What was found
FLT#909, BOS-NAS. (AIRCRAFT DIVERTED TO MCO). 'VIBRATION AND NOISE FROM ROW 23 RIGHT AREA NOISE STARTED SUDDENLY CLIMBING OUT FL 350. NOISE STARTED STEADY THEN CHANGED TO OSCILLATING NOISE STOPPED ON DECENT AT 31,000 CAB ALT OF 5000 DELTA P 7.7; REF LP 3759626 ITEM 1 (T/S, FOUND WHEN MID AVIONICS GOES INTO FLT MODE FOR EQUIPMENT COOLING.- AIRFLOW GETTING RESTRICTED TO MID BAY FAN THROUGH AFT AVIONICS FILTER ELEMENT. GAINED ACCESS TO FILTER FOUND FILTER CLOGGED AND COLLAPSED RESTRICTING FLOW. AFT AVIONICS FILTER REMOVED, FILTER REQUIRES R.R REF LP 3759626-2 FOR FILTER R.R WORK PER AMP J21-26-11-03AAA-921B-A.) AND 2 (REMOVED AND REPLACED AFT AVIONICS FILTER ELEMENT IAW AMP 21-26-11 PERFORMED LEAK AND OPERATIONAL CHECK AS PER AMP 21-22-00. OPS CHECK GOOD, NO VIBRATION NOTED) FOR CORRECTIVE ACTION.'