hi-line wasn't working.
BluSdUp
5th Jun 2019, 12:39
Now that was hard to watch. I am glad she is ok.
I lost a good friend in a long line accident some 10 years ago.
He forgot to reel in the line as he descended down a mountain for a new load, line swung up in tail rotor. It was over in less then 5 sec.
This winching stuff is no joke!
Some remedial training required here, me thinks!
You all stay safe now.
Regards
Cpt B
GrayHorizonsHeli
5th Jun 2019, 12:39
I see a niche market developing
people pay good money at carnivals to experience uncontrolled vomiting and dizziness...but I need to make money at this....would an R22 be cost effective?? or should I buy up a surplus EC225 and go big???
India Four Two
5th Jun 2019, 21:06
Makes you wonder what kind of G loading that rate of spin would cause?
I was bored and so I did a physics refresher. I timed the 10 fastest rotations to take about 8 seconds, so a period of 0.8 seconds. Assuming a 1.6 m patient, the maximum G force at her head would be about 0.6 .
That is equivalent to a continuous bunt of -0.6 G. Unpleasant but probably not red-out inducing. Probably more concerning would be the fear brought on by seeing the helicopter rotating over your head at more than once per second! I think I would close my eyes. :eek:
ShyTorque
5th Jun 2019, 21:18
That is equivalent to a continuous bunt of -0.6 G. Unpleasant but probably not red-out inducing. Probably more concerning would be the fear brought on by seeing the helicopter rotating over your head at more than once per second! I think I would close my eyes.
And if the patient already had head or other injuries....?
This should never have happened - the rotation could have been stopped as soon as it began.
The winch-operator/technical crew member in the door should have directed the pilot to descend and also winched out to increase the distance between the stretcher and the downwash - maybe they don't talk to each other much!
A simple 5 -10 knot hover taxi would also have minimised the spin.
Serious question Crab, why get the helicopter to descend? I'm experienced in winching operations and did not consider than an option. I'm interested to know why you think it is?
The winch out goes without saying.
Chesty Morgan
6th Jun 2019, 07:32
If you turn your phone upside down it's actually a woman rescuing a helicopter.
rescue520
6th Jun 2019, 07:44
I was bored and so I did a physics refresher. I timed the 10 fastest rotations to take about 8 seconds, so a period of 0.8 seconds. Assuming a 1.6 m patient, the maximum G force at her head would be about 0.6 .
That is equivalent to a continuous bunt of -0.6 G. Unpleasant but probably not red-out inducing. Probably more concerning would be the fear brought on by seeing the helicopter rotating over your head at more than once per second! I think I would close my eyes. :eek:
My quick calculation it's closer to 6.5g's assuming 1.8m patient at your calculated 85rpm
SLMFS - providing there are no obstacles to affect the safety of the aircraft, descending whilst winching out would get the patient to the ground quicker and have the small added benefit of reducing the downwash slightly - the primary aim would be to get the stretcher down within reach of the ground party asap.:ok:
Handy g calculators here (http://www.endmemo.com/bio/grpm.php) and here (http://www.calctool.org/CALC/phys/newtonian/centrifugal). Rather her than me.
dash34
6th Jun 2019, 18:43
I get an acceleration equal to 5.04g. a = 4(pi^2)r/(T^2)=4(3.14^2)(0.8)/(0.8^2) = 49.35 m/s^2, convert to g by dividing by 9.8 = 5.04g. That is probably unconscious in the absence of experience or a strain maneuver.
Unregistered_
6th Jun 2019, 20:39
At the patients age of 75 years, sustained 5+ g loading, they are so lucky this didn't result in a death.
SASless
6th Jun 2019, 23:08
That sure ain't the way to do that kind of work.
Unless I am grossly missing something....there should have been a suitable landing area (no matter how small) somewhere close by that the aircraft could have landed.
I would sure like to hear a first hand account of how all this transpired....especially with the source having had time to think over it all.
John Eacott
6th Jun 2019, 23:52
Serious question Crab, why get the helicopter to descend? I'm experienced in winching operations and did not consider than an option. I'm interested to know why you think it is?
The winch out goes without saying.
To add to crab@ reply, we were taught to descend when winching in once the bodies on the hoist were about 10ft above the surface, to maintain that height for them as a maximum for them to fall should anything go tits-up. With the move to larger machines with auto-hover/height hold this went by the board as downwash also became an issue plus accurate auto height hold.
There seem to be more and more videos of winch jobs where an unnecessarily high hover is maintained during and after the lift. A very good friend had never been taught about this, and when the crewman and 'survivor' fell from an excessive height onto the deck of the training vessel, both were killed. A transit to over water along with a lower height would have saved them both. Those of you engaged in winchops may like to review the height used by their operation with this in mind.
Re the spin and going to a lower height in this instance: the pilot held a very high hover for ages, with associated power requirement. A descent would have reduced that power and associated downwash, allowing the stretcher to be brought into the cabin without encountering the downwash problem so evidently apparent in this video.
Scardy
7th Jun 2019, 10:30
Horrifying to watch!
One surely hopes they were using a tag line and sadly it failed. To not have a tag line attached is inconceivable.
So many questions around this event.
- did they use a tag line (hi-line)
- if so to above did the weak link fail prior to spin commencement (if it failed why?)
- was there air to ground comms
- was there some form of hoist (winch) malfunction
- crew training issue
- SOPs in place to deal with a situation like this (winching out)
it appears in the video on the first attempt to bring the stretcher in once the spin began he did winch out and the spin did slow somewhat. But why in h€ll did he try again? Appears to be a small road directly in front of the AC, why not rest it there till some other solution was discussed. On the second attempt to winch in the HO must have seen the spin developing again but yet continued (??) To a point that was critical. It looks like he did winch out somewhat and as the video ends the AC had began to translate.
Hoisting ALWAYS last option. But unfortunately mostly only one at times.
Personally had a scary training exercise at night somewhat similar (but larger AC) Hoisting in a empty (though weighted litter) with all crew on goggles as the litter was approaching the sill a rapid and violent spin began. We had a tag line attached but was beyond the capabilities of the rescue man on the ground to control it. The onset was so quick and violent that there was a brief second of confusion bewteen all crew.
The litter ended up contacting the underbelly, sponson and unbelievable directlying behind the PF's window. No crewmember had ever seen such a rapid onset. The cable was immediately winched out and we regained control. We never encountered a similar situation after but became more vigilant then ever.
sometimes sh!t just happen sadly enough.
Unregistered_
7th Jun 2019, 21:58
Wonder if there's footage of 5 minutes before the start of this posted footage? @fox10phoenix
That would be very interesting.
SLMFS - providing there are no obstacles to affect the safety of the aircraft, descending whilst winching out would get the patient to the ground quicker and have the small added benefit of reducing the downwash slightly - the primary aim would be to get the stretcher down within reach of the ground party asap.:ok:
Thanks Crab, understanding the intention is to get to the ground sooner makes sense. The only counter argument could be that remaining higher means there will be more cable out and the stretcher will be less effected by the down wash. I understand your point though. See the point below for John but normally when I winch its at the lowest safe height for the operation. This doesn't really leave any significant room to descend over land but judging from the video it looks like they had plenty.
John Eacott thanks for your reply also. I agree with your points about excessive winch height. Watching the video my first thought was why are they so high? I do try to not judge though as camera angles can change the perspective or the crew may have had a good reason for winching high that we are not aware of. Generally speaking I have noticed on many videos that the winch can be very high. I prefer to be lower where the references make hovering easier, the winch time is minimised as well as the exposure for the operation. Some may argue to winch higher for OEI options but while that needs to be considered but I do not think this can be done in isolation.
Winching also needs to be done with intelligent reasoning. I once had a disagreement with a new Crewman that wanted to move during ship winch from the very large bridge wings of a massive container ship back and left over the water. When I explained that due to the size, stability and clear zones of the vessel we could remain over the wing where the winch height was about 15ft rather than move back and left over a 150ft drop to the ocean. His answer was that the operations manual stated that was the procedure. It took quite a bit of reasoning that while normally that would be the best option in this case it wasn't so we were not going to do it and be slave to a procedure. He did come around in the end when we agreed that a 15ft drop to a steel deck was bad but a 150ft drop to the ocean would surely be fatal. The aircraft safety was the first priority and the aircraft was not jeopardised to achieve this, it ended up been a very simple and easy winch.
Back door
8th Jun 2019, 16:17
In regards to the spinning of the Litter we have suspended operations in my unit until a new procedure is put in place. Our new helo has a considerable amount of rotor downwash and really moves a person or litter around depending on the hover height and wind strength. Even using the guideline attached to our litter, it was still hard to control just about the time it came to the bottom of the aircraft and would cause damage to both aircraft and litter.
As for arm chair quarterbacking, I have been doing this for a number of years and personally would of lowered the litter to the ground, depending on the suitability of the surface. Definitely a good crew debrief was had post flight to address the issue and learn from it. Thumbs up to the person in the litter, came away with no further injuries is amazing considering the spin :D
roscoe1
8th Jun 2019, 16:32
No further injuries indeed. Here is a quote from her husband who was with her. You don't endure that many g's without injury. I'll bet there are broken capillaries in her feet as well.
vto Mac and Gaydos of KTAR radio (92.3 FM) on Thursday, describing his wife's injuries as more severe than originally reported.
Metro said he and his wife, experienced hikers, were coming down the peak and were on flat terrain when the 74-year-old "stubbed her toe" and fell forward. She broke her nose, cut her face, and injured her left hand and right leg. Metro stemmed the bleeding and called rescuers, who sent the helicopter.
"I didn't know what to think," Metro said of seeing the rescue basket begin spinning wildly after it was aloft. "It was very scary and I think I went into shock."
Metro walked a mile back to his car, then drove to John C. Lincoln Hospital and was surprised to see that his wife appeared in worse shape than when he last saw her.
"I just couldn't believe her," he told the radio hosts. "Her eyes were all blackened. Her face was all black and blue. Her hands and feet were black and blue. I said 'Jesus, what happened?'"
A nurse explained to him that "the blood went all the way to her head and broke the small vessels in her face," he said.
His wife told him that "she thought she was going to die" while the basket spun. "She took deep breaths ... breathed in and out. She didn't know when it was all going to end."
Metro thanked the medical staff at the hospital. His wife is "still so weak she hasn't been able to get out of bed. We're hoping that changes. Her face is still swollen."
roscoe1
8th Jun 2019, 18:18
During the press conference they implied that the patient was none-the-worse from the operation. A bald face lie any way you look at it. At 74 she could well have died from this. I hope her recovery is complete. These folks should have stood up and taken responsibility for a very poorly executed job. They then should have explained clearly what causes this. What they did was weasel around by saying " sometimes this just happens" and that it caused no trauma to the patient. They did mention rotorwash as an issue and mumbled something about a broken tag line. Then on top of it, as the press conference ended, the Chief who introduced everyone started a round of hugs and smiles. Where were the adults during all this?
havick
8th Jun 2019, 19:21
During the press conference they implied that the patient was none-the-worse from the operation. A bald face lie any way you look at it. At 74 she could well have died from this. I hope her recovery is complete. These folks should have stood up and taken responsibility for a very poorly executed job. They then should have explained clearly what causes this. What they did was weasel around by saying " sometimes this just happens" and that it caused no trauma to the patient. They did mention rotorwash as an issue and mumbled something about a broken tag line. Then on top of it, as the press conference ended, the Chief who introduced everyone started a round of hugs and smiles. Where were the adults during all this?
^^^^This x 10
No operation is perfect all the time.
Three Lima Charlie
8th Jun 2019, 20:50
I seem to recall using a special "anti-spin" cable on the hoist that would prevent this problem.
roscoe1
9th Jun 2019, 02:55
Never heard of that. All the hooks have swivel bearings. I doubt very much that the cable was twisting during that E ticket ride. There are only one or maybe two wire rope manufacturers that make hoist cables and the construction is the same. They are a special construction that is not found in other applications that I know of but spin resistant isn't a listed characteristic.
Washeduprotorgypsy
9th Jun 2019, 13:09
Well the good news is that there has probably never been a better time to be rescued by the good looking Phoenix fire department.
Concerning the physiological effects of the incident , I suspect having the rotation point centered about the midriff and thus "centrifugal/hydraulic balanced" would mitigate lopsided blood pressure increase somewhat. I 'd hazard a guess that negative G tolerance is likely much higher in this configuration versus the oft quoted -2 to -3 of fighter pilots/astronauts.
Now can you come up with a better set of test subjects than the Phoenix fire dept. spokes team?
Perhaps a follow up press conference with the canned plastic air of a primetime TV denture advertisement.
Whirling down from 8 g's , then sitting up straight "See..just fine! Ready to start the day!"
Self loading bear
10th Jun 2019, 11:35
I seem to recall using a special "anti-spin" cable on the hoist that would prevent this problem.
All hoisting cables are generally of the low twist design.
Meaning they resist the unwinding of the twisted strands when the cable is under load.
Rotarion resistant (https://zephyrintl.com/wp-content/uploads/2014/02/Rescue-Hoist-Wire-Rope-Basics-2013-10-27_FINAL.pdf)
This has nothing to do with the rotation of the basket. If a swivel would not have been fitted. You would see the hoist cable coil up.
SLB
GrayHorizonsHeli
10th Jun 2019, 18:43
i'm no designer by any means, but one would think with all the smarter people out there, a swivel could be designed to rotate, yet resist free rotation. All it has to do is slow the spin caused by rotor wash and spin before the cable balls up. those are two values that can be determined, and in my humble opinion, a value that can be adjusted for.
We have had roller wheels in our shoes, eyeglasses that automatically adjust to the light, and light switches that clap on and clap off for ages. Can we get a swivel that does more than freewheel uncontrollably??
Bosbefok
10th Jun 2019, 19:52
The Baumann has a ring at the head through which the tag line must pass, before being secured to the upper carabiner. Failure to route via this ring renders positioning control all but impossible. I have watched the video a few times and it looks like the tag line bypasses this ring and is attached directly to the upper biner, allowing the Baumann to spin.
We don't employ a weak link. The tag line end is secured to the bag from which it is fed, and the bag weighted with a suitable rock so that the entire line can be flown, in the event of hoist failure, without fear of snagging the tail rotor.
Pilot positions back and left after lift, until he can see the tag line operator. This provides a good hover reference for the pilot, takes a workload off the hoist operator, and provides the tag line operator a good angle with which to control the stretcher. The patient's head is always forward. The distance one can move back and left is determined by the hover height, obstacle clearance and length of the tag line.
It is not possible to enter the stretcher directly to the cabin in the 109/119, one is required to seek safe landing area to repackage the patient to inside due further transportation.
One other observation - landing with the stretcher on the hook could shock load the hoist. We hoist out again from a low hover to ground handlers at the staging area.
Many basic errors here, but looks to me like the error chain started with the stretcher rigging.
henra
10th Jun 2019, 20:55
I was bored and so I did a physics refresher. I timed the 10 fastest rotations to take about 8 seconds, so a period of 0.8 seconds. Assuming a 1.6 m patient, the maximum G force at her head would be about 0.6 .
How did you calculate that?
The circumference of the circle her head executed was 5m (1,6m *Pi).
The rotational speed was thus 5m/0,8s = 6,3m/s.
Lateral acceleration =v^2/r.
=49m/s^2 = 5g.
That is not only unpleasant. That is bordering on dangerous.
Gray - if the stretcher wants to spin and you have friction in the swivel to slow it, that torque will be transmitted to the cable and could easily start to unwind it causing all sorts of problems - once you 'birdcage' a hoist cable it is pretty much unusable.
GrayHorizonsHeli
11th Jun 2019, 12:47
reading comprehension Crab, reading comprehension.
there is a value in the middle that I am looking at.
how much force to freely spin a basket, how much force to unwrap a cable designed to not unwrap.
these are two very distinct and different values. and likely very repeatable if you measured them.
8 N to spin you, 100N to unrwap a cable as a hypothetical example. I have no idea of the actual values, but if there is a specific spread you determine a friction that falls between and it does whats intended. which is stop the basket from spinning, and stop the cable from unwinding.
think of your collective friction and its designed purpose.
I have no idea of the actual values, but you feel content to criticise my reading comprehension - just consider the force required to make a stretcher spin like that in the video and then the counter force required to restrict that - you are content that won't have any effect on the cable windings despite having no idea of the actual forces involved - genius!
Perhaps if it was such a simple solution as you suggest, someone might have already invented it - stretchers have been spinning for many years under helicopters and you are the only one to come up with the solution - all hail!
FakePilot
11th Jun 2019, 21:26
She should have been a fighter pilot. Drones would black out before her.
Cabe LeCutter
11th Jun 2019, 23:53
Having kept my mouth shut whilst listening to all the arm chair experts, it is about time somebody put some realistic comment into this:
Stretchers spin, especially if there is not a winchman to assist by manoevering it to change the airflow over it.
A Tag Line (Hi Line) will stop the spin if it is rigged correctly and if it does not snap.
There is no such thing as an anti-spin cable, the layers of the cable are wound in opposite directions to resist spin, but the winch hook has a bearing to allow the hook to spin and stop the cable winding up and birdcaging.
From the video, it looks like there were better options to sort out a problem that had developed, the reasons that the problem developed are pure conjecture at this stage.
Trial by Internet video will not give the reasons, the real problem or the solution because the people involved have already been tried and found guilty by social media. Would you want to try to justify or lay open your mistakes to a bunch of people who have never been in that situation and therefore can not really understand what has happened.
I would not pass judgement on the situation without having discussed it in the bar with the crew, I have seen numerous situations that turn out to be very different from that shown on video.
What do I know, only 30 years of SAR winch operating so that does not give me much street cred compared to some posters on here. :E:E:E
Heads Down, Look out for the Flak
GrayHorizonsHeli
12th Jun 2019, 19:20
but you feel content to criticise my reading comprehension - just consider the force required to make a stretcher spin like that in the video and then the counter force required to restrict that - you are content that won't have any effect on the cable windings despite having no idea of the actual forces involved - genius!
Perhaps if it was such a simple solution as you suggest, someone might have already invented it - stretchers have been spinning for many years under helicopters and you are the only one to come up with the solution - all hail!
I suppose I can flip your comments right back at you because you offer nothing as well.
I'll try my best to continue to speak my point, totally accepting you'll jump onto my back and pummel me with the idiot comments. I have thick skin and am not deterred.
The spinning force starts off at a low value. you can comprehend that right? as soon as the stretcher lifts and the tag line is lost for whatever reason, the rotor wash imparts its forces and voila, stretcher starts to turn. basic physics. Its not immediately going at 300rpm and 5g's force right? takes more force to get them spinning, but once they are spinning, the forces tend to take over and you'll spin easier and faster, and faster yet. this lady experienced that acceleration and we watched in horror.
If you still dont follow me, go back to when you were 12 oiling your bike chain upside down in the driveway. dad on the porch swilling beers cuz the old lady is nagging at him. pedal a bike wheel in top gear at first and you see what forces i mean. Hard to turn at first, but gets easier as the wheel increases speed. and much easier to stop at the beginning. just grab it with your hand. PSA: dont stick your fingers in the spokes once it gets going though. try a stick.
hard to stop a wildly spinning stretcher once they get going too just like that ol' bike wheel. For sure the wire cable will bird cage if you allow the rotation to get to that point. just like you'll strip out bike spokes if you wait to long to put that stick in there.
what if you counteract that force early enough? no indication I want to stop it completely, only a desire to keep it under resistance to keep it from increasing at a high rate without hitting the value to damage the wire. Thats exactly what a tag line does. its simple and effective, but thats all if its lost. A resistive swivel would be a very good secondary tool to back you up if the tag line failed, but you're still going to have that secondary plan. the time you gain keeping that basket slow and getting the stretcher back on the ground might prevent further injury.
and if you do birdcage a wire, few grand to replace a cable is a cheap cost VS potentially allowing big injuries by spinning wildly out of control.
Perhaps though, someone has tested this. perhaps not. I'll gladly eat a hat if someone can offer this has been looked at. You however will likely just continue you're bullying ways because thats what you do on here. Have a nice day.
ShyTorque
12th Jun 2019, 19:58
Whether a cable birdcages surely depends on the total number of turns applied to it, rather than how quickly turns are applied.
Bird caging the cable is a very bad thing because it may jam the winch. If the cable is cut, that's the end of winching for the day. Especially bad if there is more than one person to be brought up on the wire. Hence the swivel and 'tag' line method.
Cabe LeCutter
13th Jun 2019, 00:10
Dear Mr GreyHorizonheli,
you are arguing from an academic point of view. It you are such an expert, please justify your standing.
Having flown own more hours than I care to remember with Crab, he is talking more sense than has been espoused on this topic than many.
You may be a mathematical genius, but you appear to have have no practical experience of Winch Operating environment.
This topic has been hijacked by yet another bunch of social media experts who appear to run their lives via PlayStation. If I am in error, I appologise, What makes you such an expert?
MurphyWasRight
13th Jun 2019, 00:29
Whether a cable birdcages surely depends on the total number of turns applied to it, rather than how quickly turns are applied.
Bird caging the cable is a very bad thing because it may jam the winch. If the cable is cut, that's the end of winching for the day. Especially bad if there is more than one person to be brought up on the wire. Hence the swivel and 'tag' line method.
Real question may be how many twists the torque developed by stretcher will induce on the cable before the opposing torque from the twisted cable matches, not whether the cable catastrophically fails.
A quick experiment using some ~0.1" twisted cable as a model suggests quite a few twists.
By the time the torques match the stretcher will have accumulated significant angular momentum so will continue to spin for a while before eventually stopping, at which time the counter torque from cable would be higher than downwash induced toque so the stretcher would start spinning in the opposite direction for a while.
Reminds me of a child's toy using twisted strings to spin a large button in the middle, once going wind/unwind to other limit, rinse and repeat.
So basically you might change a bad ride into a truly bad ride, I suspect high constant G is likely better than continuously changing G.
Engineering 101 "you cant push a string" probably applies here. (Unless it is wet and frozen)
BTW: My use of 'torque' in above may/may not be pedantically correct but I believe it is understandable.
Cabe LeCutter
13th Jun 2019, 00:37
Murphy,
The cable has a bearing so that you-will get minimal twist to the cable.
Will someone who knows what they are talking about please reply to this thread
Heads down. look out for the Flak
MurphyWasRight
13th Jun 2019, 00:56
Murphy,
The cable has a bearing so that you-will get minimal twist to the cable.
Will someone who knows what they are talking about please reply to this thread
Heads down. look out for the Flak
My apologies if not clear, I was replying to GrayHorizonsHeli suggestion that a friction clutch in the swivel bearing would be helpful, which as others have also pointed out would be a "bad idea".
Gray - I love your home-spun, back porch analogy (you must have had an interesting childhood if those are memories you are drawing on for inspiration.) but you miss the obvious.
Yes, the stretcher spins slowly at first because the downwash is limited at a distance below the helicopter.
If you have understood what happened on the video, you will realise that the closer the stretcher gets to the helicopter, the stronger the downwash effect and the larger the torque force applied to the cable - it is not a constant, small force that can be easily overcome with a friction device.
Bosbefok
13th Jun 2019, 06:18
Murphy,
The cable has a bearing so that you-will get minimal twist to the cable.
Will someone who knows what they are talking about please reply to this thread
Heads down. look out for the Flak
Nope, thanks. Your noble effort to enlighten the unwashed is noted, but the Dunning-Kruger effect is clear from certain responses. I could sink a pint with you though. Cheers
ShyTorque
13th Jun 2019, 08:19
Real question may be how many twists the torque developed by stretcher will induce on the cable before the opposing torque from the twisted cable matches, not whether the cable catastrophically fails.
No-one mentioned the cable "catastrophically failing".
If the cable "birdcages" it will probably not be possible to rewind it back onto the winch drum and depending on the circumstances might have to be physically cut by the winch op. Winches have a cable cutting guillotine device to allow this to be done in an emergency situation.
Nope, thanks. Your noble effort to enlighten the unwashed is noted, but the Dunning-Kruger effect is clear from certain responses. I could sink a pint with you though. Cheers You'll find that Cabe Lecutter is a clean living boy who doesn't drink at all..........oh hang on:)
Must remember the Dunning-Kruger effect next time I am tempted to postulate a theory supported by no empirical evidence:ok:
Scardy
13th Jun 2019, 10:20
Murphy,
The cable has a bearing so that you-will get minimal twist to the cable.
Will someone who knows what they are talking about please reply to this thread
Heads down. look out for the Flak
Hmmm.... this is a online forum, open to everyone, even those with less experience who may be commenting. Yes, some post may have to be filtered but maybe SOMEONE will state their opinion and if wrong (in your eyes ) take something away from it.
I have been made aware of a few things here and taken note of them. Maybe I have not said "cleared to hoist enough". I myself filter .... especially those who critize.
**** happens
MurphyWasRight
13th Jun 2019, 14:04
No-one mentioned the cable "catastrophically failing".
If the cable "birdcages" it will probably not be possible to rewind it back onto the winch drum and depending on the circumstances might have to be physically cut by the winch op. Winches have a cable cutting guillotine device to allow this to be done in an emergency situation.
Agree that "catastrophically failing" is not the best term, "permanently damaged" or "rendered unusable" would be better.
In any case no matter which way you look at it not having a bearing could lead to a number problems, my thought on cable torsional spring wind up/release interactions being just one of them.
Another question for those who do know.
Have there been any cases of having to use the cable cutting guillotine while hoisting a person?
That would be the ultimate hard decision to have to make. Gives me a queasy feeling just thinking of it.
havick
13th Jun 2019, 17:04
Agree that "catastrophically failing" is not the best term, "permanently damaged" or "rendered unusable" would be better.
In any case no matter which way you look at it not having a bearing could lead to a number problems, my thought on cable torsional spring wind up/release interactions being just one of them.
Another question for those who do know.
Have there been any cases of having to use the cable cutting guillotine while hoisting a person?
That would be the ultimate hard decision to have to make. Gives me a queasy feeling just thinking of it.
yes. When the cable gets fouled and cannot be un-fouled.
There have also been situations during engine failures or emergencies (both twin and single engine helo’s) resulting a swift winch out and cut the cable rather than the patient/rescue crewman becoming a sand anchor.
I don’t have time to trawl through reports, it’s not common but cutting the cable does happen.
Most operations also have a quick splice hook on board, so if you need to cut the cable due it it being fouled you can continue using quick splice.
MurphyWasRight
13th Jun 2019, 19:53
yes. When the cable gets fouled and cannot be un-fouled.
There have also been situations during engine failures or emergencies (both twin and single engine helo’s) resulting a swift winch out and cut the cable rather than the patient/rescue crewman becoming a sand anchor.
I don’t have time to trawl through reports, it’s not common but cutting the cable does happen.
Most operations also have a quick splice hook on board, so if you need to cut the cable due it it being fouled you can continue using quick splice.
Thanks, at least " swift winch out and cut the cable" preserves the possibility that it would not be automatically fatal to the patient/rescue crewman, no doubt a really bad day for all involved.
Back in the days of Wessex SAR in UK, a brand new, just out of the long SAR course, winch Op had to cut the cable on his very first rescue.
They were winching to a yacht in poor weather and deployed the winchman - unfortunately, the pilot lost sight of the yacht and started to drift towards the bow.
The winchman hit the mast and was being dragged up it towards the spreader for the stays and would have been sliced to bits had the winch Op not cut the cable.
I wasn't involved but worked at the SAR Taining unit next door so we had just finished training the winch Op.
ArnoldS92
14th Jun 2019, 23:39
Why did they winch at all, looked like plenty of suitable areas to land. Have not read full thread came in at the end, if answered already I apologise.
nomorehelosforme
27th Nov 2019, 11:24
Now she sues for $2million
https://www.dailymail.co.uk/news/article-7729615/Injured-elderly-hiker-74-sues-City-Phoenix-2MILLION-helicopter-rescue-incident.html
This could be interesting since the Phoenix PD organised a media event straight after the incident where the crew stated that she was uninjured by the spin..........
GrayHorizonsHeli
27th Nov 2019, 18:41
Phoenix PD should just pay up and shut up.
they wont win any popularity contests on this one
Unregistered_
27th Nov 2019, 21:52
Phoenix PD should just pay up and shut up.
they wont win any popularity contests on this one
Absolutely.
I've just watched that again. OMG, how did she even survive that?
There was a couple of opportunities to end that spin, lowering to the ground / bushes slowly, that that weren't taken.
That video will be used for the next 20 years as a crew demonstration of what happens when there's no tag line attached.
Was there initially a tag line? If so what happed to it?
John Eacott
28th Nov 2019, 02:17
Was there initially a tag line? If so what happed to it?
There appears to be the remains of a tagline at the head of the stretcher?
roscoe1
28th Nov 2019, 04:17
One thing I learned from listening to law enforcement people over 4 years of taking care of their helicopter and listening to stories of dealing with the public was their almost universal disdain when people lie to them. I'm not calling this a fault, it is completely understandable. If you watched their press conference after this you would have seen a serious song and dance, not to mention hugs all around, I assume when they thought the camera was off. This was one they should have gotten in front of and taken responsibility for. I hope that rather than dancing harder and faster they stop by the local donut shop for some humble pie. I'm sure internally they have a very good idea of how/why this happened and by now how it should have been avoided. If you want to dance, sometime you have to pay the piper.
Unregistered - in order for the tag line (we call it a hi-line) to be effective, it needs to either be attached to one end of the stretcher or attached to the aircraft hook and then routed through the end of the stretcher.
The other important factor is that the person on the ground has to know how to use the line to prevent a spin.
There was one attached initially but in the middle of the stretcher so it would be very ineffective in preventing, let alone controlling, the spin.
As I have said before - everyone thinks winching looks soooo easy - right up until it goes wrong because you weren't trained properly or didn't practice the skills.
You can see the crew chief doesn't have a scooby about what to do - he sticks his foot out to try and stop the stretcher spinning FFS.
The crew should have been very ashamed of that press conference.
PS - scooby = scooby-doo - clue:ok:
212man
28th Nov 2019, 07:24
....was their almost universal disdain when people lie to them. I'm not calling this a fault, it is completely understandable
Well, I'm pretty sure you don't have to be in Law Enforcement for this to apply - I'm not a big fan of it myself!
roscoe1
28th Nov 2019, 14:41
Well, I'm pretty sure you don't have to be in Law Enforcement for this to apply - I'm not a big fan of it myself!
Perhaps i should have said that although they were willing to tolerate bad behaviour of some sorts, lying was not one of those things easily overlooked.
jimf671
29th Nov 2019, 00:36
... ... stop by the local donut shop for some humble pie. ...
which at present is all over their faces.
Not impressed. These guys don't seem to be operating in the same universe as us. Certainly there is more of a problem with larger aircraft but just a different resultant wind direction or different shape of closure on the cas bag and it's away! They don't seem to be prepared.
NutLoose
1st Dec 2022, 21:15
Has got to be one of those every one dreads, it would feel like being in a centrifuge.
https://twitter.com/wapplehouse/status/1598147686238105600?cxt=HHwWgMCtjc624a0sAAAA
https://twitter.com/wapplehouse/status/1598147686238105600?cxt=HHwWgMCtjc624a0sAAAA
N707ZS
1st Dec 2022, 21:45
Thought they were trying to whack their victim on a cactus.
Has got to be one of those every one dreads, it would feel like being in a centrifuge.
Ouch!
Indeed I hope there was no one actually in that 'centrifuge'. At that speed of rotation it would probably not be survivable or at least with significant permanent brain damage.
RickNRoll
2nd Dec 2022, 02:04
Ouch!
Indeed I hope there was no one actually in that 'centrifuge'. At that speed of rotation it would probably not be survivable or at least with significant permanent brain damage.
Ice skater maybe?
While uncomfortable would this be dangerous? The person is spinning around their axis. It's not like you are being spun on an arm like in a centrifuge.
Remembering my childhood and being spun mercilessly on a roundabout.
Nescafe
2nd Dec 2022, 03:57
Settled in court (https://www.airmedandrescue.com/latest/news/phoenix-agrees-settle-katalin-metro-case)
It's what happens when you let poorly trained amateurs loose with a winch equipped helicopter and also a demonstration of how to make a slightly injured casualty much, much worse.
widgeon
2nd Dec 2022, 18:47
Interesting , she did not believe airlift was necessary , is it another case of the medical guys running up the bill needlessly ?.
Interesting , she did not believe airlift was necessary , is it another case of the medical guys running up the bill needlessly ?.
Not so much that I think, but they have been called out and want to justify getting airborne by making a heroic rescue. I don't know how many winching jobs they got a year but if it wasn't many they may have seen it as an ideal time to practice their 'skills'!
Not so much that I think, but they have been called out and want to justify getting airborne by making a heroic rescue. I don't know how many winching jobs they got a year but if it wasn't many they may have seen it as an ideal time to practice their 'skills'!
The decision to transport is made by on scene ground personnel based on patient condition, mechanism of injury, etc. The aircrew has no say in it.
snakepit
3rd Dec 2022, 21:24
The decision to transport is made by on scene ground personnel based on patient condition, mechanism of injury, etc. The aircrew has no say in it.
And therein lies the first problem. Only the aircrew will be fully aware of the risk of winching. They should be qualified clinically to make an assessment as to whether the risk of a winch is justified by the casualties condition. A clinical ground party cannot make the decision and non clinically trained aircrew cannot make the decision. You need a wholistic solution otherwise errors and mistakes will continue to occur.
The second problem was how the aircrew dealt with the spin and enough has been said about that already!
And therein lies the first problem. Only the aircrew will be fully aware of the risk of winching. They should be qualified clinically to make an assessment as to whether the risk of a winch is justified by the casualties condition. A clinical ground party cannot make the decision and non clinically trained aircrew cannot make the decision. You need a wholistic solution otherwise errors and mistakes will continue to occur.
The second problem was how the aircrew dealt with the spin and enough has been said about that already!
My answer had to do with the decision to call for a transport by air. The aircrew always has the right to refuse based on weather, LZ suitability, or other operational issues.
Patient condition is assessed by the first responders and they call for air transport in accordance with their protocols. Generally the only time the aircrew would refuse to transport based on patient condition would be if they were not stable enough for transport.
A professional outfit would have winched one of the crew down - and if you don't have medically qualified rear crew why are you transporting casualties in the first place - who would have given a full assessment based on medical and aviation knowledge. They would also have ensured the ground party knew how to use a line to stabilise the stretcher.
The ground party may have asked for the helicopter but the crew can make the decision not to winch.
Just amateur-hour all round.
SRFred
4th Dec 2022, 07:23
I have a friend that was involved in a similar incident in NSW many moons ago and the consequences of the spin were greater than the original injury. It was particularly noticeable in his eyes and I've never asked if he suffered permanent damage to them from the spin. Given it was Australia many years ago I suspect he simply got on with life as well as he could.
ShyTorque
4th Dec 2022, 14:12
A professional outfit would have winched one of the crew down - and if you don't have medically qualified rear crew why are you transporting casualties in the first place - who would have given a full assessment based on medical and aviation knowledge. They would also have ensured the ground party knew how to use a line to stabilise the stretcher.
The ground party may have asked for the helicopter but the crew can make the decision not to winch.
Just amateur-hour all round.
From the video, the terrain looked like it might have been possible to land on nearby, removing the need to winch in the first place!
SASless
4th Dec 2022, 14:17
How do we know what the Helicopter Crew was "thinking"?
Is there a Investigative Report available for this event that has findings for that?
We have the one news article linked reporting the settlement of the Civil Suit.
What stands out to me from that article is the following statement.
The claim was signed by lawyer K Thomas Slack, who stated that Metro ‘did not want to be taken off the trail by helicopter’ after an evaluation found that she did not need any kind of emergency transport. Slack added that despite this, the city fire department had decided to use a helicopter over any form of ground transportation.
I see more far more problems than a terribly bad Winching.....as bad as that was....the insistence by the Ground Units the Patient be Winched is the main problem that set up the failure by the Helicopter Crew.
The question that should be addressed is just why that happened....how far was it to a site where the Helicopter could be landed and the Patient ground loaded?
If it had been a Private EMS operator and the Patient refused Air Transport....that would have ended it right there and she would have gone by ground.
What Authority does the Fire Department and EMS have to overrule that Patient Refusal especially in light of her not having any critical need for transport?
Was the Helicopter Crew advised of the patient's refusal?
If so did the Crew look for a ground landing site adjacent to where the patient was located?
What alternatives were available for moving the patient by Winch?
I just see it as a problem with the city Fire Dept..........
Just amateur-hour all roundThe performance of a crew on a task may just be reflective of managements ethos - we can't afford to spend money on training, we can't afford to send people to industry forums to gain an education. You are consigned to working in a sheltered workshop tending mushrooms.
Agreed Megan and the result is an operational echo chamber
While uncomfortable would this be dangerous? The person is spinning around their axis.
The head and thereby the brain are spun at a radius of about half the size of the human. Therefore a signifcant centrifgual force will applied to the brain and blood will be pumped into Head and Brain at relatively high pressure. And for the head these are negative g's, where humans are much less toelrant than positive g's. In this case, assuming a radius of ~0,75m and a rate of ~2 gyrations per second I arrive at >-10g. Which as a sustainend load is quite a bit.
But I just saw the damage to the brain/head this case was not too big. I was concerned it might have led to intracranial hemorrage.
Additionally there is the point that they would have had to land somewhere anyway as from my fading memory I am pretty sure you can not get the stretcher/litter into the cabin from the winch on the A109 in flight.