# Service difficulty reports: JASC 6121

A list on [JASC 6121](https://openairdocs.org/jasc/6121.md).

Reports filed under 6121 · Propeller Synchronizer Section, newest first.

- [SDR LR7A2025041303753](https://openairdocs.org/sdr/LR7A2025041303753.md): Synchrophaser · inoperative · Apr 13, 2025 · N407LC · Lkheed 382G
  > DURING SCHEDULED FLIGHT #1 ENGINE RPM FLUX OUT OF LIMITS, ENGINE SHUTDOWN @2205Z IAW QRH / REMOVED AND REPLACED PROP SYNCHROPHASER REF: HAMILTON SUNDSTRAND 5059 CH.2, SECTION IV, OPS CHECK GOOD IAW HN7101. LOG PAGE #53955
- [SDR CA130822009](https://openairdocs.org/sdr/CA130822009.md): Module · inoperative · Aug 19, 2013 · Cvac 340CVAC
  > (CAN) NR 1 ENGINE HAS DRAMATIC RPM FLUCTUATIONS IN ALL BUT THE "OFF" SETTING IN THE SYNC SYSTEM.
- [SDR QMLA2013041713054](https://openairdocs.org/sdr/QMLA2013041713054.md): Screw · missing · Apr 17, 2013 · N912SM · Beech 200BEECH
  > ON FLIGHT, HAD PROPS SYNCED DURING CRUISE, TURNED PROP SYNC SYS ON AND PROPS WENT OUT OF SYNC. TURNED PROP SYNC OFF AND CONTINUED WITH PROPS SYNCED MANUALLY. UPON LANDING MECHANIC FOUND MISSING SCREW OF PROP SYNC SYS.
- [SDR CA111117026](https://openairdocs.org/sdr/CA111117026.md): Control Box · faulted · Oct 28, 2011 · Beech B200
  > (CAN) DURING A ROUTINE FLIGHT, IT WAS NOTED THE PROPELLERS WOULD NOT SYNCHRONIZE, THE PROPS WHERE SYNCHRONIZED MANUALLY AND THE FLIGHT CONTINUED WITHOUT COMPLICATIONS. MAINTENANCE FOUND A FAULTY PROPELLER SYNC CONTROL BOX, IT WAS R & R, THE SYSTEM GROUND FUNC
- [SDR MASA2011032402233](https://openairdocs.org/sdr/MASA2011032402233.md): Switch · jammed · Mar 21, 2011 · N989HA · Dhav DHC8202
  > PROP SYNC SWITCH JAMMED. MX R2 PROP SYNC SWITCH.
- [SDR NSVA2010169](https://openairdocs.org/sdr/NSVA2010169.md): Syncronizer · malfunctioned · Sep 20, 2010 · N341CJ · Saab 340B
  > RETURNED TO FLIGHT DUE TO RIGHT ENGINE TORQUE FLUX. FOUND FLUX TO BE ONLY WITH PROP SYNC ON. PLACED PROP SYNC ON MEL.
- [SDR CA090615011](https://openairdocs.org/sdr/CA090615011.md): Module · burned out · Jun 13, 2009 · Lkheed 188A
  > (CAN) SEVEN MINUTES FROM AIRPORT, CREW NOTICED SMOKE COMING FROM ELECTRICAL BAY. WITH NO SYSTEMS FAILED, THE CREW RETURNED TO DEPARTURE WITH NO INCIDENTS. MX FOUND NR 1 PROP PHASE SYNC MODULE HAD BURNED OUT. ALL ACFT WIRES WERE CHECKED OUT TO BE OK, THE SYS
- [SDR SWIA200819594](https://openairdocs.org/sdr/SWIA200819594.md): Connector · contaminated · May 5, 2008 · N236SW · Emb EMB120ER
  > FLT 3605 - RIGHT PROP NP WAS FLUCTUATING IN FLIGHT. INSPECTED AND CLEANED OIL FROM RIGHT PROP SYNC PICK-UP SENSOR CONNECTOR. OPS CHECK GOOD IAW EMB 120 MM 61-24-00.
- [SDR HNAA0800031](https://openairdocs.org/sdr/HNAA0800031.md): Pcu · defective · Jan 9, 2008 · N828EX · Dhav DHC8102
  > NR 2 PROPELLER FLUX OF 20 RPM ASSOCIATED WITH TORQUE FLUX OF 6%, RETURNED TO FIELD, PROPELLER SYNC OFF AT TIME OF FLUX, CYCLED PROPELLER SYNC DURING FINAL AND SURGE SELF CORRECTED AND ENGINES OPERATE NORMAL. GROUND RAN AT TAKEOFF POWER, COULD NOT DUPLICATE DI
- [SDR CA060424008](https://openairdocs.org/sdr/CA060424008.md): Shaft · broken · Apr 21, 2006 · Dhav DHC8301
  > FLIGHT CREW REPORTED EXCESS BACKLASH AND PROP SYNC DOES NOT SYNC. PROP WANDERING + - 5 TO 7 RPM. ENGINE SPRING STRUT ASSEMBLY REPLACED. AFTER DISASSEMBLY IN THE O/H SHOP, SHAFT P/N 87620130-101 WAS FOUND BROKEN AT POINT RIVET P/N MS204170AD3. THE SIZE OF TH
- [SDR HNAA0400109](https://openairdocs.org/sdr/HNAA0400109.md): Wire Harness · chafed · Aug 10, 2004 · N835EX · Dhav DHC8102
  > FLIGHT NR 3822 HAD TO RETURN TO FIELD DUE TO THE RT PROP RPM SURGING ON CLIMB OUT. AIRCRAFT LANDED WITHOUT INCIDENT. CONDITION DID NOT EXIST WITH THE PROP SYNCHROPHASER OFF. MAINTENANCE TROUBLESHOT SYSTEM AND FOUND CHAFED WIRES AT THE ENGINE HARNESS FOR THE SY
- [SDR 364032](https://openairdocs.org/sdr/364032.md): Switch · sparks · Dec 30, 2003 · N172MJ · Beech 1900D
  > WHEN THE NR 2 FLIGHT DIRECTOR PITCH SYNC BUTTON WAS PUSHED IT CAUSED ELECTRICAL SPARKS. REMOVED AND REPLACED NR 2 FLIGHT DIRECTOR PITCH SYNC BUTTON, SPARKS WHERE CAUSED BY LOOSE BUTTON WHICH SHORTED AGAINST YOKE.
- [SDR BAQA090685](https://openairdocs.org/sdr/BAQA090685.md): Actuator · failed · Nov 10, 2003 · N999G · Beech 100BEECH
  > ACTUATOR WILL NOT CENTER IN ONE DIRECTION. REPLACED WITH SERVICEABLE UNIT. 11/11/03
- [SDR BAQA090299](https://openairdocs.org/sdr/BAQA090299.md): Synchrophaser · inoperative · Oct 23, 2003 · N999G · Beech 100BEECH
  > PROPELLER SYCHROPHASER INOPERATIVE. REPLACED WITH SERVICEABLE UNIT.
- [SDR J7B2003F00001](https://openairdocs.org/sdr/J7B2003F00001.md): Coil · separated · Oct 10, 2003 · N421GF · Cessna 421C
  > ON TAKE OFF THE RT ENGINE FEATHERED. INSPECTION REVEALED PROPELLER SYNCROPHASER COIL HAD BECOME SEPARATED FROM THE GOVERNOR BODY, CAUSING THE PROPELLER TO FEATHER. THE ATTACHING STUDS ON THE COIL HAD SHEARED AND BECAME BOUND UP WITH THE FLYWEIGHT ASSY. PULL
- [SDR CA020722012](https://openairdocs.org/sdr/CA020722012.md): Housing · failed · Jul 11, 2002 · Lkheed 382G
  > (CAN) ENROUTE YUX FROM YUW NR 4 ENGINE WOULD NOT SYNC. PRECAUTIONARY ENGINE SHUTDOWN CARRIED OUT. MAINTENANCE REPLACED THE PROP VALVE HOSUING. THE AIRCRAFT WAS GROUND CHECKED SERVICEABLE BEFORE RETURN TO SERVICE.
- [SDR SIMA0252](https://openairdocs.org/sdr/SIMA0252.md): Warning Light · malfunctioned · Jan 25, 2001 · N250AE · Saab 340B
  > LAX - FLT 3057 - CREW ABORTED TAKEOFF DUE TO RIGHT AUTOMATIC POWER RESERVE LIGHT DID NOT ILLUMINATE. CREW ALSO REPORTED LEFT PROPELLER RPM LAGS BEHIND THE RIGHT. MAINTENANCE COULD NOT DUPLICATE DISCREPANCY. OPERATIONAL CHECK OF APR SYSTEM WAS COMPLIED WITH
- [SDR 20010112SG046](https://openairdocs.org/sdr/20010112SG046.md): Switch · shorted · Dec 12, 2000 · N228GL · Beech 1900D
  > PROP SYNC SWITCH SHORTED CAUSING ELECTRICAL SMOKE IN COCKPIT. PULLED PROP SYNC CIRCUIT BREAKER AND SMOKE CLEARED. PROP SYNC SYSTEM DEACTIVATED AND DEFERRED PER MEL 61-1 PENDING RECEIPT OF SWITCH. REPLACED SWITCH AND TESTED SYSTEM. NO DISCREPANCIES NOTED.
- [SDR 20010112SG023](https://openairdocs.org/sdr/20010112SG023.md): Switch · shorted · Nov 29, 2000 · N228GL · Beech 1900D
  > THE PROPELLER SYNCHORNIZATION SWITCH SHORTED, RESULTING IN SMOKE IN THE COCKPIT. REPLACED THE PROPELLER SYNCHORNIZATION SWITCH. OPS CHECKED GOOD. (M)
- [SDR 20010111SG008](https://openairdocs.org/sdr/20010111SG008.md): Switch · shorted · Oct 16, 2000 · N228GL · Beech 1900D
  > PROP SYNC SWITCH SHORTED CAUSING ELECTRICAL SMOKE IN THE COCKPIT. PULLED PROP SYNC CIRCUIT BREAKER AND SMOKE CLEARED. PROP SYNC SYSTEM DEACTIVATED AND DEFERRED PER MEL 61-1 PENDING RECEIPT OF SWITCH. (M)
- [SDR COMA0010315](https://openairdocs.org/sdr/COMA0010315.md): Pickup · out of adj · Aug 6, 2000 · N258CA · Emb EMB120RT
  > RIGHT HAND ENGINE NP OSCILLATING 99 T 102.8 PERCENT. ADJUSTED PROP SYNC. PULSE PICKUP GAPS TO M/M SPECIFICATIONS.
- [SDR VNAA0007003](https://openairdocs.org/sdr/VNAA0007003.md): Switch · failed · Jul 4, 2000 · N437JS · Dorner DO328100
  > DURING CLIMBOUT, THE CREW RECEIVED A LEFT HAND PROPELLER OIL PRESSURE CAS MESSAGE. THE CREW FOLLOWED THE QUICK REFERENCE HANDBOOK AND CONTACTED MAINTENANCE CONTROL WHO INSTRUCTED CREW TO RETURN TO PIT. FLIGHT 4171 LANDED WITHOUT FURTHER INCIDENT. MAINTENANC
- [SDR CA000712031](https://openairdocs.org/sdr/CA000712031.md): Hub · corroded · Jun 23, 2000 · Cessna 172D
  > (CAN) PROPELLER RECEIVED FOR CORROSION INSPECTION. (X)
- [SDR VNAA0004012](https://openairdocs.org/sdr/VNAA0004012.md): Pcu · failed · Apr 6, 2000 · N426JS · Dorner DO328100
  > WHILE CLIMBING THROUGH FLT 020, THE CREW RECEIVED AN INTERMITTENT RIGHT HAND PROPELLER LOW OIL PRESSURE CAS MESSAGE. REACHING FLT 100 THE MESSAGE REMAINED CONSTANT, THE CREW DECIDED TO RETURN TO THE FIELD. THE AIRCRAFT WAS FERRIED TO AKRON WHERE MAINTENANCE
- [SDR C2XA99CL128](https://openairdocs.org/sdr/C2XA99CL128.md): Switch · failed · Dec 17, 1999 · N81553 · Beech 1900D
  > CLE - FLT 3134 - AFTER TAKEOFF FROM CLE, LEFT AUTOFEATHER ADVISORY (GREEN) LIGHT AND REPEATER (AFX) FAILED TO ILLUMINATE. AIRCRAFT RETURNED TO CLE WITHOUT FURTHER INCIDENT. MAINTENANCE REMOVED AND REPLACED NR 1 ENGINE LOW PRESSURE AUTOFEATHER SWITCH IAW BEEC
- [SDR HEEA063064](https://openairdocs.org/sdr/HEEA063064.md): Syncrophaser · erratic · Aug 12, 1999
  > PROPELLER SYNC ERRATIC.
- [SDR MASA99084](https://openairdocs.org/sdr/MASA99084.md): Switch · loose · May 26, 1999 · N2YV · Beech 1900D
  > FLT 1031 - ABQ-ROW - EN ROUTE TO ROW,THE CREW REPORTED WHEN THE CO-PILOT PUSHED HIS PATCH SYNC SWITCH THE CIRCUIT BREAKER FOR THE FLIGHT DIRECTOR POPPED AND A SMALL AMOUNT OF SMOKE CAME FROM THE SWITCH. THE AIRCRAFT LANDED IN ROW WITHOUT INCIDENT. THE AIRCRA
- [SDR SWIA971259](https://openairdocs.org/sdr/SWIA971259.md): Synchronizer · malfunctioned · Sep 3, 1998 · N226SW · Emb EMB120ER
  > PROP SYNC CAUSES 3 PERCENT NP FLUCTUATION ON RIGHT PROPELLER. RETURNED TO LAX, MEL 61-24-1. REPLACED PROP SYNCHROPHASER IAW MM 61-24-01, OPS CHECKS GOOD.
- [SDR SWIA971237](https://openairdocs.org/sdr/SWIA971237.md): Prop Synch · malfunctioned · Aug 5, 1998 · N289YV · Emb EMB120RT
  > RIGHT ENGINE STARTED SURGING, TQ FLUCTUATIONS AT 9,000 FT. RETURNED TO LAX. TQ FLUCTUATING CONTINUED AS MUCH AS 10 PERCENT. TURNED OFF EEC PER QRH WITH NO CHANGES. NOTIFIED LAX MX. DECLARED EMERGENCY VIA ATC FOR ENGINE SURGING. DID NOT SHUT DOWN ENGINE.
- [SDR 98ZZZM639](https://openairdocs.org/sdr/98ZZZM639.md): Actuator · failed · Jul 17, 1998 · N566EA · Cvac 440
  > PROPELLERS WILL NOT SYNC IN K1 POSITION. RIGHT 13500 RPM, LT 14,000 RPM AND RISING. PITCH LOCKED PROPELLER, RPM STILL UNSTABLE. E-HANDLED LT ENGINE AND MADE UNEVENTFUL LANDING AT ANC. REPLACED LT ROTARY ACTUATOR AND REPAIRED BROKEN WIRE TO RT PROP ALTERNAT
- [SDR AU980579](https://openairdocs.org/sdr/AU980579.md): Actuator · failed · May 28, 1998 · Stbros SD360
  > (AUS) LT PROPELLER SYNCHRONIZATION SYSTEM FAILED. PROPELLER CONTROL ACTUATOR FULLY WOUND ONE WAY PREVENTING THE GOVERNOR ARM FROM REACHING THE MAXIMUM RPM STOP.
- [SDR 96ZZZX3540](https://openairdocs.org/sdr/96ZZZX3540.md): Control Box · shorted · Jun 21, 1996 · N6221C · Cessna 340A
  > DURING CRUISE FLIGHT, SMOKE FILLED THE CABIN. ELECTRICAL POWER WAS TURNED OFF. SMOKE CLEARED FROM CABIN. INVESTIGATION REVEALED THE PROPELLER SYNCROPHASER CONTROL BOX HAD SHORTED AND EMITTED SMOKE. THE NUTS THAT HOLD THE CANNON PLUG PINS HAD VIBRATED OFF A
- [SDR HEEA967054](https://openairdocs.org/sdr/HEEA967054.md): Actuator · failed · Apr 18, 1996 · N30PH · Beech 200BEECH
  > PROP SYNC INOPERATIVE.
- [SDR CA960123011](https://openairdocs.org/sdr/CA960123011.md): Connector · crimp failed · Jan 5, 1996 · Beech B200C
  > (CAN)DURING TROUBLESHOOTING OF THE PROPELLER SYNCHROPHASER SYSTEM, WIRES WERE FOUND PULLED OUT OF THE SYNCHROPHASER BOX CONNECTOR. WHEN THE SOCKETS WERE EXTRACTED FROM THE BOX THEY COULD BE SEEN TO BE IMPROPERLY CRIMPED. THERE WAS ALSO NO STRAIN RELIEF BACKSHE
- [SDR 96ZZZX3976](https://openairdocs.org/sdr/96ZZZX3976.md): Sync Actuator · failed · Nov 20, 1995 · N711PK · Stbros SD360
  > PROPELLER SYNCHRONIZATION INOPERABLE. PROPELLER SYNCHRONIZATION ACTUATOR NOT RETURNING THE PROPELLER GOVERNOR INPUT DRIVE TO THE CENTER WHEN PROPELLER SYNC WAS SWITCHED OFF.
- [SDR 95ZZZX6059](https://openairdocs.org/sdr/95ZZZX6059.md): Actuator · pin sheared · Oct 10, 1995 · N1950G · Cessna 421B
  > PILOT EXPERIENCED RAPID RPM INCREASE ON THE RIGHT ENGINE WHEN PROP SYNC ENGAGED. PILOT THEN SHUT OFF PROP SYNC AND CONTROLLED RPM MANUALLY, BUT REPORTED THE RIGHT PROP LEVER TO BE OUT OF RIG WITH THE LEFT AND WOULD NOT GO FULL TRAVEL. INVESTIGATION REVEALED
- [SDR COMA9531165](https://openairdocs.org/sdr/COMA9531165.md): Governor · defective · Sep 26, 1995 · N320CA · Saab SF340A
  > LT PROPELLER RPM DROPS TO 1370 DURING FINAL APPROACH. REPLACED THE PROPELLER OVERSPEED GOVERNOR.

## The whole list in SQL

Runs in DuckDB 1.2 or later on the release's Parquet files over HTTPS:

```sql
SELECT sdr_id, difficulty_date, n_number, aircraft_make, aircraft_model, part_name, part_condition, jasc_code, discrepancy
FROM 'https://openairdocs.org/data/latest/faa_service_difficulty_report.parquet'
WHERE jasc_code = '6121'
ORDER BY difficulty_date DESC
```

This list as a web page: https://openairdocs.org/jasc/6121/reports

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