What was found
ACRID/OZONE BURNING SMELL NOTICED BY ALL CREW MEMBERS ON ENTRY TO AIRCRAFT. TRU COVERED IN DUST, PERFORMED AMM 05-51-26-800-801-C1 PART C. COULD NOT SMELL ANYTHING THROUGH OUT CABIN, ONLY SMELLED A LITTLE IN THE FLT DECK AND E&E. INSPECTED FLT DECK AND E&E THOROUGHLY. DID NOT FIND ANYTHING BURNED, ARCED OR SMOKING. ODOR WAS THE STRONGEST AROUND THE NR 2 & 3 TRU. & TRU SCREENS WERE HEAVILY BLOCKED WITH DUST. RAN PACKS & STILL DID NOT GET ANY SMELL ANY WHERE ELSEE.SMELL DIDN'T GET ANY STRONGER ANYWHERE. WILL REQUIRE TRUS TO BE CHANGED. R & R NR 3 TRU IAW AMM 24-32-11. OPS CHECK GOOD. R & R BOTH RECIRC FILTERS PER AMM 21-25-01. RAN PACKS WITH APU & ENGINES SEPARATELY COULD NOT DETECT ODOR. OK TO CONTINUE.