Nil wind rig operations
 

Someone on an offshore rig (an offshore worker) was telling me that they were stuck there for a couple of days because of the recent nil wind conditions offshore (Victoria).

What would be the reason for this?

Are the S76's so close to the bone in terms of weight / fuel single engine climb performance in nil wind that they won't fly off a rig?

Are the operators just being tight in that they only want to go out with a full load and will only do that if there's wind?

Also is it usual practice to do the agressive dive off the platform coming within only feet of the ocean in order to fly out safely to gain speed I again assume for single engine operations?

Thanks, just curious as a fixed wing owner.

Basically 'no" to all your queries. Diving off the rig should not be necessary, maybe just a pilot showing off to his pax. Nil wind doesn't matter, just calculate your take off weight accordingly.

Mmmm ...

Yup .... I agree with Nigel ... In fact there are times when a windy day can require more power to take off from a rig then a calm day (all depending on deck construction, T/O direction and deck turbulence).


:)

Falling off the edge of the rig was, and perhaps still is in some quarters, standard practice. I note your "should not" though Nigel.

On a take off there is a period where an engine failure may deposit you in the wet stuff. Depends on environmental conditions and weight as to whether you can get away with it. Speed is life when marginal and beyond. With a failure in the 76 you can get very close and personal with said wet stuff in making a successful fly away, as in 5 feet, and that's doing everything by the book in relatively benign conditions.

The original query sounds like all cock an bull to me. can you imagine a mob of rear seat hanging-rail pax being all cheery and friendly while some clown trotted out those sorts of stories for two days?

WRT to diving off a small height, may I relate it as a dangerous pastime and illustrate.
It goes like this.
One clown that I had working for me once had developed the self same habit. diving off the pad over the edge with a clearance of about fifty feet, usual doctor from the left quarter front, albeit behind a few trees to the left. get the picture? wind tumbling over the edge even on a light wind day.

It was something of which I was oblivious otherwise what did happen would not have. Yep you guessed it, not quite enough speed or wind.

As he neared the bottom below the parapet, flaired, picked up a sickening dropping feeling, and rolled the bloody thing up in a whole heap of large rocks and flying debris.

All three pax bounced out with barely a scratch. very lucky, so was he many years later as he was gratuously handed a safety award and his citation mentioned that he had a nil accident record!!

yessir, it's a funny industry this one of ours.

I cordially suggest always lift and hold on its own engine merit, provided both horses are still kicking, in a climbing attitude, howsoever slow a RofC it be.

I'm not sure on the model of s76, Brian A would know what they are. Unless they upgraded from 10 years ago they would be just S76C. Have heard a few underpowered stories from out that way including hovering for lengthy periods as the jet-a burns off before being able to take off and the runway not being long enough in some conditions however I believe all in a days work when driving an S76 in those conditions.

The 'customer' owns the operation and S76's: there is no monetary commercial aspect to the flying.

Regarding going over the edge of the pad and then going down before going up - in the Arabian Gulf in the summer and Autumn, in something like a WS55 series 3, if you didn't use the pad height above the sea to your advantage then you would most certainly have met the warm, wet stuff not far from the rig.

I think it is wrong to say, 'No, don't do it, regardless' - from my experience it is the pilots call on the day taking into account the prevailing conditions, there can be no hard and fast rules, either way.

I would argue that this would NEVER be the case! Just ask the head of flying operations about his yearly budget. If finances were not an issue you would not be needing to dive off the deck as you wouldn't always be at or near MTOW.

XXX,

I would expect that you are referring to Esso's helicopter operation out of Longford. They own the operation, they own the helicopters, the S76C's only fly to support their production platforms. The S76's are not there to make a profit, they are there to support the Bass Strait oil production.

Where is the commercial pressure to operate any way but safely and professionally?

I'm not suggesting that they are unsafe in any way. I am suggesting however that there are ALWAYS commercial pressures regardless of the operation type. Do you not think that every aviation operation would have a budget? If not they would be flying no less than 2 year old machines half loaded as an example. There is a fine balance usually driven by finances.

They are 76C at Esso.

Re runway. There was a great deal of misunderstanding in the operation as to the requirements of Category A (full accountability for an engine failure), and Category B where there is no accountability. The charts published by the company for Cat A operations were remiss in not taking into account the distance required for a failure after the critical point, accelerating, and climbing to the screen height. There is no requirement to operate to Cat A, but despite trying to get the company to acknowledge that their Cat A was not necessarily Cat A, nothing had changed up to the time I left in 04. You can imagine the result of a failure after the critical point and a chap thinking he is Cat A capable, and finding he is not. BBQ anyone? :ooh:

Platform take off. The book procedure was to have 3% N1 margin between hover and max available. Climb vertically to 25 feet on the RADALT with at least 200 ft/min and rotate. Not always complied with as the ethos was get the bloody job done. Platforms did not have temp gauges (despite the company standards manual) so you would never knew if you were going to be over your max landing weight, and a couple of interesting events took place as a result. Planning of the take off weight could be problematical at times, and I recall having to drop 600 lbs below the book figure once. Never resorted to it personally, but did hear of the burning off of fuel to get off with the load required.

You may think there is no commercial pressure, and in a sense you are correct. But, management made it plain that pilots were to do what they were told, and remember their salary is subject to a yearly appraisal. Going to kick the traces? Unions have their place. Pretty much lip service was paid to standards. CASA went so far to add a supplement to the flight manual spelling out the alternate requirements, on top of those contained in the ops manual and AIP's. Why did we not provide for alternates? The chances of anything going wrong and requiring use of an alternate are so infinitesimal that it need not be worried about was the company reply. With logic like that you have an uphill battle on your hands.

Oh and did I mention the budget. A manager lived or died by his budget. Spend a penny? Not if you could get away with less, for that's how his appraisal was judged.

What happened to hover + 15% (TQ) needed for departure? Sure, after the initial vertical climb and rotation you will sink, but you will also clear the deck with comfort. If we didn't have that margin in the hover, we were expected to offload the appropriate amount of freight/pax. It used to be called common sense!!:ok:

I can associate with diving off the decks in an underpowered 365n way back in the mid eighties, but I put that down to the fact that I was A) single pilot ops, B) young, dumb and full of cum!! :{

It's a no brainer these days....

I think that there is a big difference between starting from a "closed" surface or deck (like concrete, for example) or a net.....

On a closed surface, you can hover in ground effect-and use that factor when taking off.

On a net, you are hovering in OGE.

When fully loaded, it can happen that the heli-when coming OGE while reaching the border of the platform-can come into a dive.
This is a really dangerous situation-the tail can hit the deck, or the tail rotor can get into a stall because of the different wind situations, which can result in an uncontrolable turn.

If you are operating a C model, MTOW from the rig, nil wind, you have no choice but to dive off the platform once clear of it to get your airspeed to 60kts ie Vtoss asap; if you don't and have to go on OEI, you will get wet. I have seen too many macho guys simply pulling 101.7 and upwards to prevent that dive... simply stupid in my books

WLM

There is some c**p written here. If you have to dive off a deck to gain air speed something is wrong, you've cocked up or you’re overweight. If, in your nil wind condition you are about to take off knowing you are going to have to dive for air speed, and when on rotation one of your engines stops what is going to stop you going in the water? If you can make a 15 to 25 foot climb at the recommended rate of climb the amount of dive is slight. Lose an engine now most will recover and fly away with about 10 ft to spare based on a 100ft helideck.

If you are at the correct weight you will take off and fly away without undue diving, even in 76A+. The answer is always in the weight. I have worked with all operators on the British and Dutch North Sea and all had limitations regarding light winds. The 155 was particularly bad and had multiple wind limits. The oil companies were quick to respond to passenger complaints that passengers had been scared by particular crew’s actions.

I have never had a comeback following passenger offloading because of wind and weather conditions.

My rant is regarding leaving the deck from a low hover, and I have been there in my distant past in the Middle East flying a B205, but then all operations were bush and nothing was weighed. Times are different now!

Really, like what? Why?

Why? easy - two of the 155 operators on the SNS had a number of overtorques in light wind conditions (fenistron et al) and so a payload penalty was imposed when winds were less than 10 kts. It was found that this payload reduction was not enough in less than 5 kts, and so a further reduction was imposed by the operators. The amount of reduction was set by the individual operators, but was up to 300kg.

By the same token both the 76A+ and B models had wind limitation payload penalties, to varying degrees.

I see. Curious as I don't recall a particular problem, but then we always flew in slack winds so possibly didn't find it a shock (compared to being used to windy conditions)

Once saw a Bo105 do a go-around from about 20 feet above the helideck & fall off the edge.It was a highly effective method of teaching the goons in the back not to ignore the safety briefing by unclipping their seatbelts before the aircraft had landed :cool: