Japanese Quake and the fall out for RNAVs

[Bort Simpson]

Hi all. as you will no doubt be aware, Japan has suffered significantly recently. Upon reading one news story today, I learned that the main Japanese Island is said to have moved 2.4m from it's original location. Pretty significant for such a large mass of land to move so far.

I was just wondering what implications this now has on Aviation. I know this is most definately not their immediate concern over there however, it does pose some interesting questions for the likes of us to ponder.

I'm not sure how or if this is enough of a movement for a review to be required nation wide over there. So if anyone has any thoughts on that please feel free to comment. I'm thinking that for RNAV apporaches that there maybe some implications for location of waypoints etc. Also for those that opperate aircraft with Inertial Reference Systems (IRS), there miay be some issues with exact locations on bays etc.

Is 2.4m enough of a move to put all this into review?

regards,
Bort.

[Capn Bloggs]

Is 2.4m enough of a move to put all this into review?
The way my machine flies RNAVs, a major earthquake/2.4m groundshift would be the least of my worries! :ok: :8 :eek:

[beat ups are fun]

I agree Bloggs. It's not going to effect any of the RNAV wpt's.

However the bay locations for IRS/INS will eventually get changed, I can't see there being any major inaccuracies/problems because of 2.4 mtrs.

[Howard Hughes]

Every time I land I'd swear the ground just shifted 2.4 metres straight up!;)

[Capn Bloggs]

Seriously, I suspect that RNP approaches may be affected.

[c100driver]

I would be more concerned with the stuff supposedly attached to the ground for calibration and serviceability, ILS, LOC or VOR.

The beauty with RNAV is that it does not rely on NAV aids attached to the terra not so firma. So opposite to your conjecture it would actually improve the case for RNAV, as the RNAV approaches are unaffected by ground equipment.

Land movement under the approach is the same issue no matter what sensor is used for an approach.

Normal RNP AR approaches would not be affected as the DA is such that it is slightly higher than CAT 1 and a few meters shift is insignificant (it still does better than VOR!) Differential approaches are a different animal and I would suspect have similar calibration and survey issues to CAT 2 and 3 ILS.

[Jabawocky]

.............. and if at the minima there is still a runway in view, albeit a couple of feet in some direction, which may be left right or fwd/back of your track, I reckon you would hardly notice anyway.

in a big jet with a crosswind the view of the centreline can be many feet either side of you so how would you tell?

Forkie would be happy :ok:

[Grogmonster]

Some conjecture in the media that the Earths axis actually shifted by 4 degrees. Some of you maths genius types out there might be able to confirm this by relating the 2.4 meter shift on the Japanese coast to a shift in the axis. Its a bit over my head but certainly a worry if there is any truth to it.

Groggy

[Angle of Attack]

I would not even bother if it was a 5m shift the RNP approaches can end you up at least a dot high and regularly around 10-15metres left or right of centreline at minima (around 300')

It is not an issue.