DECUFAULT - I think there is a fault in your decu - have you been taking the same pills as Nick?

Dave - thanks for the appreciation - how is life after Sikorsky?

HC

It's really great asking Heliconfuser for S92 technical data, like asking George Bush for political advice!

HC has said:

• That it is not worth having EGPWS since AVAD should work.
• Having a fully approved anti-icing system is a hazard.
• The size of the windows is more important than if your passengers are sitting on non-crashworthy fuel tanks

He has bet his career on the fitness and superiority of the 225 against the 92, so you can expect his demeaning comments to continue. ANYONE who thinks more safety kit increases the flight hazard is a hazard themselves, and does a disservice to the industry they pretend to support. It is thankful that his importance in the Bristow system is now just above the guy who services the windshield washer fluid.

If HC said it was 2PM and my watch agreed, I'd throw my watch away.

Nick, careful with your comparisons!
The guy who services the washer fluid is the highly trained, long serving, low paid, Licensed/Unlicensed Engineer who keeps all these flying machines in the air, French and American!! :=

It's really great asking Nick for S92 technical data, like asking George Bush for political advice, only with added hysteria and spin.
HC

Helicomparator vs NickLappos - I'm intrigued (and entertained!)

I do wonder at all this dick swinging. I have some questions:
Is a more reliable helicopter safer than a less reliable one?
(Yes crashworthy seats would be nice if the company would pay for them, but I'd rather be strapped to something that isn't going to crash in the first place)
Why does it seem that modern helicopters are less reliable than the older ones?
So are new helicopters safer than old ones?
And which is the most reliable machine on the North Sea at the moment?

I anticipate Nick hunting out his photo of a '60s automobile and asking if we think that is safe. I would pull out a photo of Mr Boeing's biggest, which is still selling (and safe).

My final question: Are the main men in Sikorsky not a little red faced at the success of a certain Mr Carson?

Droopystop,

Some answers to your apt questions:

1) Reliability is very important, but usually it is used in the economic sense, where a lost trip is an economic crusher for the company. Among helo systems, reliability is certainly a safety issue, since the triggering of failures is sometimes how accidents happen.

2) Yes, you should only strap yourself to a helo that never crashes. When you find one, let me know! It would be nice if helos didn't crash, then we could have you sit on a cement block, but the dream of a crashless helo is the dream of one without people in the loop, since about 70% of all accidents are not the helo's fault, but rather the crew's. For those cases, if nothing else, pray that your boss is wise enough to buy a modern helo with the latest safety features.

3) Modern helos are newer, and do not have the 40 years of lessons learned, part-by-part, to make them as reliable as the older ones. The original S61 had its great share of problems, but back then I was a junior pilot and you were a zygote, so you think those old helos came out of the box working like charms. The story of how the 61 became a classic is one that left more than a few machines crumpled, and many, many parts removed by tired maintenance crews. You just don't know that, so it seems in your view that "new" and "safe" are the enemy of reliability.

4) Old "reliable" or new "safety equipped" - The decision isn't yours, anyway, nor is it heliconfuser's, thank God. The safety gurus in the oil companies, in their great wisdom, help set the contract terms. The decision is up to the customers who actually pay for the service, and they have voted overwhelmingly for the newest safety features, as they are sick of flying in less safe helos with poorer margins, where a scratch can make an accident happen, and where a pilot error can take the machine and its occupants apart. The oil companies are sick of helos with fuel in the floors below the passenger seats, and with seats that break their worker's backs. They want helos with these safety features, and their contract requirements tell us so.

5) Mr. Boeing knows what I am saying, his company (and Airbus) are making millions by selling safer, more comfortable airplanes than the old ones that are being passed off the third-run air services. The 380 and the 787 are both heads and shoulders above the 707/747/300 and the like in passenger safety, since their regulations have evolved just as helo regs have.

I do detect some snide wish to show that your 1960 Chevy is a better car, with its metal dashboard, cotton ply tires, lack of seat belts, single brake system, and the structural design that assures that you eat the engine in a crash. Put your family in that clunker, if you wish, but I have my daughters ride in a modern car with dual anti-lock brakes, strengthened passenger cage, 8 air bags and steel belted tires.

Blimey Nick, those pills are at last having the right effect. Worryingly, I find myself mostly in agreement with what you say (personal insults aside). But I try to look at the big picture whereas you are stuck in the minutia of your personal achievements.

Safety is very important but designing the overall safest option is not always the most obvious option. Take your beloved RIPS, just how exactly does it improve safety? Yes, it makes the pilot's life a bit easier but is it safer? I would say not because without it, you know exactly where you are. With it, you are tempted to go places you would otherwise not go, despite the trap of the single point (and fairly common) failures, taking you from fat, dumb, & happy, to scared in the blink of a warning light.

I agree it doesn't represent much of a safety hazard in the right hands, but as you point out its pilot error that generally is the cause of the problem and the wrong hands its just another vehicle for human error to manifest itself. It would only be safer if it was totally reliable, and we all know its far from that.
And priorities in safety are role-specific. Fuel under the floor has not been an issue for offshore ops, whereas cabin escapability has. Whilst the 92 represents a safety improvement in the former (no doubt relevant if your ops are mostly over land) its a retrograde step in the latter.

But as Droopy rightly implies, safety is not just about crashworthiness. In fact crashworthiness is the part you have to design when you have admitted defeat, because as DS says its far better to design the aircraft with pilot-tolerant features, than the aircraft that is prone to "pilot error" but which might not kill all aboard in the crunch.

The 92 does have good crashworthy credentials as required by the JAR/FAR 29 amendment valid on certification but in my opinion its well behind the French offering when it comes to pilot-tolerance, the man-machine interface or whatever you want to call it. That's why I'd rather fly my machine, even though it does have fuel under the floor.

Regarding the question about the most reliable fleet on the N Sea, that has to be the AS332L. And therefore I would say that its probably the safest. But there is the dreaded bathtub curve and the 332L is starting to creep up the gentle slope at the end of its life, whilst the 225 and 92 are still decending the steep slope at the start of their lives.

If the oil companies stuck with the known technology (AS332L) then its reliability would gradually decrease and there would be an accident. So you have to suffer the pain of initial reliability (safety) problems with new types.

You cannot just stand still.

HC

Helicomp - in the last crash in UK (Morecambe Bay) , the size of the windows was wholly irrelevant - it was the crash (and possibly lack of helmets) that killed the pax. Crashworthy is good.

Yes, there are lots of helicopters that can fly into the sea at 120 kts in a diving turn and, with suitable seatbelts and the pax wearing helmets, all is well!

Crab, as 212 says you (as usual) miss the point. No amount of crashworthiness (with currently available technology), nor RIPS nor external fuel, would have helped with that one. What could perhaps have helped is a modern autopilot system where when the pilot gets into difficulty he can press the go-around button and let go, plus better training in a simulator. The S92 scores 5/10 for its autopilot system, whilst the 225 scores 9/10. On the other hand Sikorsky scores 8/10 for having a simulator at delivery, EC scores 0/10 for still having no simulator over 2 years after introduction of the 225. Take your pick!

HC

Nick, it's a minor point but the other fella is droopystop....I'm staying out of all this.

No, helicomparitor, you miss the point entirely. In fact you miss all the points,:

Point 1 = Safety is the sum of all the things we do to save the lives of our passengers, in spite of your arrogance. It is a arrogant pilot who does not fly a crashworthy helicopter because he is foolish enough to decide that he will not crash. Crashworthiness is not optional, except to pilots who decide to purposely buy older machines, less safe machines while they rationalize their decision.

Point 2 = We in the design world use reams of accident data to help guard the lives of his passengers.It is an arrogant pilot who takes the last crash he remembers, and plans his flight according to what happened. The helo in that Morecambe Bay crash has old non-crashworthiness. It is arguable that a 120K sea impact with a fully compliant modern machine could be survivable, many Sea Hawk and Black Hawk crews have escaped injuries in such impacts, in spite of arrogant pilot's calm, ignorant disbelief. The Difference in crashworthiness between the soft, crumply fuselage of the older helicopters and the crashworthy fuselage of a modern helicopter is the difference between approximately the 20th percentile crash and the 95th percentile crash. The arrogant pilot doesn't know this, he thinks all crashes are equal. His passengers die in agony when his mistake causes an otherwise survivable crash.

Point 3 = Safety does not stop at the start of the crash sequence, yet the arrogant pilot bolts his passengers to the top of a fuel tank, in spite of the reams of data that shows that post crash fires are much more likely in such an old-fashioned design. The entire General staff of one mid-east country perished in such a fire in such a poorly designed helicopter (his pet helicopter). Fire protection is important enough that the newest design regulations require belly fuel to meet extra design penalties if the manufacturer is foolish enough to put the fuel there.

Point 3 = Safety is enhanced by extra gear that widens operational capability. The arrogant pilot actually takes it as a virtue that his helicopter, if subjected to icing at 1.0 g/M3, will crash. That is a good thing, and ice protection is a bad thing.

Point 4 = EGPWS, a colored terrain hazard map and altitude warning system, with voice warning, vastly reduces the hazard of CFIT, but arrogant pilot doesn't like itbecause his pet helicopter doesn't offer it.

Point 5 = The arrogant pilot ignores newest data, argues with national experts who upgrade requirements, and belittles safety findings that make these requirements, because he, God-like in his depth, knows much more than those silly oil company experts, safety experts and design engineers. He guides newbies in his "wisdom", a pied piper of stupidity.

Point 6 = The newer helos of arrogant pilot's pet helicopter company incorporate the design virtues that he belittles. He is the apologist who must make excuses for their rear-guard products, explain why the mediocre is better, and sacrifice the truth in the process.


Droopy, I fixed it, thanks.

Nick

Good use of colour (color?) but too much repetition of "arrogant" - I made it a count of 9 plus one of "arrogance".

Hey-ho here goes

Point 1 - Crashworthiness is a good thing but not crashing in the first place is also important

Point 2 - In the case of the Morecambe Bay crash, your pet S92 would probably have broken up but even if not, the pax would have been disabled by the impact and would not have got out through the minimum-sized windows. Of the pax that died in Morecambe Bay, how many of them had unsurviveable injuries and for how many was drowning the primary cause of death?

Point 3 - Like I said, safety priorities are role specific and for offshore ops, fuel under the floor has never been an issue. Escapability is the primary issue.

Point 4 - EGPWS offshore does not give you a coloured terrain hazard map because there is no terrain (Doh again!), it has a voice warning system that is inferior to AVAD, has an incomplete and hence misleading obstacle database, and you are wrong, the EC225 does offer EGPWS but we declined to take it because in v24 guise its less safe than AVAD for offshore ops. In v26 guise I hope it will be better and we are planning to take it.

Point 5 - Not sure if this pilot is supposed to be me (yeah, right!) but if so I am well aligned with the oil company priorities - Its Sikorsky that are not. That's why, for instance, they don't consider cabin escape to be important, and don't bother with other things like HOMP (not invented here!), and have ridiculous and unsafe proposed profiles for PC2E.

Point 6 - You are rambling to the point that I am not sure what you are saying. Have another pill and do wipe that drool from your mouth please!

HC

Let me waste a bit of time explaining the most telling points:

Point 6 means that all the items that you belittle are incorporated into the latest products from EC, and are bragged about in EC's literature. You have become the unfortunate shill for the older technology, while your pet company has left your ancient views in the dust. The proof of your incorrect judgment is contained in the newer designs that EC offers.

Your ignorance is also pointed out in Point 2, where you foolishly believe that if the crash impact had disabled the victims in a 365N the it would have in any other helo. Simply wrong. The G forces that rip the seats from the weak floors and toss them around the cabin of a 365 or 225 are a paltry 2 to 6 G's. Therefore the unfortunates who picked your captaincy get bashed around the cabin, while the seats in an S92 or A-139 are still solidly in place as the structural cage of the helo (which does not allow any deformation up to 20G's) protects them. Thus, in a proper helicopter, there exists opportunity to allow pax to wait till the crash stops, release their belts and escape. Your mistaken belief that the condition of the unfortunates in the 365 offers any clues as to their survival in a stronger, safer machine shows how unequipped you are to understand the issues that you try to judge.

Regarding whose points are the more accepted, care to publish the number of 225's that have been ordered anywhere in the civil world, and those delivered?

I could go on with the other points, but it bores me, frankly, and I think that about now you are looking an awful lot like a small furry dog when wet.

Nick

You always have to spoil your point with inaccuracies. Shame! You continue to forget (though are frequently reminded) that the seats in "my" helicopter meet the latest certification requirements just as they do in "yours". And whilst it helps to have a strong fuselage, ultimately the human body is weak and would be damaged by flying into the sea at 120 knots in a dive regardless of whether or not the structure takes the load. But my point (admitedly not based on much evidence) was that it was probably not the structural failures nor g loading that killed them, rather it rendered them incapacitated and they subsequently drowned.

But lets be quite clear - you are claiming that had the same accident occurred to an S92, the pax would all have survived?

I am in possession of neither the S92 sales figures nor the 225s (though I know the waiting list for a 225 is well over 18 months) but here in the UK there are 6 EC225 in service and 2 S92s right now, and to the best of my knowledge there will be 12 EC225 in service by end 2008 and 8 S92s, so I am not sure what your point is?

Escpecially considering that the S92 is so much cheaper than the 225. Fortunately most oil companies recognise a quality product when they see it, rather than the cheap and (not very) cheerful one, and are prepared to pay the extra.

I could go on with the other points, but it bores me, frankly, and its walkies time, but I think that about now you are looking an awful lot like an old bull sea lion who is wallowing along over land when really he is suited to the ocean, and making a lot of grunting noises about it.

(Apologies to the Seal Lion Preservation Society)

HC

ps is this thread drift or what?

SP - perhaps you should give us both a good slapping?

Heliconfuser,
Again, your ignorance shows itself. The seats on the 225 meet the old standard, and are bolted to the floor against the old standard, so they can come off in 6 g's of crash loads. As can the fuel below the floor.

Regarding the 365 crash, you might brush up on your reading skills. You foolishly try to prove the crash was NOT survivable by showing that they didn't survive. I pointed out that the flimsy seats in the 365 or 225 can come loose in low impact crashes, and that the seats in a 139 or 92 would stay in place and protect the occupants in much higher crashes. It would be possible to tell if it was survivable in a modern helo, that is a question yet to be answered. What the crash PROVES is that it was UNSURVIVABLE in seats like those on the 365 or 225.

You gerrymander sales numbers to suit. I count that Bristow will have 7 92's by next spring, the SAR service will have 4, there are 6 in Norway now, and the count goes on. If we count the helos in your bathtub (one presumes 0), the sales look similar, don't they, but if we count the actual units delivered, the vast popularity of the 92 over the 225 comes clear.

No answer from you as to why all the truly new Eurocopter helos have the safety features that you say are not necessary. Cat got your brain?

No, the seats in our EC225s are certified to the current standard, with strengthened floor to boot. If you knew anything about certification you would know that grandfathering only works when you don't significantly change the design. Our 225s have an all-new crashworthy floor with all-new crashworthy stroking seats that meet the current regulations. As I have said many times before...click...as I have said many times before...

You said
which is first of all incorrect as the 365 and 225 seats are not certified to the same standard (see above) but in any case, what's your point? Did we need that to be proven? It would be more interesting to prove that the new seats fitted to the S92 and 225 would have made a difference, though I doubt that it would.

Ref the sales I think I mentioned that I was talking about the UK. Last time I looked Norway was not in the UK (but I realise that from the other side of the Atlantic it all looks much the same, and I appreciate that the World Geography classes at your school didn't cover anything beyond the USA - just like their other world series ).

I was also talking about oil and gas, though I agree I didn't make that clear. So I will give you the extra S92s for SAR. My current figures were correct, and as far as I know Bristow UK will have 6 S92s by next spring. So that makes it 12-all so hardly the runaway difference you are implying. If the oil companies and Sikorsky are such buddies with only HC as the enemy, why is it that it isn't 24 - 0 in favour of the S92 especially considering the oil companies have to pay so much more for the 225?

Not quite sure which safety features that EC are offering that i say are not necessary, and the cat ran off when I shook my wet fur. Well EGPWS for offshore perhaps but the others are good - TCAS, 30 min dry running time (remember that one - that's the one that the S92 failed to achieve), PC2E data, automatic (as in "don't touch the controls!") fly-away on 1 engine (that's another one the S92 can't quite do), crashworthy seats, HOMP (Oh yes, another one the S92 doesn't do), Intrinsic N2 overspeed protection (rather than allowing the turbine disc to burst but hoping the shielding works a la S92).

Some give greater safety contribution than others, that balance is role specific as I have said. I would not consider rotor de-icing to be a safety features. Its a feature that allows operations on days when you otherwise would not launch. That's not a safety feature, its a commercial expedient and offered by EC to those for whom its important - not N Sea-ites (unless there is no limited icing clearance), but no doubt for example SARites. Its most certainly not a new feature. The AS332L and L2 have offered rotor de-icing from a time when the S92 was just a twinkle in your eye.

Woof!, time to find a lamp post...

HC

A picture (film) is worth a thousand words.


Glidden Doman hosted the American Helicopter Society dinner meeting on Feb. 7, 1953. Igor Sikorsky attended the meeting and Flettner was the guest speaker. A film of the Flettner Fl-282 was shown. Mr. Doman said that when the lights came on he look over at Igor. He said that Igor's face showed his shock at seeing the technology in the superior Flettner craft; a craft that had been in production and in use before his.

However, in 1967 an advertisement for the S-62 helicopter said; "Leonardo had the right idea, but it took Igor Sikorsky and his Connecticut craftsmen to build a workable helicopter".

That promotional hype was four decades ago.

Nick, perhaps you would like to take us back three more decades. Would you comment on the truth or fiction regarding Sikorsky's use of a slow-motion film to promote his early single rotor helicopter?

Interestingly, Charles Lumsden has stated that in 1938; "[Young] Impressed by Igor Sikorsky's film, he concentrates on main rotor/antitorque tail rotor configurations."


Has a litany of misinformation or perhaps disinformation resulted in the state of today's rotorcraft?

Could you expand on this comparison? What goes into your rating? I would love to hear about the differences between the two. Thanks.

Dave thank heaven you changed the subject!

But do you really think a film changed the course of rotor craft history? I think it was a B-17 raid....

HC,

I shudder to think you might actually believe what you are saying.....

As I recall from my youth....the MET Forecasts for the North Sea on the odd occasion contained flawed data regarding icing....and did sometimes make life a bit interesting as rotor de-icing on commercial helicopters in those days was something we talked about over an ambient temperature beer but never saw on the aircraft.

Has the MET's crystal ball gazers improved to the extent that icing never occurs unless forecast?

Or...perhaps....there is a surplus of hot air that can be diverted to the rotor system in times of unscheduled need?

I would assume in the extreme....today's backup system is to seek warmer air just above the oggin if it can be found just as we did in those long ago years.

Nick,Naughty, naughty. You shouldn't answer a question with a question. :)


P.S. My lawyer has advised that a positive answer to your question might be construed as libel and a negative answer might be construed as nonsensical.
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Nick,
I must say that my tongue was in cheek when refering to a helicopter that doesn't crash. I am also not so naive to believe that old helicopters weren't without their teething problems. But it seems that lessons are not always learnt.

Would I be right to think that where old helicopters were designed with a slide rule and a bigger safety factor, the new ones are designed by computer and a lower safety factor? If so, why haven't helicopter manufacturers recognised that a small increase in safety factor for components might reduce costly re engineering at a later date? I am thinking of one or two specific cases here relating to a new design and of course the constant battle with airframe cracking.

I don't believe that modern analysis tools can model (with sufficient accuracy) the myriad of load cases that each component on a helicopter will see.

Also I don't believe that the oil companies are a) as bothered about safety as they make out and b) know as much about helicopters as they think. Politics (and personalities) have as much if not more to do with helicopter choice than technology, safety and reliability.

Well said, Droopystop! :D:D

bondu

HeliComparator said For the benefit of some of us that know less than you both have forgotten would you care to comment on these statements Nick?

Also sorry to be ignorant but what is PC2E?

Greetings,

Finalchecksplease

Droopystop;

I am sure that from the moment of design inception of a new aircraft or component, a fair amount of time passes. When the concept is at a point where it must be pegged before going to production, I would presume that many technological advances have been made known. The point is, that for the allocated budget of the design, will those advances be incorporated now or kept for a future design, maybe incorporated into after market production, possibly offered as an option, or whatever.

No matter how concious we are of the aviation world and its desire for safety, the harsh truth is that safety is dollars. A product will go to market with a sales estimate based on the thoroughness of the manufacturers sales team. That is why he decided to spend the money in the first place, he thought the design would produce a profit.

Then again, the design is pegged and the unit goes into production and a whole new world of tech problems are encountered. Look at the A380 problem with different software being utilised by the different manufacturers and the resultant delays and cost overruns this caused.

I am sure that when design improvements are found even during the design stage, they are seriously considered for incorporation at this time vs the investment or would they be better utilised downstream when the market may be much brighter. Possible even utilised in after market production to enhance sales.

I sometimes wonder if it is far removed from the automobile production. If you design the perfect unit, where will the future sales be after everybody owns one of these perfect units.

Regards

carholme

I feel a long post coming on so I will split into two and answer SAS and finalchecksplease first - cos that's easier!

SAS, I agree that the forecasting of icing is not particularly accurate but that does not really matter. If we are going to depart and fly at sub-zero temperatures, if by day I can avoid scattered clouds. If by night or where the cloud is unavoidable I will ensure that I have my "warm" band 1000' amsl and below. That is very predictable as its related to sea temperature, which only changes very very slowly. So if light icing is forecast but it becomes more than my aircraft's limited icing clearance can accept, I just have to descend into the warm band. Its a nuisance and reduces com range etc but not really a big deal. It would be a brave person who departed without an escape route into sub-zero cloud reliant on the fact that only light icing was forecast (brave = daft!).

So I maintain that rotor deicing does not improve safety, and unless its used cautiously (with an escape route) one day it will all end in tears. The fact the the RFM does not mention the need for an escape route is negligent IMHO.

finalchecksplease - you have not been keeping up with your reading of pprune! JAR-OPS3 used to allow Performance Class 2 (PC2) over a hostile environment (N Sea) only with conditions and only until end 2009, after which PC1 would be required. PC1 offshore is not realistic so JAR-OPS3 has been modified to allow PC2E which is Performance Class 2 Enhanced. PC2 had exposure time between the takeoff /landing decision point and achieving Vtoss/landing (exposure meaning you might crash or ditch if the engine failed during this time). PC2E uses manufacturers drop down data, deck edge clearance data etc to allow mass adjustment so that the exposure time is nominally zero. So its not PC1, but its probable (not certain) that with an engine failure at any time there will be a sucessful outcome.

HC

HC,

Guilty as charged your honour, better go and swot up on pprune, thanks for your answer.
I hope that Nick can comment on the points you made about the S92 and give straight answers and not like politicians avoid the though ones.

Greetings,

Finalchecksplease

The thought has crossed my mind :p

No helicopters are perfect
 

Gentlemen
Here are but a few opinionated views on relevant issues:

All helicopters suffer from vibration levels which are unpleasant and/or unhealthy both for man and machine. The interior noise leves are too high, and subjects a pilot to a significant risk of suffering damage to his/her hearing.

The problems of the S92A is not all the bells and whistles. High vibration levels leading to all sorts of cracks is. Also, parts falling off, dual failure of the lubrication system for the main gear box gives reason for consern.

Operating in the Norwegian sector of the North Sea the confidence in the aircraft seems to have been constantly fading since the introduction.

A few weeks back one S92A developed a crack in the main gesr box during final approach. This lead to all of the oil in the main gear box being drained. Even if the manufacuter claims dry-run capability, this is not a good thing.

The customers and the passengers organisations are not overjoyed by all of this. Still, the alternative aircraft types in the market are limited to the EC225, with its cramped cabin. According to colleagues flying the EC225, it does offer a smooth flight experience.

Since the EC products also suffer from its fair share of maintenance challenges, the whole selection process comes to down to a choice between poor alternatives, none of which really would be the preferred alternative if a smooth, quiet and reliable product entered the market place.

Keep in mind that none of the manufacturers are able to deliver aircraft in sufficient numbers at present, due to increased demand for new technology. To a certain extent this leads to the operators ordering aircraft from whomever can deliver in the next 2-5 years.

The good alternative should offer:
* Good ergonomics in the cockpit and cabin
* Standup cabin like the S61/S92.
* 5 blades like the EC225
* Performance in accordance with PC1
* De-icing, just in case, even though normal operations into known icing is not a preferred option
* Digital autopilot and flight director with quick and direct control of flight path, like the AS332L2 AND EC225, not like the S92A, which is a bit mushy
* Air conditioning, separate for the cockpit and cabin
* All sorts of bells and whistles to enhance work environment and reduce work loads, as well as impress wives, girlfriends and kids
* Etc.....


Regards, Olav

That would be the AS332 Mk3, pity they scrapped the project :{ (the 225 was known internally as the Mk2 plus)

From a frequent pax perspective, a couple of thoughts, if I may? I won't comment on servicability or front-end ergonomics and whistles and bells.

Having been invited to see inside the S-92, the school-bus style seating layout looks uncomfortable. The EC aircraft seats, which in many cases are offset from adjacent seats, offer an opportunity to stretch your legs.

A stand-up cabin isn't that attractive - once we're strapped in, we won't be wandering around too much. While the EC cabin may be cramped, again we're unlikely to do much more than grab some kip or read the Daily Sport. More serious an issue is having an adjacent window large enough to double-up as an emergency exit.

Vibration levels from a five-bladed head appear to be much lower than from four blades, which is particularly important from a passenger perspective on a long sector. (I have a susceptabilty to vibes, after 1000+ hours on Lynx, and I've only recently weened myself off Brufen after 10 years, so alighting at journey's end without buzzing knees is important to me).

A/c in the cabin has never been a problem, at least in the North Sea. If we want more, or less, the request has never gone unanswered when bleed-air is available. I'm sure an efficient a/c system would be welcome in warmer climes. A new job in Oz beckons, so I may well find out soon.

We work in an environment where we are constantly considering risk v probability. Having the fuel cells under the floor doesn't appear to be an issue that gives pax cause for concern. I has to go somewhere, or we don't get home, is how most of us would see it.

Thanks for the indulgence of intruding - please continue with the entertainment.

bobsaget123

I wrote a long tome about autopilots then clicked the wrong thing and lost it all! So here goes again...

Several books could be written about this but I will address 3 areas: 1) flight path prediction, 2) power / Nr awareness, and 3) flight envelope protection / Go-around (Flyaway) mode.

1) Most autopilots, including the 332L, L2 and S92, work by detecting a deviation, and a rate of deviation, from the required flight path. So for example when engaged on ALT mode, the datum altitude is compared with the actual altitude to get an altitude error. As that error starts to increase from zero, a correction is made according to the magnitude of the error and the rate of change of that error. This means that there has to have been an error in the first place before the autopilot does anything. In other words, the autopilot waits for an error and then fixes it.

The 225 uses accelerometer data to predict the flight path and correct it before an error has developed. In the case of ALT mode it would resolve the triaxial accelerometer data (lateral, longitudinal and normal) into the earth's plane using the pitch roll and yaw data and monitor the normal (relative to the earth) acceleration. In level flight this should of course be 1g, so if it sees the g falling to 0.99 then it knows that a descent will ensue. So before the descent has even started, it can make a correction to restore 1.0g.
This flight path prediction is why, for example, a 225 engaged on ALT and IAS in straight flight can be banked to 45 degrees by the pilot, holding it for 360 deg then rolling out and, with no pilot input to fore/aft cyclic or collective, throughout the whole manoeuvre the altitude will change by no more than 10'.

This is why it can level off at a preselected altitude having climbed/descended at 2000'/min with no more than 10' overshoot, more normally zero overshoot.

And the principle also applies to lateral navigation. Using gps ground track and wind data it of course knows what heading to fly to intercept and track the localiser (it doesn't just set the heading to match the localiser course and then adjust heading in response to a deviation), but its also monitoring the accelerometers to predict the flight path, so when a lateral gust occurs it knows that its flight path will start to deviate but doesn't have to wait for an error in the flight path to develop before it makes a correction. This is why it can hold the localiser and glidepath exactly in the centre, down to DA and below, when there is a 70kt crosswind blowing over the hills at Dyce.
This is why you can come down the ILS at 165kts / 80% torque and at 500' dial up 30kts IAS. As the torque goes from 80% to 20% in a couple of seconds to deccelerate, perhaps the glidepath might move a smigin but it would be no more that 5% of the scale.

And because its fixing acceleration deviations as they occur, its a very smooth experience for pilots and pax.

225 pilots relish really crap days because they love to fly down the ILS and have it auto-level off, slow it down to 30kts IAS and trickle up the runway exactly on the centreline, beep it down to 30' or so all on the automatics. If you can't see the ground then..... Not that we ever bust the minima, but we get a cosy feeling knowing that if despite the TAFS it all turned to rats# we are fine.

The 92 will of course fly a coupled approach but only on nice smooth days.
2) Unlike the 92 autopilot, the 225 is power and rotor rpm aware. Power is a limited commodity and the 225 will give priority to vertical mode when IAS is above Vy, and to IAS mode when below Vy. This means for instance that you can select 175 kts IAS and 5000' (or whatever) and the 225 will fly along at 5000', at max continuous power minus about 2% (allowance for turbulence etc), going as fast as it can (less than 175!) without fuss.

This means for instance that when going around from an ILS on one engine, it will climb at 1000'/min, washing off airspeed to achieve the climb rate. But as the IAS reaches Vy, priority will change to maintaining Vy and now it will sacrifice climb rate. So the OEI go-around procedure is to press go-around and watch it all happen.

The 225 is also rotor rpm aware so when an engine fails, of course there is no need to touch the controls as the collective is automatically lowered (if necessary) to give 96% Nr (the optimum Nr OEI). If the daft pilot pulls the collective up too far then lets go, it just adjusts itself to give 96% Nr again. If upper modes are engaged it will raise the collective as required to give no less than 96% Nr.

Because its power-aware if (on twin engine) you exceed MCP or takeoff power (according to airspeed), as well as an audio cue, if you release the collective it will automatically gently reduce to take you out of the transient range.

The cleverness of the S92 is limited to a statement in the RFM that tells you not to demand excessive power from the autopilot, otherwise the collective will rise without limit even though the rotor rpm slows down at the AEO FADEC stop.

3) There are various clever features - here is one: You have ALT engaged on cyclic, then you reduce power to slow down, but too much. The nose is raised to maintain altitude at the expense of IAS and in some helis this could result in excessive loss of speed so that either the mode drops out or worse, you enter a tail slide! Not in the 225 - at around 65kts it flashes a warning and then automatically engages IAS on the cyclic, moving ALT to the collective and increasing power to stabilise things.

The GA (Go-around) mode is really clever, eg you are in an OGE hover, when an engine fails. Of course there is no need to touch the controls - just press GA (under your thumb on the collective) and the aircraft will transition away by selecting 10 degrees nose down, adjusting collective to maintain 96%, then as the airspeed is around Vtoss-10kts, starting to raise the nose so that it gets to the climbing attitude just as Vtoss is reached.

We use GA mode on every takeoff. Preselect the desired IAS and altitude on the ground, preset the nominated Vtoss (if its greater than the actual Vtoss) then (for an airfield takeoff) press GA at decision point (V1) and let go. GA mode will set 1000'/min on vertical speed and raise the collective to MCP, climbing at whatever IAS it can muster. Should an engine fail, of course there is no need to touch the controls as it will reset the IAS datum to Vtoss (or current airspeed if that's higher) and climb away OEI. You do have to press the FADEC stop buttons to take the power down from 30 second power to 2 minute power, and again to continuous power. Its a hard life!

Now I am going to post this quickly before I lose it again!

HC

HC,
before you find someone jumping down your throat, you will need to correct your section 2 arguments: The S-92 became 'power aware' with the introduction of AMS 3.2.

AEO (DEO as they say) it respects the MCP limits. On the other hand, you can't fly it at MCP (86% Tq) as it would shake itself to death! Most operators either fly at 70-75% Tq, or a fuel flow or, in our case, an IAS. Many still fly the cruise in 3 axis coupling, for that reason (not us of course!)

In the event of an engine failure, it will re-datum the IAS to Vy and then respect the OEI MCP limits. This is a somewhat crude method, and the significant collective lowering to decelerate from cruise power results in a guaranteed 200 ft height loss (which slowly corrects.) One consideration is that the OEI Vne is 120 kts IAS so, it couldn't simply keep the ALT as that would posssibly result in Vne being exceeded, if the failure occured in the cruise. You couldn't use 120 kts as the datum, because in the event of a failure at a lower speed, the a/c would then accelerate, probably undesirably. So, Vy it is!

What it won't do, which ECF products do, is automatically couple the collective in the event of an engine failure, when previously 3 axis coupled. So, those operators who fly '2-cue' in the cruise will have to lower the collective promptly, whereas a 225 pilot flying 3 axis coupled would simply look up from his breakfast and say "oh, an engine failed, let's just monitor Monsieur Sagem dealing with it".

It is difficult to adequately explain in words, though HC has atempted well, how much more superior the 225 auto flight systems are by comparison to the 92: not just the physical coupling but also the MMI (Man Machine Interface) aspects. They are not perfect, but by golly they're good!

Its been a busy weekend, I haven't had the time to post some rebuttal to helicomparitor's drivel. His misrepresentation of the strength and safety shortfalls of the EC225, which is basically a 332 fuselage, with all the inherent weaknesses of that fuselage. Why did the 332MKIII not get built? Because the civil authorities would not let EC build it unless they also promised to meet the latest safety features, an impossible task in a short time and with only a few francs. That doomed the MKIII, and in its stead, the lesser 225 was born.

Helicomparitor says that it "meets" seat strength, but the FAA, JAR and EASA say he is simply either lying or misinformed (I prefer misinformed, because I think HC has integrity, he just doesn't have much else.) In the next few days, I will explain each 225 shortfall in detail. For now, let it suffice that a 332 is a 332 is a 332.
You can find this type data sheet easily, just Yahoo EC-225 TCDS and it will be one of the first hits. Note it is the same data sheet as all the other Pumas, all the way back to 1965! Change the chrome, change the paint, it is still an old, old helo. Note the shortfalls are things like overall structural safety, fatigue strength, fuel tank puncture resistance. Nothing important to HC, he will never crash.


http://webpages.charter.net/nlappos/225Oldsmall.jpg

It might have helped if in the early '90s oil wasn't $10-15 per barrel, the civil market wasn't in the doldrums and the MK3 would have been competing against the soon to be released NH-90!

Nick

Perhaps someone will go through the Gulfstream product line and look at its lineage too.

212 - thanks for the correction, I flew the 92 some time ago and I am glad to see that things have improved a bit since then.

Nick - if you read my post you will see that I said "our seats" not "the seats". When the 225 was certified it was with the original seats from the 332 family - not compliant with the latest regs as you say. But shortly after that (and probably thanks to Sikorsky) EC offered a new floor and seats that are compliant with the latest regs. Yes, its an "option" but an option that is standard for the offshore oil & gas support configuration and built into the price, and fitted to all the aircraft operating in the oil and gas sector both now and in the foreseeable future.

HC