# JASC 8300: Accessory Gearboxes - Type: JASC system/component code (FAA) - ATA chapter: 83 Accessory Gearboxes - Title in the code table: ACCESSORY GEARBOXES - Service difficulty reports: 306 - FAA code table: https://www.faa.gov/sites/faa.gov/files/JASC_Code.pdf#page=70 - Page: https://openairdocs.org/jasc/8300 ## What it covers The units and components which are remotely installed and connected to the engine by a drive shaft and which does not include those accessory drives which are bolted to and are immediately adjacent to the engine. The latter item should be filed in JASC code 7200. Does not include accessory drives bolted to and adjacent to engine which are normally filed in JASC code 7260. ## Service difficulty reports (306, newest 50) - [SDR DBCA202608190001](https://openairdocs.org/sdr/DBCA202608190001), Aug 6, 2026: Pilats PC24. GEARBOX. CONTAMINATED. RT EGINE ROLL BACK ON CLIMB OUT. EMERGENCY DECLARED BY CREW, AIRCRAFT RETURNED TO DEPARTURE AIRPORT (135 MED FLIGHT) PAT (N279AH) - [SDR DALA2026072304302](https://openairdocs.org/sdr/DALA2026072304302), Jul 21, 2026: Airbus A320212. ALTERNATOR. DETACHED. RETURNED TO DTW DUE TO LOSS OF NBR 2 ENGINE OIL QUANTITY AND PRESSURE. CREW SHUT ENGINE DOWN WHEN QUANTITY AND PRESSURE (N361NW) - [SDR N6WA2026070205](https://openairdocs.org/sdr/N6WA2026070205), Jun 30, 2026: Cndair CL6002C11. GEARBOX. BINDING. N1, ITT, N2, THRUST FLUCTUATIONS IN FLIGHT AT HIGH THRUST SETTINGS ON RH ENG. PERFORMED BORESCOPE OF THE NR 2 ENG IAW AM (N536GJ) - [SDR 2026F00138](https://openairdocs.org/sdr/2026F00138), Jun 29, 2026: Boeing 767322. CARBON SEAL. LEAKING. DURING CRUISE THE A/C FACE RT OIL PRESSURE LT INTERMITTENT ILLUMINATION AND RT ENG QTY INDICATION 0. OIL PRESS FLUCTUATE (N652UA) - [SDR 2026F00066](https://openairdocs.org/sdr/2026F00066), Mar 28, 2026: Boeing 7878. SEAL. LEAKING. LOW OIL QTY INDICATION WITH LOW PRESSURE INDICATION, UNSCHEDULED LANDING, VFSG LH OF ENGINE NR 1 WAS REPLACED IAW AMM DM (N966AM) - [SDR DALA2025110908156](https://openairdocs.org/sdr/DALA2025110908156), Nov 7, 2025: Airbus A321271NX. GEARBOX. MAKING METAL. DIVERTED TO MCO DUE TO RIGHT ENGINE OIL LOSS AND N2 VIBES. INSPECTED MCD'S AND FOUND METAL ON AGB, NR 3 AND 4 MCD'S. REP (N537DT) - [SDR ASMF2025111100304](https://openairdocs.org/sdr/ASMF2025111100304), Nov 2, 2025: Boeing 7878. SEAL. LEAKING. DURING WALKAROUND FOUND SIGNS OF OIL LEAKS COMING FROM HEATER DRAIN VFSG RIGHT PAD ON ENGINE 2. SIX DROPS PER MINUTE. RI (N966AM) - [SDR 2025FA0000687](https://openairdocs.org/sdr/2025FA0000687), Oct 7, 2025: Swrngn SA227AC. BEARING. SPALLED. IDLER GEAR [PN: 896804-2] TEETH GALLED DUE TO BEARINGS (2EA) [PN: 3103035-1, SN: 10-151725-07307 & 10-151725-07323, TSN: (N320MC) - [SDR CALA2025090308441](https://openairdocs.org/sdr/CALA2025090308441), Aug 31, 2025: Boeing 737924ER. GEARBOX. CONTAMINATED. NUMBER 1 ENG OIL FILTER BYPASS OCCURED ATFL270 300KIAS, DELCARED EMERGENCY LANDING. DURING INSPECTION, FOUND DEBRIS ON A (N69833) - [SDR NACA2025031300007](https://openairdocs.org/sdr/NACA2025031300007), Mar 13, 2025: Boeing 767323. HOUSING. LEAKING. FUEL LEAK #1 ENGINE ACCESSORY GEARBOX FORWARD MID LOWER MAIN FUEL CONTROL HOUSING. LEAK CHECK, NO LEAK FOUND. (N321CM) - [SDR FXTA20250404003](https://openairdocs.org/sdr/FXTA20250404003), Feb 19, 2025: Textrn 408. PRESSURE SWITCH. FAILED. PROP DE-ICE CAS MESSAGE ON RUN-UP. FOUND LH & RH LOW OIL PRESSURE SWITCHES WERE FAILED. (N408BA) - [SDR 2025FA0000115](https://openairdocs.org/sdr/2025FA0000115), Feb 18, 2025: Cessna 208B. SHAFT. WORN. ACCESSORY GEAR AND DRIVE IDLER ASSEMBLY [PN: 3103599-2, SN: 10P27504] FOUND DAMAGED DURING 7,000 HOUR OVERHAUL PERIODIC - [SDR 2024FA0000972](https://openairdocs.org/sdr/2024FA0000972), Dec 19, 2024: BEARING. WRONG PART. ON OCTOBER 8 2024, AGB (ENGINE LEAP 1A) P/N 362-001-242-0 S/N 1P000802 WAS RECEIVED BY STS MAINTENANCE ORGANIZATION (EAS - [SDR 2024F00312](https://openairdocs.org/sdr/2024F00312), Dec 9, 2024: Boeing 737. GEARBOX. DAMAGED. ON 2024-11-26, DURING THE DISASSEMBLY OF, IT WAS DISCOVERED THAT THREE 'TEN-POINTS NUTS' WHERE MISSING ON LINE 4, ON THE - [SDR ZD4R202410040001](https://openairdocs.org/sdr/ZD4R202410040001), Oct 4, 2024: Bell 407. SHAFT. BROKEN. DISASSEMBLED GEARBOX AND FOUND 2 BROKEN TEETH ON TORQUEMETER GEARSHAFT. GEAR TEETH WERE LOCATED AT BOTTOM OF GEARBOX. MI (N36VA) - [SDR 2024FA0000557](https://openairdocs.org/sdr/2024FA0000557), Aug 1, 2024: SPUR GEAR. CRACKED. IN FLIGHT SHUTDOWN OF ENGINE [TPE331-12UHR-702H, PN: 3103380-53]. SPUR GEAR CRACKED / MISSING TEETH [PN: 3103406-2] CAUS - [SDR DALA2024071107038](https://openairdocs.org/sdr/DALA2024071107038), Jul 10, 2024: Boeing 757232. SCAVENGE PUMP. FAULTED. SHIP 667-ATB/IFSD/DE- PERFORMED AIR TURN BACK WITH DECLARED EMERGENCY DUE TO LEFT ENGINE OIL TEMP IN THE AMBER BAND FOR (N667DN) - [SDR DALA2024070506818](https://openairdocs.org/sdr/DALA2024070506818), Jul 3, 2024: Boeing 757232. GEARBOX. MAKING METAL. SHIP 6711 -DIV/IFSD/DE- DIVERSION TO MSY DUE TO RIGHT ENGINE OIL FILTER ADVISORY MESSAGE. CREW FOLLOWED QRH AND SHUTDOWN (N6711M) - [SDR DALA2024070506817](https://openairdocs.org/sdr/DALA2024070506817), Jul 3, 2024: Boeing 757232. GEARBOX. MAKING METAL. SHIP 6711 -DIV/IFSD/DE- DIVERSION TO MSY DUE TO RIGHT ENGINE OIL FILTER ADVISORY MESSAGE. CREW FOLLOWED QRH AND SHUTDOWN (N6711M) - [SDR DALA2024050805029](https://openairdocs.org/sdr/DALA2024050805029), May 6, 2024: Airbus A330941. GEARBOX. OVERSERVICED. SHIP 3408 DIRTY SOCK SMELL. CORRECTIVE ACTION: ENGINE GEARBOX WAS OVERFILLED WITH OIL. DRAINED AND RE-FILLED TO CORRECT (N408DX) - [SDR 2024F00048](https://openairdocs.org/sdr/2024F00048), Mar 4, 2024: GEARBOX. ABNORMAL. ON 21 FEBRUARY 2024, SAFRAN TRANSMISSION SYSTEM APPROVED MAINTENANCE ORGANISATION (EASA FR.145.0229, CAAC F03300629, FAA - [SDR 2024F00047](https://openairdocs.org/sdr/2024F00047), Mar 4, 2024: GEARBOX. ABNORMAL. ON 19 FEBRUARY 2024, SAFRAN TRANSMISSION SYSTEM APPROVED MAINTENANCE ORGANIZATION (EASA FR.145.0229, CAAC F03300629, FAA - [SDR 2023FA0000668](https://openairdocs.org/sdr/2023FA0000668), Oct 17, 2023: BEARING. GALLED. ACCESSORY GEAR [PN: 3103590-2] BEARING GALLED [PN: 3103585-1, SN: 13-151725-07567, TSN: 4,525.7, CSN: 5,527]. RESULTED I - [SDR 2023FA0000277](https://openairdocs.org/sdr/2023FA0000277), May 26, 2023: Boeing 737*. GEARBOX. INCORRECT. THE ENGINE ABOVE WAS FITTED WITH ACCESSORY GEARBOX (AGB) P/N: 340-046-508-0, SN: WZ5025. DURING THE DISASSEMBLY, THE OPE - [SDR CALA2023010400022](https://openairdocs.org/sdr/CALA2023010400022), Jan 4, 2023: Boeing 7879. NOZZLE. LEAKING. OIL QUANTITY INDICATION (ENGINE) SHOWS LOW FIM TASK 31-90-F8-03A-421B-A. RT ENGINE TEST NR 1 - DRY-MOTOR - LEAK TESTED I (N38955) - [SDR PCSA202301040001](https://openairdocs.org/sdr/PCSA202301040001), Jan 3, 2023: Boeing 767300. GEARBOX. FAULTED. ON FLIGHT 99 FROM ICN TO ANC, TEN MINUTES INTO THE FLIGHT, THE FLIGHT CREW REPORTED A HIGH ENGINE VIBRATION ON #2 ENGINE (N496MM) - [SDR 2022FA0000769](https://openairdocs.org/sdr/2022FA0000769), Dec 19, 2022: Airbus A330*. BEVEL GEAR. WORN. DURING MINOR EGB REPAIR, PREMATURE BEVEL GEARS WEAR IS IDENTIFIED (EXCESSIVE WEAR), AND GEARS REMOVED. THIS IS OUTSIDE I - [SDR 2022FA0000731](https://openairdocs.org/sdr/2022FA0000731), Nov 22, 2022: Cessna 208B. LINE. LEAKING. SMOKE COMING OUT OF PILOTS SIDE VENT IN FLIGHT. UPON INVESTIGATION AFTER LANDING, IT WAS DISCOVERED THAT THE LINES GOING (N865MA) - [SDR 2022F00447](https://openairdocs.org/sdr/2022F00447), Nov 4, 2022: GEARBOX. CONTAMINATED. CUSTOMER REPORTED AOG ON SEPT 19, 2022 FOR MAGNETIC DEBRIS FOUND DURING REGULAR MCD INSPECTION. ENGINE WAS REMOVED AND A - [SDR 9JLA2022100739009](https://openairdocs.org/sdr/9JLA2022100739009), Oct 5, 2022: Amd FALCON900B. SEAL. LEAKING. DURING POST-FLIGHT CHECKS THE MAINTENANCE TECH DISCOVERED AN OIL LEAK FROM THE NO3 ENGINE. THE MAINTENANCE PROVIDER FOUN (N910TX) - [SDR 2022FA0000399](https://openairdocs.org/sdr/2022FA0000399), Jul 27, 2022: Diamon DA42. GEARBOX. SHEARED. N648KM SUFFERED A GEARBOX SHAFT FAILURE ON ENGINE S/N 02-02-11284 @ 115 ENGINE HRS. THIS HAPPENED WHILST CONDUCTING POST (N648KM) - [SDR 2022F00229](https://openairdocs.org/sdr/2022F00229), May 16, 2022: Cessna 680A. ENGINE. CORRODED. RH ENGINE AGB AFT COVER IS CORRODING. (N512QS) - [SDR 2022F00228](https://openairdocs.org/sdr/2022F00228), May 16, 2022: Cessna 680A. ENGINE. CORRODED. LH ENGINE AGB AFT COVER IS CORRODING. (N512QS) - [SDR 2021FA0000431](https://openairdocs.org/sdr/2021FA0000431), Dec 31, 2021: Cessna 680A. GEARBOX. CORRODED. LH ENGINE AGB HAS CORROSION UNDER HYDRAULIC PUMP. (N620QS) - [SDR 2021F00350](https://openairdocs.org/sdr/2021F00350), Dec 15, 2021: Cessna 680A. ENGINE. CORRODED. RH ENGINE AGB CORRODED IN MULTIPLE LOCATIONS. (N542QS) - [SDR 2021FA0000395](https://openairdocs.org/sdr/2021FA0000395), Dec 13, 2021: Cessna 680A. ENGINE. CORRODED. RH ENGINE AGB REAR COVER HAS MULTIPLE AREAS OF CORROSION. (N536QS) - [SDR 2022F00017](https://openairdocs.org/sdr/2022F00017), Dec 13, 2021: Cessna 680A. ENGINE. CORRODED. LH ENGINE AGB REAR COVER HAS MULTIPLE AREAS OF CORROSION. (N536QS) - [SDR 2021FA0000394](https://openairdocs.org/sdr/2021FA0000394), Dec 13, 2021: Cessna 680A. ENGINE. CORRODED. RH ENGINE AGB COVER HAS MULTIPLE AREAS OF CORROSION. (N536QS) - [SDR 2021FA0000393](https://openairdocs.org/sdr/2021FA0000393), Dec 13, 2021: Cessna 680A. ENGINE. CORRODED. LH ENGINE AGB REAR COVER HAS MULTIPLE AREAS OF CORROSION. (N536QS) - [SDR 2021FA0000309](https://openairdocs.org/sdr/2021FA0000309), Nov 2, 2021: Cessna 680A. GEARBOX. CORRODED. RH ENGINE GEARBOX AFT COVER CORRODED IN MULTIPLE LOCATIONS. (N548QS) - [SDR 2021FA0000308](https://openairdocs.org/sdr/2021FA0000308), Nov 2, 2021: Cessna 680A. GEARBOX. CORRODED. LH ENGINE GEARBOX AFT COVER CORRODED IN MULTIPLE LOCATIONS. (N549QS) - [SDR 2021F00208](https://openairdocs.org/sdr/2021F00208), Oct 16, 2021: Cessna 680A. COVER. CORRODED. THE ACCESSORY GEARBOX REAR COVER IS CORRODING ON THE FLANGES AND AROUND BOLT HOLES. ACCOMPLISHED STEPS (1) THRU (4) OF T (N578QS) - [SDR 2021F00207](https://openairdocs.org/sdr/2021F00207), Oct 16, 2021: Cessna 680A. COVER. CORRODED. THE ACCESSORY GEARBOX REAR COVER IS CORRODING ON THE FLANGES AND AROUND BOLT HOLES. ACCOMPLISHED STEPS (1) THRU (4) OF T (N578QS) - [SDR 2021F00279](https://openairdocs.org/sdr/2021F00279), Oct 4, 2021: Cessna 680A. MOUNT. CORRODED. RH AGB AFT SIDE HAS CORROSION ON OIL LINE MOUNTING PAD JUST INBOARD OF HYDRAULIC FAN. (N649QS) - [SDR 2021F00278](https://openairdocs.org/sdr/2021F00278), Oct 4, 2021: Cessna 680A. MOUNT. CORRODED. AFT SIDE OF LH AGB OUT BOARD SIDE HAS TWO OIL LINE MOUNTING PADS WITH CORROSION. (N649QS) - [SDR 2021FA0000277](https://openairdocs.org/sdr/2021FA0000277), Oct 3, 2021: Cessna 680A. COVER. CORRODED. THE ACCESSORY GEARBOX REAR COVER IS CORRODING ON THE FLANGES AND AROUND BOLT HOLES. ACCOMPLISHED STEPS (1) THRU (4) OF T (N559QS) - [SDR 2021F00253](https://openairdocs.org/sdr/2021F00253), Oct 3, 2021: Cessna 680A. COVER. CORRODED. THE ACCESSORY GEARBOX REAR COVER IS CORRODING ON THE FLANGES AND AROUND BOLT HOLES. ACCOMPLISHED STEPS (1) THRU (4) OF T (N559QS) - [SDR 2021F00246](https://openairdocs.org/sdr/2021F00246), Aug 25, 2021: Cessna 680A. GEARBOX. CORRODED. RH ENGINE GEARBOX AFT COVER CORRODED IN MULTIPLE LOCATIONS. (N550QS) - [SDR 2021F00245](https://openairdocs.org/sdr/2021F00245), Aug 25, 2021: Cessna 680A. GEARBOX. CORRODED. LH ENGINE GEARBOX AFT COVER CORRODED IN MULTIPLE LOCATIONS. (N550QS) - [SDR 2021FA0000228](https://openairdocs.org/sdr/2021FA0000228), Aug 10, 2021: Cessna 680A. GEARBOX. CORRODED. L/H ENGINE AGB AFT SIDE SHOWS SEVERAL AREAS OF CORROSION AND WAS REPAIRED IAW P&W MAINTENANCE MANUAL PART NO. 30B7302 72 (N509QS) All 306: https://openairdocs.org/jasc/8300/reports.md ## Other codes in chapter 83 - [JASC 8397](https://openairdocs.org/jasc/8397): Accessory Gearbox System Wiring (1 reports) --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.