BA ERJ145 doing a little waltz at Southampton

[JamesT73J]

I was photographing aircraft at SOU early this evening when I saw a curious incident with an ERJ. The aircraft taxied off the ramp as normal, and looked like she was going to do a regular backtrack down the runway to depart when the aircraft stopped (in the middle of the runway as far as I could tell) and commenced a series of turns on the spot, at one point turning right round.

I suspected a change of rwy, but then the a/c piroutted gently again, then stopped, then turned again. There was a pause and then it turned round and scooted back to the gate.

I was just curious what it was. Perhaps the DI's weren't 'swinging', or disagreed?

[Onan the Clumsy]

Swinging the compass?

[redsnail]

If no pax deplaned then it's a possibility. Although I have only done a compass swing in a small aircraft.

A compass swing is done to see what deviation the metal around the compass does to the magnetic reading of the compass. Has to be done with engines and systems running and all points 360 deg. A runway is useful as it's magnetic direction is already known.

[witchdoctor]

I thought most airfields had a dedicated compass swing area. Can't be bothered to look up Southampton's plates, so don't know if they have one or not. Sounds a bit odd for a pax jet (albeit a Barbie jet) to do it on the runway. Maybe a suspected nosewheel steering problem, hence the return to ramp for inspection?

[witchdoctor]

Would expect that would be an item to check prior to leaving the stand, also a known GPS co-ordinate point.