search and rescue in extreme weather
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search and rescue in extreme weather
Wondering if someone can enlighten me on the most extreme weather conditions a SAR helicopter can fly in.
Am fixed wing rated, so little knowledge of rotary wing.
Assuming there is no equivalent to a crosswind limit as a heli can simply hover into the wind.
Presume that Sea Kings, Sea Stallions, Blackhawks can fly in atrocious conditions - given many have blade de-icing, auto-hover and ability to use NVG's.
Can anyone supply ideas of wind limits, loadings, restrictions on winching etc?
Am fixed wing rated, so little knowledge of rotary wing.
Assuming there is no equivalent to a crosswind limit as a heli can simply hover into the wind.
Presume that Sea Kings, Sea Stallions, Blackhawks can fly in atrocious conditions - given many have blade de-icing, auto-hover and ability to use NVG's.
Can anyone supply ideas of wind limits, loadings, restrictions on winching etc?
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wind can go up to 50 kts, visibility several hundred meters, icing, heavy rain, in mountains one can encounter heavy turbulence and sudden wind change, usually not all at same time.
check out for British rescue of SAS team during Falkland war, or Hong Kong rescue mission couple of years ago with wind around 90kts.
It is not unussuall to send a rescue party to save rescuers
check out for British rescue of SAS team during Falkland war, or Hong Kong rescue mission couple of years ago with wind around 90kts.
It is not unussuall to send a rescue party to save rescuers
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Winds in the order of 100 kts at the tops of British mountains are possible, though rather tricky to winch in (thankfully I've only experienced it a few times). Visibility can be zero, which again is not easy to work with if you're hovering next to a mountainside (either cloud can form around you when you're winching, or you need to hover taxi through cloud). It's a little easier if the zero vis is over the sea, assuming the auto-hover works ok in the Sea King and the doppler doesn't unlock (then you have to hold position manually, but you do also have an automatic radalt height hold). Only speaking from personal experience.
The SAR rules at the time I was in allowed for flight in any weather conditions, with due regard to the safe conduct of the flight. So you'd ask yourself, what am I trying to achieve, and is it worth risking the crew and aircraft to try and do it? The aim being, as Tartare has pointed out, to try to avoid becoming a statistic yourself.
SBW
The SAR rules at the time I was in allowed for flight in any weather conditions, with due regard to the safe conduct of the flight. So you'd ask yourself, what am I trying to achieve, and is it worth risking the crew and aircraft to try and do it? The aim being, as Tartare has pointed out, to try to avoid becoming a statistic yourself.
SBW
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or Hong Kong rescue mission couple of years ago with wind around 90kts.
Helicopter Heroism: 72 Kt in a Hover
The evening before, the difficult decision had fallen to Capt. Brian Butt, controller of the Government Flying Service. His crews were running out of daylight and the weather was worsening. With the typhoon within 50 nm of Hong Kong, the weather conditions had been extreme. For instance, when he positioned his Super Pumas over the barge Hai Yang Shi You 298, drifting 71 nm (132 km) southwest of Hong Kong, to start rescuing 68 of its crewmembers, Capt. Michael Chan told us earlier this year, he encountered strange conditions.
After assessing the situation carefully, the crew agreed to lower Winchman Jack Chak to the barge’s helideck. But Winch Operator Kenny Cheng couldn’t open the cabin door. Chan checked his instruments; the airspeed indicator read 72 kt (133 km/hr). "That is quite unusual," he said, "for an aircraft sitting in a hover."
After assessing the situation carefully, the crew agreed to lower Winchman Jack Chak to the barge’s helideck. But Winch Operator Kenny Cheng couldn’t open the cabin door. Chan checked his instruments; the airspeed indicator read 72 kt (133 km/hr). "That is quite unusual," he said, "for an aircraft sitting in a hover."
Rotor & Wing Magazine :: Search and Rescue: One Day in Hell
The weather deteriorated en route. The crews encountered fierce turbulence, wind shear, rain, and winds up to 85-95 kt (160-175 km/hr), with their severity increasing as the aircraft approached the typhoon’s track.
On scene, the J41 found the rescue helicopter was not responding to radio calls. Back at the command center, everyone was scrambling to locate the Super Puma. But there was an uneasy silence.
After some 15 min, Leung in the J41 heard a transmission — "Conducting winching, standby." It was Lam, the AS332 copilot.
On scene, winds gusted to 97 kt (180 km/hr). Visibility was less than 1/3-mi (0.5 km). Seas were very rough, with waves nearly 40 ft (10 m). The helicopter spotted the vessel. Her hull was on rocks, her bow pitching with the waves. A cliff was close in, and the superstructure and rigging made rescue difficult.
On scene, the J41 found the rescue helicopter was not responding to radio calls. Back at the command center, everyone was scrambling to locate the Super Puma. But there was an uneasy silence.
After some 15 min, Leung in the J41 heard a transmission — "Conducting winching, standby." It was Lam, the AS332 copilot.
On scene, winds gusted to 97 kt (180 km/hr). Visibility was less than 1/3-mi (0.5 km). Seas were very rough, with waves nearly 40 ft (10 m). The helicopter spotted the vessel. Her hull was on rocks, her bow pitching with the waves. A cliff was close in, and the superstructure and rigging made rescue difficult.
Last edited by zhishengji751; 15th Jul 2009 at 07:48. Reason: more info
Fort William Inverness-shire, Ben Nevis Race Association. 1988, 1st Edition. Coloured Card Covers, Tall 8vo. Unpaginated Ben Race program for the1988 Race - which turned out to be one of the most dramatic in the Ben's History - with 17 runners lifted off the hill by helicopter in a severe storm.
In 1988 the weather at the start of the race was acceptable but deteriorated rapidly after the race had started. Heavy fog descended on the mountain, obscuring the runners and the path. Although there were no fatalities that day, the potential for disaster was there. The suddenness of fog on the mountain creates unique race-day worries for the race officials on keeping track of the runners on the mountain
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Interesting, I had too look this up... is this the one you are referring too?
Helicopter Heroism: 72 Kt in a Hover
Helicopter Heroism: 72 Kt in a Hover
Thread Starter
Thanks guys
Most intrguing... thanks all... very helpful - I wouldn't have believed that you could operate in such extreme conditions - fascinating.
They still do not beat the single engined RAF Whirlwind that rescued the crew of a trawler that had wrecked itself at the base of the 300 ft. cliffs on the west coast of Hoy in a howling gale.
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The Sentosa cable car rescue in 1983 link here:
MINDEF - History - 1983 - Cable Car Tragedy (Volume 3 Issue 1)
I met one of the pilots involved- an Aussie on exchange flying Hueys- sounded pretty hairy!
The Sydney hobart a few years ago was apparently nearly as bad as Fastnet, according to one of the Sea King pilots who flew in both!
MINDEF - History - 1983 - Cable Car Tragedy (Volume 3 Issue 1)
I met one of the pilots involved- an Aussie on exchange flying Hueys- sounded pretty hairy!
The Sydney hobart a few years ago was apparently nearly as bad as Fastnet, according to one of the Sea King pilots who flew in both!
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We stopped sharing these sorts of stories at the SAR squadron before I got there. It quickly turns into a contest of who can beat the worst conditions, and does run the potential of affecting judgement. Missions like that still happen, but for the right reasons.
For many missions, waiting a few hours to see the weather improve is a possibiliy. For others, the bad weather is localized and you can get out of it fairly easily by climbing, or by knowing there are no obstacles along a path that can be flown without ground reference (ie departing over water). These should be considered before pressing into the worst weather. (and probably were in the previous posts...I'm talking in general here)
Ignoring the unique cases where waiting isn't an option, there are outs or an extremely compelling reason to operate without an out, and ignoring missions where the exact location is known and can be found with very poor reference, then the realistic weather limits for SAR should probably be between 100-300'AGL and 1/4 - 1/2 mi visibility, depending on the capabilities of the machine. Anything less than that and the Search part of SAR is quite difficult or at least time consuming. The Rescue part can normally be completed in much worse weather conditions than is needed for the Search.
As far as wind limits go, the helicopter can hover in any wind up to its vne, provided that wind is on the nose. However, the winch may not be able to support the additional loads created by the wind, when you consider the effect of the wind on the people or equipment on the hook.
For many missions, waiting a few hours to see the weather improve is a possibiliy. For others, the bad weather is localized and you can get out of it fairly easily by climbing, or by knowing there are no obstacles along a path that can be flown without ground reference (ie departing over water). These should be considered before pressing into the worst weather. (and probably were in the previous posts...I'm talking in general here)
Ignoring the unique cases where waiting isn't an option, there are outs or an extremely compelling reason to operate without an out, and ignoring missions where the exact location is known and can be found with very poor reference, then the realistic weather limits for SAR should probably be between 100-300'AGL and 1/4 - 1/2 mi visibility, depending on the capabilities of the machine. Anything less than that and the Search part of SAR is quite difficult or at least time consuming. The Rescue part can normally be completed in much worse weather conditions than is needed for the Search.
As far as wind limits go, the helicopter can hover in any wind up to its vne, provided that wind is on the nose. However, the winch may not be able to support the additional loads created by the wind, when you consider the effect of the wind on the people or equipment on the hook.
