As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) PILOT EXPERIENCED FLUTTER THROUGH THE CONTROL COLUMN AND AIRFRAMEWHICH COMMENCED AT MACH 0.67 TO 0.69 - FLUTTER WORSENED TO PUMPING ACTION AND CEASED WHEN SPEED WAS REDUCED TO BELOW 0.67 MACH - SUSPECT LH ELEVATOR UNBALANCED - WEIGHTS ADDED TO LHELEVATOR