Twins operating without Onshore Diversion Fuel in GOM

[rotordk]

PPF#1 said :
We assume that they are inherently "safer" than singles. Statistically, that doesn't always seem to be the case.

You just can't back that up, can you ? Proff please, or is
this just a "belief" of yours ? Then say so !! Bringing up
light twins from the 70's is NOT proof. Different criteria back
in those days !! So, I ask again AGAIN...prove your statement !
Or should I assume your statistically wrong ?

[gasax]

OGP (Int. Assoc of Oil and Gas Producers) - Safety Performance of Offshore Helicopters 1998.

Shows that the safety performance of single engined choppers is appreciably better than that of twins.

The data needs a bit of interpretation (definitely not aimed at pilots!!). Largely it demonstrates that helicopter safety is not determined by the type or class of machine but by the environment that it is operated in. If conditions are hostile (Canada, N.Sea etc) then many accidents lead to deaths. Where they are clement (in terms of survival), the result is a walk, swim, lift home after what is generally a forced landing. Catastropic in-flight failures are not surivvable - so here the number of people at risk becomes the important variable.

So the point of real interest is that larger helicopters kill more people -two reasons, there are many more people exposed to each accident, and the energies are potentially very much greater. The single fatal Chinook crash accounts for nearly 50% of all UK offshore helicopter deaths!

Perhaps to some extent this corresponds to the EMS argument (let alone the cost of twins versus singles).

The sad aspect of this is that suppposed 'safety rules and arrangements' do not show a significantly better accident or death rate than other less stringent regimes. Indeed the same argument can be used to show that newer designs are not much better than the old techology aircraft . But then given such a high percentage of accidents are caused/accentuated by pilot error this should not be a surprise.

[Mikila1A]

ARA.........

We here on the Grand Banks go to 1/2 mile and 50' above helideck height......night or day, and at this time of year that will be 5 days out of the week. There is a rumor that they are looking for the "lower then standard" down to 1/4 mile in certain condition of wind, but it is meeting some oppostion so who knows.

Then again the 600 RVR take off and landings were once thought to be a little ridiculous too but are now as common as your morning coffee.............


off to work I go, BTW it is 100 & 1/2 everywhere here today.......sheesssssh I love my job

[PPRUNE FAN#1]

rotordork demanded:

PPF#1 said :
We assume that they are inherently "safer" than singles. Statistically, that doesn't always seem to be the case.

You just can't back that up, can you ? Proff please, or is
this just a "belief" of yours ? Then say so !! Bringing up
light twins from the 70's is NOT proof. Different criteria back
in those days !! So, I ask again AGAIN...prove your statement !
Or should I assume your statistically wrong ?

Oh dear........you just can't please some people.....

Rotordick, if you take exception to my vague statement about accidents, then you are free to challenge or contradict it with data of your own. I think everyone involved in aviation comprehends that most helo accidents are the result of pilot "involvement" in some way (pilots getting involved with the earth inadvertently or some such). That you, rotordink, do not understand this says much about your own involvement with aviation. Please try to keep up.

gasax reported:

OGP (Int. Assoc of Oil and Gas Producers) - Safety Performance of Offshore Helicopters 1998.

Shows that the safety performance of single engined choppers is appreciably better than that of twins.......

Well thank you, gasax!

So there you go. I wish it were true that twin-engine helos were twice as "safe" as singles. But you know, "safety" is a hard thing to quantify. What criteria do you use? What types of accidents are happening? It's all very fine to think "I have two motors so I must be safer than if I were in a helicopter with only one." But that would not be entirely correct. In fact, to think so (even in a general way) would be wrong.

[rotordk]

Go for a read on this report :
http://www.ogp.org.uk/pubs/333.pdf

And guess what.....there are no single engine failures in
in the North Sea :-)

And there where several singel engine failures in GOM !!

Anyway, my original questions was to PPF#, who apparently
doesn't kn.......nevermind......notice the silence !!

I do agree with gasax..... interpertation is everything !!

[BlenderPilot]

somthinsfishroundhere . . . . .


Quoted from AIN:

The JAA based operational restrictions on FAULTY offshore safety data. In fact, these restrictions were based on CAA accident data, which did show a higher accident rate with single-engine helicopters when compared with twins. In the U.S., a separate set of accident data on operations in the Gulf of Mexico does not show a significantly higher rate for singles.

[rotordk]

PPF#1...thanks for showing your true colour...
Can't even provide proof to your own statement..

Anyway, here is the dribble from PPF#1:

Rotordick, if you take exception to my vague statement

Ohhh, your vague now....nice answer .....

I think everyone involved in aviation comprehends that most helo accidents are the result of pilot "involvement" in some way

Yahoo serious, get a grip......... The statement was single vs. multi.........which part confused you ?

That you, rotordink, do not understand this says much about your own involvement with aviation. Please try to keep up.

.......your redirection BS only works in your own mind. My 11 yr. old nephew has more inventive remarks than you.

So, where is your statiscally vague proff of single.vs.multi, that's really not the issue, cause it's pilot induced Mr. PPF#1 ?
Show some involvement here.......share your wisdom, make
me a believer in your ways !

BTW, your hovercraft is definately and unquestionably topped of with eels !!

[GLSNightPilot]

I don't know about all companies in the GOM, but the one I fly for permits aircraft that have sufficient single-engine performance to land offshore to launch with destination plus 30 minutes VFR, and offshore alternate plus 30 minutes IFR. The only medium twin that requires onshore diversion fuel is the S76A, and we have none of them left, they've all been converted. The A++ and the C+, as well as the Bell 412 have engines powerful enough to permit a single-engine offshore landing, and these are practiced in recurrent training. One-way fuel is the only practical way of getting the job done 200NM offshore, at least until the BA609 is certified and in use. On takeoff, we often are too heavy to land on a platform, but by the time we've flown a couple of hundred miles we're much lighter. Inbound, we obviously have enough fuel to get to the beach.

We use offshore alternates IFR, with only a few authorized, and these alternates require weather reporting, fuel, and radio communications. Prior to launching IFR, the offshore alternate has to be reporting 800/2 or better, and a point of no return, or PNR, has to be computed, and the alternate still has to be 800/2 or better prior to passing the PNR. In actual practice, this isn't a huge problem. If the weather is low offshore, it's likely to be widespread, & we don't launch unless we have fuel to return. Often, however, the weather is down on the beach, but much better far offshore, so we depart IFR, and often cancel IFR before reaching the destination, because we can't talk to ATC out there below a few thousand feet altitude anyway, nor is there radar coverage. I file IFR every time I can, just in case, & just to keep me and ATC in practice at it. But if we can't carry enough fuel for IFR reserves, we go VFR, because we can go VFR with lower weather than what is required for IFR. Our offshore VFR minimums are 300/2, and sometimes there is no choice but to go out VFR with that weather. As I said in another thread, the oil companies' safety requirements are flexible - they do what is required by regulation, not much more, unless they're forced to by other pressures. Over here, it's get the job done, & don't bother us with regulations or details. The only organization that seems to be concerned with safety is the PHPA.

[Red Wine]

rotordk

Just ignore it.......it will fade away with time if no-ones talks to it.

Most folk here have done that already.

[offshoreigor]

I always thought FAR 135 required a rotorcraft with an offshore destination to carry a land alternate + 30 mins VFR and +45 IFR just like CARS in Canada.

Hmmm, I wonder what all those guys in the GOM think will really happen if they are on fumes 10 minutes from shore and they have to blow the floats? I can see it now....."Gee Mr. District Attorney, I was only following Orders...." Duhhhh. Give me a break guys, if there is actually someone out there that is that Brain Dead that they would intentionally flaunt the rules, I'm not talking FAA, I'm talking Oil Company, then they should go back to sheep hearding or news reporting in a Robbie.

We are dealing with a very educated customer these days and if you think you can pull the wool over their eyes, you are sadly mistaken. I have not had the unfortunate displeasure of dealing with a customer who wanted me to cut corners, do they really exist and are they worth pursuing as a customer?

As for the argument that local operaters in unregulated countries will be able to get ahead of an international operator is utter horse sh@t. I would say that if that were the case, the contract would not be worth bidding on in the first place.

Cheers, OffshoreIgor

[Old Man Rotor]

GLSNightPilot

Its an interesting aspect.......flying to a "landing area" without any reasonable assurance that you can actually land, and knowingly not have sufficient fuel to go to the beach.

What really interests me is the "Practicing of OEI" on Prof Checks.

Lets talk B412's, it seems that you are "Made" to squeeze every lb/Kg into your beasts, so its not unreasonable to assume that you would be lifting from base at MTOW [In a Classic or SP...thats not possible over 30C.....check the WAT Chart]...........in Nil wind, you will have used about 1250 lbs of fuel at your offshore destination............giving you an AUW of around 10650 lbs...thats still heavy.
Now suffer an OEI............

Are you really going to tell me that every pilot in your company, could and does succesfully get a B412 at 10650 lbs in the OEI onto a 17.1 D Helideck exactly every time without overtemping/exceeding N1, falling short or sliding over the edge....?

I have heard that belief before.......It just doesn't work out in reality.

I am not aware of the circumstances of your OEI training, however speaking generally, if you paint a circle somewhere on your training field, no larger the the "D" value of your helicopter, and load your machine to 1250 lbs below MTOW and enter an OEI exercise, my experience is that most pilots will not make the "Deck" everytime, yet alone the damage potential to the helicopter....and of course the platform.

Your working for the wrong operator and an Oil Company that is putting their profits in front of your safety.

[rotordk]

Red Wine........wilco :-)

[GLSNightPilot]

OMR, in the 412 we do it in the sim at FSI. Load the thing up heavy, fail an engine, & land it on the platform. In the S76, we do it to the ground, generally a concrete pad. In real life, I don't care if I overtemp the other engine. If one fails, the other had better watch out, I'll do whatever I have to do to make a landing. We almost always take off from the beach at 11,900lb in the 412, there just isn't enough range to do anything else & get out there. You're always fuel critical in a 412, so max gross takeoffs are the norm, not an exception. That's why the 412 is almost useless for deepwater use. For 80NM or so out, it works fine, but increase the range & it makes life difficult, and it's not at all unusual for me to do a 300NM+ trip. It's not that far off the beach, but the flight is at an angle, and a trip from Galveston to southeast of New Orleans is just business as usual. These trips are doable in an S76A++, but take all night in a 412, so I only take a 412 if the flight is less than an hour roundtrip (and there are a few of these) or all the S76's are down for maintenance.

And I do think it's possible to get a 10K+ lb 412 onto a deck without sliding off or overtemping it, with proper technique. Fortunately, we've never had anyone who had to try it. And I'm well aware that EVERY oil company puts its profits ahead of my safety, I fly for all of them eventually. That's why I look out for it myself.

[donut king]

OEI..real life

Excuse my lack of 412 knowledge!!!

Are you guys doing single engine landings at max. gross weight during your training?

Are these only in the sim. or done actually in the a/c?

On our 76's, we do OEI landings to a runway( actual) but try to simulate a deck/ helipad. We restrict weights but still always end up with a small forward component( run-on).

Appreciate any input!

D.K

[Nigel Osborn]

As I said earlier, there are very few twins that can make a SAFE single engine landing on rigs at anywhere near max weight for a 2 engined landing. Yes, one can practice at FSI, great simulators, and on the runway or grass with little decks marked out but that controlled environment is not the same as real life. It appears accepted in the GOM, haven't flown there, but everywhere else I've been it is not the accepted practice.
The other good reason to carry round trip fuel is that for a variety of reasons the rig may not give you landing clearance. On at least 5 occasions I have had to return without landing; on 2 occasions the rig sank!
I presume when some pruners write "max weight" take offs, you mean max weight for the OAT, weather problems, etc and not the a/c max weight as per the RFM??

[chopperman]

In the North Sea area of ops, flight to a rig without onshore diversion fuel has been accepted practice, but with some stringent conditions attached.
Primarily, the aircraft should plan to arrive at the destination at a single engine weight for the ambient conditions.
Secondly, another rig should be nominated as a 'diversion' in the event that the primary destination becomes unusable.
Thirdly, the weather must be above certain limits and forecast to remain so for the duration of the flight plus.
Fourthly, prior to PNR, a confirmation of all necessary criteria must be obtained from all agencies involved, or a RTB/land diversion becomes mandatory.
I haven't gone into great detail, there is much more but I'm sure you get the idea, it's very regulated as to what you can and can't do. It seems to work best on the longer flights where fuel burn is sufficient to get down to the single engine landing weight required.
At the present time I don't know of any operator (in the NS) who uses this practice and personally I’m quite happy never to use it again.

Fly safe

[Old Man Rotor]

GLSNightPilot and Chopperman.

Sorry to persue the issue, but I am interested in the technique used in this training...as we can all learn from each others procedures.

I take your point regarding using FSI B412 Sim in DFW for Platform OEI. Sims are great for some things, and invaluable for others, but rig work is not their strongest aspect, even the Cat D sims.
The problem that we experienced with these sims for OEI work was that there were un-natural flight characteristic in the approach and landing.....also there was a more solid deacceleration on the deck, which in the real event would not be there and may put you over the side.

With the S76 OEI "Helideck" practice, did you load your aircraft to a realistic Offshore Approach weight????....or simulate the weight by retarding the throttle of the "Good" engine?

Chopperman......I gather you are talking about SA332's???

[chopperman]

OMR,
Apologies, yes, you're quite correct; I was talking about the 332.
Just to clarify my post a little, the OEI helideck weight is calculated from a different graph than that used for the Helipad (onshore ) weight and is much reduced, in fact it is not much different to the Helipad take off weight, with the exception that in certain circumstances 50% of the wind can be factored in.
As I remember we practiced to a Helideck size circle on the runway, or to a rig in the simulator, with the aircraft ballasted to the correct AUW. I don’t ever remember having a problem landing on the deck at those weights.
Flew the 76 for a while myself, nice aircraft, but wouldn’t want to land OEI on a helideck if I could help it.
I’m rushing this as I am running late, so hope it all makes sense.

Fly safely,

[GLSNightPilot]

First, let me clarify one thing. We carry fuel to the destination, plus to another landing platform. Often there are many platforms within a couple of miles, but if there aren't, we carry enough fuel to get to another landing deck, plus reserve. We do not commit to landing on only one deck, just to not returning to the beach. Keep in mind, there are around 3000 platforms in the GOM, plus drilling rigs, barges, etc.

The technique we use for a single-engine approach is to set up a slightly steeper than normal approach, make a rather slow descent with some power, & put it on the deck. In the 412, it's now done only in the sim, AFAIK. I haven't done one in the aircraft for some years, but we used to do it in the aircraft, to a small platform set up at one of the bases on land. In the S76, we do it to a pad or runway. We don't load the aircraft to gross, we limit the amount of torque that can be pulled by using the checkpilot's hand on the collective, or just torque callouts, which should be used in any case. With one engine at idle, we make the approach & use the minimum amount of collective possible, usually less than 80% TQ, but this varies with temp, weight, etc. The extra power is there to prevent bent metal, and if the approach is screwed up & too much power is required, we can go around & try it until we get it right. Admittedly, this isn't a perfect simulation, but it's better than nothing, and it appears we'll always be committed to single-engine offshore landings, as oil production moves further and further offshore.

[zalt]

Do rig-based shuttle aircraft carry on-shore diversion fuel thesedays in UK and Norway?

I seem to remember the 212s on Treasure Finder never did.

The concerns I've heard about GoM have more tended to be that twins are being overloaded to operate 'Class 2' for half the flight rather than half a minute!