# JASC 2434: DC Generator-Alternator

- Type: JASC system/component code (FAA)
- ATA chapter: 24 Electrical Power
- Title in the code table: DC GENERATOR-ALTERNATOR
- Service difficulty reports: 849
- FAA code table: https://www.faa.gov/sites/faa.gov/files/JASC_Code.pdf#page=21
- Page: https://openairdocs.org/jasc/2434

## What it covers

The engine driven component generating a direct current (DC) or a rectified alternating current for aircraft with DC electrical systems. For reports of alternators on light aircraft with piston engines. Does not include mounting brackets, drive belts and pulleys external to the unit. Typical parts are bearing, housing, coupling, fan, capacitor, drive, brush, seal, clutch, armature and bell, shaft, field winding, case bolt, ground stud, etc.

## Service difficulty reports (849, newest 50)

- [SDR 9WQR202609170736](https://openairdocs.org/sdr/9WQR202609170736), Sep 15, 2026: Cessna 182P. BOLT. UNSECURE. DURING AN ANNUAL INSPECTION THE ALTERNATOR WAS FOUND TO BE LOOSE BUT STILL WEDGED IN THE MOUNT, AND THE FAN BLADES RUBBI (N7299)
- [SDR N3XR2026090100002](https://openairdocs.org/sdr/N3XR2026090100002), Sep 1, 2026: Cessna 172S. CONTACTOR. BURNED. ALTERNATOR FAILED ON THE FINAL APPROACH WITH IGN PWR OFF ANNUNCIATOR. IP RECYCLED SWITCHES, BUT THE ANNUNCIATOR STILL EX (N870ER)
- [SDR N3XR2026090100001](https://openairdocs.org/sdr/N3XR2026090100001), Aug 8, 2026: Cessna 172S. CONTACTOR. BURNED. BUSS E & M VOLTS AT 24.2 AFTER ENGINE START. NO CHANGE IN VOLTAGE AT ANY POWER SETTING. BATTERY AMPS DISCHARGE -7 AT ALL (N813ER)
- [SDR 141A2026080300001](https://openairdocs.org/sdr/141A2026080300001), Aug 2, 2026: Cessna 208B. GENERATOR. MALFUNCTIONED. PHNY TO PHNL FLT 663, CREW NOTICED A STANDBY POWER INOP CASS MESSAGE ILLUMINATED. GETTING READY TO COMPLETE STANDBY POWE (N932SP)
- [SDR 2026FA0000329](https://openairdocs.org/sdr/2026FA0000329), May 7, 2026: Mooney M20K. ALTERNATOR. DESTROYED. ALTERNATOR DRIVE COUPLING DESTROYED CAUSING SUBSEQUENT FAILURE OF ENGINE'S DRIVE GEAR P/N 657984. ALL FOUR BOLTS P/N 649 (N252AN)
- [SDR 2026FA0000327](https://openairdocs.org/sdr/2026FA0000327), May 7, 2026: Cessna 340A. ALTERNATOR. DESTROYED. ALTERNATOR INPUT SHAFT HAS BEEN DAMAGED DUE TO DETROYED DRIVE COUPLING. DRIVE COUPLING HUB NO LONGER ROUND AND WOODRUFF  (N6823D)
- [SDR 2026FA0000211](https://openairdocs.org/sdr/2026FA0000211), Mar 24, 2026: Cirrus SR22T. BRUSH BLOCK. EXPLODED. ALTERNATOR WOULD INTERMITTENTLY FAIL DURING FLIGHT. LANDED. ALT CHECKED FINE. PULLED BRUSH BLOCK ASSEMBLY. AND IT FELL I
- [SDR 2026FA0000210](https://openairdocs.org/sdr/2026FA0000210), Mar 13, 2026: Cirrus SR22. ALTERNATOR. FAILED. FACTORY NEW ALTERNATOR SUDDENLY FAILED AFTER ONE MONTH AND 52 FLIGHT HOURS SINCE INSTALLATION. FAILURE OCCURRED IN CRUIS (N993MM)
- [SDR 2025FA0000691](https://openairdocs.org/sdr/2025FA0000691), Oct 2, 2025: Piper PA28161. DRIVE BELT. FAILED. ALTERNATOR BELT BROKE IN FLIGHT, AIRCRAFT LANDED SAFELY WITH APPROXIMATELY 20 MINS A BATTERY POWER REMAINING. THE BELT W (N9454C)
- [SDR ELYA10012025006](https://openairdocs.org/sdr/ELYA10012025006), Oct 1, 2025: Tecnam P2012. ALTERNATOR. BROKEN. LEFT ALTERNATOR FAILED CAS MESSAGE. WHILE TROUBLESHOOTING SMOKE SMELL BEGAN IN CABIN. LT ALTERNATOR WAS FOUND WITH TWO B (N260US)
- [SDR 2025FA0000653](https://openairdocs.org/sdr/2025FA0000653), Aug 13, 2025: Cessna 750. GENERATOR. BOWED. LOST EVERYTHING ON THE RIGHT SIDE. INCLUDING MACH TRIM FEDEC FAULTS FIVE INDICATIONS. DAU FAILS, TRIM FAIL. (N577JC)
- [SDR 4USA2025072100510](https://openairdocs.org/sdr/4USA2025072100510), Jul 19, 2025: Cessna 750. GENERATOR. FAILED. DURING CRUISE, CREW REPORTED “GEN FAIL R”. APPROXIMATELY 5-10 MINUTES LATER, IT WAS FOLLOWED BY “OIL LEVEL LOW R”. ABOUT (N734DJ)
- [SDR 2025FA0000458](https://openairdocs.org/sdr/2025FA0000458), Jul 8, 2025: Beech F33A. ALTERNATOR. INOPERATIVE. ALTERNATOR FAILED IN FLIGHT CAUSING AN UNSCHEDULED LANDING AT HERITAGE AVIATION IN BURLINGTON, VT. ALTERNATOR WAS A FAIR (N413SL)
- [SDR AALA202506209012](https://openairdocs.org/sdr/AALA202506209012), Jun 19, 2025: Boeing 7378. ALTERNATOR. FAULTY. AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: DURING CLIMB, "REVERSER LIMITED" LIGHT ILLUMINATED FOR THE NUMB (N334TL)
- [SDR AALA202506202065](https://openairdocs.org/sdr/AALA202506202065), Jun 19, 2025: Boeing 7378. STATOR. FAULTED. AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: DURING CLIMB, "REVERSER LIMITED" LIGHT ILLUMINATED FOR THE NUMB (N334TL)
- [SDR AALA202504063856](https://openairdocs.org/sdr/AALA202504063856), Apr 5, 2025: Airbus A321253NX. STATOR. FAULTED. AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT DIVERTED TO PHX DUE TO THE FLIGHT CREW REPORTING AN EC (N429AN)
- [SDR HEEA202412180001](https://openairdocs.org/sdr/HEEA202412180001), Dec 17, 2024: Skrsky S76C. STARTER GEN. INOPERATIVE. #2 GENERATOR FAILED DURING OUR HIGH ORBIT OF MC773. CONTINUED ORBITING AND FOLLOWED THE EMERGENCY PROCEDURE CHECKLIST. U (N794P)
- [SDR HYIA20241205001](https://openairdocs.org/sdr/HYIA20241205001), Nov 28, 2024: Tecnam P2012. BELT. WORN. PILOT REPORTED DUAL ALTERNATOR FAILURE IN FLIGHT. USED EMERGENCY: BACK UP ESSENTIAL PATH AND BATTERY DID NOT PROVIDE POW (N357CA)
- [SDR 2024FA0000862](https://openairdocs.org/sdr/2024FA0000862), Nov 4, 2024: Beech 58. ALTERNATOR. INOPERATIVE. PILOT EXPERIENCED LH ALTERNATOR FAILURE IN FLIGHT. TURNED LH ALTERNATOR SELECTOR TO OFF POSITION. SHORTLY AFTER, THE G10 (N5ZR)
- [SDR 2024FA0000957](https://openairdocs.org/sdr/2024FA0000957), Oct 29, 2024: Raythn G36. ALTERNATOR. FAULTED. ALTERNATOR WOULD INTERMITTENTLY GO OFF-LINE. ULTIMATELY HIGH FIELD RESISTANCE WAS DETERMINED TO BE A FACTOR....VOLTAGE R
- [SDR 2024FA0000980](https://openairdocs.org/sdr/2024FA0000980), Oct 18, 2024: Cessna 172S. ALTERNATOR. FAULTY. REPAIR FACILITY HAS ENCOUNTERED APPROX 3 NEWLY OVERHAULED ALTERNATOR UNITS THAT HAVE FAILED OPERATIONAL CHECKS ONCE INST (N715MT)
- [SDR 2024FA0000545](https://openairdocs.org/sdr/2024FA0000545), Jul 29, 2024: Piper PA28181. ANNUNCIATOR. FAILED. PILOT RECEIVED ALTERNATOR FAIL ANNUNCIATION IN FLIGHT DUE TO FAILED LAMAR ALTERNATOR INOP SWITCH A-00258-2. (N516AF)
- [SDR 2024FA0000534](https://openairdocs.org/sdr/2024FA0000534), Jul 26, 2024: Cirrus SR20. DRIVE COUPLING. BROKEN. GEAR PORTION OF COUPLER SLIPS INSIDE METAL/RUBBER HOUSING, CAUSING ALTERNATOR #2 TO REMAIN OFFLINE. A SECOND ALTERNATOR  (N2117)
- [SDR 2024FA0000543](https://openairdocs.org/sdr/2024FA0000543), Jun 27, 2024: Piper PA28181. ALTERNATOR. FAILED. PILOT RECEIVED ALTERNATOR FAIL ANNUNCIATION ON PFD DUE TO FAILED LAMAR ALTERNATOR INOP SWITCH A-00258-2. (N500AF)
- [SDR 2024FA0000549](https://openairdocs.org/sdr/2024FA0000549), Jun 22, 2024: Piper PA28181. SWITCH. FAILED. PILOT RECEIVED INTERMITTENT ALTERNATOR FAIL INDICATIONS ON PFD. BELIEVED TO BE CAUSED BY FAILED ALTERNATOR INOP SWITCH.  (N523AF)
- [SDR 2024FA0000550](https://openairdocs.org/sdr/2024FA0000550), Jun 10, 2024: Piper PA28181. SWITCH. FAILED. PILOT RECEIVED ALTERNATOR FAIL ANNUNCIATION IN FLIGHT DUE TO FAILED ALTERNATOR INOP SWITCH. LAMAR A-00258-2. (N6031F)
- [SDR HYIA20240514001](https://openairdocs.org/sdr/HYIA20240514001), May 10, 2024: Cessna 402C. HUB. EXCESS PLAY. UPON REMOVAL OF AN ALTERNATOR, THE HUB NUT WAS FOUND TO BE LOOSE, ALLOWING THE THRUST WASHER TO ROTATE BY HAND. THE COTT (N903CA)
- [SDR 2024FA0000242](https://openairdocs.org/sdr/2024FA0000242), Mar 21, 2024: Cessna 172P. CONTROL MODULE. INOPERATIVE. AMMETER SHOWING DISCHARGE, NO VOLTAGE TO FIELD. (N24155)
- [SDR IPXA2024022777693](https://openairdocs.org/sdr/IPXA2024022777693), Feb 27, 2024: Doug MD11F. BATTERY. NO TEST. EMERGENCY POWER TEST FAIL R/R BATT 1 AND BATT 2 REF AMM 24-34-00 OPS CHK GOOD (N274UP)
- [SDR DXTA2024013010753](https://openairdocs.org/sdr/DXTA2024013010753), Jan 29, 2024: Cessna 680A. GENERATOR. DEFECTIVE. ON TAXI OUT RECEIVED DC GEN OFF L AMBER CAS MESSAGE. RAN QRH, AND MESSAGE CLEARED. APPROXIMATELY 10 MINUTES LATER, STILL (N593QS)
- [SDR HYIA20230901002](https://openairdocs.org/sdr/HYIA20230901002), Aug 29, 2023: Tecnam P2012. ALTERNATOR. FAILED. PILOT REPORTED THE RIGHT HAND ALTERNATOR OUT LIGHT ON MOMENTARILY AND ELECTRICAL FUMES ON FINAL. MAINTENANCE REPLACED TH (N396CA)
- [SDR 2023FA0000463](https://openairdocs.org/sdr/2023FA0000463), Aug 21, 2023: Beech P35. ALTERNATOR. SHORTED. THE ALTERNATOR IS MOUNTED AS DESCRIBED IN THE STC SA01436AT INSTALLATION INSTRUCTIONS. THE POSITIVE CONNECTION IS TOUCHI (N8588M)
- [SDR 2023FA0000395](https://openairdocs.org/sdr/2023FA0000395), Jul 31, 2023: Cessna 182T. ALTERNATOR. SEIZED. CREW REPORTED DURING GROUND RUN AND PRIOR TO TAXI, ENGINE MADE A LOUD NOISE, AND THE ENGINE WAS SHUT DOWN IMMEDIATELY. T (N859JA)
- [SDR 2023FA0000394](https://openairdocs.org/sdr/2023FA0000394), Jun 23, 2023: Cessna T206H. ALTERNATOR. SEIZED. DC ALTERNATOR FAILED DURING GROUND RUN. UPON REMOVAL FOUND THE ALTERNATOR TO HAVE SEIZED. ALTERNATOR WAS SENT TO HARTZEL (N437H)
- [SDR 2023FA0000296](https://openairdocs.org/sdr/2023FA0000296), Apr 28, 2023: Piper PA32260. ALTERNATOR. FAILED. ENROUTE, CLOSE TO DESTINATION THE PILOT HAD A NEGATIVE RATE OF CHARGE AND WAS ON BATTERY POWER ALONE DUE TO ALTERNATOR F (N3756W)
- [SDR 9JLA2022120139205](https://openairdocs.org/sdr/9JLA2022120139205), Nov 7, 2022: Amd FALCON7X. GENERATOR. FAULTED. THE FLIGHT CREW REPORTED THAT THE NO3 ENGINE GENERATOR FAILED DURING CLIMB AFTER TAKEOFF. THE FLIGHT CREW ELECTED TO RET (N998RW)
- [SDR 2022FA0000679](https://openairdocs.org/sdr/2022FA0000679), Sep 10, 2022: Cessna 177RG. ALTERNATOR. DEFECTIVE. ALTERNATOR FAILED DURING FLIGHT. UPON DISCOVERING THE LACK OF CHARGE ON THE AMMETER, WE CYCLED THE ALTERNATOR POWER SWIT (N3MK)
- [SDR AALA202206176440](https://openairdocs.org/sdr/AALA202206176440), Jun 16, 2022: Boeing 737823. CONTROL UNIT. FAULT MESSAGE. AIRCRAFT WAS GROUNDED: AIR RETURNED TO MIA ACCOUNT GENERATOR ISSUE/STANDBY POWER LIGHT ILLUMINATED MESSAGE. EMERGENCY WA (N321RL)
- [SDR 2022FA0000041](https://openairdocs.org/sdr/2022FA0000041), Jan 21, 2022: Beech 100BEECH. NONE. NONE. OPERATOR REPORTED "ALTERNATOR OUT" LIGHT ILLUMINATES INTERMITTENTLY. VISUAL INSPECTION OF WIRING AT ALTERNATOR REVEALED  (N488HP)
- [SDR 2021FA0000392](https://openairdocs.org/sdr/2021FA0000392), Jun 30, 2021: Hawbee 4000. NONE. WORN. PILOT REPORTS THE RIGHT HAND STARTER GENERATOR HAS SMOKE COMING FROM IT DURING START UP. COMPLIED WITH R&R OF AIRCRAFT S (N946WT)
- [SDR N3XR202106030001](https://openairdocs.org/sdr/N3XR202106030001), May 24, 2021: Diamon DA42NG. BELT. SEPARATED. DURING THE LANDING APPROACH, THE SERPENTINE BELT (P/N-E4A-00-740-000) ON THE REAR OF THE INSTALLATION FAILED. THE FLIGHT (N304ER)
- [SDR 2021FA0000112](https://openairdocs.org/sdr/2021FA0000112), Apr 20, 2021: Cessna 414A. DRIVE SHAFT. SHEARED. LEFT ALTERNATOR FAIL ANNUNCIATOR LIGHT ILLUMINATED. NO VOLTAGE INDICATION ON LEFT ALTERNATOR. WIRING TERMINALS WERE INTA (N311BT)
- [SDR 9JLA2021022524810](https://openairdocs.org/sdr/9JLA2021022524810), Feb 14, 2021: Emb EMB145. GENERATOR. DEFECTIVE. THE FLIGHT CREW REPORTED THAT DURING FLIGHT THE GEN 2 BEARING FAIL EICAS MESSAGE ILLUMINATED. THE MAINTENANCE VENDOR DET (N10HC)
- [SDR 3EJA727MM1/1/21](https://openairdocs.org/sdr/3EJA727MM1%2F1%2F21), Jan 1, 2021: Cessna 750. GENERATOR. INOPERATIVE. LOSS OF AIRCRAFT PRIMARY AND SECONDARY ELECTRICAL POWER. LOST ELECTRICAL DISPLAYS. DIVERTED TO KABQ. EMERGENCY DECLARED. (N727MM)
- [SDR BEMA202012280001](https://openairdocs.org/sdr/BEMA202012280001), Dec 28, 2020: Beech 65A808800. ALTERNATOR. BURNED OUT. ALTERNATOR IN THE NR 1 POSITION FAILED IN FLIGHT. THE MAIN POWER STUD IS ATTACHED TO A PORTION OF THE RECTIFIER PLATE JU (N134BA)
- [SDR IKBR2020111200015](https://openairdocs.org/sdr/IKBR2020111200015), Nov 10, 2020: Cirrus SR22. ALTERNATOR. FAILED. ALTERNATOR NR 1 FAILED INSTALLED OVERHAULED ALTERNATOR. (N922BP)
- [SDR COEA2020110506899](https://openairdocs.org/sdr/COEA2020110506899), Nov 4, 2020: Cessna 208B. ALTERNATOR. FAILED. FLIGHT 8690, ENROUTE PDX-RBG AIR TURNBACK/DISCREPANCY. ON CLIMBOUT, THE ALTERNATOR FAILED, AS WELL AS, THE NR 1 COMM AND (N899FE)
- [SDR YV3R2020112100393](https://openairdocs.org/sdr/YV3R2020112100393), Nov 2, 2020: Robsin R44. ARM. BROKEN. MAINTENANCE DISCOVERED ARM (ALTERNATOR ADJUSTMENT) BROKEN DURING 100 HOUR/ANNUAL INSPECTION. (N171WC)
- [SDR YV3R2020102200369](https://openairdocs.org/sdr/YV3R2020102200369), Oct 13, 2020: Robsin R44RAVENII. ARM. BROKEN. CUSTOMER REPORTED ARM P/N: D728-1 BROKE (ALTERNATOR ADJUSTMENT ARM). (N930DK)
- [SDR HYIA20200918001](https://openairdocs.org/sdr/HYIA20200918001), Sep 18, 2020: Cessna 402C. ALTERNATOR. DAMAGED. THE PILOT REPORTED AFTER LANDING SMOKE AND BURNING PLASTIC SMELL COMING FROM THE AREA OF THE RIGHT ENGINE. MAINTENANCE I (N706CA)

All 849: https://openairdocs.org/jasc/2434/reports.md

## Other codes in chapter 24

- [JASC 2400](https://openairdocs.org/jasc/2400): Electrical Power System (1,186 reports)
- [JASC 2410](https://openairdocs.org/jasc/2410): Alternator-Generator Drive (891 reports)
- [JASC 2420](https://openairdocs.org/jasc/2420): AC Generation System (1,302 reports)
- [JASC 2421](https://openairdocs.org/jasc/2421): AC Generator-Alternator (4,273 reports)
- [JASC 2422](https://openairdocs.org/jasc/2422): AC Inverter (557 reports)
- [JASC 2423](https://openairdocs.org/jasc/2423): Phase Adapter (15 reports)
- [JASC 2424](https://openairdocs.org/jasc/2424): AC Regulator (480 reports)
- [JASC 2425](https://openairdocs.org/jasc/2425): AC Indicating System (137 reports)
- [JASC 2430](https://openairdocs.org/jasc/2430): DC Generating System (1,120 reports)
- [JASC 2431](https://openairdocs.org/jasc/2431): Battery Overheat Warning System (82 reports)
- [JASC 2432](https://openairdocs.org/jasc/2432): Battery/Charger System (2,249 reports)
- [JASC 2433](https://openairdocs.org/jasc/2433): DC Rectifier/Converter (197 reports)
- [JASC 2435](https://openairdocs.org/jasc/2435): Starter-Generator (2,052 reports)
- [JASC 2436](https://openairdocs.org/jasc/2436): DC Regulator (313 reports)
- [JASC 2437](https://openairdocs.org/jasc/2437): DC Indicating System (98 reports)
- [JASC 2440](https://openairdocs.org/jasc/2440): External Power System (169 reports)
- [JASC 2450](https://openairdocs.org/jasc/2450): AC Power Distribution System (872 reports)
- [JASC 2460](https://openairdocs.org/jasc/2460): DC Power Distribution System (608 reports)
- [JASC 2497](https://openairdocs.org/jasc/2497): Electrical Power System Wiring (2,202 reports)

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