Sikorsky S-76: Ask Nick Lappos
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Good for the EC-135
But the EC135 carries half of the passengers of the S76 and spends twice the time in the shop than a S76C++. So the machine to depend on to get 700 workers safely off the platforms is not a 5 passenger EC135 but a 12 pasenger S76. Deck time is expensive and only one helicopter can occupy the deck at any time You move more people in a shorter time span per landing with the S76 than a EC135. And at over $100 per barrel time is money.
But monsieur.....zee bakseez is better from Euro than Sikorsky! Why else would Shell have bought the 155's in the first place?
It was the 155 I was referring to, not the 135. No reason why it can't do the same job as the 76, and with a bigger more spacious cabin and lower noise and vibration levels.
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Geoffersincornwall,
You rose to the bait!
Please note that training is great, and necessary, but mostly because we make flying so hard! Training is NOT the key to ultimate safety, we must fix the rest of the transport system that we operate in. Without Instrument procedures, and without modern helicopters, we are doomed to keep flogging the pilot and not really improve our lot.
The message is best told in the talk I gave at Heli Expo last month:
http://webpages.charter.net/nlappos/HeliExpoTalk.pdf
Jack,
ALL helicopters have fuel systems designed to FAR/JAR. The problem is that MOST of them have been designed to OLD FAR/JAR, and so they are not crashworthy, at all.
You rose to the bait!
Please note that training is great, and necessary, but mostly because we make flying so hard! Training is NOT the key to ultimate safety, we must fix the rest of the transport system that we operate in. Without Instrument procedures, and without modern helicopters, we are doomed to keep flogging the pilot and not really improve our lot.
The message is best told in the talk I gave at Heli Expo last month:
http://webpages.charter.net/nlappos/HeliExpoTalk.pdf
Jack,
ALL helicopters have fuel systems designed to FAR/JAR. The problem is that MOST of them have been designed to OLD FAR/JAR, and so they are not crashworthy, at all.
Avoid imitations
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But I really don't want to crash my fuel tanks. Can't we just design the rest of the aircraft not to crash? 
Nick/Rotorbrent
The implication here was that the EC135 was designed and certified to the latest most current version of FAR/JAR27. I was not implying that the EC135 was a competitor to the S-76 for of shore transport, only that it was designed and built to the latest standards. It is a fine little light twin that performs quite well in the EMS market.
The following is an excerpt from a technical paper given by a Mr. Mark Butler in the UK in 1997: “This new middleweight helicopter, successor to the BO 108, is the first European helicopter built from conception to the new FAR 27/29 regulations. The high crashworthiness requirement of the new regulations has been met at a weight that does not represent a significant premium over previous non-crashworthy systems, and this is of particular relevance in view of the likely extensive use of this helicopter in police, paramilitary and medevac operations.”
The implication here was that the EC135 was designed and certified to the latest most current version of FAR/JAR27. I was not implying that the EC135 was a competitor to the S-76 for of shore transport, only that it was designed and built to the latest standards. It is a fine little light twin that performs quite well in the EMS market.
The following is an excerpt from a technical paper given by a Mr. Mark Butler in the UK in 1997: “This new middleweight helicopter, successor to the BO 108, is the first European helicopter built from conception to the new FAR 27/29 regulations. The high crashworthiness requirement of the new regulations has been met at a weight that does not represent a significant premium over previous non-crashworthy systems, and this is of particular relevance in view of the likely extensive use of this helicopter in police, paramilitary and medevac operations.”
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Theory vs Reality
I could write a certification standard that every seat would be able to jettision and have its own flotation, emergency air, epirb, satcom link and voice activated systems with internet with dvd player safety systems for land sea mountian dessert survial.
Or better yet a certification standard that it must run on something other than fossil fuels or petroleum products.
So show me the crash data where a fatal S76 crash would have been less fatal with the fuel somewhere else and at what price in operation cost. Just what I thought.
I am sure we will have all those things while you pay $6-7 dollars a gallon car gas in the US
Or better yet a certification standard that it must run on something other than fossil fuels or petroleum products.
So show me the crash data where a fatal S76 crash would have been less fatal with the fuel somewhere else and at what price in operation cost. Just what I thought.
I am sure we will have all those things while you pay $6-7 dollars a gallon car gas in the US
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S76 Height Velocity Diagram
I wonder if Nick or one of you other experts could clarify the S76 Height Velocity Diagram.
Simply put, does the diagram in the RFM refer that if you are in the shaded area and you lose 1 engine then you will not be able to fly away on the other engine OR perform a safe landing?
or
Does it refer that if your in this shaded area and you lose an engine. ie now you are operating like a single engine helicopter, and you then lose the remaining engine, you may not be able to perform a autorotation to a safe landing?
This discussion arose between my colleagues and i when we were discusiing the AW139, and how it has been reported on the 139 thread that it does not have an H-V Diagram being Cat A and able to maintain flight on one engine.
But what happens if you lose both engines?
Surely there is an area, depending on height and airspeed, where you will not be able to perform a safe autorotation and doesn't the manufacturer have to demonstrate an H-V Diagram for certification?
Simply put, does the diagram in the RFM refer that if you are in the shaded area and you lose 1 engine then you will not be able to fly away on the other engine OR perform a safe landing?
or
Does it refer that if your in this shaded area and you lose an engine. ie now you are operating like a single engine helicopter, and you then lose the remaining engine, you may not be able to perform a autorotation to a safe landing?
This discussion arose between my colleagues and i when we were discusiing the AW139, and how it has been reported on the 139 thread that it does not have an H-V Diagram being Cat A and able to maintain flight on one engine.
But what happens if you lose both engines?
Surely there is an area, depending on height and airspeed, where you will not be able to perform a safe autorotation and doesn't the manufacturer have to demonstrate an H-V Diagram for certification?
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From my limited brain,
H-V curves pertain to the ability to autorotate safely. If I recall, the S76 graph is titled something like "limiting heights and speeds AFTER an engine becomes inop." ???
Sorry to answer a question with a question, but how can the 139 not have an H-V graph? Is autorotation not part of the certification process? We've all youtubed the s92 auto' certification video!
Cat A guarantees OEI flyaway predicated on the WAT charts. I've never referenced the H-V graph when calculating CAT A performance....just the WAT chart!
Cat B has NO OEI flyaway guarantee and therefore treat it like a single engine a/c....i.e look for a place to land/reject along your path.
Interesting question! Makes me think.....brain hurting! must stop now!
DK
H-V curves pertain to the ability to autorotate safely. If I recall, the S76 graph is titled something like "limiting heights and speeds AFTER an engine becomes inop." ???
Sorry to answer a question with a question, but how can the 139 not have an H-V graph? Is autorotation not part of the certification process? We've all youtubed the s92 auto' certification video!
Cat A guarantees OEI flyaway predicated on the WAT charts. I've never referenced the H-V graph when calculating CAT A performance....just the WAT chart!
Cat B has NO OEI flyaway guarantee and therefore treat it like a single engine a/c....i.e look for a place to land/reject along your path.
Interesting question! Makes me think.....brain hurting! must stop now!
DK
The HV diagram defines the area in which a safe landing is not assured after sustaining an engine failure. Category A defines an operating doctrine which, if followed would guarantee either a safe takeoff of a safe land back after sustaining and engine failure. Included in the Cat A takeoff profile is the land back area and drop down altitude from a raised heliport. The FAA’s definition of Cat A is:
Category A, with respect to transport category rotorcraft, means multiengine rotorcraft designed with engine and system isolation features specified in Part 29 and utilizing scheduled takeoff and landing operations under a critical engine failure concept which assures adequate designated surface area and adequate performance capability for continued safe flight in the event of engine failure.
Category A, with respect to transport category rotorcraft, means multiengine rotorcraft designed with engine and system isolation features specified in Part 29 and utilizing scheduled takeoff and landing operations under a critical engine failure concept which assures adequate designated surface area and adequate performance capability for continued safe flight in the event of engine failure.
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Jack is right (he was a Sikorsky Test Pilot, after all!) The HV curve shows the area where the loss of the FIRST engine (one engine left, working its heart out) will result in a hard landing or worse, under the specified "worst case" environment. This means max gross weight, still air, so that lighter weights and some wind above perhaps 5 knots will result in much better aircraft response.
Even though this is in the limits section, it is generally treated as a performance chart (chapter 4) by the FAA, since strict adherence to the chart could preclude operations to rigs, heliports and such. For example, on short final to a rig at 125 feet and 10 knots of speed, you are clearly in the avoid area. Every day.
Even though this is in the limits section, it is generally treated as a performance chart (chapter 4) by the FAA, since strict adherence to the chart could preclude operations to rigs, heliports and such. For example, on short final to a rig at 125 feet and 10 knots of speed, you are clearly in the avoid area. Every day.
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Thanks for your input guys. You certainly clarified the question i had about the S76 diagram.
But regarding the certification process, it seems then that a manufacturer does not have to provide a HV Diagram for both engine loss, as i'm sure there is still an area where you will not be able to perform an autorotation to a safe landing.
But regarding the certification process, it seems then that a manufacturer does not have to provide a HV Diagram for both engine loss, as i'm sure there is still an area where you will not be able to perform an autorotation to a safe landing.
Avoid imitations
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Why bother about that? If I lost just the one, I'd be on my way down anyway... 
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HV Curve AW 139
The 139 most definitely has an HV curve the size and shape of which varies with DA and Mass. Of course - with all that power it's not very big. The Cat A and B profiles are designed to keep you in the clear by the way.
G
G
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So does the AW 139 H-V curve pertain to the first engine failure avoid area, as mentioned by Nick for the S76, or relevant to a dual engine autorotation avoid area???
DK
P.S. Is it in the limitation section or performance section?
DK
P.S. Is it in the limitation section or performance section?
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H-V diagram
The H-V diagram is part of the limitations section and refers to the safe recovery from a single engine failure whilst operating over a smooth, flat surface.
As far as I am aware a twin engine helicopter does not need to demonstrate the ability to comply with a simultaneous double engine failure H-V curve. I don't think Cat A or Cat B even comes into it.
G
As far as I am aware a twin engine helicopter does not need to demonstrate the ability to comply with a simultaneous double engine failure H-V curve. I don't think Cat A or Cat B even comes into it.
G
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S-76 questions.
Just have a couple of questions to satisfy my curiousness on this aircraft. Although pushing 30, I still think it's the prettiest heli on the block.
1. Is the front wheel differential braking steered, lever steered or tail rotor steered? And if they're brake steered, are these brakes on the pedals?
2. I've sometimes seen them do rolling take-offs into TL, but never seen them land that way. Could you land the S-76 in an airplane-style rolling touch-down?
3. The instrument panels height in combination with the nose high hover attitude must make it tricky to see straight out. Is this a problem in a steep approach?
4. Are they nice to fly?
1. Is the front wheel differential braking steered, lever steered or tail rotor steered? And if they're brake steered, are these brakes on the pedals?
2. I've sometimes seen them do rolling take-offs into TL, but never seen them land that way. Could you land the S-76 in an airplane-style rolling touch-down?
3. The instrument panels height in combination with the nose high hover attitude must make it tricky to see straight out. Is this a problem in a steep approach?
4. Are they nice to fly?
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1/ The front wheel castors and the brakes are on the rear wheels controlled by the foot pedals, you push the upper pedal to brake. Taking the skin off your shins on the lower panel...
2/ Yes
3/ Yes, you just turn the nose to the left
4/ Very nice, you can see a pilot had an input into the design.
I miss the S76...
2/ Yes
3/ Yes, you just turn the nose to the left
4/ Very nice, you can see a pilot had an input into the design.
I miss the S76...
Last edited by Old Skool; 14th Aug 2008 at 02:11.
Yes, the 76s are so nice to fly....but as with some other tamed creatures we have to know and like each other!
I wouldn't like to change for another type of the same class.
I wouldn't like to change for another type of the same class.