EMS helicopter down Oklahoma
 

An EMS helicopter ( AS 350 ) crashed in Oklahoma, two fatal and one injured.



Helicopter Crashes Near NW Expressway, Killing 2 - News9.com - Oklahoma City, OK - News, Weather, Video and Sports |


skadi

Interesting photo.....shows all three Main Rotor Blades pretty much intact and a mostly intact tail rotor blade.


http://kwtv.images.worldnow.com/images/21305802_BG2.jpg



http://kwtv.images.worldnow.com/images/21305802_BG3.jpg

RIP to those lost and condolences to those left behind.2013 is shaping up to be a horrible year for EMS.:sad:
Alt3.

This one happened almost in my back yard, literally. Less than a half mile, from their departure point to the accident site, the route of flight would have been right over our house. I did not hear the accident for a couple of reason, one I was sound asleep and secondly our house is so well insulated we cannot hardly hear anything from inside the house. I never heard any of the emergency equipment responding to the scene, but the local news helicopters did finally wake me up just after sunrise.

Sad event for sure. I have not bothered to go to the site and will not do so, seen enough accident sites in my life/career.

Two fatal, one survivor, no report on how serious the survivor is injured.

Nurses from the Nursing home on the rushed to the crash and pulled out the sole survivor before a secondary explosion consumed the fuselage.

Why do all ASTARS seem to end up as a pile of ashes?

The Sultan

Very sad - RIP to the crew.

I see sunrise in Oklahoma at the moment is 7.06am so it was clearly 'Night'. Con-pilot: any first hand info on the weather this morning?

WX NOT a factor:

22 07:53 NW 9 9.00 Fair CLR 20 13 74% 10 NA 30.10 1020.6
22 06:53 NW 7 10.00 Fair CLR 20 13 74% 11 NA 30.08 1019.8
22 05:53 NW 8 10.00 Fair CLR 20 13 23 74% 10 NA 30.04 1018.6
22 04:53 N 12 10.00 Fair CLR 20 13 74% 8 NA 30.02 1017.7
22 03:53 NW 10 10.00 Fair CLR 21 14 74% 10 NA 30.00 1016.9
22 02:53 NW 12 G 21 10.00 Fair CLR 22 14 71% 10 NA 30.00 1016.9
22 01:53 NW 8 10.00 Fair CLR 22 14 71% 13 NA 30.03 1017.8
22 00:53 NW 13 10.00 Fair CLR 23 15 72% 11 NA 30.02 1017.6
21 23:53 NW 9 10.00 Fair CLR 23 15 35 72% 13 NA 30.00 1016.9

Respect to the people that pulled the survivor out!!! :D

Clear with unlimited visibility, light winds and cold. No factor really, least not that I can see.

It is now being reported on the local news stations that there was a fire in the cabin before the crash. Take that as you may, as I have read and been on accident sites where the aircraft was reported on fire before the accident, but when on scene, there was no sign of a post accident fire, let alone one airborne. So I don't put a lot of faith in these types of reports.

The accident site is approximately 2.5 miles north from Wiley Post Airport (KPWA). The airport is controlled, but at that time in the morning, the tower is closed. So whatever happend, it happend fast for them not to it make to Wiley Post, just two and a half miles away.

Looks like it landed rather than crashed. So near, yet so far. :(

O2 fires have killed crews before.....one that stands out is the Greenville, North Carolina Bell 206 crash many years ago. The O2 bottle was in the baggage compartment and sprung a leak.....during a night flight.

I do not know but local TV Helo pilot says they are equiped with a 140 gallon plastic fuel tank right under the main gear box rather than a bladder.

His assumption was that a hard landing breaks the gear box and crushes the fuel tank or a hyraulic shock from the fuel in the tank on a hard/crash landing causes the tank to rupture.

I had an idea from your previous posts that you probably lived pretty close to the accident.

VFD

Could be a possibility.
However, it doesn't explain the apparently low energy state of the Rotor system during impact. Looks at least like there must have been other factors involved...

Oxygen leaking may support combustion but doesn't cause it. In any case modern medical pipeline systems or simple cylinder supplies don't leak. The O ring seals are only used on anaesthetic machines not aircraft. Provided you check the system daily which is mandatory for patient safety I would put this right at the bottom of the possibilities

Homo.....that being so....why then have there been aircraft destroyed on the ground while crew members were doing the preflight checks on the O2 systems? I am familiar with several.

Oxygen does not burn....but it sure provides for a hotter, more intense fire should there be an Oxygen enriched atmosphere....as you well know.

There are multiple ways of experiencing a fire in flight but if the report of a cabin fire is correct then it rules out many possible scenario's don't you think?

The 350 amongst its many issues....does seem to wind up in a heap of ashes more often than not.

Medical helicopter crash in Oklahoma City claims 2 flight crew members, injures another | News OK

RIP. Very sad. On the barest of initial information, it does not seem to be the "normal" HEMS accident. Given the circumstances, I think it would be unwise to discount oxygen. If you do get enrichment it changes the whole game with fire. Things you would not think of turn into great fuels and innocuous ignition sources leap to start the thing up.

Forensic investigation should give us a clue, the fire spread is likely to be different if O2 is involved.

Helinut

Totally agree - oxygen does indeed support combustion. I was just saying it wasn't the cause: ie there must have been another source of fire, but the oxygen may then have acted as an accelerator

SASless

Can't comment without more information. Correct checking of a medical oxygen system does NOT involve release of more than about 4 litres of gas at no more than 1.5 atmospheres. Unless you squirt this at an open flame it won't cause a problem.

Changing old style cylinders does require releasing at high pressure. This should be done away from the airframe before fitting the cylinder. Modern cylinders do not require venting or any release of oxygen

As with helicopters, failure to follow correct procedures with oxygen cylinders can be dangerous

If you look at the rotor against the tree there does not appear to be any damage to the rotor blade or significant damage to the other rotor blades.

So unless the craft slid to that position from forward velocity just does not look like the rotor was rotating with any authority.

VFD

"I do not know but local TV Helo pilot says they are equiped with a 140 gallon plastic fuel tank right under the main gear box rather than a bladder."

The Astar fuel tank is a 'plastic' cylinder in the central truss box upon which all the airframe is built. Baggage compartments either side and aft of that box, and the bulkhead between the cabin and other areas is the forward face of the 'box'. O2 is commonly installed in one of the baggage bays and will directly abut the 'box' containing the fuel cell.
The main gear box is attached to the top of the central 'truss box' over the tank.

I am unfamiliar with this accident aircraft configuration, but many O2 installations have a separate pilot controlled master cutoff valve installed at the LOX tank. I respectfully disagree with "Homonculus', O2 leaks can occur, but I believe they are infrequent. The only time I've used the O2 cutoff was after a hot patient unloading with O's left on.

I would be interested in the cabin heat and demist system in situations similar to that described this event.

I think we are getting a little off message but

A 350 would only carry a few thousand litres of oxygen in an EMS role. If you have a leak of more than a couple of litres a minute you will very soon put your patient at risk due to inadequate oxygen. If the leak is in the pipeline you will also immediately be unable to provide high flow oxygen again putting the patient at risk. If is happens in a hospital it is a major reportable event. in the UK at least we use hospital standard pipelines in aircraft. Leaving a flow meter turned on with 4 litres a minute running is hardly an issue

A LOX is a totally different system from cylinders. The oxygen is low pressure and liquified. Spillage of high volumes of gaseous oxygen cannot occur because the portable systems vaporisation systems are only capable of 10 to 20 litres a minute. That is why we can't run high consumption equipment such as heart lung machines off LOX. Of course, in a high G impact the actual container can rupture leading to leakage of liquid oxygen. But otherwise it is so safe that we have clearance to carry 50000 litres on commercial flights

There appears no evidence to implicate oxygen in this accident, but having spent many years getting LOX approved by the CAA I am keen to ensure the excellent safety record is not besmirched

It could indeed be the cause. Spontaneous combustion is a possibility whenever an organic material is introduced into a 100% oxygen atmosphere.

Know of a case where a surgical patient died as a result of oxygen igniting a (presumably synthetic) stent in the trachea.

There is a very good reason fighter jocks are admonished about wearing lip balm, it typically contains beeswax or carnauba wax, camphor, cetyl alcohol, lanolin, paraffin, and petrolatum. Some have found out the hard way.

It's a worry that those in the medical profession seem to have no/little appreciation of the dangers involved. Advice from a medical site,A humorous (true) story,

Brian

As a specialist in difficult airways I am on my home ground when I say there has never been any spontaneous combustion in the trachea as you describe. You are describing a very specialised operation for patients with cancer where we use diathermy or laser to resect the trachea in the presence of a Montgomery tube. The patients are very ill and need enriched oxygen into the lungs. The oxygen can support combustion from the naked flame of the diathermy or the burn of the laser and the tissues then ignite. We simply squirt water from a syringe onto the flame and it goes out. Has happened to me twice.

You simply don't get 100% oxygen is a helicopter cabin. I did the tests in the 1980s. Even with an old style cylinder fully open with doors shut on the ground the cabin O2 concentration was only in the 0.4s.

We use very high flows of oxygen every day in operating theatres where the controlled air changes are far far lower than those in a 350 in flight and where Medical electrical equipment is merely checked for ground leak as opposed to aviation equipment which has to be additionally Checked for flammability and electrical circuit safety. We simply don't get fires.

When we need approval in the uk to mount medical equipment it has to be bench checked for flammability and circuitry (as well as flight tested for interference). Many many items I use in my operating theatre have failed these bench tests. In other words my operating theatre is far more flammable and has far more ignition points and higher concentrations of oxygen. Yet we don't get fires.

I accept we don't have a turbine, and if the oxygen store is totally disrupted or the entire operating theatre breaks up then oxygen may accelerate any fire, but oxygen doesn't just catch fire and nor does it leak significantly.

I have never come across the advice you mention about lip balm in children. It is medically daft. Of course if you add a spark to a petroleum based substance don't be surprised if it ignites, and if there is enriched oxygen the fire will accelerate. That is many I don't smoke while I am refuelling. But in my EMS ship at least we wear nomex and don't have flammable substances. So we don't have a fire in the first instance........we hope

It may be worth reading about an Australian Longranger VH-CHP accident back in May 1997 where The report found that the oxygen system had not been properly cleaned, but essentially it self ignited as a result.

Thanks Adroight

1997 in Australia. They used a faulty adapter to connect a piece of plastic hose to an old style cylinder. The system was thought to be dirty. No wonder there was a problem. The CAA would not have approved this in the UK in 1987

All UK pipelines in hospitals and I hope helicopters (certainly the ones I have overseen) use a specifically designed braided material that prevents static charges building up, and are lifed and sealed. The pipeline ends in a specifically designed Schroeder probe or is welded to the housing. All connections spring off if not fully engaged and the system self seals

We remove and separate the system from the aircraft for maintenance to avoid any oil or grease coming into contact, and place warning decals to this effect.

I suspect grease had got into the system and the pipeline then failed.

Please note the report states 'oxygen is non flammable but will support combustion'. That is all I am saying.

John - just seen your post. The issue is you do not clean oxygen systems. They are totally sealed so dirt can't get into them. We do take precautions to avoid external dirt. The hose itself has a date on every metre and is replaced when it expires. Oxygen does not self ignite, but when in contact with grease it can explode.

Another one ( happened while checking the O²-system ) some years ago at Stuttgart airport:

Rettungshubschrauber ausgebrannt [ Einsatzbericht / Flughafen Stuttgart ]

skadi

homonculus,

I respect your experience, but I have noticed before that your responses appear somewhat dogmatic and reluctant to listen to the experience of others. I was a bit delayed with my last post and was pipped by Adroight, but you (again) were quite dismissive of the report and the background of the 206L accident. Read it thoroughly and the comments about the fit being to a similar standard as the FAA at the time: how can you be so adamant that the UK wasn't fitting helicopters to a similar standard 16 years ago?

You dismissed Brian's comment about a tracheal fire and death, yet a simple Google search indicates that not only have there been such deaths in the past, but current medical papers on the procedure highlight it as a very real concern. One death in 2007 is offered as proof that it can and has happened.

A little more understanding by you would garner lot more respect from your aviation peers.

homonculus, you seem to dismiss the dangers of oxygen with gay abandon. Organic compounds run the risk of spontaneous combustion in a 100% oxygen environment. End of story, based on the destruction of aircraft and injuries suffered by aircrew. Reread my previous post and the moustache fire. An event that has occurred to more than one fighter jock.

Access forbidden!

Or this recent one: Certified modern B777, source of fire, FO Emergency Oxy System

http://i197.photobucket.com/albums/a..._110729_2.jpeg

http://i197.photobucket.com/albums/a..._110729_1.jpeg

Thanks John

I fear you have misunderstood my response. I am not at all dismissive of the report. Somebody was injured and if this had happened in flight the consequences would have been worse. The report itself hits the target. I merely highlighted the salient points. The report quite rightly identifies that dirt, and in particular grease, can cause a problem, and that the tubing and connector used were inappropriate.

I indeed do not know what the FAA was mandating at the time, although the fits I was flying in in the USA before this were of a higher standard. I have also been careful not to state that all system in the UK are of an adequate standard - I merely expressed my hope that they were.

What I can be sure of is that from 1987 the CAA has mandated that all medical equipment, including oxygen systems, permanently mounted in aircraft, are of an adequate standard. I wont tell you how I know for fear of being labelled dogmatic!

It is of ongoing concern that many aircraft continue to carry oxygen and medical equipment that is not of this standard on the basis of temporary, carry on, and captains discretion.

As to your reference I am afraid the link clearly states that diathermy was involved. In other words there was a naked flame and an intense heat source. I am sorry to appear pedantic but if you apply a naked flame to a patient's airway when it is contains 100% oxygen we can all accept the result may be a fire. What I do not accept is the extrapolation that oxygen systems simply spontaneously combust. There has to be a source of the fire.

There is no evidence currently that this was a factor in this accident. However day after day my colleagues struggle to provide safe standards of care for critically ill patients who need to be flown. The biggest hurdle after financial restrictions is the argument that it is dangerous; doctors tell us helicopters are dangerous, pilots tell us oxygen is dangerous. If my frustration appears dismissive, I apologise but the report summed it up: 'oxygen is non flammable'. We can carry oxygen safely in aircraft, accepting that if there is a major impact that results in fire that fire may be accelerated by the oxygen. Posts on PPRUNE, oft quoted elsewhere as definitive statements, implying otherwise do need dogmatic replies.

TOD.....Talking about being in the Hot Seat!:uhoh:

Thridle Op Des

The emergency Ox System according to the report had stainless steel pipelines, plastic tubing with no specification as to conductivity, and the design allowed high pressure oxygen to step down to low pressure in one stage which can cause heating if there is failure. In addition there were electrical components involved and issues over the wiring.

I have no knowledge of these systems, but none of these factors relate to medical gas systems which only use flexible pipelines with specified conductivity and flammability, step down in two stages, and do not have any electrical components.

Medical gas systems in hospitals did have these failings, but a number of fires in the 1950s plus the involvement of several eminent doctors and an enlightened BOC led to standardised systems and hospitals have proven to be safe. Brian Abraham's reference also details military systems using alloys, differing metals and silicone plugs as well as high flow transfers. Again issues the medical systems avoid.

There doesn't have to be an ignition source when organic matter and pure oxygen meet, they combust spontaneously, a fact taught by the military in flight school, and the FAA. The usual triangle of fuel, oxygen and ignition source is reduced to oxygen and fuel.

Brian Abraham

If as you say when oxygen and organic matter meet they combust spontaneously, why can we give 100% oxygen to patients day after day in safety? Patients are organic matter. Sorry, I just don't follow this

Sorry homunculus, I'm with BA and JE on this. Here is another, possibly more famous Oxy event:

http://i197.photobucket.com/albums/a...000-001834.jpg

Before you get too excited, in the Egyptair and the NASA events the actual ignition source was never determined with any degree of certainty. If you want another graphic demo of oxygen and grease interaction, look no further than Valujet.

In chemistry flesh is not considered to be an organic compound, being composed of 75 percent water, 19 percent protein, 2.5 percent intramuscular fat, 1.2 percent carbohydrates and 2.3 percent other soluble non-protein substances.

While there is no "official" definition of an organic compound, an organic compound is generally regarded as a compound with carbon/carbon or carbon/hydrogen bonds. Organic matter typically contains 45-55% carbon, 35-45% oxygen, 3-5% hydrogen and 1-4% nitrogen. The mix of those elements is what makes organic compounds potentially explosive in a 100% oxygen environment.

Flesh will decay into organic compounds, as will vegetation.

Agreed TOD nothing was proven. Particularly spontaneous combustion! So I wasnt getting at all excited. But issues with electrical wiring were identified. Whether it was a spark in the oxygen system or grease as you allude to, I have no issues. I agree this creates a risk, and if you add a spark or have oil in the system you have a real likelihood of ignition. That is why the medical systems have been designed as closed systems.

I still dont understand your point BS. Are you suggesting we have rotting flesh on board, or vegetation? Even if you did have this, how can it get inside the medical oxygen system??? The oxygen concentrations outside the system, with the exception of about 10cm around the patient's mask or the ventilator exhaust valve, are hardly increased above 21%. A poorly trained mechanic I accept might smear grease accidentally on the outlet or probe. That is why we cap them and remove them. I dont understand where this 'organic compound' comes from, how it gets into a closed oxygen system, and how it creates a risk in a helicopter but doesnt create a risk in an operating theatre or land ambulance. Given how many more land ambulances there are compared to EMS helicopters, and given they are not cleaned or maintained to aviation standards, we would expect to see regular 'spontaneous combustion'. We dont in the UK.

For a more in-depth understanding of the Australian Longranger fire, the full ATSB report is here.

I don't know whether you are being purposely obtuse. You may wish to visit your dictionary, my Concise Oxford defines organic as,

physiological - of or relating to a bodily organ or organs
medical - (of a disease) affecting the structure of an organ
chemistry - (of a compound etc) containing carbon

So flesh is not an organic compound, and it is ORGANIC COMPOUNDS that we are talking about.

Your failure to understand spontaneous combustion is a worry, given the cases in aviation where it has occurred. A Moderator on these forums, who has a wide background in aviation, posted in one thread "most of us have seen various training films (or demonstrations) wherein an oxygen stream ignites a flammable substance without any external ignition".

You might wish to familiarise yourself with http://www.boconline.co.uk/internet....3410_39599.pdf Particularly where it says,

May cause or intensify fire
Contact with combustible material may cause fire

First of all, Condolences to the families.

Stepping away from O2

These are just speculations on what the photo shows:
Look at the first photo. Notice the tail stinger is broke and the tail rotor is still attached to the gear box. This most likely happens in a high vertical decent impact with the tail rotor turning slow or not at all. Had the tail rotor been turning at normal speed, it would have broken and catapulted a few yards away. Also the main rotors have very little damage. At 390 RPM, the rotors should have chopped the little tree down. I don't see any cut branches. It's possible it slid there but I don't see any skid marks on the cement. I would think that an impact strong enough to break the stinger off the tail could also rupture the fuel tank which would cause the fire. Hard to tell but it looks like the skid tube is broke on the right side, typical of a very low rotor (retreating blades stall first and, in the case of an Astar, it would roll right.)
Anyone know what direction they were going in relation to where it came to rest?