Sikorsky S-76: Ask Nick Lappos
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Nick, Peter & Brian
I know how to practice engine failures but how do you practice flying into mountains?
How many helicopter pilots have flown a perfectly serviceable machine into an oil rig? How many have had engine failures, problems, governor malfunctions, etc,etc to & from oil rigs? I think all companies I have flown for during the last 40 years since my first oil rig landing in 1964 off Borneo, have had the requirement to be single engine capable after CDP and before LDP. This is not a problem if you operate at the correct weight. It appears on reading these threads that this possibly does not happen in GOM, one place I have never been.
In those 40 years I have lost count of the number of engine and other mechanical failures that I've had but CFIT is something I have control over, the helicopter doesn't.
Sure discuss CFIT as on shore it seems to be a newly common problem but surely one must keep practising to overcome any mechanical problem that may come your way.
The only single engine failure that I didn't fly away from was in a float equipped 206 and fortunately that company had taught me how to auto into the sea as I did my endorsement on floats!
I know how to practice engine failures but how do you practice flying into mountains?
How many helicopter pilots have flown a perfectly serviceable machine into an oil rig? How many have had engine failures, problems, governor malfunctions, etc,etc to & from oil rigs? I think all companies I have flown for during the last 40 years since my first oil rig landing in 1964 off Borneo, have had the requirement to be single engine capable after CDP and before LDP. This is not a problem if you operate at the correct weight. It appears on reading these threads that this possibly does not happen in GOM, one place I have never been.
In those 40 years I have lost count of the number of engine and other mechanical failures that I've had but CFIT is something I have control over, the helicopter doesn't.
Sure discuss CFIT as on shore it seems to be a newly common problem but surely one must keep practising to overcome any mechanical problem that may come your way.
The only single engine failure that I didn't fly away from was in a float equipped 206 and fortunately that company had taught me how to auto into the sea as I did my endorsement on floats!
Nick...I take your point. However you may have misunderstood. I am not putting TRF before CFIT or OEI...that's just the order I wrote it. Obviously , as others and you have said..we can actually practice OEI but CFIT and to a large extent TRF is going to be a classroom exercise....but can still be of benefit nonetheless.
I will kick off another thread on the subject "CFIT - Helicopters" when I get back from work today. I think it is a subject that will generate a lot of comment and may even help with my current project.
I dont have statistics.
I got my initial motivation from reading that the airlines are now doing CFIT courses along the same lines as CRM courses. Once I started to dig into the subject (but concentrating on helicopters only) I found a wealth of material....and was , in fact , quite shocked.
I will kick off the new thread with a list of accidents/incidents with dates. Where possible , they will come from official reports but will throw in anecdotal cases as well.
standby......
I will kick off another thread on the subject "CFIT - Helicopters" when I get back from work today. I think it is a subject that will generate a lot of comment and may even help with my current project.
I dont have statistics.
I got my initial motivation from reading that the airlines are now doing CFIT courses along the same lines as CRM courses. Once I started to dig into the subject (but concentrating on helicopters only) I found a wealth of material....and was , in fact , quite shocked.
I will kick off the new thread with a list of accidents/incidents with dates. Where possible , they will come from official reports but will throw in anecdotal cases as well.
standby......
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OK, Peter, NIgel andBrian,
I admit I was trolling...... a bit. But the stats don't lie. About 30 to 40% of the accidents twins have is caused by CFIT, and the cures are many, if we all start working on it.
EGPWS is a great start.
I admit I was trolling...... a bit. But the stats don't lie. About 30 to 40% of the accidents twins have is caused by CFIT, and the cures are many, if we all start working on it.
EGPWS is a great start.
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For a rig take off the procedure we use for the 76C is as follow,
Establish the aircraft in a 5 foot hover to check N1 margin (as a guide 3% between hover and max of 100% ie max hover of 97%). Climb vertically until the aircraft is at least 25 feet RADALT with at least 200 feet/min rate of climb. Rotate to a max of 15 degrees nose down and accelerate to Vtoss (60kts) as soon as possible. Climb straight ahead until 250 feet VBROC before commencing a turn, select gear up at 60kts and disarm floats approaching 75kts.
CDP is the point of rotation - a failure prior to 25 feet you land/crash back on the deck (you are inside the HV curve) and a failure after rotation will require either a ditching, or if you have the performance, fly away.
I have experienced a failure at the CDP and was able to fly away under the conditions which prevailed at the time ie 500 pounds below gross, 20 kts of wind and 12 degrees OAT. Would not have guaranteed success at gross necessarily.
Hope this helps.
Brian
Establish the aircraft in a 5 foot hover to check N1 margin (as a guide 3% between hover and max of 100% ie max hover of 97%). Climb vertically until the aircraft is at least 25 feet RADALT with at least 200 feet/min rate of climb. Rotate to a max of 15 degrees nose down and accelerate to Vtoss (60kts) as soon as possible. Climb straight ahead until 250 feet VBROC before commencing a turn, select gear up at 60kts and disarm floats approaching 75kts.
CDP is the point of rotation - a failure prior to 25 feet you land/crash back on the deck (you are inside the HV curve) and a failure after rotation will require either a ditching, or if you have the performance, fly away.
I have experienced a failure at the CDP and was able to fly away under the conditions which prevailed at the time ie 500 pounds below gross, 20 kts of wind and 12 degrees OAT. Would not have guaranteed success at gross necessarily.
Hope this helps.
Brian
G'day again Brian.....interesting. I guess what I am intrigued about is WHERE your particular profile came from ? Did Sikorsky finally address an "elevated helipad" profile with the C or is your profile derived in house.
I know that with my time on the A , A+ and A++ with two different Canadian companies....we derived our profiles over many years and a lot of trial and error.....I am reasonably happy with them. I will agree with Nick that they won't guarantee a 100% happy conclusion on engine failure but they are better than what we had when we started on the S76 in 1979.
Many years ago in the Songkhla Helibase library (Thailand) , there was a book by the BHAB (British helicopter Advisory Board) in which they set out to establish helideck take off profiles for different helicopters. They did a lot of work with the current simulators as well actual flying. I guess one of the things that fascinated me with this report was a series of take off data (on the sim) which showed various combinations of rotation height....many with a "FAIL , tail rotor hit deck edge"....so I am encouraged to see you guys rotating at 25 feet. That puts us (A models) in the red of the H/V graph but I would rather splatter the aircraft with a hard reject back to the deck than hit my T/R on the edge as I try and flyaway froma rotation at too low a height. My 212 OEI in BBY was on rotation at about 15 feet but the radio operator said that as we passed over the deck edge , the T/R was inches from it !
Always fascinated by the fact that I have flown the 61 under 3 different authorities (CAA , CASA and TC) and they all had different helipad take off profiles.
Fly safe........Peter
this is our S76 (A model) rig take off profile. We are operating in the tropical south of China.
Normal profile has us in the hover looking for a T5 of less than 700 (limit768). T5 more than 700 requires a "hot" take off procedure and my personal cut off is 715. Obviously during the colder months we are torque limited and a good IGE hover limit is 85%.
Normal Take off:
Full power
rotate at 20 feet to 10 degrees nose down DAY
(5 degrees NIGHT)
35 knots pitch nose up to the horizon
74 knots Post Take off check (gear and floats etc)
"Hot" Take off Technique - not often used these days as we have signifigantly reduced our limiting weights but sometimes..
Lift to hover T5 at 700+
Move the helicopter closer to the deck edge and put it back with the main wheels lightly on the deck , nose wheel is off.
Set about 102% Nr so that when you pull collective you are down to the optimum 100% Nr.
Pull to 768 (preferably on the analog gauges - easier to read)
As you sense the helicopter starting to lose its vertical climb (usually less than 20 feet !)
5 degrees nose down
as your eye passes the deck edge rotate further to 10 degrees.
With both
- OEI at CDP (rotation) - return to the deck
- OEI after rotation increase to 20 degrees nose down (only if the OAT is < 30 degrees C....this one was learnt the hard way) IF ABOVE 30 DEGREES OAT THEN MAXIMUM NOSE DOWN 15 DEGREES.
I used to hate the HOT technique but it did work. Not very comfortable.
I know that with my time on the A , A+ and A++ with two different Canadian companies....we derived our profiles over many years and a lot of trial and error.....I am reasonably happy with them. I will agree with Nick that they won't guarantee a 100% happy conclusion on engine failure but they are better than what we had when we started on the S76 in 1979.
Many years ago in the Songkhla Helibase library (Thailand) , there was a book by the BHAB (British helicopter Advisory Board) in which they set out to establish helideck take off profiles for different helicopters. They did a lot of work with the current simulators as well actual flying. I guess one of the things that fascinated me with this report was a series of take off data (on the sim) which showed various combinations of rotation height....many with a "FAIL , tail rotor hit deck edge"....so I am encouraged to see you guys rotating at 25 feet. That puts us (A models) in the red of the H/V graph but I would rather splatter the aircraft with a hard reject back to the deck than hit my T/R on the edge as I try and flyaway froma rotation at too low a height. My 212 OEI in BBY was on rotation at about 15 feet but the radio operator said that as we passed over the deck edge , the T/R was inches from it !
Always fascinated by the fact that I have flown the 61 under 3 different authorities (CAA , CASA and TC) and they all had different helipad take off profiles.
Fly safe........Peter
this is our S76 (A model) rig take off profile. We are operating in the tropical south of China.
Normal profile has us in the hover looking for a T5 of less than 700 (limit768). T5 more than 700 requires a "hot" take off procedure and my personal cut off is 715. Obviously during the colder months we are torque limited and a good IGE hover limit is 85%.
Normal Take off:
Full power
rotate at 20 feet to 10 degrees nose down DAY
(5 degrees NIGHT)
35 knots pitch nose up to the horizon
74 knots Post Take off check (gear and floats etc)
"Hot" Take off Technique - not often used these days as we have signifigantly reduced our limiting weights but sometimes..
Lift to hover T5 at 700+
Move the helicopter closer to the deck edge and put it back with the main wheels lightly on the deck , nose wheel is off.
Set about 102% Nr so that when you pull collective you are down to the optimum 100% Nr.
Pull to 768 (preferably on the analog gauges - easier to read)
As you sense the helicopter starting to lose its vertical climb (usually less than 20 feet !)
5 degrees nose down
as your eye passes the deck edge rotate further to 10 degrees.
With both
- OEI at CDP (rotation) - return to the deck
- OEI after rotation increase to 20 degrees nose down (only if the OAT is < 30 degrees C....this one was learnt the hard way) IF ABOVE 30 DEGREES OAT THEN MAXIMUM NOSE DOWN 15 DEGREES.
I used to hate the HOT technique but it did work. Not very comfortable.
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Pete,
Our procedure was developed by check and training in the simulator at West Palm. On my event rig personel said the tail rotor missed by about 20 feet. In the A model days it was just a case of get into the hover and fall off the edge. It was left to pilot judgement as to how to handle the situation. It was not until we had been operating multi's for quite some time that consideration was given to the "what if" and the stated procedure developed.
Brian
Our procedure was developed by check and training in the simulator at West Palm. On my event rig personel said the tail rotor missed by about 20 feet. In the A model days it was just a case of get into the hover and fall off the edge. It was left to pilot judgement as to how to handle the situation. It was not until we had been operating multi's for quite some time that consideration was given to the "what if" and the stated procedure developed.
Brian
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S76C+ Info'
Anyone have any good links to find info on the C+ Arriel 2S1 power plant and engine control. I'm comfortable with the A++ and 1S1 but hunger for more!!! Thanks in advance.
VTA
VTA
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You could also try FlightSafety. They have very nice description texts. But, you'll probably have a hard time getting them to *give* you one. Find someone who has taken the course and borrow their manual.
Better yet, hit up your rich uncle and actually attend the FSI course!
HO5S
Better yet, hit up your rich uncle and actually attend the FSI course!
HO5S
S-76A CAA MMEL: Revision 3
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S76 Vne gear down
The RFM of the S76 limit the speed off the A/C with gear down at 130 KTS. The operator for who I work restricted this speed at 120 KTS, the reason is for the float bags under the gear door. I wonder if it is a valid reason, cause I guess Sikorsky did the test with those bag on and that why the don't mention anything about it in the RFM.
Cheers
FH
Cheers
FH
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Quite often the float bags are second hand and a bit tatty, so that some companies have reduced the vne to save wear and tear. However I'm quite sure that 130 kts is perfectly safe for bags in good condition.
I'd agree, though not sure about the second hand bit! Maybe they are also considering a Vno relative to the lower Vne, to avoid exceeding Vne?
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We use the RFM 130 kts as the limit, but recommend lower speeds for raising and lowering the gear just to reduce wear and tear on all the parts. I try to keep it under 120, and often lower, depending on the situation, just as something I feel is good practice. If I need to move the gear at 129.75 kts, I'll do it.
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my company use 130 kts purely because of the gear itself, consideration of float condition is not made in this respect.
i seems to me that the floats are servicable or they are not !,
i seems to me that the floats are servicable or they are not !,
It isn't the gear. You won't bend that in a hurry.
Its all about the doors. They are the issue with the speed.
Your company probably doesn't trust the pilots not to exceed the VNE for the gear so they knock it down to 120kt.
It's all about legislating commonsence.
Its all about the doors. They are the issue with the speed.
Your company probably doesn't trust the pilots not to exceed the VNE for the gear so they knock it down to 120kt.
It's all about legislating commonsence.
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Steve76 is right on, the airloads on the doors are the thing that helps set the max gear down speed. I must say there is a rumour that the doors are made of stout stuff, however. A crew is said to have left the gear down during a flight to 1.2 Vne, with no ill effects. Of course, I wouldn't know WHO the pilot was.
This story, if true, means that you should respect the gear limit speed of 130 knots, but not fear that limit.
This story, if true, means that you should respect the gear limit speed of 130 knots, but not fear that limit.
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120kts & gear
I think I've worked for THE COMPANY in question.
As explained to me, it is a wear and tear/ commercial operator issue. Yes, Sikorsky certifies 130 kts., but to extend the life of the gear components( in the world of making money) this operator wants 120kts or less to lower the gear. After that, you can speed up to 130kts as per Sikorsky.
There are a couple of other scenarios like this regarding the use of "lesser" limits for wear and tear.... due to the world of commercial op's and managing maintenance costs.
Good discussion!
D.K
As explained to me, it is a wear and tear/ commercial operator issue. Yes, Sikorsky certifies 130 kts., but to extend the life of the gear components( in the world of making money) this operator wants 120kts or less to lower the gear. After that, you can speed up to 130kts as per Sikorsky.
There are a couple of other scenarios like this regarding the use of "lesser" limits for wear and tear.... due to the world of commercial op's and managing maintenance costs.
Good discussion!
D.K
This might seem a stupid question but why, other than flying at low level where an emergency might require a very quick landing, would you want to fly at 120 or 130 kts with the gear down?
I know the S76 is a good machine but surely even it can't land at that speed!!
What's wrong in delaying the gear selection until short finals - then you'll never overstress?
I know the S76 is a good machine but surely even it can't land at that speed!!
What's wrong in delaying the gear selection until short finals - then you'll never overstress?
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Crab,
When operating to numerous rigs/platforms offshore you might have the next deck only a short distance away (5 nm in our case, which is only about 4 minutes from wheels off to wheels on). That extra few knots gained by retracting the gear isn't going to make much of a dent in the flight time but leaving the gear down can add up to a whole lot less gear cycles over the day, month, year, etc.
On the short legs there is the unwritten rule that you have to exceed 130 kts to justify pulling the gear up. eh Steve!
When operating to numerous rigs/platforms offshore you might have the next deck only a short distance away (5 nm in our case, which is only about 4 minutes from wheels off to wheels on). That extra few knots gained by retracting the gear isn't going to make much of a dent in the flight time but leaving the gear down can add up to a whole lot less gear cycles over the day, month, year, etc.
On the short legs there is the unwritten rule that you have to exceed 130 kts to justify pulling the gear up. eh Steve!