Sikorsky S-76: Ask Nick Lappos
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Hey Steve
There is no crash on this profile.....it is a certified Cat A profile from Sikorsky for the S76C model. (By the way as far as I know is is certified DAY ONLY.)
Does anyone know what the gross weight restriction is.....I am sure there must be one.
Cheers Mate
There is no crash on this profile.....it is a certified Cat A profile from Sikorsky for the S76C model. (By the way as far as I know is is certified DAY ONLY.)
Does anyone know what the gross weight restriction is.....I am sure there must be one.
Cheers Mate
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It is a very comfortable procedure once you are accustomed to it. The official procedures are in Supplements 8 and 9, you pays yer money and chooses...
The steep approach angle is maintained with collective; about 6 degrees nose up bleeds the speed progressively from 400 feet/45kts to 100 feet/35kts at LDP. Now you are committed to land and are watching groundspeed; as the speed continues to fall you maintain the glideslope with a touch more collective to that "point in space" about 30 feet vertically above the circle, at which point all groundspeed should cease. As you are stopping, hopefully over the right spot, lower the nose and let her fall vertically. Do NOT hover there. The fall will be gentle, I assure you! LEAVE the collective alone.
As she falls onto the ground cushion you will feel her slowing; a very slight squeeze on the collective will arrest the fall and allow you to anchor the left wheel before she starts to dance on you...
Before you attempt this manoevre you must have a very clear mental picture of what you're trying to do... get it right and it'll result in an easy single engined approach and landing. Get it wrong and it could be very messy. How you get to that 30 foot position is a matter of personal opinion; some people use blobs on the screen, some align the pitots etc etc. I prefer the mental picture of the point in space.
Nick may be horrified by this, but it does work. Any other ideas anybody?
The steep approach angle is maintained with collective; about 6 degrees nose up bleeds the speed progressively from 400 feet/45kts to 100 feet/35kts at LDP. Now you are committed to land and are watching groundspeed; as the speed continues to fall you maintain the glideslope with a touch more collective to that "point in space" about 30 feet vertically above the circle, at which point all groundspeed should cease. As you are stopping, hopefully over the right spot, lower the nose and let her fall vertically. Do NOT hover there. The fall will be gentle, I assure you! LEAVE the collective alone.
As she falls onto the ground cushion you will feel her slowing; a very slight squeeze on the collective will arrest the fall and allow you to anchor the left wheel before she starts to dance on you...
Before you attempt this manoevre you must have a very clear mental picture of what you're trying to do... get it right and it'll result in an easy single engined approach and landing. Get it wrong and it could be very messy. How you get to that 30 foot position is a matter of personal opinion; some people use blobs on the screen, some align the pitots etc etc. I prefer the mental picture of the point in space.
Nick may be horrified by this, but it does work. Any other ideas anybody?
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Hey XNR (old man)
I tried the "Pitot tube" approach tonight into PN3 and again at YMO....as long as you manage the ground speed/closing rate to the spot, it was a pretty nice approach. Sfc winds were light and variable but low level winds (200-700') were 15 kts...
Who would've thought?
wde
I tried the "Pitot tube" approach tonight into PN3 and again at YMO....as long as you manage the ground speed/closing rate to the spot, it was a pretty nice approach. Sfc winds were light and variable but low level winds (200-700') were 15 kts...
Who would've thought?
wde
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Xnr
Supp. 8 Ground Level Heliports has a Maximum Takeoff and Landing Gross weight of 11,000 pounds.
Supp. 9 Elevated Heliports has a Maximum Takeoff Gross Weight of 11,700 pounds and a Maximum Landing Gross Weight of 10,700 pounds.
Curiously, Supp. 8 is certified Day and Night while Supp. 9 is certified Day/Night for Takeoff but Day only for Landing.
Supp. 8 Ground Level Heliports has a Maximum Takeoff and Landing Gross weight of 11,000 pounds.
Supp. 9 Elevated Heliports has a Maximum Takeoff Gross Weight of 11,700 pounds and a Maximum Landing Gross Weight of 10,700 pounds.
Curiously, Supp. 8 is certified Day and Night while Supp. 9 is certified Day/Night for Takeoff but Day only for Landing.
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Thanx JW
I don't have the supp. (cause I don't fly the "C")
wde
Half the problem is that guys are not comfortable flying a "steep" approach. (lack of bush time maybe or they dont like the reduced vis out of the front of a IFR machine)
My opinion is that it is the only way to approach if you are going to guarantee success in the unlikely event of a donk failure post LDP.
Food for thought....412 Cat A helipad approach angle is 30 degrees.....430 is very close to that also. Some 76 guys want a helipad approach angle of 3-4 degrees. Personally I can't understand that line of thinking.
Cheers
I don't have the supp. (cause I don't fly the "C")
wde
Half the problem is that guys are not comfortable flying a "steep" approach. (lack of bush time maybe or they dont like the reduced vis out of the front of a IFR machine)
My opinion is that it is the only way to approach if you are going to guarantee success in the unlikely event of a donk failure post LDP.
Food for thought....412 Cat A helipad approach angle is 30 degrees.....430 is very close to that also. Some 76 guys want a helipad approach angle of 3-4 degrees. Personally I can't understand that line of thinking.
Cheers
Prob: "Half the problem is that guys are not comfortable flying a "steep" approach. (lack of bush time maybe or they dont like the reduced vis out of the front of a IFR machine)"
Solution: I agree wholeheartedly.
Pay the cojoes more to get a better candidates and to retain all the good ones. In doing this raise the entry requirements to reflect a "bush" background of experience.
Lack of Vis: "kick" it out of balance! No big deal and pretty much the safest way to fly the 76. No point in both the pilots being unable to see the approach clearly because of a reluctance to deal with the poor vis....
"My opinion is that it is the only way to approach if you are going to guarantee success in the unlikely event of a donk failure post LDP."
....been there....proved that
Onya XNR WDE cobbers!
Solution: I agree wholeheartedly.
Pay the cojoes more to get a better candidates and to retain all the good ones. In doing this raise the entry requirements to reflect a "bush" background of experience.
Lack of Vis: "kick" it out of balance! No big deal and pretty much the safest way to fly the 76. No point in both the pilots being unable to see the approach clearly because of a reluctance to deal with the poor vis....
"My opinion is that it is the only way to approach if you are going to guarantee success in the unlikely event of a donk failure post LDP."
....been there....proved that
Onya XNR WDE cobbers!
Are you sure about that 30 degrees on the 412/430? I'm all for steep but that seems excessive.
If you do the math on 1/2 mile at 500 feet, pretty comfortable in my opinion, you are getting just over 9 degrees of glideslope. At 50 knots groundspeed in zero wind you'll get about 750 fpm ROD.
35 knots and you're down to 300 fpm.
30 degrees gives you 1500 feet at 1/2 mile, 1350 fpm ROD at 50 knots, and 890 fpm at 35 knots. I'm not sure my collective goes that low
But you know me Xnr, I trim my turns.....would you trust my math????
If you do the math on 1/2 mile at 500 feet, pretty comfortable in my opinion, you are getting just over 9 degrees of glideslope. At 50 knots groundspeed in zero wind you'll get about 750 fpm ROD.
35 knots and you're down to 300 fpm.
30 degrees gives you 1500 feet at 1/2 mile, 1350 fpm ROD at 50 knots, and 890 fpm at 35 knots. I'm not sure my collective goes that low
But you know me Xnr, I trim my turns.....would you trust my math????
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Steve 76: I'm not sure you want to "kick it out of balance" if your flying a 76 with allison engines; there have been numerous incidents where the oil skavenge pumps have cavitated and therefore been unable to return the oil to the reservoir ultimately causing the engines to run out of oil necessitating an emergency landing.
This has happened to 3 carriers in Canada including the one you fly for.
Got to run they've called my flight.
This has happened to 3 carriers in Canada including the one you fly for.
Got to run they've called my flight.
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30 degrees approach???
Hi bladestrike!
Just to confirm,
Do your calculations give you 1500 feet above the heliport/ helideck @ half mile back?????( given a 30 degree slope??)
If so, can anyone validate this approach procedure/ angle.....all you fellow offshore dudes and ems guys as well.
I've never seen this done on normal op's.
Thanks.
D.K
Just to confirm,
Do your calculations give you 1500 feet above the heliport/ helideck @ half mile back?????( given a 30 degree slope??)
If so, can anyone validate this approach procedure/ angle.....all you fellow offshore dudes and ems guys as well.
I've never seen this done on normal op's.
Thanks.
D.K
There's 6080 feet in a nautical mile, half that is 3040 feet.
Tha tangent of 30 degrees mulitplied by 3040 gives you 1755 feet (Tangent of an angle is opposite over adjacent in a right angle triangle), so its actually abit better than the 1500 I very roughly rounded too.
I'm certainly not advocating that steep of an approach, as any groundspeed will give you a very high rate of descent, I was just questioning my old buddy Xnr's 30 degree claim. It seems extreme to me.
Using the same math 500 feet at a half mile gives you a 9.34 degree slope, which is about what I would recommend.
If my math is off, and it works out to something more reasonable, I'll buy the first five rounds next time Xnr is in town.
Tha tangent of 30 degrees mulitplied by 3040 gives you 1755 feet (Tangent of an angle is opposite over adjacent in a right angle triangle), so its actually abit better than the 1500 I very roughly rounded too.
I'm certainly not advocating that steep of an approach, as any groundspeed will give you a very high rate of descent, I was just questioning my old buddy Xnr's 30 degree claim. It seems extreme to me.
Using the same math 500 feet at a half mile gives you a 9.34 degree slope, which is about what I would recommend.
If my math is off, and it works out to something more reasonable, I'll buy the first five rounds next time Xnr is in town.
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sounds reasonable
Your math jives well, Bladestrike !!!
I've been going through the numbers here and compared them to how my company wants us to operate our a/c.
Basically, for me, I set up 700-800 agl( max. 1000agl) base leg, one mile back at approx. 120 kts. Turn onto final, then decel the a/s from 120 to achieve 74kts @ 500agl...... 50kts@ 100agl......and so on. All this given into wind, no obstacles.....
Any other input from you guys/gals.
BTW....S76A
D.K
I've been going through the numbers here and compared them to how my company wants us to operate our a/c.
Basically, for me, I set up 700-800 agl( max. 1000agl) base leg, one mile back at approx. 120 kts. Turn onto final, then decel the a/s from 120 to achieve 74kts @ 500agl...... 50kts@ 100agl......and so on. All this given into wind, no obstacles.....
Any other input from you guys/gals.
BTW....S76A
D.K
Thats the numbers the Cat A approach calls for if I recall, but personally, I found 50 knots a tad quick at 100 feet, requiring a very well-timed flare. I preferred about 40 knots and 40% Q and then loading her up but below 55% until over the deck, coming into a farely high hover with very little flare. Big hairy flares or dragging your arse low over the edge of the deck always makes me nervous. At night and/or with any tail-wind and/or snow on the ground, things could get fun, especially with the cone sites you guys go into.
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IHL, all depends how long you fly the aircraft out of trim.
If you need to fly it out of trim for the final 30sec's before landing, why not do it and actually see where you are going to put the aircraft.
You never know if another aircraft is already on the pad.....
If you need to fly it out of trim for the final 30sec's before landing, why not do it and actually see where you are going to put the aircraft.
You never know if another aircraft is already on the pad.....
I found that to arrive 400ft above the target landing area at bang on 60kts would carry a comfortable controlled approach to the hover. Keep the ROD at 500ft a minute and it is lovely and smooth...
Trick is to arrive at 400agl and 60kts at zero ROD. That's the perfect position for the profile. Too many lads let the nose tuck and it bu&&ers the whole approach. What do BS and DK reckon? Where are you OffshoreIgor!
At night even more cautious with lots of power in earlier and absolutely no more than 500ft ROD. Leaves one with no suprises at the bottom.
Thanks for that IHL. Never heard of the scavenge pumps running dry....first I heard of it. Will check it out.
Start scoping your airport for the site XNR..... If you need help with the site map lemme know.
Trick is to arrive at 400agl and 60kts at zero ROD. That's the perfect position for the profile. Too many lads let the nose tuck and it bu&&ers the whole approach. What do BS and DK reckon? Where are you OffshoreIgor!
At night even more cautious with lots of power in earlier and absolutely no more than 500ft ROD. Leaves one with no suprises at the bottom.
Thanks for that IHL. Never heard of the scavenge pumps running dry....first I heard of it. Will check it out.
Start scoping your airport for the site XNR.....
If you need help with the site map lemme know.
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well said
True enough Steve76!
On the last bit of the approach, I tend to load up the disc to achieve as you stated, a comfortable 500fpm rod. For myself, I am comfortable PASSING 50 kts/ 100 ft and then decel. further to 35 kts....disc loading up more.... approx. 40 % torque. All that's left at the bottom is a slight aft cyclic input..about 10% nose up flare.... level and pull pitch into the hover.
Regarding your post about the junior co-joes. Try having them fly around at 35kts level flight. Maybe that will show them power and airspeed control at the bottom end of a textbook approach.
Maybe it wont!!! What do I know??
P.S.
Tis true about the oil pumps cavitating with I believe a left pedal input/ out of trim approach.( A models as far as I recall)
D.K
On the last bit of the approach, I tend to load up the disc to achieve as you stated, a comfortable 500fpm rod. For myself, I am comfortable PASSING 50 kts/ 100 ft and then decel. further to 35 kts....disc loading up more.... approx. 40 % torque. All that's left at the bottom is a slight aft cyclic input..about 10% nose up flare.... level and pull pitch into the hover.
Regarding your post about the junior co-joes. Try having them fly around at 35kts level flight. Maybe that will show them power and airspeed control at the bottom end of a textbook approach.
Maybe it wont!!! What do I know??
P.S.
Tis true about the oil pumps cavitating with I believe a left pedal input/ out of trim approach.( A models as far as I recall)
D.K
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Hey Blade
The portion of the approach from LDP to the pad Cat A for the 412 shows a 30 degree approach angle.
Don't have the supplement at home but I will check it at work tomorrow to confirm.
Yes it is very steep.
Cheers Buddy
D.K.
Passing thru 100' at 50 knots to a helipad seems pretty fast to me and you only need 10 degrees nose up to slow her down.....she must be pretty nose heavy.
The portion of the approach from LDP to the pad Cat A for the 412 shows a 30 degree approach angle.
Don't have the supplement at home but I will check it at work tomorrow to confirm.
Yes it is very steep.
Cheers Buddy
D.K.
Passing thru 100' at 50 knots to a helipad seems pretty fast to me and you only need 10 degrees nose up to slow her down.....she must be pretty nose heavy.
What I find is that for an approach to a rig commencing from 500' AMSL, start slowing down for a straight in approach at 40 seconds to run off the GPS, fairly positively, usually the power is down around 82-84% N1 (in the C model). Hold 500' until the profile fits, lining up the end of the pitot tube with the helideck and then start your descent.
One interesting thing I find quite consistently is that (roughly) your Radalt height equals your groundspeed X 10. Ie at 400 AGL/GS 40 Kts, 300 AGL/GS 30 Kts etc. ROD is bang on 500FPM. I use the far side of the helideck as my aiming point for the approach angle, this seems to bring me in over the pad not too low and not too high. Torques are usually well below 50% until coming over the deck so I think no probs landing on should an engine fail after the LDP.
Try it and let me know what you think.
One interesting thing I find quite consistently is that (roughly) your Radalt height equals your groundspeed X 10. Ie at 400 AGL/GS 40 Kts, 300 AGL/GS 30 Kts etc. ROD is bang on 500FPM. I use the far side of the helideck as my aiming point for the approach angle, this seems to bring me in over the pad not too low and not too high. Torques are usually well below 50% until coming over the deck so I think no probs landing on should an engine fail after the LDP.
Try it and let me know what you think.
