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SAR: Search & Rescue Ops [Archive Copy]

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SAR: Search & Rescue Ops [Archive Copy]

Old 27th Jun 2004, 07:15
  #321 (permalink)  
 
Join Date: Apr 2004
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Exceeding limits on SAR

Re the RN SAR scenario, we just don't know what happened. Hopefully, if it happened, the reason we know is because the crew came home and owned up.

In extremis, potentially trashing an aircraft, and risking the crew, can be justifiable but the captain had better be prepared to stand up and explain himself whatever the outcome. From personal experience, senior officers with a fixed-wing background, who may see SAR as rather peripheral, are unlikely to understand or be sympathetic.

I took a SK into a situation some would not approached and came away with people who would otherwise have died (smiles all round) but the aircraft was badly damaged in the process. This did not involve exceeding limits (unless of natural caution!) but the implications are similar and the evidence more obvious. I would put this alongside battle damage as "what can happen when you take calculated risks to complete missions" Again, being honest and being able to justify it afterwards is all important.

OBTW, the whole crew discussed the risks in advance and agreed with the plan so let's drop this chip-on-shoulder line about medal-hunting, two-winged master race etc. blah, blah.

As for exceeding aircraft limits, this is not to be lightly undertaken. As for guessing what the designers factored in, forget it. Especially with helicopters, its is an imprecise art and aircrew should treat limits with respect. If it happens, minimise it, get the aircraft back in the hands of the engineers asap, own up and hope it doesn't fall appart two flights later with your mates aboard.
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Old 27th Jun 2004, 10:25
  #322 (permalink)  
 
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Provocative Helo Thread, Nicked from Mil Forum

Would be interested in the thoughts of Messrs. Coyle, Lee, Lappos et al. with regard to the exceedence of limits/certificatoin of limits in the SAR environment, as discussed above - nicked from the mil forum.
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Old 27th Jun 2004, 13:00
  #323 (permalink)  
 
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I can't think of a helicopter that I have flown where you could exceed Vne in the cruise without pulling higher than max continuous power.

Best range speed is usually approx equal to Vno (roughly 10kts or 10% below Vne if memory serves!) so, unless they were experiencing high head winds, there wouldn't be any benefit from exceeding Vne.

I would put this part of the story down to inacurate reporting - there again I am always open to being proven wrong

Cheers

TeeS
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Old 27th Jun 2004, 15:13
  #324 (permalink)  
 
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Actually, some rotary Vne limits are set because they cannot be reached without a ridiculous rate of descent being reached, so why bother going faster. eg EC-155 Vne 175 kts, manufacturer has taken it to 210 kts and the head/blades to 240 on a dauphin.

On the other hand, they also take into account the wear and tear on the controls and hydraulic servos; ie componant life consideratioons.

I don't think one can consider exceeding Vne or any other FLM limit deliberately without snagging the aircraft after; not really fair on your colleagues, or you the next time you fly it, really?
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Old 27th Jun 2004, 16:26
  #325 (permalink)  
 
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Can and aircraft limit be broken for SAR?

NO.

It's really quite simple. The rules must be followed. Whenever a crew operates outside the rules, they may be subject to the consequences. With valid reasons to operate there, I'd hope that the consequences would be the exception.

One of the mistakes that is frequently made is the crew isolates themselves. Instead of being a part of a National SAR response, they become, in their mind, the only resource. If your rules, crew or machine is not capable of completing the mission, then perhaps there is another resource that can.

Once you determine that there is no resource, then the outcome of repenting must be compared to the outcome of pressing. Sometimes your best efforts are still not enough. If that's obvious early on, then don't break rules.

You now deem that there is a good reason to operate outside your rules (risk analysis) and there is no other resource to complete the mission. Now is the time to confirm your crew agrees with your plan, and if so execute it.

Sometimes all of the above happens in seconds, sometimes it can happen whilst flight planning on the ground.

I can give examples of exceeding parameters to save lives, exceeding parameters for no good reason, turning down missions that could have been completed by exceeding parameters (some with fatal outcomes), etc. In all but one of the examples, neither I, my peers, nor my superiors found fault in the decisions. In the one exception only a debriefing occurred.

The crews should never feel pressured to go beyond. When a National SAR system is designed, the limitations of the resources would have been considered. A high percentage of mission completion will be a part of the plan, but it won't be 100%.

Time to sum up. SAR crews don't have blanket authority to break rules. If they choose to they must consider other resources, risk analysis, the crew, the machine, and the rules. They mustn't feel pressured to provide what their country has chosen not to provide. All that being said, I think the best way of summing this up comes from our orders:
A too literal interpretation of these orders, that negatively affects the provision of SAR services, was never intended.
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Old 27th Jun 2004, 18:04
  #326 (permalink)  
 
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This topic has done the rounds of the SAR crewrooms and raised some interesting questions - the crew involved justified their actions stating that they exceeded Vmax by an amount less than the manufacturers 10% allowance.

The terms Vmax, Vne and Vno are not defined anywhere in military documentation although it is widely taken that Vmax is the speed at which you have no more power left to accelerate the aircraft in level flight, Vne is the absolute maximum speed permissible in the aircraft (only achievable in a dive) and Vno (not used in the military) is actually the maximum figure one should fly at based on AUM and DA (ie what we actually term Vmax in the Sea King world).
What certification requirements do rotary wing manufacturers have to abide by? John Farley has stated the case for fixed wing on the other thread but what about helos?
The biggest threat on a Sea King at high speed is retreating blade stall which is why we have a cruise guide indicator fitted (a sensor in the stbd lateral jack) to assess in flight vibration ie proximity to RBS.
I would like to know where the RN crew got their information regarding a 'manufacturers 10% allowance' which may or may not exist. I just hope they applied a factor for ASI inaccuracies (a hot topic since the sandfilter box was fitted).

Any thoughts from the TP community? Or Westlands?
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Old 27th Jun 2004, 21:30
  #327 (permalink)  
 
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AbiW

Very gracious of you.

I do hope you're on holiday at the moment, as there are far superior beverages available in Wilts!


heedm

I am confused. Quote:

"Can and aircraft limit be broken for SAR?

NO."

Then followed by a somewhat cotradictory post, in which you seem to agree that a sensible risk assessment must take place.
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Old 27th Jun 2004, 23:21
  #328 (permalink)  
 
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You're not allowed to break a rule. When you do so, you do so without consent. Thus the answer to the question remains 'no'.

I admit this may seem a bit confusing, however that must be the attitude to go in with. I know of many people who were very lucky, and others who weren't so, that got themselves into trouble by thinking that while on a SAR mission they operate without a rule book.
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Old 28th Jun 2004, 01:39
  #329 (permalink)  
 
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Bomber ARIS,

I would be surprised to find that the captain had that much more speed, as the max level flight speed is usually below Vne, or near it.

What aircraft are we talking about, and what was the Vne and the cruise speed the pilot selected?
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Old 28th Jun 2004, 05:47
  #330 (permalink)  
 
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Nick, the aircraft was a RN Sea King and they were going on a long range job (about 240 nm from the Scilly Isles). They calculated that flying at their Vmax (the term used in our Operating Data Manuals) they would not have enough time on-scene for the winchman to recover the casualty.
So, rather than accept that they could not do the job (The rescue coordination centre would have then sent an RAF Sea King which has better range) they flew in excess of their calculated figure (probably around 105kts at MAUM) to improve the situation. Once they had completed the job (and flown home from the hospital in a technically unserviceable aircraft) they justified their exceedance of the Vmax by stating that it was inside the manufacturers 10% allowance. No such allowance exists in the Release to Service or the Operating Data Manual.
Discuss....
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Old 28th Jun 2004, 06:44
  #331 (permalink)  
 
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Gentlemen,
As many of you will know, I AM ex SAR helos, and whilst I cannot confirm or deny it, I would treat the 'report' with a great deal of caution.
I would be astonished if the said helo managede to get faster than Vne (assuming it was under control of course!)
Rules are very very rarely broken, and I can say that I have never knowingly broken them, or even been able to break them, although I will admit that long distance SAROPS have called for some extremely accurate calculations which have been a bit 'iffy'
Gorilla, you are a fool Sir, and your comments prove it.

Kind regards to all SAR boys and girls
The Swinging Monkey
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Old 28th Jun 2004, 14:15
  #332 (permalink)  
 
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You can break regulations and not have much of a problem (most of us have).
You can exceed limits and not have much of a problem (again, most of us have).
You cannot break physical laws without some problems arising. Unfortunately, we don't give any guidance about where the line between limitations and physical laws is drawn.
Are all limitations wise and reasonable limitations? Unfortunately not.
Are all limits set by the manufacturer? In the UK and other militaries, limitations may be set for reasons other than strict engineering reasons. The US Army's 'no more than 60 degress of roll or 30 degrees of pitch because that's aerobatics, and the helicopter was not certified for aerobatics' is a prime example.
Brother Lappos' upside Blackhawk on the cover of a magazine shortly after this edict is a case in point of how silly this limitation is.
It's been more than 20 years since I flew a UK Sea King, so I have forgotten all the numbers, and they have probably changed as well, so I can't comment on what numbers are given as limits.
For the scenario given, if the air was smooth, and the aircraft well tracked, exceeding the Vne by the small amount claimed may not have had any adverse effect. It would be wise to check with the manufacturer on things like pitch link life, etc.
Such are the rigors of a real operation - in the US civil world, rules can be broken to save human life, and a regulation permits this.
It appears from the discussion that most people take this into account wisely.
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Old 28th Jun 2004, 16:20
  #333 (permalink)  
 
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Black, White or Grey........

It appears that there are a lot of people out there, who from the cosy confines of their computer desks are making assumptions based on less than 100% of the true facts. (For a change)

YES there are rules that should never be broken....
YES there are limits that should never be exceeded.....
YES there are situations that should never be approached.....

Ladies and gentlemen, let me ask you this:

IF you are unfortunate enough to crash your aeroplane into the sea, and you are just outside the radius of action of any of our SAR assets, if they stuck to all their limits, and

IF the weather was so bad on scene that, even if they did make it to you, they would be operating beyond their legal limits, and

IF there was a no chance that they would have any fuel remaining for an instrument recovery, if the bad weather caught them out, and certainly no diversion fuel, as is required by the big book, (or sets of books now), thatís if they reached you, and if they found you in the fog, and if they managed to rescue you,

In fact to lift at all would be just stupid.....

Would you want them to try?
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Old 28th Jun 2004, 18:06
  #334 (permalink)  
 
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17 years..........

I would agree wholeheartedly, however as the 'facts' of this particular incident are now emerging on the rotorheads forum it would appear that a nearby RAF asset was capable of conducting the mission within their limits as they carry a greater fuel load. So why did the RN crew push on? Service rivalry perhaps?
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Old 28th Jun 2004, 20:58
  #335 (permalink)  
 
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Swinging Monkey - the information is not in doubt as the crew included it all in their incident report!!! Both barrels - both feet!!
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Old 28th Jun 2004, 22:31
  #336 (permalink)  
 
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Whatever happened to the "...the aircraft captain may act in the best interests of the services..." clause in the mil flying regs? Still there? Probably misquoted (not my bed time reading anymore)but the essence was that if you did something, broke a rule, as long as it was done in the best interests etc etc and could be justfied it wasn't a problem.

This is obviously a different matter to breaking vne limits and risking RBS/jack stall/ bits falling off.

I too have flown sea kings up to vmax (iaw ODMs) and the laws of physics will stop you if you get much faster than that, ie before you get to VNE anyway.

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Old 28th Jun 2004, 22:54
  #337 (permalink)  
Couldonlyaffordafiver
 
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Surely Vne is set a certain percentage below the point when the test pilot chickened out....
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Old 29th Jun 2004, 09:33
  #338 (permalink)  
 
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Human Factor,

Please read John Farley's post on this thread before posting yours!
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Old 29th Jun 2004, 21:25
  #339 (permalink)  
 
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Whilst around the house of triple Torque I was made aware of the recent interest in my "INCIDENT". As the pilot of the aircraft in question I am obviously interested in all of the points of view that have been expressed - some sensible - some based on rumour (the purpose of this site??) - and some perhaps from self proclaimed experts who I hope never have to come to save me.

I have nothing to hide and so shall set the story straight.

As some of the more informed (experienced) commentators guessed straight away - the limit that was broken was actually Vmax and not Vne, (although Vne is not published for the Sea King - Check with the TPs and Design Authority at Westlands if you disbelieve that).

Whilst I can't address all of the points raised individually I'm sure that the answers will become self evident.

The call came from the RCC that a suspected heart attack victim was currently on a yacht 192 nm south west of the Scillies and required immediate assistance. Our ROA for the conditions of the day was 195nm (with all necessary safeguards built in). We launched and refuelled to max at the Scillies and then relaunched.
After about 20 - 25 mins en-route from the Scillies (55 mins into the job) we received an updated position that now gave his location as 205 nm SW of the Scillies. This now put the job beyond our declared range and if this had been the case from the outset it would have been passed to Chivenor automatically by the RCC and by matter of course had we received the info much earlier on we would have done the same.
So for the commentator who suggested inter-service rivalry - grow up because you are obviously part of this problem. We have an RAF SAR pilot on exchange and by the way Chivenor are covering our SAR during an annual dining out night next month.

Now faced with a stark choice - either come up with a plan to continue or call the RCC for Chivenor - this would then entail at least another hour delay - for a guy in the throws of a heart attack??? Our on board paramedic advised that the benefit of every minute early would have a direct effect on the subsequent longevity of the patient.

Now with a more accurate fuel burn calculation we assessed that we could reach the yacht but only achieve 10 minutes on task - which even had we been piloted by an RAF crew might not be long enough for a night time highline transfer (Nil moon - sea state 6). Therefore we took advantage of the strong tailwind and climbed with the resulting reduction in Vmax and achieved an altitude that gave an airspeed that exceeded Vmax by 8 kts (for about 15-20 minutes) which would then provide 20 minutes on task with a refuel required at Scillies prior to our return.
This deliberate exceeding of Vmax was discussed and although only an average QHI I was nevertheless aware of the implications of exceeding Vmax in the Sea King - namely the initial danger of retreating blade stall. Now for those of you that are familiar with the expression of "flying on the cruise guide" - this is a practise much frowned upon by the RN, however is an SOP for S61 ops in the States. Basically you get a vibration indication on a gauge that is quantified by a detector on the primary jacks with a green and red (unacceptable) band on the gauge. We experienced a low green reading throughout. And dare I say it to the non Sea King guys but the old girl soon tells you if she is not happpy.

Now I don't condone the willful exceeding of any limits unless you can a. justify the requirement and b. are aware of the implications of so doing.

The various other contributors to this subject confirm what was suspected by me and later confirmed by Westlands. Vmax is 10% less than the Vne which is 10% less than Vd which is the max design speed.

In addition to this course of action we requested that the RCC arrange for the in company MayDay relay merchant ship to attempt to transfer the casualty and make best speed towards us. This was eventually achieved and a transfer was completed from the merchant ship in 8 minutes (not bad for RN SAR!!).

The aircraft was then returned (within Vmax) but now into the known about strong headwind although the fast transfer, better than worst case fuel burn etc allowed a return to Culdrose to be made and a refuel was required even though Treliske was only 8 minutes further flying since obviously flying below MLA was a limit with very different implications and one we were not willing to exceed!! I take the hit that we then took off in an unserviceable aircraft (exceeded Vmax) however after nearly 5 hours in the saddle and approaching midnight I beg consideration and forgiveness.

The patient was discharged from hospital 3 days later with a clean bill of health and no lasting ill effects (he had suffered the initial stages of a heart attack) about the same time that I was warned of possible Courts Martial proceedings against me.

The Courts Martial threat receeded (I can now sleep at night!! without the threat of jail) and we all agreed not to break any limits unless we could a. Justify them and b. understand the implications of doing so.

We reported honestly and accurately our exceeding of Vmax which lead to routine inspections and a seviceable aircraft shortly afterwards.

I do stand by the decisions made although accept that a whole raft of other opinions may be offered although as one commentator stated you don't know unless you are there!!



Thanks for posting and setting the record straight.
..... rumour (the purpose of this site??)
No. Not the purpose of the Rotorheads Forum anyway, although rumours are inevitably posted from time to time. We prefer hard facts here, and I'm sure I speak for everyone when I thank you for posting the facts.
Congratulations to you and your crew.

Heliport
Hope you don't mind but I've changed the colour of your post to draw attention to it.
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Old 29th Jun 2004, 23:00
  #340 (permalink)  

Crazy Scandihooligan
 
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Mil discussion

Vnooooo, it would be said is the best performance related "V" factor to go with, isn't it? But if i was on the waiting end for the SAR Helo to arrive,; If it had to get to Vne to get to me, so i would be alive, then i would be very, very grateful.

I am sure we have all broken rules, and all risked more than we needed to, but unfortunately like all areas of aviation SAR are needed to do more for less, and thus they stretch a little more than other firms. (Lucky I don't have the maintenance bill).

I take my hat off to the SAR boys and girls and good luck.

MD
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