I've just had an urgent call from Pat Scotter, apparently an aircraft mass balance was found on the runway at NZRT this morning. If you have been flying recently, check your aircraft URGENTLY! Obviously the lack of a mass balance would pose a serious risk, with a likely nasty outcome.
The mass balance is a 'large lump of lead', somewhat less than a kilo, that doesn't appear to be a factory made piece. No matter what - check your aircraft! If you want it back, Pat at Rangiora Aircraft Engineering is the man to see.
Please pass this on to anyone relevant, it's a serious safety risk.