S92 start/shut down wind question.
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S92 start/shut down wind question.
Hi,
As a regular in the back of N Sea flights, I hope you dont mind me asking a question but a situation came up yesterday I cant find an accurate answer for.
Thanks to multiple flights, triggered lightning and a VIP visit to the rig I am on yesterday a situation occured where the S92 could have shut down n deck but was unable due to the wind. I know its a startup shutdown windspeed issue to avoid blade flap and resultant really loud banging noises from the tail boom but my question is, is there a stated windspeed value for S92 in oilfield N Sea operations above which startup shutdown is forbidden?
Thanks
As a regular in the back of N Sea flights, I hope you dont mind me asking a question but a situation came up yesterday I cant find an accurate answer for.
Thanks to multiple flights, triggered lightning and a VIP visit to the rig I am on yesterday a situation occured where the S92 could have shut down n deck but was unable due to the wind. I know its a startup shutdown windspeed issue to avoid blade flap and resultant really loud banging noises from the tail boom but my question is, is there a stated windspeed value for S92 in oilfield N Sea operations above which startup shutdown is forbidden?
Thanks
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In a nutshell, yes, the maximum wind speed for a planned offshore startup or shutdown is 35kts for the S92, arguably this includes gust, which yesterday were quite severe.
The crew also need to consider the turbulence coming off the rig or is the deck sheltered from the wind. In yesterdays conditions they would make a dynamic risk assessment of whether shutting down or remaining rotors running is the safest option, they will always go for the safest option. If they elect to shutdown they need to consider how long they may be shutdown and if they can tie the blades down, this may require a working at height permit which can take time. If you have a technical issue and the rig has fuel, it will often be safer to remain rotors running while troubleshooting the issue and speaking to the engineers onshore.
Next time I would advise asking the pilots, they will always be willing to chat to the passengers about their decisions.
The crew also need to consider the turbulence coming off the rig or is the deck sheltered from the wind. In yesterdays conditions they would make a dynamic risk assessment of whether shutting down or remaining rotors running is the safest option, they will always go for the safest option. If they elect to shutdown they need to consider how long they may be shutdown and if they can tie the blades down, this may require a working at height permit which can take time. If you have a technical issue and the rig has fuel, it will often be safer to remain rotors running while troubleshooting the issue and speaking to the engineers onshore.
Next time I would advise asking the pilots, they will always be willing to chat to the passengers about their decisions.
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Thanks for the answer, unfortunately i was not in a position to ask the pilots as i was not lucky enough to be departing yet myself but more in a position wondering when the vips would leave.......
Interesting info though, ta.
Interesting info though, ta.
I'm assuming it's an operator limitation imposed with a buffer to cater for unexpected increases in speed that then put the aircraft outside limits for start. I remember an operator shut an S76 down in the SNS, and the wind pick up so quickly that the crew were unable to get to the aircraft from the restroom before a blade had been bent up and written off.
Yes there is a big difference between planning to shutdown - ie departing base to visit a rig to shut down for hours, versus having to shut down on the spur of the moment due to a problem and then restarting. The former has to have a big buffer as funnily enough, the offshore weather forecast is not always totally accurate! The latter can be based on the actual conditions of the moment and RFM limits.
We carried a 2 part aluminium pole with slots cut in the end that allowed us to install the tiedowns without "working at height". Worked well when required, which was not very often.
In a nutshell, yes, the maximum wind speed for a planned offshore startup or shutdown is 35kts for the S92, arguably this includes gust, which yesterday were quite severe.
The crew also need to consider the turbulence coming off the rig or is the deck sheltered from the wind. In yesterdays conditions they would make a dynamic risk assessment of whether shutting down or remaining rotors running is the safest option, they will always go for the safest option. If they elect to shutdown they need to consider how long they may be shutdown and if they can tie the blades down, this may require a working at height permit which can take time. If you have a technical issue and the rig has fuel, it will often be safer to remain rotors running while troubleshooting the issue and speaking to the engineers onshore.
Next time I would advise asking the pilots, they will always be willing to chat to the passengers about their decisions.
The crew also need to consider the turbulence coming off the rig or is the deck sheltered from the wind. In yesterdays conditions they would make a dynamic risk assessment of whether shutting down or remaining rotors running is the safest option, they will always go for the safest option. If they elect to shutdown they need to consider how long they may be shutdown and if they can tie the blades down, this may require a working at height permit which can take time. If you have a technical issue and the rig has fuel, it will often be safer to remain rotors running while troubleshooting the issue and speaking to the engineers onshore.
Next time I would advise asking the pilots, they will always be willing to chat to the passengers about their decisions.
Yes there is a big difference between planning to shutdown - ie departing base to visit a rig to shut down for hours, versus having to shut down on the spur of the moment due to a problem and then restarting. The former has to have a big buffer as funnily enough, the offshore weather forecast is not always totally accurate! The latter can be based on the actual conditions of the moment and RFM limits.
skadi
60 for engagement
60 knots seems a bit high, the brain cells suggest 45 knots.
It was certainly 60 knots for operating on a deck with an enroute wind of 75.
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35 knots is an ops manual planned offshore shutdown 'limit'. The RFM obviously allows start and stop at higher speeds with the appropriate procedure. But you don't plan to shutdown offshore at more than 35 knots.
On the 92 in my company.
On the 92 in my company.
Last edited by tu154; 7th Mar 2018 at 20:24. Reason: Added the last line...
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I'm fairly sure the max wind speed for rotor engagement on the S-76s I flew (A, A++, B, C, C+, about 4,400 hours in total) wasn't as high as 60 kts.
It's well over ten years since I last flew the type but I think the manufacturer's limit was 40 kts. It would be a brave operator who disregarded that.
Edit: Just found my old SK-76 question bank, as issued by Flight Safety International. 40 kts was the rotor engagement wind speed limit.
It's well over ten years since I last flew the type but I think the manufacturer's limit was 40 kts. It would be a brave operator who disregarded that.
Edit: Just found my old SK-76 question bank, as issued by Flight Safety International. 40 kts was the rotor engagement wind speed limit.
Last edited by ShyTorque; 7th Mar 2018 at 20:16. Reason: As above
I'm fairly sure the max wind speed for rotor engagement on the S-76s I flew (A, A++, B, C, C+, about 4,400 hours in total) wasn't as high as 60 kts.
It was certainly 60 knots for operating on a deck with an enroute wind of 75.
Around 1980 the helideck crews where told to stop attaching ropes between the access stairway and the helicopters structure so that the passengers had something to hold onto crawling across the deck.
Quite frequently used the attached safety line routine....but that was in the Cowboy Days of the North Sea.
Some commonsense has crept into and out of Ops since then it appears.
More than a few aircraft got damaged while shutdown and tied to the decks during the early days of offshore shuttle operations where the aircraft lived on an open deck.
Some commonsense has crept into and out of Ops since then it appears.
More than a few aircraft got damaged while shutdown and tied to the decks during the early days of offshore shuttle operations where the aircraft lived on an open deck.
