So where is AnFI and his "one is better than two" theory?

I'm betting a twin engined 407 would be back on terra firma, instead of waiting for a wave to tip it upside down!

Classic photo though. Just classic :)

Noooby,

A twin 407 would be a modification from the production 407 and would still be in flight test getting certified. 407's are singles.:confused:

Safe landing done with no engine it would appear to me.

You are absolutely 100% correct, Otterotor.

However, do a quick search for 'AnFI' to see the point that noooby is making. :ok:

Bravo - I think I see why some people support twins now. is it because they are too thick to understand that this is an example of why singles are a good idea.

This is a successful outcome further undermining the justification for twins.

Is it worth having a gearbox failure to avoid this outcome - er? NO!

Pay the performance penalty of lugging a spare engine/gbox/fuel around?
All those extra "critical component.hours" incurred?
All those crammed in pax tripping over their 'just in case' STASS, tangled in their lifejacket, cumbersome in their survival suits trying to get down a corridor to a window before the top heavy twin capsizes, at night, in a swell ! Doh!

Gimme a calm auto in a 407 anyday.

Get a grip noooby - an engine failure needs to have an x% chance of being fatal to justify the other downsides of a twin.
x is probably in the region of 90.

Jungle - twin
Northsea - evens
GOM - single
Green 'auto-friendly grass' - ban twins

There's no honest maths in this debate: corrupt

AnFI

The NS is considered a hostile environment by OGP. It is hostile most of the time due water temperature, sea state, wind or a combination. Even the GOM can be hostile in winter. Jungle is always a hostile environment, at least you are more mainstream on jungle.

You are entitled to your extreme views. You may class it as being an alternative thinker, good, the world needs them. However, you fly (until your engine quits) in the face of many years of experience, statistical analysis and industry practice.

Anfi

Your analysis may add up from an aviators perspective, but PAX may prefer to stay in the air. Regardless of fact, PAX perception of safety ultimately pays your bills so the maths may need to factor this??

Term,

You consider a Bell 212/412 to be multiengine helicopters and if so then you are quite comfy flying over Jungle and the other "Hostile Terrain/Enviroments" as an Engine Failure will not put you into that which you do not wish to land in?

No Boudreaux, anything with a C Box is not a twin.

Well, seeing as you have tried to drag me down to your level and into your pit, I guess I'll have to bite.

An aircraft has ditched and you are saying that this is a good idea? A situation that might well have been avoided by having a second engine. That's genius. Just absolute genius. :rolleyes:


Nurse - increase his medication, please.

Yet they get flown like Twins. The other small problem in that concept is that main drive shaft.

Believe it or not, I am aware that a 407 is a single and that the closest that Bell came to a twin 407 was the 206LT, which was a disaster.

And while singles do have a place, I don't think that place is over water, with passengers who have no say in what they fly in. I also don't think that is a place for twin engined helicopters where the second engine just takes you a bit further to the crash site.

Yiu forget the...forgettable 427. Yet another example of Bell engineering solidly planted between their buttocks

Anything with only one transmission is not a twin, or one tail rotor, a CH-46 or CH-47 doesn't qualify either - only one connecting shaft. Seems helo jocks are totally out of luck in the redundancy stakes. :p

Sure Brian, I take your point but having additional single failure modes like a C Box in an old generation helicopter is not on my OK list.

Term

From a flight safety standpoint the 412 config has proven far safer in the past ten years than the S-92 and the Super Duper Puma.

No one has died in a 412 due to loss of lube like Cougar S-92, maybe because Bell did not actively market it as having a run dry capability. Therefore when loss of oil pressure occurred the crews new to land as soon as they could. Even in these rare events the 412 transmissions lasted as long or longer than the 92 due to superior design.

As to the Puma's their lack of drive system safety needs no repeating.

The Sultan

Note: One 412 that had a main shaft loss of drive was because they never torqued the bolts. Even then no one hurt.

I made my comment just to remind folks that our use of terminology can present false impressions as despite the 212/412 design as both a Combining Gearbox and a Single Driveshaft from the C-Box to the Main Transmission, it has been a very reliable Twin Engined Helicopter.

The same can be said for the Chinook and Phrog with their Gearbox designs and Sync Shafts.

When it comes to helicopters we will never have complete "redundancy" as there are too many "Single Point" failure points that will take the whole thing down.

Those that see Single Engine Operations over water as being a "Sin" should really look at the Statistics and see if their position holds water.

As in most things in the helicopter business there are combinations of factors that must be considered when making decisions about what type of aircraft to operate. Numbers of engines alone is not the full Monte.

I would suggest the 212/412 series of helicopters are well proven and reliable although in the strict definition of a Single Engine Helicopter, they might well qualify.

If One were to be very strict in One's thinking every helicopter has a combining gearbox in the form of the MGB which has an Engine input for each engine. Despite the individual Inputs which have Over Riding Clutches of some design, the single Transmission makes that Single Point for failure.

quite right bob

Combining happens; topologically somewhere, how complex is a modern twin gearbox? 16 gears !? how many bearings?


I think terminus and Bravo have a point; the reason people think they want twins is that they think they don't want to get wet if they have to land on water. Yes NS may be considered as 'hostile' because you might get your feet wet and chilly (once every 10,000 years), but it needs to be factored by the chance of being dead because your gearbox (etc) breaks.
The logic doesn't add up, and the maths is FRAUDULENT!!

You have to have a pretty good chance of death on engine fail to justify a twin. Should twins even be allowed day/VMC/non hostile environment: NO! It is stoopid.
Over jungle, if it is a high proportion of the operating regime, then yes - but only just.



Bravo something in your post made me want to look up the origin of the term; "as thick as monkey f@£k" i don't know exactly what it was but google could not help me....

Agree Bob. We flew 205s for many years, and in that time had two ditchings (both aircraft recovered essentially undamaged). One was due to an engine failure when a piece of the FOD screen broke away due fatigue, and the other when a circumferential crack developed around one main blade yoke, leaving the blade attached only by the tension/torsion strap.

I do so love selective statistics to 'prove' a theory: let's compare the last 10 years of a 40 year-old transmission/airframe with the first 10 years of a 10 year-old transmission/airframe. Luckily I have been around long enough to know how the 204/205/212/412 worked out historically. I am sure we can ignore a few quill drive issues as being 'irritating noise' in that statistical analysis (literally).