As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CRACKS ON AILERON INBD TE BETWEEN INBD AND CTR RIB. DURING SINGLE ENGINE TRAINING, ONE SHUTDOWN OR SET TO 0 THRUST AND THE WORKING ENGINE IS BROUGHT TO FULL POWER. AS THE ACFT IS SLOWED TO DEMONSTRATE LOSS OF DIRECTIONAL CONTROL THE AILERON ON THE WORKING ENG IS DEFLECTED UP INTO HIGH TURBULENCE AND PRESSURE CAUSING STRESS AND VIBRATION BEYOND THE DESIGN LIMITS, RESULTING IN STRESS CRACKS.