What is the circle on a helideck for?
 

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?

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

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

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.

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?

..don't know about you, I always used (and taught) using a backdrop technique....

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.

Deck Net
 

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

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 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

Nets
 

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.

Deck Net
 

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
:) :) :) :) :)

blowing foam!
 

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].

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

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

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!

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?

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.
;)

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."

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

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?