New xstar pilot,have only flown it twice and both times it did not hold its altitude ! After take-off i took it up about 6-8 ft and when i stopped to hover it immediatly began to drop. It got within a foot of the ground and i had to fly it back up. It seems to wander up and down about 4-5 feet !I was flying over snow both times, would that affect the starpoint positioning system? Anyone else have this problem? This is not acceptable as i plan on doing some low-level flying and cant have it dropping unexpectedly !