# JASC 6320: Main Rotor Gearbox - Type: JASC system/component code (FAA) - ATA chapter: 63 Main Rotor Drive - Title in the code table: MAIN ROTOR GEARBOX - Service difficulty reports: 1,930 - FAA code table: https://www.faa.gov/sites/faa.gov/files/JASC_Code.pdf#page=57 - Page: https://openairdocs.org/jasc/6320 ## What it covers The component which transmits engine power to rotary motion in the main rotor mast. Includes mechanical power take-off and accessory drives but does not include the accessories such as hydraulic pumps and alternators. Includes gearbox lubricating system. Typical parts are gearbox, case, shaft, gear, pump, seal, sun gear, etc. ## Latest service difficulty reports - [SDR QMLA2026070420042](https://openairdocs.org/sdr/QMLA2026070420042), Jul 3, 2026: TRANSMISSION, MAKING METAL (N865NC) - [SDR JTAA20260504001](https://openairdocs.org/sdr/JTAA20260504001), May 4, 2026: TRANSMISSION, FOD (N825WL) - [SDR 2026F00097](https://openairdocs.org/sdr/2026F00097), May 4, 2026: TRANSMISSION, FOD (N825WL) - [SDR QMLA2026040620026](https://openairdocs.org/sdr/QMLA2026040620026), Mar 29, 2026: TRANSMISSION, MAKING METAL (N528AM) - [SDR QMLA2026032020021](https://openairdocs.org/sdr/QMLA2026032020021), Mar 20, 2026: WARNING LIGHT, FALSE ACTIVATION (N645AM) - [SDR 2026FA0000161](https://openairdocs.org/sdr/2026FA0000161), Mar 5, 2026: TRANSMISSION, MAKING METAL (N454JH) - [SDR QMLA2026012520005](https://openairdocs.org/sdr/QMLA2026012520005), Jan 23, 2026: CHIP DETECTOR, FALSE ACTIVATION (N473RA) - [SDR 2026FA0000002](https://openairdocs.org/sdr/2026FA0000002), Jan 4, 2026: GEARBOX, WARNING LIGHT (N540SF) - [SDR HEEA202510300001](https://openairdocs.org/sdr/HEEA202510300001), Oct 25, 2025: CHIP DETECTOR, DIRTY (N673P) - [SDR HEEA202509220001](https://openairdocs.org/sdr/HEEA202509220001), Sep 19, 2025: GEARBOX, MAKING METAL (N673P) - [SDR CHIA202508149805](https://openairdocs.org/sdr/CHIA202508149805), Aug 14, 2025: TRANSMISSION, OVERHEATED (N246CH) - [SDR QMLA2025070220071](https://openairdocs.org/sdr/QMLA2025070220071), Jul 2, 2025: GEARBOX, WARNING MESSAGE (N328CH) - [SDR QMLA2025062920070](https://openairdocs.org/sdr/QMLA2025062920070), Jun 29, 2025: GEARBOX, MAKING METAL (N328CH) - [SDR HEEA202505270002](https://openairdocs.org/sdr/HEEA202505270002), May 25, 2025: TRANSMISSION, MAKING METAL (N454PH) - [SDR QMLA2025052020058](https://openairdocs.org/sdr/QMLA2025052020058), May 20, 2025: GEARBOX, MAKING METAL (N328CH) - [SDR QMLA2025051520056](https://openairdocs.org/sdr/QMLA2025051520056), May 16, 2025: GEARBOX, WARNING LIGHT (N328CH) - [SDR QMLA2025051020054](https://openairdocs.org/sdr/QMLA2025051020054), May 9, 2025: TRANSMISSION, WARNING LIGHT (N338AM) - [SDR HEEA202504100001](https://openairdocs.org/sdr/HEEA202504100001), Apr 7, 2025: TRANSMISSION, MAKING METAL (N448PH) - [SDR QMLA2025031720036](https://openairdocs.org/sdr/QMLA2025031720036), Mar 17, 2025: CHIP DETECTOR, CONTAMINATED (N697AM) - [SDR QMLA2025020220011](https://openairdocs.org/sdr/QMLA2025020220011), Feb 2, 2025: GEARBOX, MAKING METAL (N136HN) - [SDR HEEA202501200001](https://openairdocs.org/sdr/HEEA202501200001), Jan 17, 2025: GEARBOX, MAKING METAL (N151PH) - [SDR HEEA202501020001](https://openairdocs.org/sdr/HEEA202501020001), Dec 31, 2024: GEARBOX, MAKING METAL (N932PH) - [SDR HEEA202411260001](https://openairdocs.org/sdr/HEEA202411260001), Nov 22, 2024: TRANSMISSION, MAKING METAL (N406PH) - [SDR KY1R20241101001](https://openairdocs.org/sdr/KY1R20241101001), Nov 1, 2024: COOLING FAN, SEPARATED (N382MD) - [SDR QMLA2024101520132](https://openairdocs.org/sdr/QMLA2024101520132), Oct 12, 2024: TRANSMISSION, MAKING METAL (N535LN) - [SDR 2024FA0000762](https://openairdocs.org/sdr/2024FA0000762), Oct 9, 2024: BEARING, WRONG PART - [SDR MHR22024092400733](https://openairdocs.org/sdr/MHR22024092400733), Sep 24, 2024: BEARING, FLAKING (N216MH) - [SDR HEEA202409230001](https://openairdocs.org/sdr/HEEA202409230001), Sep 22, 2024: GEARBOX, MAKING METAL (N940PH) - [SDR QMLA2024092420124](https://openairdocs.org/sdr/QMLA2024092420124), Sep 21, 2024: GEARBOX, MAKING METAL (N534LN) - [SDR HEEA202407290001](https://openairdocs.org/sdr/HEEA202407290001), Jul 26, 2024: TRANSMITTER, INOPERATIVE (N725P) - [SDR 2VKA2024072453407](https://openairdocs.org/sdr/2VKA2024072453407), Jul 23, 2024: WASHER, CRACKED (N390SF) - [SDR HEEA202407150001](https://openairdocs.org/sdr/HEEA202407150001), Jul 11, 2024: SENSOR, INOPERATIVE (N936PH) - [SDR QMLA2024062520071](https://openairdocs.org/sdr/QMLA2024062520071), Jun 23, 2024: BYPASS VALVE, FAULTED (N586AM) - [SDR M3XA20240425006](https://openairdocs.org/sdr/M3XA20240425006), Apr 24, 2024: TRANSMISSION, MAKING METAL (N516MT) - [SDR QMLA2024042220040](https://openairdocs.org/sdr/QMLA2024042220040), Apr 13, 2024: TRANSMISSION, MAKING METAL (N697AM) - [SDR AC2R921GL03192024](https://openairdocs.org/sdr/AC2R921GL03192024), Mar 19, 2024: BUSHING, CRACKED (N921GL) - [SDR 2024FA0000135](https://openairdocs.org/sdr/2024FA0000135), Feb 6, 2024: OIL COOLER, SHEARED (N455MH) - [SDR HEEA202401310001](https://openairdocs.org/sdr/HEEA202401310001), Jan 30, 2024: TRANSMISSION, MAKING METAL (N794P) - [SDR 7ALA202407240174](https://openairdocs.org/sdr/7ALA202407240174), Jan 24, 2024: WASHER, CRACKED (N314SF) - [SDR 7ALA2024F00175](https://openairdocs.org/sdr/7ALA2024F00175), Jan 24, 2024: WASHER, CRACKED (N314SF) - [SDR 2023FA0000809](https://openairdocs.org/sdr/2023FA0000809), Dec 5, 2023: SEAL, FAILED (N553XB) - [SDR QMLA2023101220089](https://openairdocs.org/sdr/QMLA2023101220089), Oct 13, 2023: CHIP DETECTOR, UNKNOWN (N138HN) - [SDR YV3R2023111500585](https://openairdocs.org/sdr/YV3R2023111500585), Sep 29, 2023: GEARBOX, DEFECTIVE - [SDR 2023F00280](https://openairdocs.org/sdr/2023F00280), Sep 18, 2023: GEARBOX, BYPASSING (N940PH) - [SDR AC2A2023062213901](https://openairdocs.org/sdr/AC2A2023062213901), Jun 18, 2023: ACTUATOR, UNSERVICEABLE (N639MM) - [SDR JYDR20230413094](https://openairdocs.org/sdr/JYDR20230413094), Apr 12, 2023: BEVEL GEAR, CRACKED - [SDR 2023FA0000361](https://openairdocs.org/sdr/2023FA0000361), Mar 27, 2023: FITTING, SHEARED (N412VC) - [SDR 8NZY202301180001](https://openairdocs.org/sdr/8NZY202301180001), Jan 18, 2023: PLANETARY GEAR, DAMAGED (N350HC) - [SDR 2023FA0000024](https://openairdocs.org/sdr/2023FA0000024), Jan 11, 2023: TRANSMISSION, MAKING METAL (N416CF) - [SDR EVCA20221115001](https://openairdocs.org/sdr/EVCA20221115001), Nov 11, 2022: HOSE, SPLIT (N891GT) --- From OpenAirDocs.org, an independent open copy of FAA data. 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