Best Takeoff and landing procedures from oilrigs
Thread Starter
Join Date: Jan 2011
Location: Univers
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for everyone's contribution
I was actually trying to stimulate a discussion on more detailed aspects of the helideck procedures, specifically:
Takeoff
Landing
I appreciate any useful feedback from all the operators
I was actually trying to stimulate a discussion on more detailed aspects of the helideck procedures, specifically:
Takeoff
- Is the takeoff procedure considering passenger comfort?
- What is considered an acceptable maximum TDP height, rate of climb to and pitch down attitude after TDP
- What are the crosswind limits considered
- What are the minimum power margins (AEO) accepted
- What kind of climb and at what speed is achieved to reach cruise altitued
Landing
- What maximu height is acceptable for the LDP
- What maximum ground speed is acceptable at LDP
- What is the minimum height at which start the descending to reach LDP
- What speed is the best reference parameter (IAS or GS) to define LDP
I appreciate any useful feedback from all the operators
Join Date: Oct 2003
Location: Over here
Posts: 1,030
Likes: 0
Received 0 Likes
on
0 Posts
IME, passenger comfort and preference are not considered at all.
Once upon a time, we loaded the helicopter to max gross weight, and if it hovered at 100% torque or less, that was close enough. Hover to the edge of the deck, get the rotor over the water and the skids (or wheels) at the very edge, and hold the hover completely steady, moving nothing. Wait for enough wind to come up to get more lift, and then go over the edge. Use judgement to prevent going forward too soon, so as to not hit the tail rotor on the fence. If you couldn't get off at gross, you weren't going to last as a pilot unless you had pictures of bosses or some such. These days, performance charts may actually be used, but certainly not always. Newer aircraft have better performance, and PC2 takeoffs are usually possible. Get a stable hover in the center of the deck, pull collective briskly to reach 100% torque or other first limit, at ~10ft call rotate, and put the nose down to accelerate. The exact nose-down attitude isn't specified AFAIK, but it should be enough to accelerate somewhat quickly. The climbout speed should be Vy, or thereabouts, and you want to reach it as soon as practical. Airspeed is life, even in a twin.
For landing, it seems to vary a lot. I want to start the descent from ~300' above the deck. Once the descent starts, I don't care about airspeed, just groundspeed. Airspeed varies wildly, depending on the wind speed. The wind might actually be a little behind you, depending on the rig. Sometimes you simply cannot approach into the wind, and there are various ways around that. None of them that I know of consider airspeed, at least late in the approach. Part of the PNF's callouts should be rate of closure, both vertically and horizontally from the GPS. We didn't have that years ago, but now it's always there, so why not use it.
Once upon a time, we loaded the helicopter to max gross weight, and if it hovered at 100% torque or less, that was close enough. Hover to the edge of the deck, get the rotor over the water and the skids (or wheels) at the very edge, and hold the hover completely steady, moving nothing. Wait for enough wind to come up to get more lift, and then go over the edge. Use judgement to prevent going forward too soon, so as to not hit the tail rotor on the fence. If you couldn't get off at gross, you weren't going to last as a pilot unless you had pictures of bosses or some such. These days, performance charts may actually be used, but certainly not always. Newer aircraft have better performance, and PC2 takeoffs are usually possible. Get a stable hover in the center of the deck, pull collective briskly to reach 100% torque or other first limit, at ~10ft call rotate, and put the nose down to accelerate. The exact nose-down attitude isn't specified AFAIK, but it should be enough to accelerate somewhat quickly. The climbout speed should be Vy, or thereabouts, and you want to reach it as soon as practical. Airspeed is life, even in a twin.
For landing, it seems to vary a lot. I want to start the descent from ~300' above the deck. Once the descent starts, I don't care about airspeed, just groundspeed. Airspeed varies wildly, depending on the wind speed. The wind might actually be a little behind you, depending on the rig. Sometimes you simply cannot approach into the wind, and there are various ways around that. None of them that I know of consider airspeed, at least late in the approach. Part of the PNF's callouts should be rate of closure, both vertically and horizontally from the GPS. We didn't have that years ago, but now it's always there, so why not use it.
Join Date: Dec 2006
Location: UK and MALTA
Age: 61
Posts: 1,297
Likes: 0
Received 18 Likes
on
4 Posts
Margins,
Safety in offshore landings is about momentum!
During take-off you want as much as possible before you commit to crossing the deck edge. This takes precedent over PAX comfort and all modern profiles and performance systems are written to generate this momentum.
Landing however is the exact opposite. We want as little vertical momentum as possible as we cross the deck edge. We don't want to give the Devil a head start if the engine fails. For this reason, most committal points are at slow speed, near zero ROD, as close to deck edge as possible at around 40-50 feet. This is correspondingly much more comfortable for the PAX.
DB
Safety in offshore landings is about momentum!
During take-off you want as much as possible before you commit to crossing the deck edge. This takes precedent over PAX comfort and all modern profiles and performance systems are written to generate this momentum.
Landing however is the exact opposite. We want as little vertical momentum as possible as we cross the deck edge. We don't want to give the Devil a head start if the engine fails. For this reason, most committal points are at slow speed, near zero ROD, as close to deck edge as possible at around 40-50 feet. This is correspondingly much more comfortable for the PAX.
DB
Join Date: Mar 2010
Location: Across Continents
Age: 65
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
Offshore take off and landings
Margins ,
If you can get hold of the RFM of the AW-139 you'd get a fairly good idea of Offshore take offs and landings including sight pictures for LH or RH side landings .
It however does not answer all you questions of subsequent climbs after the take off segment is complete .
If you have obstructions ,adequate guidance is not provided and would need to be ' intelligently applied '
Hope this helps ??
Cheers
If you can get hold of the RFM of the AW-139 you'd get a fairly good idea of Offshore take offs and landings including sight pictures for LH or RH side landings .
It however does not answer all you questions of subsequent climbs after the take off segment is complete .
If you have obstructions ,adequate guidance is not provided and would need to be ' intelligently applied '
Hope this helps ??
Cheers
Join Date: Dec 2003
Location: texas
Posts: 117
Likes: 0
Received 0 Likes
on
0 Posts
The technique about hovering to the deck edge that Gomer Pylot described worked pretty well in the 214ST.
In the 76, I found that for a gross weight takeoff into the wind a little trick about the pedals. If your hover was near 100% torque over the deck, reposition to the deck edge with the nose 10-20 degrees left of the wind line. Set the AC back down and lower the collective to eliminate rotor wash. When ready, pull collective to 100% and as the AC lifts and the nose goes forward, feed in a little right pedal and pull more torque, still not exceeding 100%. Now the caveat. This technique is not for someone new to the aircraft. Needless to say, you screw it up and you will probably overtorque the transmission. Practice when light and work your way up on the loads as you get comfortable.
In the 76, I found that for a gross weight takeoff into the wind a little trick about the pedals. If your hover was near 100% torque over the deck, reposition to the deck edge with the nose 10-20 degrees left of the wind line. Set the AC back down and lower the collective to eliminate rotor wash. When ready, pull collective to 100% and as the AC lifts and the nose goes forward, feed in a little right pedal and pull more torque, still not exceeding 100%. Now the caveat. This technique is not for someone new to the aircraft. Needless to say, you screw it up and you will probably overtorque the transmission. Practice when light and work your way up on the loads as you get comfortable.
Thread Starter
Join Date: Jan 2011
Location: Univers
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
I appreciate all the posts and I would like to thank for the contributions. My aim was to try to stimulate an open discussion on what the offshore operational pilots consider the best techniques and what would be ideal to be achieved, with respect to the type of machine they fly, in the scenario of the operational rules and the challenging conditions they operate, in order to improve safety taking into account the operational constraints.
Thanks again to everyone that has contributed to this discussion
Thanks again to everyone that has contributed to this discussion
Hover power plus 20% or your pushing the limits..
But we've all been there at 100% and no options, it's just not acceptable these days (says the 139 driver, awesome power)
But we've all been there at 100% and no options, it's just not acceptable these days (says the 139 driver, awesome power)
