S-92 Underslung Load Q:
 

Hola,

Any ideas why the S-92 max load on the hook is so low? 8000lb seems a tad low?

Interesting question
Not a clue. Pretty sure someone will be along with a reply.
Never even heard of anyone doing sling loads with a civilian 92.

I think it's because the load is taken by the fuselage structure, unlike some types where a panel can be removed from the floor and the hook attached to the MGB itself. I recall that the hook itself has a limit of 10,000 lbs, but I'm a bit rusty these days!

https://cimg6.ibsrv.net/gimg/pprune....4b64e9930.jpeg
https://cimg7.ibsrv.net/gimg/pprune....dd9ac0991.jpeg

What makes you think its a structural issue?

Maybe because a PTM says the cargo hook has a 10,000 lbs capability.
https://cimg5.ibsrv.net/gimg/pprune....a7fcbea89b.jpg

So if the "cargo hook has a 10,000 lbs capability" but it has only been "tested to 8,000 lbs", it doesn't seem its a structural issue.

Limits
 

TC data sheet:


https://cimg4.ibsrv.net/gimg/pprune....8453100786.png

A 10,000 lb hook attached to an 8000 lb capable structure?

Sounds about right.

I would say the reverse. The 'tested' bit is on the airframe - not the hook itself. The hook will be rated to 10,000 lbs by its (third party) OEM and Sikorsky will have looked at the market to find suitable hooks that would allow the aircraft to carry 8,000 lbs as a design load maximum. I can't recall which OEM they use, but I see, for example, that Breeze Eastern market a hook with a 9,000 lbs limit, so that would be a good example of a suitable fit. Dart market hooks with a 25,000lbs rating, which would be overkill and unnecessarily heavy/bulky.

It might be a legacy from the Blackhawk, which had an 8,000 lb hook upgradable to 9,000 lb.

The M model has the 9k hook standard.

Is it possible that it is a dynamics of flight, flight controls and/or handling limitation? Such things might have an impact on the certified limits for the carriage of underslung load. In some cases flight test and evaluation may be the only obstacle to increasing such a limitation. A costly process that someone will have to pay for.

As I recall, the aircraft cargo hook design load includes a 2.5 G factor. Thats a number I definitely recall from the UH-60. The 92 will have the appropriate FAA requirement and that may include some variation that I cannot at the moment recall. Trying to check with someone.

There is a organization in Canada that utilizes the hook. Mainly to carry out flaretip changeouts and other jobs at times (although no frequent)

Regarding weights each A/C and manufacturer are quite different. Let's take a quick look at various types:
BH06 / BH47 - both have hook attached directly and only to belly. The 206 would never have the power to do any damage to airframe. The 407 is similar but the weight permitted is quite low compared to what the AC could possbily pull and you end up running in to MTOW way early.
BO105 is attached to four points on the airframe. It is acutually attached to the undercarriage if memory serves and the load is shared between each stanchion in the airframe. (The BowCow would never have enough power to damage any structure believe me)
AS332 - Here is a different system which utulized two points of hook loading. The first is that the hook may be attached directly to the airframes underbelly but has a load 60% lower then the the prefered way. The most common way is that the hook is attached to a "stripper pole". The pole is attached directly to the bottom structure of the main gearbox and down though through a hole in the floor. Similar idea as that of the 212.

Regarding longline with either of these airframes maybe my prefered AC was the 92 at times. It was a extremely stable AC to work.
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As explained to me years ago, aircraft long line external cargo weight limits were determined by the airframe structural load path from the external load to the primary lifting structure. Not all airframes have a direct structural link to the primary lift structure which limit the amount of weight on the hook. There is also the reverse where some aircraft have a lower internal weight limit vs a higher external hook weight limit. In those cases the airframe structural limit can be the landing gear, floor loading limits, CG envelop issues, etc. As to the cargo hooks, it's been my experience that hook mfg'r tend to design/produce hooks to fit groups of aircraft models rather than one hook type for each model. Unless they get a specific OEM contract. So comparing a hook wt. limit to an aircraft external weight limit may not be an accurate comparison.

Hey thanks for the comprehensive replies - has anyone here actually flown it with 8000lb on the hook? Looking at a potential Helitack operation - so kick out the troops then clip on the bucket on a long-line then go dipping.. with the 900 US Gal bucket and throw some water at the ground.

You may wish to review the restrictions on the use of Power by the Hour components and engines in external load operations. Many helicopters have STC's permitting even greater external load capacity than those specified by the OEM - the limitation is the combined weight of the equipped helicopter and external load, and the certified ambient performance. If these factors are combined it is possible to lift loads in excess of the certified hook weight with a light aircraft, at dawn, flown by racing snake flight crews and very little gas and still be within the certified external gross weight limitation for the aircraft. The increased gross weights permitted for external loads with helicopters are a function of the ability to instantly jettison the load and immediately reduce gross weight and perform all kinds of recovery manoeuvres in the event of a power loss in a multi-engine aircraft.

And/or landing gear/skids limitation, right?

And i you do exceed the `certified` load limit of the hook,and there is an incident,you may well have to do the `awkward carpet -shuffle`,with no biscuits,in front of an audience.....
You may also reflect ,if you are so `cavalier` to limitations ,that they may well fail whilst someone else is driving.....:=

I have flown the H-70 with just under 9,000lbs on the 9,000lb hook, on a 100 foot strop. It was an interesting job, especially as we had to carry out an out of wind, OGE hover over steeply sloping, inhospitable terrain to place the load on a narrow access track. Probably more straightforward than with its bigger brother.

The Puma had a load pole directly attached to the bottom of gearbox. The crewman could monitor the load through a 2'x1' hole in the floor. The pole was steadied by a bracket at the front of the hole and attached to a ring on the gearbox, as was the crewman's harness.

About fifty years ago a gearbox bottom fractured and the pole, with a jeep attached to it, went though the hole in the floor.

So did the crewman.

That's why they invented load cells. If you're out hauling external loads that you either haven't weighed, don't know the weight of, or don't have your load cell to provide that information, maybe you should get someone who knows what they're doing to complete the task.

Hi all,

To wake up this thread, do you know if there are maintenance penalties (K-factor) for external loads operations?

Thx

jmdsm,

IIRC, there are no component penalties below 4000lb on the S-92.

Between 4-8000lbs there are huge penalties on the gearbox and restrictions on time spent doing load cycles per hour, rendering the S-92 basically uneconomic to use in the repetitive heavy external load category. I'm sure this is to do with what has been previously discussed here, but also to do with the OEM not having any plan as to what the S-92 does next once it's done in it's offshore role.

A rough rule of thumb was around 90% reduction in component life on the dynamic parts even if the cycles with weight attached part was obeyed.

Understood, the S-92A is not a S-64F!

By the way about the plans for the S-92, the VPGlobal Commercial and Military Systems at LM said recently: "There’s obviously been a lot of chatter in the market about the S-92 but what I will say is that we are ready and able to build aircraft when customers want them. We are currently building five S-92s in West Palm Beach, these are of course VVIP and SAR machines and not the oil and gas ones you are following closely. We build aircraft in many places and have previously built S-92s in two other locations. Sikorsky is committed to the commercial business and the order book is open. We are watching the market closely, engaging with our customers, attending events... We have a good aftermarket business." and "We continue to invest in new product performance and safety enhancements including the S-92A+. The demand signal hasn’t been strong just yet and currently timing for the first kits is 2025. As I said before, we are ready to respond when the demand is there, LM is a huge business and can switch on investment very quickly when it needs to. The A+ has some additional investment required to complete the certification."

Many thanks

I was told that the reason you don’t see Pumas doing logging is that the cycle count for every pick is huge. Leading to numerous components cycling out very quickly and requiring $$$$++ overhauls. Basically Eurocopter did not want the aircraft doing such operations.

I lost a good friend in the early 80s when the BBQ plate on a Puma failed during logging operations. The transmission rotated ripping out one engine drive shaft which led to an overspeed on that engine and engine overspeed protection shut the engine down. ( overspeed protection on the second engine is disabled when this happens ). The transmission rotated back and tore out the other engine drive shaft which led to the a massive engine overspeed on the now unprotected engine and a engine explosion as the aircraft descended from the high hover. Both crew were killed in the crash and fire.

I well remember when the only cycles we counted were engine starts on all of our turbine helicopters. Nothing else was recorded.Then suddenly you had to record 0.25 of a cycle for each subsequent takeoff or sling load pickup. ( I may be wrong on that 0.25 number)
Then years later they came up with RINS which were, initially so confusing as to be useless unless you carried a secretary to record them. Merely adding power to climb above max continuous incurred a penalty.Lowering power for a descent then increasing power to land another “event” Torque, N1, T4 all were factors. Just how we were supposed to record all that crap and fly the aircraft was not explained. Nor was the requirement for all this explained on aircraft that had been reaching TBO with no problems for years.
Towing a survey bird up and down hilly terrain for 7-8 hours a day was a nightmare. Needless to say some gross estimates +- were made.

They long line out of a 92 down in NZ.

There will be multiple videos on the World Wide Web on the operations.

Would You be kind enough as to post a link? I can’t find one on WWW or Utube..
Thanks.
Albatross.

Are you sure it’s not just that outfit picking up rockets on parachutes?

Friend used to long line with a Puma supporting drilling operations in the mountains, best question he asked was what are the minimums on an NDB approach with a load attached, a get out of trouble moment he had.

212man is right. Only 1x S-92 in NZ and it's with advanced flight/ rocket lab doing this:

Yes that’s it, but they have lifted with it also.

I believe it's not as bad on the L/ L1 as it is on the L2 and H225 but there is a penalty on the Puma series for loads. it's not as expensive as the S-92 penalties though. The main reason I guess is that AH at least designed the Puma with the military application in mind so Loads were factored in from the outset.

NWS, a worthwhile point re the external load operations impact on CRT’s ( Component Replacement Time ). SA’s eyes were opened after the S-64 started logging ( and the 61 as well ). Drive train cycle frequency went way up and naturally the fatigue spectrum compared to the spectrum used with the US Army was very, very different. I don’t know this with certitude, but that may have been a factor in selling the type certificate to Erickson i.e., the inability to get a handle on the real usage in the field when logging. Erickson is a sharp outfit-curious as to how they approach the issue.

Published Minima plus longline and load length? ( adjusted as required for cold WX ops of course ).
We can debate correct VASI / PAPI sight picture too!

Talked to and had the pleasure of flying with various folks who had done long distance IFR long line ops in the Arctic winter night using S-61s and B212s….an interesting job they said. All turns at. rate 1/2 and you didn’t want to get the load swinging. It was mandatory to make sure the load would fly stable. “ Darker than the inside of a polar bear! “ was the descriptor used. They had some very funny stories to tell.

Operators in Alaska did IMC/IFR night sling loads routinely on the North Slope and out over the Arctic and Chukchi.

Load stability checks were done VMC before going IMC and as Albatross mentions.....there were some very interesting stories of Loads appearing in front of the helicopter which at night in cloud must be a very sobering thing to experience.

Not so much after landing I am thinking?

S92 in NZ is used for catching the boosters which are not that heavy. The issue they have is how far they have to go to catch it. Thanks to big tanks and GE engines they have a good range.

"Down range" normally involves a lot of water naturally.

As I don't think they have successfully caught a used booster from a mission yet I am not sure if the procedure is to drop it on a support vessel or drag it home which may not be feasible.

ZK-HEV and you can track it obviously but it doesn't seem to have done much for a couple of months. There was talk of it being used for PAX flights between manufacturing facility and launch site.

I seem to recall they successfully caught a booster but had to pickle the load after it began oscillating and became unstable. But the core concept seems to be feasible