Rig Radar Approach

[gnow]

I would like to find out if the operators out there requires the rig NBD to legally do a rig radar approach.I am of the opinion that the NDB is a must to do a radar approach(to cross check track and drift) but sometimes operationally in marginal weather we use the radar to break clouds but do not do a full radar approach to the minimas .

[rotordk]

How would you do get QDM/QDR information with a radar and no NDB ?
Alternate procedure I would make a GPS point for the letdown distance, and continue to the rig with the aid of the CDI, but full procedure I don't see happening without a Locator/NDB....

[NickLappos]

rotordk,

I think an ADF is quite redundant in today's world, but comforting nontheless and also legally necessary.

A good GPS with its FMS functions makes even the radar only useful to clear the approach path of tall ships. As far as determining the course, even a glance at the radar blip while progressing inbound will tell the course to greater accuracy than an ADF (which engineers set to only plus or minus 5 degrees!)

In the wilds of the third world, an ADF is very useful just because.

[OopsNearly]

Most of our rig radar approaches, 90% or more are carried out without the aid of an NDB. One oil company on our patch has almost finished removing their beacons from their platforms. With FMS and radar they are a piece of cake, and as Nick says NDB's are becoming a thing of the past.

That said, for those who don't have FMS then it's a different story, but once you've tried it especially with a coupled FMS it's a walk in the park on a beautiful day.

[Gomer Pylot]

I'm not sure what the requirements for your rig radar approach are, but in the GOM there are no NDBs at all. There may be an isolated unit somewhere, but we have no information on any of them, nor do we use them. We use a combination of GPS and radar. GPS is orders of magnitude more accurate than NDB, and gives us very good positioning. We have very accurate coordinates for all platforms and rigs - after all, the rigs use DGPS to locate themselves, so we have positions more accurate than our GPS units can even use. NDBs are being decommissioned in the US very rapidly, and those still commissioned often are NOTAMed OTS. They're going the way of the AN range equipment. I certainly don't claim to know the situation elsewhere.

[Mama Mangrove]

Nick,
I agree that a good FMS almost makes the NDB redundant, but the radar is useful for more than just clearing the approach path of tall ships. Quite a few of our approaches are to tankers which have now been converted to floating oil storage facilities. As these are normally moored, or connected, by either the bows or the stern, with the helideck at the opposite end, the GPS position of the helideck can be up to 600 feet out (depending on which way the ship was pointing when the position was recorded). If the weather is down at the minima, it's essential to be using the radar as the primary aid in the final stages of the approach to avoid going around to early or, even worse, getting too close.