Twins operating without Onshore Diversion Fuel in GOM

[SASless]

During a conversation with a friend who flys in the Gulf of Mexico...he remarked his company requires pilots flying twins to operate at gross weights that preclude making safe single engine landings to rig decks and simultaneously mandate the use of only 30 minute reserve fuel which prevents the aircraft from making it to a safe landing area (on or offshore).

A previous poster noted current industry practice in the GOM is to operate twins at max weights that do not allow for any margin of power and in his view presented a real danger of not being able to maintain flight following an engine failure during or shortly after takeoff.

Two different pilots....both very experienced....two different companys involved....and both telling accounts of a lack of concern by GOM operators and customers regarding safety issues. Some of the customers are the very same ones that operate on the North Sea and demand high safety standards....related helicopter operators in one case.

Wonder why the difference in attitudes between the UK...Europe...and the GOM?

[Old Man Rotor]

From your first paragraph, it would seem there is a whole bunch of guys/girls flying around the GOM in multi-engine singles!!!
If you enter the OEI configuration in these machines….you can’t land on a deck, and with no return fuel??....splash.

Surely no pilot in a medium twin in the OEI configuration, would consider using an Offshore Helideck to land on??...what a recipe for a fiery ball.

I would also think that no respected owner of an Oil Platform would invite you to crash on his deck and set fire to his home, because you didn’t take enough fuel when you left your home!!!

Our fuel policy on a normal two hour IFR sortie is:

Flight fuel, + 10% Variable of your flight fuel, + 30 minutes Fixed Reserve.

[Flightfuel: is the total outbound and inbound fuel without landing offshore]

You must always carry enough fuel to get you to a land based suitable flat area….[the size, surface is specified in the B412 RFM]

When you land offshore with AEO, you can then burn that unused 10% Variable of the outbound leg as deck fuel. As the return flight is considered a new leg, the Variable on that leg will only be 10% of the return leg only….classic case of making fuel!

"Reprinted from another thread….

Presently we utilize three limitations when operating 412's as far as AUW is concerned. Our Restricted Take Off Weight [RTOW] must be the lesser of:

1. MTOW [11900 lbs]
2. WAT Chart [Limitations Section of the RFM]
3. OEI capacity at MC or 30 mins to maintain zero % climb gradient at 500 agl [VFR]..... or 1% climb gradient at LSALT in IFR."

Its interesting to note the times folk don’t heed the WAT Chart Limitation…..its a limitation of the RFM.

With the fuel policy of carrying return fuel, plus the above three RTOW Limitations…………..we feel comfortable that should a PT6 fail at any time, we should have the fuel and performance to arrive safely home.

[verticalflight]

All companies are in business for a profit, whatever they say, and safety morals are not to get on the way. High safety standards (particularly those that cost lots of money) are set only in those areas where local culture and legislation so call for. OSHA (USA) and HSE (UK) are known for setting the most stringent safety standards in the world, which also costs companies losts of money, always understanding that regulatory frameworks generally reflect the cultural values and beliefs of the countries where they apply.

International companies simply would not be able to compete with local operators on areas of 'more relaxed' safety attitudes if they were to apply the highest common denominator standard across the board. Sad as it sounds, life and the environment are priced commodities as far as companies are concerned, regardless of what their marketing campaigs make us believe. Only when trouble-makers like greenpeace and human right activists rock the boat at home (i.e. where shareholders with strigent safety expectations are watching) companies take notice. When the safety matters at question are heavily technical in nature, like above, they are unlikely to be picked up by those groups and its exactly there where the major discrepancies occur.

[md 600 driver]

excuse my thickness where is gom

[rotordk]

GOM = Gulf of Mexico

Different country, different rules :-)
Ask the Canadians on this forum about their minimas for ARA.....interesting stuff !

[PPRUNE FAN#1]

It's a funny thing about multi-engine aircraft. We assume that they are inherently "safer" than singles. Statistically, that doesn't always seem to be the case. This explains why so many hospitals in the U.S. have traded their Twin-Stars and BO-105's for Astars and 407's. So my question is: Is this really a "safety" issue?

Why do we use multis in the first place? Is it because continued flight is always assured after the failure of one powerplant? Not in the U.S. it isn't! Nor is it a legal, moral or corporate requirement (AFAIK on that last part). I believe that the oil companies understand and accept this. The "majors" all have aviation departments, and they do not operate in a vacuum (i.e. the U.S. aviation people talk to the U.K. aviation people). And they're not stupid. The redundancy of the second engine gives us some comfort, but does not guarantee that the aircraft won't end up in the water.

To that end, all twin-engine aircraft in the GOM are equipped with emergency flotation gear and have life rafts installed. All passengers must wear PFD's at all times. About 99.9% of all rigs/platforms in the GOM do not even fall under the US FAA's definition of "extended overwater flight" although that is changing as exploration heads deeper.

Except for a very short period between January and early March, the Gulf Of Mexico itself is surviveably warm. The weather in the Gulf is fairly benign most of the time. Many aircraft- both singles and twins- have been successfully ditched with no injury or loss of life.

Without the ability to continue flight on only one engine from every flight regime, a twin is going into the water if one quits at an inopportune time. But even if it can continue flight, without enough fuel to fly back to the beach a twin may still go in the water after an engine failure if the crew does not feel like putting it on a rig/platform.

Statistically, the FAA and insurance companies must have extensive experience with twin-engine operations in the GOM. I wonder just how many engine-failures the twins have? What's the calculated risk? And just how far do we go to insulate ourselves or guard against every possible failure mode in a helicopter?

I guess it gets back to: Is this unacceptable? Is this unsafe? We'd like to make the issue as black/white as possible, but I think it's not that simple. Operators in the U.K. do things one way. Operators in the U.S. do things differently. But before coming to any firm conclusion as to which way is better, I think some questions need to be asked...and answered.

P.S. As a pilot, I know which way I prefer- and that would be to guarantee that I'll be able to keep my feet dry at all times ;)

[rotordk]

PPF# said :
It's a funny thing about multi-engine aircraft. bla bla bla....Statistically, that doesn't always seem to be the case.

Proof please, cause that just doesn't make sense !

[Old Man Rotor]

Stats are Stats...................and I have had two engine problems in a twin and thats also a stat.......

Twins [Triplets] will always offer something a single can't..........engine redundancy?

However if you don't capitalise on the advantages of the Multi's, by way of Performance Limitations....then the multi will get you wet nearly as soon as the single will.

We must remember there are other Offshore fields in the world other than GOM when we discuss these topics.

Some of these are Exploration holes....320 nm out from the point of departure, and 120 nm from dry land.....try that in other than a multi.

[gulliBell]

Under the scenario described, at least if a twin can't keep you out of the water OEI then it can help you get on the water safely, and once you're safely on the water there might be the option of an extended water taxi to get you to the beach or closer to a rescue boat or offshore platform. Of course it depends on the sea state prevailing at the time, and whether your passengers have made an instinctive exit as soon as the waves start lapping at their feet, but at least it's an option available to you that you don't have in a single.

[verticalflight]

Water taxi? Does any twin with inflatable flotation have that facility?

It would take Old Man Rotor a long way to get back home, though!
:\

[Devil 49]

Requiring an operational profile that guaranteed single engine capability in most light twins would render them useless, and extinct, in the GOM. Lots of guys (including me) have exercised less than perfect options in light twins that were OEI and improved their survival probabilities-I don't want to take that chance off the table to "improve safety." Talk to a few more pilots...

The greatest hazard in the GOM is weather. Most operators allow (read allow as REQUIRE) outbound fuel loads of destination and 30 minutes, singles and twins, VFR. There's a lot of flights made with NO fuel available enroute, and a fair few made that would require a significant diversion to find a dry place to land if the weather deteriorated. This catches a few pilots every year-it's damn difficult to make yourself put a pefectly good helo in the water. Want something that WILL improve safety in the GOM? Close this hole and give the line pilot more choices.

[Bladestrike]

Rotordk, we Canucks use 50' above the deck down to 150', to one half mile. All weights to at least maintain 50 fpm climb at our MOCA (plus a staggering array of takeoff/landing charts), so the chance of going for a swim OEI is slim. As a matter of fact, lost a can last year, and managed to keep my feet dry! Pretty much the same fuel carried as Old Man Rotor pointed out, and always a land based alternate.

[rotordk]

Thought you guys had ARA's with 1/4 mile MAP for some locations !!
Or am I mistaken ?

[Bladestrike]

You'd be mistaken. I'm not saying its never been done, just you'd be breaking the rules. I don't know of anyone that goes closer than 1/2. There's still rumours of guys crawling up legs and that sort of nonsense but I've never seen it done.

Speaking of twins vs. singles, I've had a 47 and a 206 quit on me, had another 206 that I had to get to the ground NOW, had a 222 roll one back to idle, had to shut down one can on a 76, and had the aforementioned failure on a 61 last year. I'll take a twin please! Of course, the water is a little warmer in the GOM compared to the North Atlantic.

[rotordk]

Still a difference though...You guys have 1/2, JAR gives 3/4 mile.
And please don't ever tell people your EMS story about preborns while people are drinking....EVER !! That one is still nagging me !

[Bladestrike]

Yea, I think its best to keep that rather horrific evening to myself, I sometimes forget how it can bother people. Ten years of EMS in that enviroment and you tend to get a tad jaded.

Next time we hook up for brews I'll have some stories that'll put a smile on your face.........

[Nigel Osborn]

I'm surprised to read that some countries and/or oil companies don't require helicopters, single, twin or triple, to carry sufficient fuel to reach a land base in the event a rig landing can not be made for what ever reason. I know some twins are approved for single engine landings on some rigs but not too many.
In Australia back in 1968 we used to operate two Bell 206A ( i.e C18 ) to the Sedco 135G some 154nm off the beach which was 100nm down the coast from Darwin. We had fuel drums near the beach to top up before heading out to sea and carried fuel to the rig plus 30 mins, i.e. not enough for a round trip. Eventually Murphys Law prevailed and when the 206 was past PNR, the rig had a gas leak and went up in flames and was abandoned. The second 206 told the outbound one to go back to the beach. The fuel dump was about 2 nms inland but as the fuel gauge had sat on E for a while, he decided to land on the beach and not risk the extra 2 nms. On touching down the engine stopped.
Since then CASA changed the requirement to always have round trip fuel for all types of helicopters and having flown offshore in Australia, Thailand, India, Arabian Gulf, North Sea, Phillipnes, China and Malaysia, all the companies I have worked for require round trip fuel. Also I find it hard to believe that any twin when in the cruise would have to ditch if it loses an engine. Must be very over weight or the second engine stuffed!:O

[Red Wine]

In Oz, the MAP is 3/4 at 250 Rad Alt at Vy.

We can also use the "Enroute Descent" down to 500 Rad Alt ......and considering the weather here, that would normally get you visual. If it does'nt then its probably fog, and apart from Bass Strait [Southern Oil Field] fog is as rare as hens teeth in Aussie Offshore. :D

[Old Man Rotor]

Old Fella we miss your lopsided views on life....................

Oh your at Church I see.............

Well salvation at last.

[PPRUNE FAN#1]

OMR asked where I am:Old Fella we miss your lopsided views on life....................

Oh your at Church I see.............

Well salvation at last.Well as a matter of fact I do go to church on Sunday. But I have already commented on this subject, what more is there to say?

Either you believe that multi-engine helis should always have the capability to continue flying OEI or you don't.

And if you do, does that belief extend down to Twinstars, BO105s and the 222-series?

Or just the more "serious" IFR aircraft?

Personally, I do not see a controlled landing to the water to be anything other than an emergency. It's not a "crash," nor does it need to be a catastrophe. Of course I'd prefer it didn't happen to me, but things don't always go the way I fantasize they should be.

Now, Old Man Rotor, aside from quoting the specific rules in your specific operation without allowing that there are other possibilities that are considered "safe," would you care to actually offer us your opinion of the entire issue? Or are you just the world's oldest and more boring troll?

[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]

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:ok: :sad:

[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]

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, :eek: OffshoreIgor :eek:

[Old Man Rotor]

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]

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]

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!

[rotordk]

zalt
read JAR-OPS 3.295 from part E
:-)

[Decks]

While I understand all these inputs I spent many days out to 100nm and sometimes more in 206Ls with P*I... when I flew the 412 out there I always felt that on a benign day I would be better off doing a controlled ditching than a potentially very hazardous landing on any deck...regardless of its size.
Maybe Im naive but I still wonder about our incessant obsession with S/E performance. The one major thing I like about flying in Europe is the HUMS.... Now Im not an expert but there are so many things that can and do go wrong throughout the drive system that focusing in the engine...something we perceive we can control.. is a far too simple a way of looking at things.

[The Auditor]

Nice point about HUMS or IHUMS............

They will measure vibration essentially...........what blade failure or rotor failure gives a vibration before failure........???

HUMS may tell you when a Generator bearing MAY fail......great, I have two or three of them and a battery. Or perhaps numerous drive shaft couplings that the engineers already know about.

But I have only one set of blades............[I assume the IHUMS on the S76 last year in the North Sea suggested ZERO prior to dispatch?].......

Many things will put you in the water............and IHUMS KNOWS NOTHING about some of them.

Its only another tool....

[chopperman]

The Auditor,
IHUMS does, however, know about MGB's (and you only have one of those), it picked one out for me just before I was due to fly it. Gearbox failures I can do without, so it definately gets my vote.

Fly safely,

[MaxNg]

GlsNightpilot

You said

"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".

Why would you set up a diferent approach angle when practising a OEI approach ?, wouldn't you be better placed making your normal approach this steep in case of a real engine failure.

There are to many shallow approaches flown to decks and its only due to better engineering and design that this is allowed to continue unchecked.

Decks

The IHUMS on the AS332 L2 failed to detect any onset of the bearing failure on the engine that failed instantly last saturday dropping the compressor onto the stator and triggering fire bells and whistle,s along with Pwr and Diff Ng warnings luckily this happened in the cruise and the crew responded correctly to the situation. well done to them

Chopperman

Never used a offshore alternate myself as the L2 doesn't have a single engine perf chart, but I was allways curious as to why we didn,t lower the u/c prior to PNR and accept the extra fuel penalty (+6%fuel flow) over the chance of metal to metal landing or ditching.




:uhoh:

[The Auditor]

Ok............

Playing the Devils Advocate now............

Sure the HUMS may have identified a MGB problem................was that before or after the Chip Plugs did their job???.

Once had a HUMS warning that a Generator was troublesome............44 hours later we changed it when engineering "felt" a problem.

Great.....

Don't get me wrong......................the system is a good aid to safer flight..................but don't put all your eggs in the computer system of IHUMS.

[zalt]

rotordk: Ta!

The Auditor: I agree that HUMS is not too good on rotor blade failures because as you say they work on vibrations. Blade cracks, until the last few minutes tend to expand on start-up, then the loads in the blade stop vibration until the end of the flight.

chopperman hits the nail on the head with MGBs (and other GBs, shafts etc). You only get one of each and there is almost no way of inspecting inside gearboxes in service. Mag plus are only good at picking up wear debris. Fatigue cracks don't produce debris but they do give vibrations so HUMS works like a dream.

Remember the lessons from the fatal HKS accident in 97 - if they had fixed the accelerometer the failure would have been averted - 12 lives saved. What we don't know is how many accidents have been avoided by HUMS.

Have a look at rotorcraft page on http://www.jaa.nl/certification/certification.html to see the JAA policy.

[Lu Zuckerman]

HUMS monitors against an established standard for vibration and temperature in lubricated gearboxes. However long before the vibration or temperature reach and exceed this established standard there is a precursor to those conditions. That is the increase in wear metals in the oil. Wear metals are not to be confused with metallic chips. The buildup of wear metals can be detected through the use of a consistent SOAP analysis program, SOAP or Spectrometric Oil Analysis Program monitors the rate of increase of wear metals in the oil and compares this with new oil which is the standard. The analysis program can determine the types of wear metals (steel, bronze, aluminum, magnesium or any other internal working parts bathed in the oil). The only drawback in the use of SOAP is frequent oil changes.

:ooh:

[zalt]

Lu: SOAP has had a long history or poor results in the North Sea. On the S61 the Sikorsky limits are so high that unless someone has angle ground your gears you'll never get a indication. And just like mag plus have minimal capability against fatigue failures (until really late in the day).

One view of the problem is that civil flying is normally so intensive (a good AS332L2 operation can be close to 2000FH/pa), the time to get results means you are always chasing your tail.

Out in more remote areas (and I don't mean Shetland!) the problems getting the samples back to a lab is even worse.

Another view is all you get back is a mish mash of data that rarely points to a single defect (as opposed to general wear) until the whole thing goes bang. As most gears are made of the same material and all wear its no wonder SOAP rarely provides the insight it does in gas turbines wee the material mix.

At least HUMS can be processed on-site in minutes and can point to the shaft the vibrations are coming from. SOAP was trialled back-back with HUMS in the CAA trials in the late 80s - with HUMS coming out by far and a way superior.

The Canadians have spent a lot of money developing an on-line debris monitor (OilScan ??) which apparently could complement HUMS well.

Don't understand why oil changes are more frequent with SOAP though - surely you don't want to change your oil so you can build up a trend??

Also Lu: IHUMS, NSHUMS, 101AMS and the two EC systems do not measure oil temperatures, these remain standard aircraft instrumentation.

[GLSNightPilot]

Max, you make a good point. My normal approaches are pretty much what we're taught for a single-engine approach. However, many fly a flatter normal approach, for whatever reason, so they would need to steepen it for a single-engine approach.

[Lu Zuckerman]

To: Zalt

SOAP does not contribute to frequent oil changes. The point I was trying to make was that periodic oil
changes mean that you must start over because you are throwing the baby out with the bath water the baby being the wear metals.

On the EH-101 as it was originally designed had a HUMS system built into it which monitored bearing temperature, gear vibration patterns, oil temps and vibratory frequencies at various points on the helicopter.

Regarding the debris monitor being developed by the Canadians Douglas had incorporated a similar system on the original DC-10. This was a part of a precursor to HUMS that was mounted on the aircraft when it originally rolled out in 1968-69. The purpose of the system was to monitor the health of the hydraulics system and down load any problems to a landline in middle America. When the plane landed for turn around the repair crew would be waiting with the replacement parts and the tools necessary to fix the problem. There were so many problems that the system was removed saving a considerable amount of weight.

Regarding fatigue failure without the presence of chips an Italian navy S-61 suffered a fatigue failure in one of its free wheeling units and within twenty seconds the pilot made a safe autorotation into the water. In those twenty seconds the parts of the free wheeling unit were either worn down or welded together. No warning. No chips and no vibration. Most likely HUMS could not have detected it.


:confused:

[offshoreigor]

Wow!

Is this discussion for real? Am I really hearing Pilots actually considering OEI Landings on a rig?

Someone actually said it is the accepted practice in the North Sea to use another rig as an alternate providing you arrive at OEI performance?

EXCUSE ME that means you dont have enough fuel to reach the beach. And if you think your going to make a successful OEI landing on the rig, GOOD LUCK TO YA. (Unless ofcourse its an aircraft carrier your landing on) BUT I DONT THINK THATS THE CASE, IS IT? My God, what company are you working for anyway?

Have we worked our a$$es off for the past 20+ years to make things better, only to see this kind of "Get the job done at any cost" attitude re-surface?

There's nothing wrong with getting the job done. Just do it safely and that means holding a shore-based OEI alternate. I dont think JAR allows for any less, nor CAA.

Just my two cents worth.

Cheers, :eek: OffshorIgor :eek:

[Old Man Rotor]

There have been occasions where AS332 have been approved to hold offshore facilities as OEI alternates.......but under very strict controls. And also because of the unique OEI capacity of this helicopter.

[I think the B214ST may have also been approved...not sure on this one]

GLSNightPilot works for a company which allows Mediums to hold platforms as OEI alternates.

The wisdom of undertaking such an activity has certainly be questioned by most [if not all] other pilots outside the GOM.

Each to their own standards I guess.........

[SASless]

The GOM continues to suffer from a lack of oversight by the FAA...they continue to ignore that segment of the aviation industry. One quarter of a million passengers per week moved....pilots making non-precision approaches to precision approach minima....then circling to land......poor weather reporting....terrible comms with ATC (if at all)....no radar traffic separation....flying mediums at MAUW all the time....no onshore diversion fuel....Cat A ignored....."Wunderbar!" One operator is having or has just had the worst year for accidents and the Corporate Safety Officer continues to draw his bonus and exercise his stock options.....what a deal !

[Old Man Rotor]

Quarter of a million a week????....250,000???

Thats:

62,500 B206b flights [at least 2 done by Poo Prawn]
20,833 S76 flights
17,857 B412 flights
13,888 AS332 flights
555 B747-400 flights!!!!

Of the 2000 platforms,,,thats an average crewchange of 125 folk/week/platform???

I'll do my 4 a week and enjoy.

[SASless]

One must also count the inter-field hops...taking the Beaudreu's to and from lunch....well checking....fetching tools....etc.....that is sorties multiplied by occupants I am sure.....but an impressive number notwithstanding. Well checkers are doing a hundred sectors per day in some fields....that adds up over the week....and by the sheer number of fields in the GOM. Just using some numbers quoted by an industry insider.

[GLSNightPilot]

Things have slowed down considerably, but there's still a lot of activity. I used to do 120+ takeoffs every day, guaranteed. I didn't go far, but I did it often. There are still fields where you do 50 or better every day, some more. The average medium makes probably 3 trips/day, and more isn't unusual. There are very few places where you do one trip out, come back, & then have a beer. The limit is usually allowable flight time, 10 hrs/day with a crew of 2, or duty time, which is 14 hours. Timing out in either category is common. Also, keep in mind that there are probably close to 500 helicopters flying out there. PHI alone has close to 200 in the GOM.

[zalt]

OGP offshore figures are:
3.1mn pax in GoM in 2001 (average flight time 18 mins) i.e. 60000 per week
2.4mn pax in North Sea in 2001 (average flight time 40 mins)
3.4mn pax in ROW for oil industry in 2001 (average flight time 18 mins)

[Red Wine]

Extracted from the May 2003 issue of Time Magazine [Oz Edition].....

The US had [has] 508,000 active Oil Wells producing an average of 17 barrels / well /day.

Iraq had [has] 250 active Oil Wells producing an average of 13,700 barrels / well / day.

[Stats are a tad old....but still proportional]

No wonder there are different rules for the GOM.....or those wells may not be viable. [I accept some of those are "Rocking Horse" wells belonging to the Hillbillies in the backblocks of Texas]

Tell me George......truthfully now......Oil was not really on the agenda...was it??

[GLSNightPilot]

The wells offshore produce much more than many of the onshore wells, or they wouldn't be viable at all. The majority of the offshore wells in the GOM produce gas, not oil, especially in the shallow water. But your main point is well taken - there is a reason we invaded Iraq & not North Korea. Not much profit to be made from North Korea.

[JimL]

SASless - regarding FAA oversight.

That's an impressive number of complaints - what exactly do you want done about it?

[Blue Rotor Ronin]

Chaps.... it's very simple better HUMS and HOMP than nothing at all. Plus if you've only got one donk, fly it like a single hot n high pinnacle landing. It aint rocket science.:ok:

[squib66]

With all their apparent emphasis on global standards, would it be right to assume that Air Logistics / Bristow GOMBU are now operating their mediums and heavies to the same procedures as Bristow BUs in other parts of the world on issues like diversion fuel?

[Chopter]

No...At least not yet, and I would imagine that it would be a while. the OPS manual between Bristow eastern hemisphere and western hemisphere still differs quite a bit..