# Service difficulty reports: Lycoming AL5512

A list on [Lycoming AL5512](https://openairdocs.org/engine/lycoming-al5512.md).

Newest first. General aviation reporting is voluntary.

- [SDR CHIA202511059838](https://openairdocs.org/sdr/CHIA202511059838.md): Engine · overtemp · Nov 5, 2025 · N235CH · Boeing 234 · Engine (Turbine/Turboprop)
  > DURING DESCENT TO DROP OFF PASSENGERS AND CARGO, THE NR 2 ENGINE PTT BEGAN TO RISE TO 905C AND THE N1 WAS AT 102% FOR AT LEAST 15 SECONDS. ACFT RETURNED TO BASE. NO DUPLICATION OF INCIDENT COULD BE MADE ON THE GROUND. ENGINE AND FCU WILL BE REPLACED.
- [SDR CHIA202407187623](https://openairdocs.org/sdr/CHIA202407187623.md): Control Box · activation error · Jul 18, 2024 · N235CH · Boeing 234 · Engine Controls
  > THREE MINS AFTER TAKEOFF, THE COPILOT NOTED A SPLIT IN TORQUE SHOWING THE #1 ENGINE HAD ROLLED BACK TO 40% TORQUE. THE ENGINE WAS BEEPED UP AND THE AIRCRAFT WAS RETURNED TO BASE. TROUBLESHOOTING FOUND NO DEFECTS NOTED. FOR PRECAUTIONARY MEASURES, REPLACED #1 E
- [SDR CHIA2020091064669](https://openairdocs.org/sdr/CHIA2020091064669.md): Control Box · failed · Sep 6, 2020 · N239CH · Boeing 234 · Engine Controls
  > PILOT ACCOUNT: DURING FIRE FIGHTING MISSION, NR 2 ENGINE ROLLED BACK TO INTERMEDIATE SETTING (LESS THAT FLIGHT RPM WITH RRPM DECAY, ABOVE GROUND IDLE). THIS OCCURRED WHILE DROPPING WATER. EMERGENCY POWER WAS NECESSARY TO MAINTAIN RRPM. AFTER GAINING AIRSPEE
- [SDR CHIA202009064669](https://openairdocs.org/sdr/CHIA202009064669.md): Control Box · failed · Sep 6, 2020 · N239CH · Boeing 234 · Fuel Control/Reciprocating Engines
  > INTERIM SUPPLEMENTAL INFORMATION: THE OVERSPEED CONTROL BOX LISTED BELOW HAS BEEN RETURNED TO THE OEM (HONEYWELL) AND IS PRESENTLY UNDER EVALUATION BY THE OEM AND THE TC HOLDER. THIS SUPPLEMENTAL INFORMATION WILL BE UPDATED ONCE A ROOT CAUSE HAS BEEN ESTABLIS
- [SDR CHIA2020090624671](https://openairdocs.org/sdr/CHIA2020090624671.md): Control Box · failed · Sep 2, 2020 · N239CH · Boeing 234 · Engine Controls
  > NR 2 ENGINE ROLLBACK ON APPROACH TO WATER SOURCE. ENGINE SECURED PER EMERGENCY ABNORMAL CHECKLIST. COULD NOT FIND ANY DEPENDENCY DURING T/S. REMOVED AND REPLACED NR 2 CONTROL BOX AND ACTUATOR FOR T/S. ALL SUBSEQUENT CHECKS GOOD AND AIRCRAFT RETURNED TO SER
- [SDR CHIA202009174694](https://openairdocs.org/sdr/CHIA202009174694.md): Engine · power loss · Sep 17, 2019 · N239CH · Boeing 234 · Engine (Turbine/Turboprop)
  > ON APPROACH TO DIP SITE NR 2 ENGINE FAILED TO RESPOND. NR 2 HUNG BACK AT AROUND 20% TQ, PILOTS WENT INTO EMERGENCY ENGINE TRIM & MANUALLY BEEPED ENGINE WITH NO RESPONSE. NR 2 ECL WAS BROUGHT BACK TO GROUND POSITION TO AVOID A POTENTIAL OVERSPEED CONDITION.
- [SDR CHIR020165022375](https://openairdocs.org/sdr/CHIR020165022375.md): Case · debonded · May 2, 2016 · Boeing 234 · Turbine Engine Compressor Section
  > (P2-CH) NR 2 ENGINE CHIP LIGHT, CONFIRMED METAL CONTAMINATION ON CHIP PLUG AND OIL FILTER. AFTER RECEIPT AT REPAIR STATION, DIFFUSER AND GP AREA INSPECTED PRIOR TO PRELIMINARY TEST CELL RUN WITHOUT ANY EVIDENCE OF DELAMINATION. POST TEST, DURING ROUTINE REPA
- [SDR CHIR050220162375](https://openairdocs.org/sdr/CHIR050220162375.md): Compressor · debonded · May 2, 2016 · Boeing 234 · Turbine Engine Compressor Section
  > THE ENGINES OEM WAS ABLE TO CONFIRM THE PLASMA REPAIR OF THE COMPRESSOR CASE WAS DONE TO APPROVED DATA. NO DETERMINATION OF THE CAUSE FOR THE FAILURE HAS BEEN MADE. THE OWNER/OPERATOR HAS MADE A BUSINESS DETERMINATION THAT MAGNESIUM CASES WITH PLASMA REPAIRS W
- [SDR CHIR201603312325](https://openairdocs.org/sdr/CHIR201603312325.md): Manifold · leaking · Mar 31, 2016 · N242CH · Boeing 234 · Fuel Controlling System
  > NR 1 ENGINE FIRE WARNING IN-FLIGHT AT END OF DAYS OPERATIONS AT HOVER. MECHANIC CONFIRMED FIRE AFTER ACFT WAS SET DOWN. FIRE AT 12:00 ON TOP AND BACK OF BURNER CAN. AFTER ENGINE WAS SHUTDOWN, THE FIRE WENT OUT. ENGINE WAS INSPECTED. NO EVIDENCE OF CRACKING
- [SDR CHIR201511172182](https://openairdocs.org/sdr/CHIR201511172182.md): Bolt · broken · Nov 11, 2015 · N242CH · Boeing 234 · Main Rotor Transmission Mount
  > DURING DISASSEMBLY OF COMPONENT, SCUFFING ON BOTH THE SPIRAL BEVEL GEAR AND PINION GEAR WAS NOTED. THE CUSTOMER HAD REPORTED A SINGLE BOLT BROKEN UPON ON-WING TORQUE CHECK INSPECTION AND NO OTHER BOLTS APPEAR CRACKED AFTER DISASSEMBLY. NDT PENDING RESULTS.
- [SDR CHIR2015090102057](https://openairdocs.org/sdr/CHIR2015090102057.md): Bolt · cracked · Aug 28, 2015 · Boeing 234 · Main Rotor Drive System
  > DURING DISASSEMBLY OF COMPONENT IT WAS NOTICED THERE IS SEVERE SCUFFING ON BOTH THE SPIRAL BEVEL RING GEAR AND THE SPIRAL BEVEL PINION GEAR. AT DISASSEMBLY, 2 BOLTS WERE FOUND CRACKED AFTER FAILING TORQUE CHECK ON WING. THIS BOLTED JOINT HAS NOT HAD THE UPDA
- [SDR CHIR2014040400236](https://openairdocs.org/sdr/CHIR2014040400236.md): Nozzle · misoverhauled · Apr 4, 2014 · Fuel Injector Nozzle
  > T3 NOZZLE WAS RECEIVED OVERHAULED, INSTALLED IN ENGINE AND RAN IN TEST CELL. DURING TEST CELL A COAST DOWN NOISE WAS NOTED. DURING DISASSEMBLY, PIECES OF THE NOZZLE FELL OUT, FURTHER INSPECTION FOUND THAT THE LAB SEAL RIVETS IMPACTED THE NR 3 WHEEL AND GROUN
- [SDR CHIR201412120057](https://openairdocs.org/sdr/CHIR201412120057.md): Case · overtemp · Dec 9, 2013 · Boeing 234 · Engine (Reciprocating)
  > THE ENGINE WAS ORIGINALLY REMOVED FOR HIGH PTIT. HIGH PTIT WAS CONFIRMED IN THE TEST CELL. DURING DISASSEMBLY IT WAS NOTED THAT THERE WAS EVIDENCE OF PLASMA SPRAY EXITING THE AIR DIFFUSER. FURTHER DISASSEMBLY REVEALED A COMPLETE SECTION OF PLASMA REPAIR MIS
- [SDR CHIR201310071464](https://openairdocs.org/sdr/CHIR201310071464.md): Impeller · damaged · Oct 3, 2013 · Boeing 234 · Turbine Engine Compressor Section
  > THE ENGINE WAS ORIGINALLY REMOVED FOR HIGH PTIT. HIGH PTIT WAS CONFIRMED IN THE TEST CELL. DURING DISASSEMBLY IT WAS NOTED THAT THERE WAS EVIDENCE OF PLASMA SPRAY EXITING THE AIR DIFFUSER. FURTHER DISASSEMBLY REVEALED A COMPLETE SECTION OF PLASMA REPAIR MISS
- [SDR CHIR20131609001](https://openairdocs.org/sdr/CHIR20131609001.md): Inverter · out of adjust · Sep 12, 2013 · N246CH · Boeing 234 · Engine BMEP/Torque Indicating
  > OPERATOR HAS EXPERIENCED ISSUES WITH MALADJUSTED TORQUE INVERTER, SIGNAL CONDITIONERS, ALSO KNOWN AS RATIO DETECTOR POWER SUPPLY, RDPS, ASSOCIATED WITH THE ENGINE TORQUE INDICATING SYSTEM. THE FAULT IS ASSOCIATED WITH THE IMPROPER VOLTAGE OUTPUT FROM THE RDPS
- [SDR CHIAMJ017/09/002](https://openairdocs.org/sdr/CHIAMJ017%2F09%2F002.md): Actuator · restricted · Aug 22, 2009 · N246CH · Boeing 234 · Rotorcraft Flight Control
  > DURING (FLIGHT CONTROLS TRAVEL AND FLIGHT BOOST SYS CK) AS PART OF PRE-FLIGHT CHECKS (DESCRIBED IN FLIGHT MANUAL PART 1, SECTION 2 PAGE 2-11 ITEM 29 (A)) PILOTS NOTICED ABNORMAL RESISTANCE OF LONGITUDINAL CYCLIC CONTROL MOVEMENT. AT THIS POINT ACFT WAS GROUND
- [SDR MJ01709002](https://openairdocs.org/sdr/MJ01709002.md): Trunnion · binding · Aug 22, 2009 · N246CH · Boeing 234 · Rotorcraft Flight Control
  > DURING THE "FLIGHT CONTROLS TRAVEL AND FLIGHT BOOST SYS CHECK" AS PART OF THE PRE-FLIGHT CK, COMPANY PILOTS NOTICED ABNORMAL RESISTANCE OF LONGITUDINAL CYCLIC CONTROL MOVEMENT. AT THIS POINT THE ACFT WAS GROUNDED AND TURNED OVER TO MX. UPON FURTHER INVESTIGA
- [SDR 2005FA0000871](https://openairdocs.org/sdr/2005FA0000871.md): Adapter · cracked · Jun 8, 2005 · N242CH · Boeing 234 · Engine (Turbine/Turboprop)
  > DURING OVERHAUL OF ENGINE AWN ADAPTER, NDT FOUND.450 INCH TOTAL LENGTH CRACK IN THE BOLT HOLE OF LUG NR 1. IN THE BORE OF LUG, CRACK LENGTH IS.300 OF INCH AND ACROSS FACE OF LUG, THE CRACK LENGTH IS.150 OF INCH. ILLUSTRATION DEPICTS LOCATION AND SCHEMATIC
- [SDR CA050315012](https://openairdocs.org/sdr/CA050315012.md): Vent · failed · Mar 10, 2005 · Boeing 234 · Fuel Storage
  > (CAN) DURING REFUELING, A LOUD BANG WAS HEARD FROM CABIN OF AIRCRAFT. FUEL WAS THEN SEEN LEAKING RAPIDLY FROM AIRCRAFT. PILOTS NOTED FUEL INSIDE CABIN SECTION BUT NOT IN COCKPIT. ENGINES WERE SHUT DOWN, ELECTRICAL SYSTEMS TURNED OFF AND PILOTS EXITED AIRCRAFT
- [SDR CA040410001](https://openairdocs.org/sdr/CA040410001.md): Drive Assy · cracked · Apr 1, 2004 · Boeing 234 · Main Rotor Drive System
  > (CAN) DURING INSPECTION IAW AD 2004-06-51 A CRACK WAS DETECTED IN THE UPPER EXTENSION 37 INCHES FROM THE TOP. SHAFT WAS REMOVED FROM SERVICE AND RETURNED TO MFG FOR INSPECTION. MFG IS CONDUCTING INSPECTIONS OF ALL IN-SERVICE SHAFTS AND SPARES TO ELIMINATE AN
- [SDR CHI2003F00004](https://openairdocs.org/sdr/CHI2003F00004.md): Engine · making metal · Jul 27, 2003 · N246CH · Boeing 234 · Engine (Turbine/Turboprop)
  > DURING FLIGHT NR 2 ENGINE CHIP LIGHT CAMP ON. PILOTS REF EMERGENCY CHECKLIST AND IT INSTRUCTED THEM TO MONITOR ENGINE OIL PRESSURE AND TEMP, THEN LAND AS SOON AS PRACTICAL. AFTER LANDING THE NR 2 ENGINE CHIP DETECTOR WAS INSPECTED AND 2 METALLIC SLIVERS AND
- [SDR CHI2003F00003](https://openairdocs.org/sdr/CHI2003F00003.md): Engine · making metal · Jul 23, 2003 · N246CH · Boeing 234 · Engine (Turbine/Turboprop)
  > ENGINE CHIP LIGHT CAME ON IN FLIGHT, PILOTS REFERENCED EMERGENCY CHECKLIST AND IT INSTRUCTED THEM TO MONITOR ENGINE TEMP AND OIL PRESSURE AND TO LAND AS SOON AS PRACTICAL. INSPECTED CHIP DETECTOR AND FOUND A SINGLE METALLIC SLIVER, ALSO MAIN OIL FILTER BUTTON
- [SDR CA030716007](https://openairdocs.org/sdr/CA030716007.md): Engine · failed · Jun 25, 2003 · Boeing 234 · Engine (Turbine/Turboprop)
  > (CAN) LOUD BANG, SMOKE, NR 2 ENGINE STOPPED. AIRCRAFT RETURNED TO BASE SINGLE ENGINE. SMALL PIECES OF ENGINE FOUND CONTAINED IN NACELLE THAT APPEAR TO HAVE BEEN EJECTED THROUGH BLEED BAND. ENGINE RETURNED TO OVERHAUL SHOP FOR INVESTIGATION AND REPAIR. THIRD TH
- [SDR CHI2003F00000](https://openairdocs.org/sdr/CHI2003F00000.md): Bar · cracked · Jun 4, 2003 · N239CH · Boeing 234 · Main Rotor Head
  > DURING NORMAL ROTOR HEAD MAINTENANCE, THE TWO REPORTED TIE BARS WERE FOUND WITH NUMEROUS DEFECTS. THE DEFECTS CONSISTED OF SEVERAL CRACKED PLATES AT THE TIE BAR PINHOLE. THE TWO TIE BARS WERE SENT TO THE MANUFACTURER FOR EVALUATION AND AFTER DISASSEMBLY, ADD
- [SDR CHI2003F00002](https://openairdocs.org/sdr/CHI2003F00002.md): Compressor Wheel · cracked · Mar 14, 2003 · N242CH · Boeing 234 · Turbine Engine Compressor Section
  > TWO CRACKS WERE FOUND IN THE 1ST STAGE COMPRESSOR DISC (PN210133105) DURNG AN INSPECTION. THE CRACKS ARE LOCATED IN TWO OF THE COMPRESSOR BLADE RETENTION SLOTS. THIS IS THE SECOND TIME CRACKS HAVE BEEN FOUND EMANATING FROM THE BLADE RETENTION SLOTS OF THIS P
- [SDR CA000501009](https://openairdocs.org/sdr/CA000501009.md): Transmission · making metal · Apr 12, 2000 · Boeing 234 · Main Rotor Gearbox
  > (CAN) DURING DESCENT, CHIP WARNING LITE ILLUMINATED. MAINTENANCE PERSONNEL THEN CLEANED CHIP PLUG & CHANGED FILTER. SERVICEABILITY CHECK CARRIED OUT AS PER BOEING MAINTENANCE MANUAL SECTION 63-25-00 & 63-23-00 AND TRANSMISSION FOUND SERVICEABLE. HOWEVER, ROTO
- [SDR CHIR3488](https://openairdocs.org/sdr/CHIR3488.md): Driveshaft · cracked · Aug 16, 1999 · N238CH · Boeing 234 · Engine (Turbine/Turboprop)
  > TWO CRACKS IN OUTBOARD ADAPTER END. CRACKS GO THROUGH AN OUTBOARD RIVET HOLE AND EXTEND AT A 45 DEGREE ANGLE INBOARD AND OUTBOARD TO THE ADAPTER EDGE. P/N 114D3204-3 ADAPTER END. (X)
- [SDR CA990818003](https://openairdocs.org/sdr/CA990818003.md): Bearing · failed · Aug 3, 1999 · Boeing 234 · Main Rotor Mast/Swashplate
  > (CAN) AFTER SHUTDOWN (FOLLOWING LOGGING OPERATIONS), A LOT OF BLACK GREASE AND METAL HAD BEEN SLUNG FROM THE SWASHPLATE SEAL AND PIECES OF BEARING CAGE WERE FOUND ALL OVER THE AFT SWASHPLATE AREA AND THRUST DECK. SWASHPLATE WAS REMOVED AND BEARINGS WERE EXTRE
- [SDR CHIA3099](https://openairdocs.org/sdr/CHIA3099.md): Pump · worn · Jun 13, 1998 · N241CH · Boeing 234 · Engine Fuel Pump
  > DURING TAKEOFF CHECK, PILOT NOTICED NR 2 FUEL PRESS 12 PSI LOWER THAN NR 1. THIS IS LOWER THAN IT NORMALLY OPERATES WITH ENG AT FLY AND BOTH FUEL TANK BOOST PUMPS ON. PILOT VERIFIED FUEL TANK BOOST PUMPS OPERATIONAL. VERIFIED FUEL PRESS IND READING PROPERLY
- [SDR CA970707007](https://openairdocs.org/sdr/CA970707007.md): Turbine Rotor · blade fractured · Jun 23, 1997 · Boeing 234 · Turbine Section
  > (CAN) ENGINE WAS SHUTDOWN IN FLIGHT AND AIRCRAFT RETURNED TO POINT OF DEPARTURE. INSPECTION FOUND COMPRESSOR BLADE FROM THE FIRST TURBINE ROTOR HAD SEPARATED AND DAMAGED ADJACENT BLADES.
- [SDR CHI1512](https://openairdocs.org/sdr/CHI1512.md): Engine · damaged · Oct 26, 1995 · N234CH · Boeing 234 · Turbine Section
  > INFLIGHT ENGINE SHUT-DOWN DURING LOGGING OPERATION. NO VISIBLE DAMAGE TO INLET OF ENG OR FIRST STAGES OF COMPRESSOR. COMPR WOULD ROTATE, BUT WITH DIFFICULTY, & RUBBING NOISES. VISIBLE DMG TO EGV & NR 4 TURBINE WHEEL. PT WOULD NOT TURN. NO VISIBLE DMG TO C
- [SDR CHI1477](https://openairdocs.org/sdr/CHI1477.md): Switch · broke · Aug 21, 1995 · N2FOR · Boeing 234 · Turbine Engine Reduction Gear
  > DURING REMOVAL OF ENGINE SCREEN AND NOSE BOX COWL, NOTICED NR 1 ENGINE TRANSMISSION TEMP SWITCH WAS HANGING BY THE CANNON PLUG WHERE IT HAD BROKEN IN HALF AT THE WELDED SEAM. NO SIGN OF LEAKAGE. CAUSE UNKNOWN. (X)
- [SDR CHI1478](https://openairdocs.org/sdr/CHI1478.md): Switch · broken · Aug 8, 1995 · N239CH · Boeing 234 · Turbine Engine Reduction Gear
  > PILOTS REPORTED INTERMITTENT NR 1 ENGINE TRANSMISSION HOT LIGHT. DURING TROUBLESHOOTING, FOUND M2001-517 TEMP SWITCH BROKE IN HALF AND WIRES PULLED OUT AT CANNON PLUG. REPLACED TEMP SWITCH AND CANNON PLUG. CHECKED GOOD. CAUSE UNKNOWN. SUBMITTER SUGGESTS PO

## 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 engine_model_key = 'AL5512'
ORDER BY difficulty_date DESC
```

This list as a web page: https://openairdocs.org/engine/lycoming-al5512/reports

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