Helideck Turbulence Report?

[Treg]

I have had a request from a client about a "Helideck Turbulence Report" for a new ship. Can anyone offer advice as to who would supply one, or is it left to the airmanship of pilots using the deck?

Cheers

[Troglodita]

Turbulence

Treg,

UK CAP 437 (Used a a standard document for helideck inspections in virtually all non FAA locations worldwide) refers to Air Turbulence in three places.

• Once with reference to operations to merchant vessels fitted with non standard landing areas.

• Once with reference to poop deck operations to vessels.

• Once in the suggested check list to be used during any deck inspection.

Bottom line is that it is up to a qualified deck inspector (usually HCA trained) of the helicopter operator (or HCA inspector in the UK or overseas if they are so contracted) to identify areas of possible turbulence for specific relative wind conditions for a helideck on any structure.
The findings will then be included in the helideck clearance report often included in the Operations Manual Part C (for JAR compliant ops)
For fixed structures, the "turbulent sectors" will often have a maximum wind speed and direction for unrestricted/restricted or NO Operations.

Much more to this than originally meets the eye.

Cheers

Trog

[Treg]

Thanks mate, I will pass your advice on.

[SARREMF]

There is a company that we have used before for just this activity. I think their web address is www.helidecks.co.uk. The chap who runs it is very helpful give him a call, he may well give you advice over the phone as to where to start. Hope this helps.

[Troglodita]

Helideck Certification Agency

http://www.helidecks.org/helidecks/h...s_abouthca.asp

Above link to the HCA website.

These guys took over from BHAB and are now responsible for Helideck Standards in the UK and Norwegian sectors of the North Sea.

Cheers

Trog

[JimL]

Treg,

Apart from talking to the team at HCA, you could do no better than to visit the CAA site and pull down "CAA Paper 2004 - Helicopter Turbulence Criteria for Operations to Offshore Platforms":

http://www.caa.co.uk/application.asp...detail&id=1390

Alternatively approach the International Chamber of Shipping and ask about their "Guide to Helicopter/Ship Operations" (although this is in the process of being amended, the staff at ICS will point you towards the experts).

Jim

[RVDT]

Also keep in mind that depending on the type of operation PVT or COM, and the "flag state" of the vessel and/or aircraft, you probably will not need it.

[Troglodita]

To RVDT

Also keep in mind that depending on the type of operation PVT or COM, and the "flag state" of the vessel and/or aircraft, you probably will not need it.

Mmmmm!

Maybe this explains why most incidents of helicopters striking objects on or adjacent to helidecks (Onshore or Offshore or on vessels) occur in areas where there are no rules or the rules are so lax (e.g. API in the GOM) that helipad, rig or vessel operators pare down or ignore any regulations that will cost them money or cause them inconvenience!

[RVDT]

Trog,

Didn't see any reference to Treg's post regarding where the "new ship" is going to be operated or who was going to land on it and in what capacity.

You seem to have assumed it would be in UK / EU / JARLAND.

Is this a wind up or just being a "troll" for someone with a commercial interest?

Treg, SARREMF, Troglodita - jobs for the boys a bit slow this week, Mr Cholmondely-Smythe?

Over to the Mod.

[Troglodita]

Standards

You seem to have assumed it would be in UK / EU / JARLAND.

Is this a wind up or just being a "troll" for someone with a commercial interest?

RVDT - My point (As a current offshore Pilot but also HCA qualified deck inspector - unpaid!) is that it should not matter where the vessel or rig or platform is registered or operated.
Any Operator should inspect a facility with SAFETY OF OPERATIONS as the primary concern - not "What can we get away with?" We are not being paid to put ourselves or our passengers in harms way.
CAP 437 which is generally regarded as the best written set of standards available is merely a better explained version of ICAO Annexe 14 Part 2 which recommends standards for all ICAO Contracting States which covers a pretty big part of the globe.
The system in the USA (Non ICAO) has been historically to operate to API (American Petroleum Industry) guidelines. The unfortunate result of this was a rash of helidecks especially on run down "Mom & Pop" platforms but even on locations owned and operated by the "Majors" which were built or maintained to the absolute minimum specs that the person picking up the tab could "get away with"
These specs were so far below the minimum standard recommended by ICAO that it was hardly a surprise that helicopters came into contact with obstructions on or adjacent to helidecks.

The API standard is being superseded even in the US by more stringent requirements which is a trend that I am suggesting should be supported by us no matter how few regulations exist wherever we are working.

Trog

[212man]

The system in the USA (Non ICAO)

Sorry to be a pedant - though I accept that it is not at all obvious that the US is an ICAO contracting state, it actually is:

http://www.icao.int/cgi/statesDB4.pl?en

[Troglodita]

Thanks 212 Man

Thanks Mate - I was as surprised as you suggest when I saw them on the list when I was arguing over the Annexe 6 Helicopters "Definition of Flight Time" with a bunch of Die Hard GOM Good Ol Boys several years ago. They seem to lag slightly behind Andorra and the Cook Islands when it comes to active input to ICAO matters.

What I was suggesting was a total non compliance with any of the recommendations and no notification of differences to these recommendations - e.g. Canada states that deck sizes will be based on Rotor Diameter rather than "D" value which is overall length.

Their decision to trust helideck standards to the Petroleum Industry rather than follow ICAO or even set up a dedicated division of the FAA suggests "Big Oil" $$$$ at work in Washington even if it is not true.

A mythical scenario?

OK Guys - I have 2 helideck designs here -

• this one meets all the ICAO recommendations and costs $20 million
• this one was designed by Chuck the toolpusher and costs $2 million

Which one should we go for?

[peterperfect]

Treg,
The reference documents provided by the previosu ppruners are all valid, but if it is a modelling of the airflow your contact is looking for, I saw a presentation from BMT Fluid Mechanics of Teddington UK and they do that sort of thing. Find them by googling.
pp

[JimL]

Yes Peterperfect - and they did it again yesterday at the RAeS; always entertaining and Stephen Rowe is a master presenter. However the material is contained in the CAA paper - the reference to which I provided earlier.

Jim

[albatross]

Interesting short paper on the subject

http://www.fluent.com/solutions/marine/pdfs/ex190.pdf

While not providing a solution. -This may be of interest.

lots of other neat stuff on this site.

Cheers
Albatross

[Phrogman]

So is the "new ship" commercial or a private ship? Trog's points about the regulations on this stuff is on the mark. It still amazes me how many pilots go out and do ship landings underway with no formal training (a popluar subject to me). There is so much more to that initial question that started this thread than turbulence evaluation. One should look at the type of helicopter to be used, skidded or wheel, deck ratings, surface, pitch & roll limit evaluation, tie down capability...the list is long. But at the end of the day, it is that pilot I worry about the most because most assume it is like landing on a dolly in front of the hangar (an analogy I once heard from a person who's picture should be next to the definition of Moron in the dictionary).

[BASys]

FPSO Helideck

Hi Folks

Albatross -
Cheers for the Fluent link.



Surprised at the FPSO document content,
and lack of context that it relates to a failure state,
particularly given the wind velocities inferred by the bottom diagram.

AFAIK
The Leadon FPSO, (Kerr-McGee’s Global Producer III),
should remain head-to-wind at all times, weathervaning on the riser turret.

Together, the turret and swivel system
allow the ship to rotate into the prevailing wind
while maintaining oil, gas, and water production.

Interested to know if there's an issue with
Leadon maintaining head-to-wind,
or any other FPSO/FSU with a fore-ends helipad.



ATB
Paul

[Troglodita]

The orientation of a FPSO or similar using a swivel and turret system will depend on the resultant of wind and tide i.e. there will often be occasions when the wind can come from the rear of the vessel causing potential temperature increase or (less commonly) turbulence from the hot exhaust gases.

The problem with this scenario is that the bad orientation normally coincides with low wind velocities so that the increased temperature and low windspeed have a greater effect on power margins on approach and departure.

A similar scenario exists on storage tankers moored to SBM's. One solution often used is to permantly employ a tug vessel to choose the preferred orientation.

Trog

[BASys]

Hi Folks

Cheers Troglodita
Tide...... Hide's head in shame.
I really should have known better.

Though as previously noted,
the wind velocity inferred by the bottom diagram was not 'low'.

Additionally, given the vessel's windage,
and that the tidal streams are < 1kt
I'd expect head to wind be maintained.

No idea if Leadon/GP3 has -

• Active drive mechanism for turret rotation.
• Thrusters to allow controlled positioning of vessel in variable weather conditions.

Are these used to offset FPSO vessel heading
ensuring helideck approach/depart is sufficiently clear of exhaust plume ?

Many thanks
ATB
Paul