What was found
AIRCRAFT CONTINUED TO HAVE TRACK AND BALANCE ISSUES FOR PRIOR 2 MONTHS. EACH TIME THE TRACK AND BALANCE COULD BE ALLEVIATED BUT THE AIRCRAFT CAME BACK NOW IN ITS WORST ITERATION, READING .7 IPS VERTICAL AND .7 LATERAL. I MADE A LARGE ADJUSTMENT ON BLUE AND RECEIVED .1 INPUT DIFFERENCE. THESE TWO CHARACTERISTICS BROUGHT SUSPICION OF A GREATER PROBLEM WHICH I THEN MOVED ALL BLADES IN A FLAPPING MOTION AND FOUND BLUE MAKES A "CRACKLING" SOUND INTERNALLY WHILE THE OTHERS DO NOT. WE REMOVED YELLOW AND BLUE, (BEING OPPOSITE BLADES) AND FOUND WHAT APPEARS TO BE A CRACK BUT WITHOUT ANY WAY TO TEST BESIDE A GVI, WE'LL BE REPLACING S/N 890 ANYWAYS. THIS BLADE SHOULD BE SENT FOR FURTHER ANALYSIS.