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.