Pitch & Roll Limits - Oil Rig Deck

[CAMSHAN]

Could anyone please help with the pitch and roll limits for a Jet or Long Ranger on an oil Rig deck please. I need this info. for the use of a Jet Ranger landing and transporting crew to and from an oil rig. Any ideas on the limitations as well please on the shutdown and limits with the blades pitching and rolling with the deck. Most appreciated.

[Gomer Pylot]

I don't recall exact numbers, but I've landed and taken off on a rig that was pitching at least 10 degrees, maybe more. It was an independent-leg jackup that got into rough seas, tried to jack the legs down, but took seawater into a motor and got a leg stuck halfway. The tugs couldn't hold it, so I was sent out to evacuate all the 'non-essential' personnel. It was quite a ride, and I just waited until the deck was coming level and pulled pitch on the takeoff. The landing was much easier, because I was empty, and only had minimum fuel because the rig was only about 5 miles off the beach. I certainly wouldn't try to shut a 206 down in those conditions, but as long as it doesn't slide around on the deck, it's not a huge problem as long as you keep the rotor level with the deck, not the horizon. Under normal circumstances, there's no need to take the risk. I've also landed on pitching boats, tenders and barges over the years, with no ill effects to anything other than my stomach.

Again, the real problem can be the helicopter sliding on the deck. Some decks are very slick and uneven, while some are very skid-resistant. It's impossible to say from long distance, or even up close in many cases, until you put the skids on the deck and see what happens. Do not send out a new guy for this.

[flyer43]

I think there is a little more to worry about than simply sliding about on the deck. If you know just how much lift is really generated by a rotor system at flat pitch in a reasonable wind, then convert that into a horizontal component due to the pitch or roll of the helideck, you'll be surprised at how easy it can be to roll any helicopter on a sloping surface, with or without and sliding around.
As for accepting 10 degrees of movement - hopefully you mean full movement, i.e. 5 degrees either way, even then it is a pretty large movement by public transport standards!
Another consideration - is the 206 mentioned on high or low skids? This will also affect the maximum pitch and roll limits as the height of the C of G will be different, changing the likelihood of a rollover........... and I don't mean the sort you get on the lottery.

CAMSHAN - It worries me that you seem to be prepared to conduct operations to moving decks without any prior experience or training. Shouldn't you think more of your clients and ensure that you can operate safely before you offer the service???????

[NickLappos]

The motion of the deck is only one factor, the wind is a bigger factor, IMHO. I have investigated roll-overs where the combination of angle and wind created hazardous contitions where the basic zero wind slope capability of the helicopter was easily met.

Cross winds are the problem, of course. With wind from the high side of the deck, the double whammy can get you. The issue is usually not the slope/lateral stick capability of the helo, it is the fact that with Pax milling about, you don't dare use that much stck (disk tilt).

flyer43 is right, use extremely conservative numbers until you get your operations down pat, and recognize that deck procedures are as important as cockpit.

I investigated one tragedy where the helo was on a barge, in 25 knots of wind, when the barge was turned to take the wind abeam. The pilot had a sandwich in his hand, and the crew change was millng about the deck. The deck angle increased and the wind went to accompany it, and the aircraft rolled over.

[peterperfect]

Camshan,

Contact your local CAA for advice, absolutely don't fly offshore until you are competent and qualified. Huge number of issues you should seriously consider before leaping offshore, starter: are you insured should you write off the whole rig ?, yes it is possible even with a 206 !!

The UK CAA produce CAP 437 (Offshore Helicopter Landing Areas)which you can download for free in .pdf format I believe from their website, that will show you how many considerations needed to be taken into account (if flying under UK jurisdiction though, which you are not) but will show you how many factors, apart from experience and training need to be considered.

UK BHAB website again gives advice (again for UK) find it in google

Colin Sole on 27 83 229 4847 is pretty savvy on oil support operations; he's based in Joburg.

Which Oil Company want you to do this, don't they have standards or requirements that you must satisfy before flying their staff and to their platform ??

Take care, hope you have safe flying onshore until you get up to speed.

pp

[Gomer Pylot]

I agree with Nick that the wind is a big factor, and Bells don't like crosswinds. A large drilling rig moves rather slowly, even if the ultimate tilt may be large. Legs that are several hundred feet long don't change direction quickly, about any axis. A barge or seismic boat is more of a problem here, IME, because it changes direction much more quickly and the pitch can be much higher. The most stable moving platform I've landed on is a fully-loaded ULCC - supertankers don't pitch and roll very much.