What is the circle on a helideck for?

[Mars]

At the moment there is some discussion about helideck markings.

Exactly what is function of the circle on the helideck? What size is it and what do pilots use it for?

[roundwego]

Extracted from UK CAA publication CAP 437
Offshore Helicopter Landing Areas - Guidance
on Standards;-

Aiming Circle -
Described in other publications as ‘landing circle’ or ‘touch down
marking’; the aiming point for normal landing, so designed that the
pilot’s seat can be placed directly above it in any direction with
assured main and tail rotor clearances.

Full document available at www.caa.co.uk/docs/33/CAP437.PDF

[HeliComparator]

No, surely its an entertainment device - hours of fun competing for the sticky buns with the copilot to see who can land with the aircraft exactly in the centre (trouble is they usually win!)

HC

Oh you wanted a sensible answer?....

Well first its an aiming point and approach aid (approach angle measured by degree of apparent oval-ness (?)

Then it helps you to land in the best part of the helideck to maximise distance from bits of your aircraft to the nearest obstacles.

But where should you land on it? Conventional wisdom says bum on line but surely that depends on the geometry of your aircraft? Bum on line worked well for S61 with its long fuselage in front of the rotor hub, but I suspect its puts you too far forward on a Super Puma. But pilots being conservative chaps, stick to what they did 20 years ago! (and probably better too far forward than too far back).

As to size, doesn't that depend on the D value of the deck?

HC

[teeteringhead]

And as a known shape, it facilitates the assessment of approach angle, and/or (more importantly) change in approach angle - just like a NATO Tee is supposed to .....

Except that it will work for all directions of approach.

[SASless]

How ever did we land on mountain pinnacles or confined areas without them circles to aim at? Heck....no circles on runways either!

If you cannot figure your angle by looking at the entire deck....what in the heck is the circle going to do for you?

If you have a "standard" circle.....what is a standard helicopter?

Throw in a deck edge refuelling point....do you use the circle then?

[teeteringhead]

How ever did we land on mountain pinnacles or confined areas without them circles to aim at?..don't know about you, I always used (and taught) using a backdrop technique....

[13snoopy]

I HAVE A QUESTION!:
What is the netting I see in a lot of photos that is stretched across the decking area where a heli lands for? It would seem like this sort of thing would be dangerous to land on re the chances of a skid getting hung underneath, etc.
Thank you for any reply.

[bondu]

It's main use seems to for twisting the pilot's ankle! Have you ever tried walking across a deck with a new net? Take care!! Should carry a Health and Safety warning! :O

bondu

[Gomer Pylot]

Nets are banned on helidecks in the GoM, and we are prohibited from landing on any deck that has a net. They get caught on the landing gear, and can result in dynamic rollover.

[HeliComparator]

Nets are a hazard for skidded aircraft but in the N Sea everything has huge wheels these days. That said, there is a general move to get rid of nets in favour of high friction surfaces (ie paint with sand in it!) which is definitely better for my ankles.

To answer 13snoopy directly, they are to increase the friction between the wheels and the deck, esp for moving decks so that you don't slide on the deck. Probably also helps to stop you sliding off the edge when you make that unexpectedly OEI landing with lots of fwd speed.

In the good old days also used by passengers to claw their way across the deck in 80kt winds - now not allowed to fly in those conditions I am glad to say!

HC

[LIMIT NOT TARGET]

Don't know about you fancy rig flying blokes, but on tuna boats you lay down fishing net or rope, so said helicopter with metal skids does not slide off said boat with metal roof.

[josi]

Good morning out there

In case of a helicopter crash on a rig helideck you want to cover the deck wit foam, and the net prevents the foam from blowing off the deck.

The new generation of helidecks have high friction surface and therefore they do not need a net.

Take care

O.B. from sunny Denmark
:) :) :) :) :)

[SoundByDesign]

Good morning out there

In case of a helicopter crash on a rig helideck you want to cover the deck wit foam, and the net prevents the foam from blowing off the deck.

The new generation of helidecks have high friction surface and therefore they do not need a net.

Take care

O.B. from sunny Denmark
:) :) :) :) :)

how does a net prevent the foam from blowing off [to the sea]?

in HK they're employed [retractable] on two rooftop helipads to prevent sight seeing PAX and their cameras from falling onto the Rollers [please correct me if wrong].

[MPT]

G'day LNT,

I always preferred the coiled up rope, the nets always concerned me with all the bolts sticking out of a 500's skids!! But given a choice of a bare metal deck or a net........ the way those things move about, you need something more than the "sandy paint". All it does is take skin off when you've had a bit much soju.:=

Cheers,

MPT

[Teefor Gage]

In case of a helicopter crash on a rig helideck you want to cover the deck wit foam, and the net prevents the foam from blowing off the deck.


Never heard such a lot of b*lls in my life. OK, so I have heard worse, but not on a "Professional Pilots" site!!

Nets are banned on helidecks in the GoM, and we are prohibited from landing on any deck that has a net. They get caught on the landing gear, and can result in dynamic rollover.

Nets shouldn't get caught on landing gear if they (the nets) are maintained at the correct tension etc.

Don't know about you fancy rig flying blokes, but on tuna boats you lay down fishing net or rope, so said helicopter with metal skids does not slid off said boat with metal roof.

Helideck nets are generally only used for helicopters with wheels as skids can still slide across the netting very easily. If the metal roof was coated with a high friction surface it would be far safer for a helicopter on skids.

Perhaps the circle is an aiming point for passing military jets!

[SASless]

Tee,

One must remember running takeoffs and landings are closer to the norm in the GOM where Boudreaux HSE standards rule. Perhaps you are under the mistaken idea that Boudreaux bothers maintaining something beyond his fishing equipment and ESPN link?

[helilad]

As heli pilots initially were mostly male,the authorities decided to make an aiming point that was a familiar sight to them.Studies proved a circle resembled something that could be approached from many angles and directions.Some enhanced this further by adding nets etc to give it the "furry" look.

Cautions.

1.Red lights on-danger ahead,go-around.
2.Be careful with wind direction-you may get sucked in.
3.Keep wx-radar on and expect the unexpected.
4.Try to stay upwind to avoid fishy smells.
;)

[farsouth]

Helicomparator - you said "there is a general move to get rid of nets" - is that your observation or a stated policy, as it is contrary to CAP 437

Quote - "Recent experience has shown that the removal of landing nets on some installations
has provided undesirable side-effects. Although the landing net was designed
specifically to enhance the friction properties of helideck surfaces, it would appear
that its textural properties can also provide pilots with a rich set of visual cues in terms
of rate of closure and lateral movement which are essential for pilots in what can
otherwise be a poor cueing environment. Serious consideration should be given to
this aspect before a landing net is removed. The helicopter operator should be
consulted before existing landing nets are removed and Installation operators should
be prepared to replace landing nets if so advised by the helicopter operator in the case
that visual cueing difficulties exist. For these reasons it is also recommended that the
design of new Installations should incorporate the provision of landing net fittings
regardless of the type of friction surface to be provided."

[HeliComparator]

Just my observation, which could be wrong. But in the old days I am sure virtually all helidecks had nets, but now this is by no means true. However this trend may be reversing based on experience as per your quote from CAP437

HC

[check]

Teefor Gage,

I can't believe your post, but if you have no experience offshore, then I do, however if you do have experience you should be concerned at your lack of awareness of what goes on around the helideck.

The net does contain the foam, should you ever watch a fuel fire demonstration on a deck with and without a net you will find that out!

As for nets, their prime function is to contain the helicopter, pilots and passengers are secondary. If you walk on them using a ladder principle then you will have no problem. Walk diagonally and it's difficult. As for tension, that is more difficult, wet or dry the tension is different, hense loose or not so loose. Very few decks use the rubber tensioners which if used correctly mean tight or tighter nets.

I have experienced an inadverdant brake release on a deck without a net, the main clue was the helideck crew making a rapid exit from the helideck. Also there have been cases reported of at least two helicopters moving on guano contaminated decks without nets. Both examples would have been contained if nets were fitted.

Amongst the other posts there are other misconceptions etc. although there are one or two out there who are on the same wavelength as myself.
Pprune or is it just prune?

[tistisnot]

Couldn't agree more .... sadly I suspect he is experienced offshore

[josi]

Never heard such a lot of b*lls in my life. OK, so I have heard worse, but not on a "Professional Pilots" site!!



With a reply that that, I do not understand why The British won the war.
But I do understand why the Vikings conquered England in a few hours.

:ugh: :ugh:

[Teefor Gage]

Come on you guys, try to keep somewhere close to the original thread and don't take comments as personal insults. My comments are mere expressions of my own thoughts, be they good or bad, with the intent of encouraging further discussion on the subject.

I have many years of offshore experience under my belt, both on wheeled and skid fitted helicopters and know only too well how each on reacts on different surfaces, with or without nets, moving or stable.

OK, so a net might help to keep a little foam on the helideck but it is certainly not its primary purpose and I find it hard to believe it would make a substantial difference in the event of a real fuel fire. Maybe one of you less sensitive chaps out there can point me to the source of info on this??

As for lots of helidecks not having the correct tension due to the use of different methods of attachment and tightening, this doesn't surprise me but does demonstrate the ability of both helideck managers and pilots to accept "second best"!! If a net is fitted it should be secured and tensioned properly at all times.

OK, so who have I upset this time?

PS: Don't mention the war!!

[LIMIT NOT TARGET]

For MPT, yes to all, and I also do MPT now, we must love the boat life?

[SoundByDesign]

Starts on page 102:

http://hse.gov.uk/offshore/guidance/helideck.pdf

[helopat]

I HAVE A QUESTION!:
What is the netting I see in a lot of photos that is stretched across the decking area where a heli lands for? It would seem like this sort of thing would be dangerous to land on re the chances of a skid getting hung underneath, etc.
Thank you for any reply.

Snoop,

In the world of military air capable ships (helicopters, not jets) the nets are to make sure that if people get blown over by the downwash they don't go in the drink.

With regard to the original question, the circle on warship decks is designed such that if you put your main wheels anywhere in the circle (assuming, of course that the tail is pointing aft) the main rotor blades won't go 'boink' against anything.

[MPT]

G'day LNT,

Much as I enjoyed my tuna time, this has to be classed as an improvement, if only for the standard of the tucker. I also appreciate the 2nd engine ocassionally, although I do miss the old "sun's gone, time for a quiet ale (or soju)" times. This flying in the dark caper has hairs on it I reckon.:eek:

OK, back to topic. On geared bulk carriers (landing between the crane and the bridge front), if you pick the middle of the circle, you avoid very expensive type noises.:{ That is of course if the circle is the correct diameter, but that's another story entirely.:ugh:

Cheers,

MPT

[B Sousa]

Circle is the same as a Bullseye in Darts. You hit it, you win.....
If there is a number inside....its the amount of times the usual piolt takes to hit it correctly.

As been said its the aiming point for a safe landing for certain size Helicopters, make sure you know that before you take your MI-26 in a small one.
Number inside usually refers to class or size that the pad will support

[check]

I think it is a bit of an old wives tale that the aiming circle is just that and you can judge your approach angle from the ovoid or otherwise shape of the circle. At night you can't see it, you look for the blackest hole and the odds are you will find the deck there, when you get there you find the circle is partially obscured with bird poop, by this time you have almost hit the thing so as an approach aid it is next to useless.

In practicle terms the circle is sized to 50% of the deck size i.e. 16 metre deck, D value of 16. The inner measurement of the circle is 8m. If you land with the nose of the helicopter on the circle (bum line for the S61 drivers, because that's where you put it) you can be sure that the stickyout bits at the back and front will always be clear of obstruction. This only works if you land your helicopter that has a D value of 16 or less, stick your Puma/Tiger or S61 there you have more than one problem. This should't happen because we all know our particular helicopters' D value and the meaning of all the other deck markings.

Helidecks that meet all the requirements are very few indeed and teefor gage is right when he says pilots are to blame. Too many go for the easy life and don't make reports, it is so easy to put restrictions on helidecks that are poor so that sooner or later they bite and repairs/cleaning is carried out.

I can see I'm boring you so I will wind my neck in, until the next time that is.

[JimL]

An interesting thread and a wide spread of ideas: all credit to ‘roundwego’ for the quote from CAP 437; and to ‘Silberfuchs’ for a pointer to the Canadian Regulations and CAP 437 (not yet the JAA Spec.). Interestingly in the Canadian regulations in Fig. 4 Helicopter Decks, the ‘aiming circle’ appeared to be about 0.25D which - if in accordance with the requirement for it to be 6m - would have made the size of the deck about 24m. This appears to be in conflict with the un-amended ICAO Standard which calls for the inner dimensions of the circle to be “half the D value of the helideck or 6m whichever is the greater” (the amended version will specify only an ‘Aiming/Positioning Marking” with the inner dimensions half the D value of the helideck).

Leaving aside the discussion on the net - which was not the subject of the thread but which has been well covered; and an interesting side discussion about the ovality of the deck lights in assessing the glide slope at night (not really sure what the relevance of that was to pinnacle landings); on the original question there appear to be three different schools of thought:

1. Those who thought that the aiming circle was an S61 anachronism, the pilots landing in the centre of the deck; this could work and is an interesting method but does rely upon the (exceptional) judgement of the pilot knowing (a) where the centre of the deck is and (b) more importantly, where the centre of the helicopter is - and matching one to the other.

2. One view that “if you put your main wheels anywhere in the circle…the main rotor blades won’t go ‘boink’ against anything”; once again it would work but it does rather rely upon the main wheels being in the centre of the helicopter (see the discussion later) and in any case, unless it is a small circle in the centre of the deck, there is too much leeway (the size of the deck would then have to reflect that). The circle could be tailored to the particular helicopter and be made smaller to reduce the leeway but why have a circle in which to ‘put the wheels’ when what is required is a ‘visual cue’ for the pilot that can be used without having to see where the wheels are. If, as implied, the tail always has to point aft then no more than a shoulder line would be necessary. (Note that skidded helicopters were not considered.)

3. Those who considered that the circle is a ‘bum line’ on which the pilot positions himself/herself. ‘Check’ - in a well argued post - almost agreed with this but stated that it was the ‘nose’ of the helicopter that had to be on the aiming circle (which with an S76, EC155 or AW139 on a 1D deck, would put the tail two metres into the obstacle environment).

As ‘check’ says, the aiming circle should have an inner circle 0.5 times the declared size of the deck (declared in the markings at the edge of the FATO - not in the aiming circle) with a 1m yellow boundary; it is situated in the middle of the deck unless using the permitted offset of 0.1D (ICAO and CAP 437).

Positioning on the helideck by using the wheels/skids is not accurate enough; the S76, EC155, AW139 have all of their wheels ahead of the centre line; the AS332, EC225 and S92 have their main wheels aft of the centre line and their nose wheels forward; the S61 and S70 have the main wheels forward of the centre line and the tail wheel aft (in the S70 by a considerable distance). The length of undercarriages ranges extensively - suffice to say that if you want to have an area in which the wheels/skids are always contained it will require a circle of 0.83D (centred on FATO).

In spite of variations in size of helicopters and configuration of wheels and skids; for all single rotor helicopters recently examined it was observed that, for a 1D deck, when the pilots seat is positioned on a circle of 0.5D, all of the parts of most helicopters will be within the boundaries of the deck and where there are exceptions, the extent of the overlap of the boundary is measured in centimetres. (Remember that on a 1D deck the main rotor is already at the front edge and the tail rotor (fenestron) at the back edge).

Regardless of the type of helicopter; when landing on a deck (which is of a size of 1D or greater), positioning with the pilot’s seat on the 0.5D (of the size of the helideck) aiming circle will always provide the pilot with the safest option. When using any other method, or when using a circle of any other size, there is a possibility of an unsafe outcome.

Jim

[flyer43]

I wondered how long you would be able to resist this one!! Glad you ventured in though!!

[LIMIT NOT TARGET]

Yeh, we all know that the circle is something to aim for, but, especially on geared ships( ships with cranes and other structures), it all comes down to how smart the cheap arse, slave laboured, non english speaking deck worker, was in reading the measuring tape, with the brush in his hand.

[SASless]

JimL,

Can you put that into plain old tea room English?

It gets back to my questions....what is a standard circle? What is a standard helicopter?

If one flys for Mobil in Nigeria there is no such thing as a standard circle. Those that have flown there can easily describe the railroad track decks (the old wooden decks platforms that had all of the wood removed from the two I-beam supports that required one to land parallel to the I-beams.

Or....perhaps the survey boats that have the fold down helidecks that are marked for small aircraft and not the mediums being used.

The comment about landing on a pinnacle comparison defeats most RN pilots I know. They prefer to arrive at a hover and transition across to the deck as if there is a marshaller waving wands at them clearing them to the 3 Spot.

The elevated helideck is simply a pinnacle landing without the mountains. The deck markings are useful if they have any pertinance to the aircraft you happen to be flying at the time. Angle of descent and rate of closure are discernable by the rig/platform apparant movement and deck alone with the markings being just something else to use to ad detail to the deck surface. Nets work a treat for that purpose as well.

Does this not get back to basics....standard entry height above the water, standard speed, find the angle....maintain the angle and rate of closure till you pick up all those cues as you approach the deck surface. (Remember the old Chinagraph (grease pencil) mark on the windscreen? I will bet you that a survey of decks will show a decided favor of landing towards the uncluttered edge vice bum on circle in the exact center of the deck.

One simply has to know where to place the wheels/skids on each deck to ensure avoiding the 'boinking noises"....and that depends more on the geometry of the landing gear compared to the bits that are flopping about looking for something to beat themselves to death upon than the "D's and .5D's" crap.

[MPT]

G'day All,

LNT, :D :D , I don't actually recall "aiming circles" on the boats, all I know is that I had a leeway of around 3 inches in any direction or the belly hook tie down wasn't in the right position. It certainly taught me to look AT what I'm about to put my skids on rather than out the front!!

SASL, We've seen the "hover over the water" problem with ex navy guys coming into the MPT stuff. It's very scary when they try and hover OGE off the side of a perfectly good IGE deck (especially at night). Quite often, on the ungeared vessels, we completely ignore the circle (non slip paint is the exception rather than the rule on >90% of the ships we see) and land on a clear spot on the marked hatch cover in order to hang the T/R over the edge and out of the way of suicidal crew members:ugh:

Cheers,

MPT

[JimL]

SASless,

Let me attempt to answer two of the questions you have asked - or more correctly put my previous answer into context.

A standard ‘touchdown marking’ (soon to be called the ‘touchdown/positioning marking’) is a circle with the inner diameter of half the ‘D’ value of the helideck; the line width should be 1m. That these circles are not 0.5D in Nigeria does not alter the fact that it is the de jure Standard, only that the Standard is not being applied - the same is true for survey boats.

I totally agree with ‘check’ that a non-standard marking should be reported (confidentially if necessary). Once it has been reported that the ‘touchdown marking’ is incorrectly marked/positioned, any accident/incident that results from the incorrect marking will then be the joint responsibility of the ‘duty holder’ and the ‘operator’; an extremely powerful way of achieving rectification.

The second question - what is a ‘standard helicopter’ was addressed in my first post; to expand further, the 0.5D appears to be a ‘magic circle’ - go to the Flight Manual of your offshore helicopter and measure from the end of the tail rotor to the pilot’s seat, it usually comes out extremely close to 0.75D. There is no such thing as a standard helicopter but, as a generic marking to assist the pilot with the positioning of any helicopter on a helideck, it is as good as it gets (without individual tailoring). The geometry of the undercarriage appears to have no relevance to this equation.

The geometry of the undercarriage does have relevance to the size of the required TLOF - required in the sense that it will work for any helicopter within the D limits of the helideck - which has to be as large as 0.83D.

I would not disagree with your contention “one simply has to know where to place the wheels/skids on each deck to ensure avoiding the ‘boinking noises’” - but it results in an individual exercise for each deck and for each specific helicopter; for that reason I fail to see why you regard the use of ‘D’ and the ‘0.5D’ touchdown marking as crap.

As an initiator of many a call for safer practices, surely you see the logic of the use of an existing, and safe, Standard.

Jim

[md 600 driver]

saw a program on discovery wings last night showing a wasp turning into wind on a ship Lz using the wheels and keeping them in the circle
ITS A MINI ROUNDABOUT LOL

[helopat]

saw a program on discovery wings last night showing a wasp turning into wind on a ship Lz using the wheels and keeping them in the circle
ITS A MINI ROUNDABOUT LOL

Ya know, that reminded me of a coupla crazy Brits back in the Persian Gulf in 1990...I was on a Ticonderoga cruiser at the time with the USN and a Lynx came over for a cuppa. On takeoff we (Seahawk) used to just lift into a hover and depart...very conservative... but these guys wanted to demo how useful it was to have a steerable nosewheel so they turned the wheel and then proceeded to move the nose left and right through about 30 degrees...much to the astonishment of our flight deck marshaller AND the ship drivers on the bridge (watching through the closed cct camera).

Oh, wait, sorry...I didn't mention that we had a circle on the deck...I think all three of their wheels were in it most of the time...there...managed to stay with the thread after all.

[SASless]

Jim,

All that being said and nicely translated....I found the practice, of an operator we both worked for in the past, of doing an inspection of all decks and markings upon start of an operation or when new decks were put into operation worked to prevent any such problems.

As others have mentioned, monitoring the condition of the decks and reporting as a standard procedure by the Safety Officer, Training Captain, Captains, and Chief Pilot works towards discovering problems. A good Safety Program will also have a system that follows up on reported problems and ensures hazardous issues are resolved, shutting down decks if necessary until corrective action is taken.

[JimL]

After considering the responses to this thread, it was clear that, although most were aware of the presence of the circle on the helideck (soon to be also used on heliports), these markings were not in use throughout the world - even though they are essential elements of safety for offshore operations.

The continuing work on Annex 14 Part II (heliports) has resulted in amended Standards and Recommended Practices for helideck/heliports, one of which is the acceptance of helidecks of less than 1D for helicopters below 3,175kg (7,000lbs). There has also been acceptance that even with 1D (or larger) decks, accurate positioning is critical to safe operations (an incident in Norway where a pilot performed a spot turn, without maintaining positioning on the Touchdown and Positioning Markings (TD/PM) - i.e. the bum line, indicated that there was room for further reinforcement of the reasons for markings and accurate positioning.)

In view of that we took a commitment to produce a paper to explain the principles behind the markings, and explain why their use is important. That paper has now been produced and the Helideck Certification Agency (HCA) has kindly agreed to host the paper on their site. It can be found at:

http://www.helidecks.org/download%20files/Touchdown%20and%20Positioning%20Marker%20-%20Paper%20V1%209.pdf

We welcome any comments on this paper and will amend it in accordance with those comments.

NB the revised Standard for helidecks of less than 1D can be found at Appendix C to this paper.

Jim

[3PARA]

& I always thought on warships the circle was there as all You Jolly Jack Tars like a chopper in Your ring :E


I'll get Me coat :}

[topendtorque]

I'll get Me coat http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/badteeth.gif


an, you'll probably be labelled as a "Proper Bastard" as you leave.

me, just lol

[JimL]

Clearly the dangers of manoeuvring on the helideck (as discussed in this thread) are still underestimated.

The statement about the 'height of the helideck skirting' is not really understood. Aren't the regulations about the height of any object on/surrounding the helideck being observed? It was matter of extensive debate in the ICAO heliport working group, where the US were lobbying for a reduction (in Volume II).

Jim


NTSB Identification: CEN11CA232
14 CFR Part 91: General Aviation
Accident occurred Thursday, March 17, 2011 in Gulf of Mexico, LA
Aircraft: BELL 230, registration: N974RH
Injuries: 1 Uninjured.

The pilot was asked to reposition the helicopter on the helideck to make room for a helicopter that was coming in to land. He performed a walk around inspection of the area, and was aware of the location and height of the helideck safety skirting. During the repositioning landing, the pilot felt a high frequency vibration and the helicopter began to shudder. After the accident, a piece of tail rotor skin was found lodged in the skirting. The tailrotor had impacted the skirting. Substantial damage occurred to the helicopter's tailboom. The pilot reported that there were no mechanical malfunctions with the helicopter in reference to the accident flight.

[malabo]

In that NTSB example it was partly self-inflicted. 230 with only a pilot on board will hover extremely tail low, might even bounce off the stinger - with the pilot usually praying that the stinger is keeping the tail-rotor from hitting something. Other NTSB reports have the stinger slipping into the gap between the net stanchions and causing a tailrotor strike SEA95LA068 (http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20001207X03199&key=1). I once came back with the 222 stinger looking like the toe on an Aladdin slipper, but it saved the T/R.

Tough to write regulations that account for helicopters both with intermediate gearboxes and without, but thanks for trying, Jim.

I've reviewed the paper and one comment I can make is that the industry has to put more effort ( ie training and checking) into ensuring the pilots understand markings in the first place.

[Gomer Pylot]

There are still angled fences in the GOM that are rather high and have not been changed in decades, especially on platforms that would be contracted to that company. The bottomfeeders won't spend the money to have it corrected, nor the money to simply maintain the platforms in an acceptable condition. Current profits trump absolutely everything else out there.

[JimL]

I see that the draft revised FAA Heliport Design Advisory Circular - AC 150/5390-2C - is out for comment; it now includes use of the TD/PM circle, for accuracy in positioning the helicopter.

Interestingly, there is an objection to use of the touchdown positioning marker (or touchdown positioning circle - why change the name?) by Rex Alexander - president of the National EMS Pilots Association (NEMSPA) - stating that whilst it may work at ground level, it might not be so useful on a rooftop pad. Not sure I understand the logic of the argument as it will provide accurate placing, and access for loading should not be adversely effected.

For information and arguments for use of the TDPM(C), see the paper previously pointed to in an earlier post:

http://www.helidecks.org/download%20files/Touchdown%20and%20Positioning%20Marker%20-%20Paper%20V1%209.pdf

Jim