AIR CENTER HELICOPTERS, INC.

DURING A ROTOR TRACK AND BALANCE FLIGHT, THERE WAS AN ISSUE. AFTER COMPLETION OF THE FINAL MCP TRACKING STAGE, A MODERATE TO SEVERE VIBRATION WAS FELT THROUGHOUT THE AIRFRAME. THE DECISION WAS MADE TO RETURN IMMEDIATELY TO THE SHIP'S DECK, AT WHICH POINT THE AIRCRAFT SHUT DOWN. DURING THE SHUTDOWN, A MAINTENANCE TECHNICIAN CAME ON BOARD TO CONFIRM THE VIBRATIONS IN THE CABIN AREA. UPON VISUAL INSPECTION AND CROSS REFERENCE WITH THE HUMS DATA IT WAS DISCOVERED THAT THE BLACK BLADE TAIL ROTOR DRAG DAMPER COUPLING HAD CRACKED AND SEPARATED, DURING THAT PROCESS IT HAD ALSO DAMAGED THE ROTOR BLADE ITSELF. THE MAINTENANCE PERSONNEL REMOVED AND REPLACED ALL BROKEN ITEMS.

RT, EXTERNAL FUSELAGE AT STA 1655, BETWEEN STR 24R & 25R, HAS A DENT. DENT FOUND OUT OF LIMITS PER SRM 53-00-01, FIG.101, DETAIL 3, PG.104. CLEANED DAMAGED SKIN PER SRM 53-00-01 AT RH EXTERNAL FUSELAGE BY BS 1655, BETWEEN S24-25R. FABRICATED A REPAIR DOUBLER AND INSTALLED PER SRM 53-00-01, REPAIR NR 16, AT BS 1655, BETWEEN S24-25R. THIS IS A CAT. "B" MAJOR REPAIR WITH THE FOLLOWING TRACKING; INITIAL INSPECTION AT 37,000 FC, THEREAFTER EVERY 3,000 FC.

(997FD/ 473AC) LT PYLON REAR BULKHEAD, LT LOWER CORNER IS CHAFED. COMPLIED WITH EA F-5450-146255: NACELLES/PYLONS-AD2003-18-05, EO F-5450-7-5010, NR 1 ENGINE STRUT AFT BULKHEAD REPAIR USING PARTS FABRICATED. REPAIR IS CLASSIFIED AS A CAT. "A" MAJOR.

LT PYLON AFT BULKHEAD LOWER RT CORNER HAS A GOUGE. COMPLIED WITH EA F-5450-146255; BULKHEAD REPAIRED USING PARTS FABRICATED. REPAIR IS CLASSIFIED AS A CAT. "A" MAJOR.

FLOORBEAM UPPER CHORD STIFFENER AT STA 365 BETWEEN BL 0 AND RBL 60 HAS GOUGES AND CORROSION. REMOVED DAMAGE IAW SRM 53-00-51, FIG 101, DETAIL 3; ORIGINAL MATERIAL -.090", AFTER REWORK -.038", LOSS - .012", MORE THAN 10 PERCENT ALLOWABLE, OUT OF LIMITS IAW SRM 53-00-51, FIG 101, DETAIL 3. FABRICATED NEW FLOORBEAM UPPER CHORD, USING BAC 1505-100880/12, BATCH 1895840, IAW SRM 53-00-51, REPAIR NR3. REPAIR STRAPS FABBED ON TRAVELERS, T10/862191 AND T10/862192. INSTALLED NEW FLOORBEAM UPPER CHORD REPAIR IAW SRM 51-40-02 AND SRM 53-00-51, REPAIR NR3, AT BS 365, BL0 - RBL 60. (L=1", W=2", D=.012"). MAJOR REPAIR.

STA 1681, FLOORBEAM UPPER CAP LOWER SIDE IS CORRODED AROUND FLOOR PANEL HOLES. REMOVED DAMAGE IAW SRM. CORROSION DETERMINED TO BE OUT OF LIMITS IAW SRM 53-00-51, FIG 101, DETAIL 6, P 103; ORIGINAL MATERIAL .156", REMAINING - 090", LOSS - .066". FABRICATED NEW FLOORBEAM IAW DWG 146N5314. TREATED/PRIMED AND TOP COATED NEW FLOORBEAM IAW SRM 51-20-01/AMM 51-21-00-7. INSTALLED NEW FLOORBEAM AT BS 1681, LBL 58-RBL 58, IAW SRM 51-40-02. MAJOR REPAIR.

RT SEAT TRACK AT RBL 24.75, BS 418-440, HAS SEVERAL NICKS, GOUGES, AND CORROSION. REMOVED CORROSION IAW SRM 51-10-02; AFTER REMOVAL OF NICKS, GOUGES, AND CORROSION, FOUND OUT OF LIMITS IAW SRM 53-00-52, FIG 101, DETAIL 7; ORIGINAL MATERIAL; .070", AFTER REWORK; .050", EXCEEDS 20 PERCENT ALLOWED, L=1.5", W=1". FABBED NEW SEAT TRACK FROM BS 418-440, RBL 24.75, MATERIAL BAC 1520-792, BATCH NR 1904663, IAW SRM 51-10-01. TREATED/PRIMED. INSTALLED NEW SEAT TRACK IAW SRM 51-40-02, AT BS 418-440, RBL 24.75. MAJOR REPAIR.

MDC RT SEAT TRACK AT RBL 45.5, FROM BS 418-440, HAS SEVERAL NICKS, GOUGES, AND CORROSION. REMOVED CORROSION IAW SRM 51-10-02. AFTER REMOVAL OF NICKS, GOUGES, AND CORROSION, FOUND OUT OF LIMITS IAW SRM 53-00-52, FIG 101, DETAIL 7; ORIGINAL MATERIAL; .070", AFTER REWORK; .051", EXCEEDS 20 PERCENT, ALLOWED, L=2", W=2". FABBED NEW SEAT TRACK FROM BS 418-440, RBL 45.5, IAW MATERIAL BAC 1520-792, BATCH NR 1904663, IAW SRM 51-10-01. TREATED/PRIMED. INSTALLED NEW SEAT TRACK FROM BS 418-440, RBL 45.5, IAW SRM 51-40-02. MAJOR REPAIR.

BS 1661 FLOORBEAM UPPER SURFACE CORRODED AT RBL 58. REMOVED CORROSION AT BS 1661, RBL 58, PER SRM 51-10-01. CHECKED LIMITS; ORIGINAL MATERIAL - .125", AFTER REWORK - .110"; L=12", W=2", D=.015", FOUND TO BE OUT OF LIMITS PER SRM 53-00-51, FIG.101, DETAIL 3. REMOVED AND REPLACED FLOORBEAM AT BS 1661, FABRICATED FROM BAC 1518-338, BATCH 1918947, PER SRM 53-60-51, FIG.1, PAGE 5 AND DWG 146N5090. INSTALLED NEW FLOORBEAM PER SRM 53-60-51 AND DWG 146N5090, AT BS 1661. MAJOR REPAIR

FLOORBEAM UPPER CHORD AT STA 1640 NEAR LT SIDEWALL HAS CORROSION. REMOVED CORROSION ON FLOORBEAM IAW SRM 51-10-02,ORIG MATERIAL 0.125" AFTER REWORKED 0.015" AT LBL 60, MEASURED AREA,L= 3.7", X W=2.00", X DEPTH=0.110" FOUNDED OUT LIMITS IAW SRM 53-00-51, FIG 101, DETAIL III, REMOVAL FLOORBEAM STA 1640 BETWEEN LBL 70 TO RBL 70 IAW SRM 51-40-02, INSTALLED NEW FLOORBEAM FABRICATED FROM MAT BAC 1518-338, BATCH 1918947, IAW DWG 146N5089 AND SRM 53-60-51, FIG 1, PAG 5 (SHEET 5 & 6 AND 6 OF 7) MAJOR REPAIR.

FLOORBEAM UPPER CHORD AT BS 1640 HAS CORROSION APPROX LBL30-RBL35.

AN INSPECTION WAS CONDUCTED ON THE UPPER BOX BEAM OF THE CABIN. UPON REMOVAL OF THE INSULATION BLANKET, MULTIPLE CRACKS TO THE BOX BEAM ASSY WAS DISCOVERED. THE AC HAS BEEN INVOLVED IN 2 INCIDENTS.

FOUND ELEVATOR SKIN CRACKED FROM THE INSIDE. INVESTIGATION REVEALED CRACKS IN SPAR RADIUS OUTBOARD HINGE BRACKET.