MLG ACFT LNDG ENCOUNTERED SAND AND GRAVEL WHEN REVERSING ENGS RESULTING IN MAJOR DAMAGE TO ENGS; FLAPS AND CTLS. ARPT HAD BEEN RPTED AS CLRED AND SWEEPED.

Narrative

DET CITY TWR RPTED DRY RWY. ON LNDG TOUCHDOWN AND ROLLOUT WITH NORMAL REVERSE THRUSTS; BOTH (2) ENGS INGESTED LARGE AMOUNT OF SAND AND GRAVEL CAUSING DAMAGE AND JAMMED FLT FLAPS/CTLS AND DAMAGED FAN BLADES. GRAVEL INSPECTION FOUND LARGE ACCUMULATION OF SAND AND GRAVEL ON RWY THAT HAD BEEN RPTED 'CLRED AND SWEEPED' BY ARPT AUTH. INGESTION CAUSED VAPOR AND SMOKE/DUST TO ENVELOP ACFT CABIN AND COCKPIT ON CLRING RWY. RECOGNIZED SMELL AS NON SMOKE AND DID NOT EVAC ACFT. MADE PA TO PAX AND CREW AND CONFIRMED SAND AND GRAVEL VISUALLY ON TAXI BACK. DET TWR MADE CALL; 'ACR X; ARE YOU OK? ACR X; ARE YOU OK?' REPLIED OK AND THEN TWR REPLIED; 'ALL I COULD SEE WAS SAND AND DUST.' TOLD TWR THAT REVERSERS HAD KICKED UP LARGE AMOUNTS OF CONTAMINANTS ON RWY. AT GATE; NOTED ENG DAMAGE AND TRAILING EDGE FLAP ACFT L WOULD NOT RETRACT. INSPECTED LARGE AMOUNTS OF SAND GRAVEL IN WHEEL WELLS; LEADING EDGE FLAP/SLAT CAVITIES AND WHEEL RIMS. SUBSEQUENT DAMAGE RPT FOR ENGS ESTIMATED OVER $1;000;000 UNITED STATES DOLLARS AND ACFT OTS FOR 5 DAYS. AIRLINE GND MGMNT HAD IDENTED SAND/GAVEL AS NOT TO SPECS. DAY BEFORE ARPT AUTH ASSURED THAT SAND/GRAVEL HAD BEEN USED UP AND CLRED FROM RWY (SWEPT). FIRST FLT LNDG NEXT MORNING (DEC/XX/97) DAMAGE OCCURRED. ACFT LNDG AFTER MY FLT RPTED DAMAGE AS WELL.