# Service difficulty reports: JASC 4990 A list on [JASC 4990](https://openairdocs.org/jasc/4990.md). Reports filed under 4990 · APU Oil System, newest first. Page 1 of 54 · 2,651 reports - [SDR AALA202610220912](https://openairdocs.org/sdr/AALA202610220912.md): Apu · inoperative · Oct 19, 2026 · N979AN · Boeing 737823 > AIRCRAFT WAS GROUNDED: APU WAS RUNNING IN FLIGHT DUE TO MEL REQUIREMENT. APPROXIMATELY 10 MINUTES AFTER LEVEL OFF WHILE CRUISING AT FL 390, APU AMBER LOW OIL PRESSURE LIGHT ILLUMINATED WITH ASSOCIATED MASTER CAUTION. QRH PROCEDURE ACCOMPLISHED. UPON CONSULT - [SDR WX0A2026102132984](https://openairdocs.org/sdr/WX0A2026102132984.md): Oil Cooler · leaking · Oct 19, 2026 · N194NV · Airbus A320214 > (AIRCRAFT NOT GROUNDED) FA REPORTED, ON DESCENT SMELLED CHEMICAL SMELL TURNED INTO DIRTY MUSKY GYM SMELL, IN AFT GALLEY. / REF AML 2210448 FOR REMOVAL AND REPLACEMENT OF APU OIL COOLER AND FAN OUTLET DUCT. REF WO # 564339 FOR COMPLETION OF TASK CARD A32X-21-0 - [SDR DALA2026101805704](https://openairdocs.org/sdr/DALA2026101805704.md): Oil System · leaking · Oct 17, 2026 · N528DE · Airbus A321271NX > AFT FA SUSPECTED DIRTY SOCK ODOR DURING FINAL APPROACH. REPLACED APU ASSY PER A321 W/C 4900-9002. (LP 8966926, 1870241 - AIRCRAFT WAS GROUNDED) - [SDR AALA202610192245](https://openairdocs.org/sdr/AALA202610192245.md): Pressure Switch · inoperative · Oct 16, 2026 · N979AN · Boeing 737823 > AIRCRAFT WAS GROUNDED: --DECISION WAS MADE TO DIVERT TO GEG. EMERGENCY DECLARED; AIRCRAFT LANDED WITHOUT INCIDENT -- APU SHUT DOWN WITH LOW OIL PRESSURE MESSAGE IN CRUISE AT FL380 TWO TIMES WHILE IT WAS BEING USED AN AN ELECTRICAL SOURCE DUE TO SOURCE 1 OFF. - [SDR AALA202610123316](https://openairdocs.org/sdr/AALA202610123316.md): Oil System · leaking · Oct 11, 2026 · N974UY · Airbus A321231 > AIRCRAFT WAS GROUNDED: FLIGHT ATTENDANTS SAY THERE IS A STRONG FUMES SMELL IN THE MAIN CABIN - MAINTENANCE FOUND OIL ON THE APU PLENUM V-BAND SEAL (OPEN) - [SDR YENA2026100900934](https://openairdocs.org/sdr/YENA2026100900934.md): Oil System · leaking · Oct 8, 2026 · N947JB · Airbus A321231 > FLT#101, FLL - LAX. STRONG OIL FUMES WITH PACK ONE ON. APU OR ENGINE BLEED IN USE. ( APU SYSTEM). COMPLIED WITH INFO NOTICE 2017-T015 IDENTIFIED ODOR AS TYPE 1, MAY BE EXTERNAL APU OIL LEAK, DECONTAMINATION LEVEL WAS ACCOMPLISHED PER TAM 21-00-00- - [SDR AALA202610108681](https://openairdocs.org/sdr/AALA202610108681.md): Carbon Seal · leaking · Oct 7, 2026 · N932AM · Airbus A321231 > AIRCRAFT WAS GROUNDED: FLIGHT ATTENDANTS REPORTED A CRAYON TYPE BURNING SMELL DURING APPROACH AND TAXI AFTER LANDING. SMELL DISSIPATED AFTER SINGLE ENGINE TAXI - MAINTENANCE FOUND THE APU GEARBOX VENT LINE HAD EVIDENCE OF COKING AND REPLACED IT *AALA2026101043 - [SDR AALA202610102521](https://openairdocs.org/sdr/AALA202610102521.md): Valve · leaking · Oct 7, 2026 · N134AN · Airbus A321231 > AIRCRAFT WAS GROUNDED: DIRTY SOCK ODOR DURING CLIMB THEN AGAIN DURING DESCENT - MAINTENANCE FOUND THE APU OIL LUBE UNIT VALVE ASSEMBLY LEAKING OIL AND REPLACED THE O-RINGS ON THE VALVE ASSEMBLY - A DECONTAMINATION OF THE ENVIRONMENTAL CONTROL SYSTEM WAS ACCOMP - [SDR AALA202610062176](https://openairdocs.org/sdr/AALA202610062176.md): Guide Vane · leaking · Oct 4, 2026 · N903NN · Boeing 737823 > AIRCRAFT WAS GROUNDED: EMERGENCY DECLARED, AIRCRAFT LANDED WITHOUT INCIDENT. DECESION WAS MADE TO DIVERT TO BNA, FUMES IN CABIN. ACCOMPLISHED JC 08L00021001 FOUND APU INLET GUIDE VANE LEAKING. REMOVED AND REPLACED IAW AMM 49-42-12. NO ODOR NOTED. REF MIC - [SDR ASAA2026100367267](https://openairdocs.org/sdr/ASAA2026100367267.md): Duct · contaminated · Oct 3, 2026 · N488HA · Boeing 717200 > STRONG DIRTY SOCK SMELL ON TAKEOFF DISSIPATED BUT LINGERED ON THROUGHOUT THE FLIGHT AND CABIN. GROUNDED - YES. INSPECTED PNEMATIC SYS & NO DEFECTS NOTED. SUSPECTED RESIDUAL OIL IN DUCTING. ACCOMPLISHED LONGER THAN NORMAL PACK BURNOUT. NO ODOR THROUGHOUT CABIN - [SDR ASAA2026092767072](https://openairdocs.org/sdr/ASAA2026092767072.md): O-Ring · loose · Sep 27, 2026 · N383HA · Airbus A330243 > CHEMICAL, DIRTY SOCK PASSING 10,000' W/ THRUST AT IDLE. STRONG INTENSITY DURATION PERSISTENT FOR 12 MINUTES. DETECTED MORE AFT BUT THROUGHOUT A/C. LEVEL 2 SEVERITY. GROUNDED - YES. PERFORMED TSM 05-50-00-810-829-A, FOUND APU OIL FILL O-RING LOOSE, REF DMI 550 - [SDR AALA202609287875](https://openairdocs.org/sdr/AALA202609287875.md): Oil System · leaking · Sep 27, 2026 · N831AW · Airbus A319132 > AIRCRAFT WAS GROUNDED: AFTER TURNING APU ON AND TURNING ON APU BLEED A HYDRAULIC OR CRAYON SCENT CAME OUT OF THE VENTS, MAINTENANCE FOUND EVIDENCE OF OIL IN THE APU INLET AREA AND PLACED THE APU OM MEL. (OPEN) - [SDR ASAA2026092567105](https://openairdocs.org/sdr/ASAA2026092567105.md): O-Ring · loose · Sep 25, 2026 · N383HA · Airbus A330243 > PUNGENT ODOR IN CABIN AND COCKPIT WHEN USING APU AIR ( APU BLEED AIR SUPPLY SYSTEM, APU AIR NOT AVAILABLE; WILL NEED GRND AIR CON AND AIR START CART). GROUNDED - YES. FOUND APU OIL CAP O-RING LOOSE, REF LOG 100258621-1, PERFORMED TSM 05-50-00-810-829-A, FOUND - [SDR DALA2026092805370](https://openairdocs.org/sdr/DALA2026092805370.md): Oil Cap · leaking · Sep 25, 2026 · N435DX · Airbus A330941 > ATB - DIRTY SOCK SMELL AFTER TAKEOFF. RETURNED TO BOS. CORRECTIVE ACTION: FOUND APU COMPARTMENT CONTAMINATED WITH OIL FROM LEAKING OIL CAP. REPLACED OIL CAP PACKING. PERFORMED LEVEL B ECS DECONTAMINATION. RAN ENGINES AT IDLE AND APU WITH BOTH PACKS. NO SMELLS - [SDR AALA202609249984](https://openairdocs.org/sdr/AALA202609249984.md): Oil System · leaking · Sep 22, 2026 · N816AW · Airbus A319132 > AIRCRAFT WAS GROUNDED: FLIGHT CREW REPORTED AN ODOR IN THE CABIN A FEW MINUTES AFTER TAKEOFF AND THEN AGAIN ON DESCENT GOING THROUGH 10K - THE FLIGHT CREW ALSO REPORTED A STRONG OIL ODOR IN FLIGHT DECK AFTER LANDING - MAINTENANCE HAS ISOLATED THE SOURCE OF THE - [SDR AALA202609180655](https://openairdocs.org/sdr/AALA202609180655.md): Oil System · leaking · Sep 17, 2026 · N657AW · Airbus A320232 > AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND TRHGE AIRCRAFT RETURNED TO PHL DUE TO THE FLIGHT CREW REPORTING THAT AN ODOR WAS PRESENT IN THE AFT CABIN INITIALLY AFTER ENGINE START BUT QUICKLY DISSIPATED HOWEVER AFTER TAKE OFF THE FLIGHT ATTENDANTS REPO - [SDR AALA202609181936](https://openairdocs.org/sdr/AALA202609181936.md): Oil System · leaking · Sep 15, 2026 · N4032T · Airbus A319115 > AIRCRAFT WAS GROUNDED: PUNGENT DIRTY LAUNDRY SMELL MID CABIN AT ROW 24 DURING DESCENT - MAINTENANCE FOUND EVIDENCE OF AN OIL LEAK IN THE APU COMPARTMENT OPEN - [SDR CALA2026090919336](https://openairdocs.org/sdr/CALA2026090919336.md): Lubrication Unit · faulted · Sep 7, 2026 · N78013 · Boeing 777224 > LARGE PLUME OF WHITE SMOKE FROM APU EXHAUST ON NORMAL SHUTDOWN. VERIFIED APU OIL AT A SERVICABLE QTY ON EICAS 5.7 WITH APU OFF. OPERATED APU FOR 30 MINS WITH NO LOAD. PERFORMED A NORMAL SHUTDOWN & STILL SAW WHITE SMOKE AFTER INTIAL SHUTDOWN. NO WHITE SMOKE - [SDR DALA2026090605006](https://openairdocs.org/sdr/DALA2026090605006.md): Drain · leaking · Sep 5, 2026 · N821NW · Airbus A330323 > AFTER NR 1 & 2 ENG START STRONG OIL ODOR WITH HAZE IN CABIN, REPORTED BY MULTIPLE F/A'S COULD ALSO SMELL IN FLIGHT DECK. FOUND APU GEN DRAIN PLUG LEAKING. REPLACED SEAL WASHER PER AMM 24-23. (LP 8655628, 1794180 - AIRCRAFT WAS GROUNDED) - [SDR AALA202609069698](https://openairdocs.org/sdr/AALA202609069698.md): Oil System · leaking · Sep 4, 2026 · N705UW · Airbus A319112 > AIRCRAFT WAS GROUNDED: FLIGHT ATTENDANT IN AFT GALLEY REPORTED SMELLING A MUSTY ODOR DESCENDING THROUGH 10000 AND AFTER LANDING - NO SMELL WAS NOTICED IN THE FLIGHT DECK OR FROM THE FORWARD FLIGHT ATTENDANT - MAINTENANCE FOUND EVIDENCE OF THE APU LEAKING OIL L - [SDR IPXA2026090472160](https://openairdocs.org/sdr/IPXA2026090472160.md): Drain Line · leaking · Sep 3, 2026 · N150UP · Airbus A300F4622R > DESCENDING OUT OF FL 30500, APU AUTO SHUTDOWN. STATUS PAGE STATES APU INOP. REPLACED APU PER AMM 49-10-00/401. - [SDR AALA202609063169](https://openairdocs.org/sdr/AALA202609063169.md): Vent Line · coked · Sep 2, 2026 · N912UY · Airbus A321231 > AIRCRAFT WAS GROUNDED: DIRTY SOCK MUSTY SMELL IN FLIGHT DECK ONLY UPON STARTING DESCENT ALL THE WAY THROUGH ENGINE SHUTDOWN - MAINTENANCE FOUND THE APU GEARBOX VENT LINE HAD EVIDENCE OF COKING - MAINTENANCE REPLACED THE APU GEAR BOX AIR OIL SEPERATOR *AALA2026 - [SDR AALA202609066516](https://openairdocs.org/sdr/AALA202609066516.md): Separator · leaking · Sep 2, 2026 · N912UY · Airbus A321231 > AIRCRAFT WAS GROUNDED: DIRTY SOCK MUSTY SMELL IN FLIGHT DECK ONLY UPON STARTING DESCENT ALL THE WAY THROUGH ENGINE SHUTDOWN - MAINTENANCE FOUND THE APU GEARBOX VENT LINE HAD EVIDENCE OF COKING - MAINTENANCE REPLACED THE APU GEAR BOX AIR OIL SEPERATOR *AALA2026 - [SDR AALA202608274465](https://openairdocs.org/sdr/AALA202608274465.md): Oil Tank · overserviced · Aug 23, 2026 · N579UW · Airbus A321231 > AIRCRAFT WAS GROUNDED: FLIGHT ATTENDANTS REPORTED A STRONGER THAN NORMAL CLEANING OR CHEMICAL SMELL EMANATING FROM THE MIDDLE SECTION OF THE CABIN DURING TAXI THAT SEEMED TO DISSIPATE BUT AFTER AN HOUR AT CRUISE THE ODOR RETURNED WITH A STRONGER THAN NORMAL OD - [SDR AALA202608198150](https://openairdocs.org/sdr/AALA202608198150.md): Oil Cooler · inoperative · Aug 17, 2026 · N874NN · Boeing 737823 > AIRCRAFT WAS GROUNDED: APU WAS RUNNING AND THE LIGHT EXTINGUISHED. AFTER 15 MINUTES APU SHUTDOWN AND THE R IGHT SOURCE OFF LIGHT CAME BACK ON. AFTER QRH PERFORMED DUE TO SOURCE OFF LIGHT, APU WAS RUNNING AND THE LIGHT EXTINGUISHED. AFTER 15 MINUTES APU SHUTDOW - [SDR AALA202608144736](https://openairdocs.org/sdr/AALA202608144736.md): Oil System · leaking · Aug 12, 2026 · N971UY · Airbus A321231 > AIRCRAFT WAS GROUNDED: FLIGHT ATTENDANT REPORTED INTERMITTENT BURNING PLASTIC SCENT MID CABIN DURING CRUISE - MAINTENANCE FOUND THE APU LEAKING OIL OUT OF THE COMPRESSOR FLANGE AND THE CENTER DRAIN PORT RESULTING IN MAINTENANCE REPLACING THE APU PER JOB CARD 2 - [SDR DALA2026080804585](https://openairdocs.org/sdr/DALA2026080804585.md): Oil System · leaking · Aug 7, 2026 · N501DA · Airbus A321271NX > A MODERATELY STRONG OIL / MUSTY ODOR. ODOR PERSISTED UNTIL DESELECTING PACK 1. AT THAT POINT ODOR REDUCED BUT WAS STILL PRESENT. AFTER LANDING SELECTING APU BLEED RESULTED IN STRONGER ODOR. NO ODOR IN CABIN. REMOVED LT & RT ENG SPINNER COVERS FOUND EVIDENCE - [SDR DALA2026080804586](https://openairdocs.org/sdr/DALA2026080804586.md): Oil System · leaking · Aug 5, 2026 · N549DN · Airbus A321271NX > FLIGHT ATTENDENTS REPORTED DIRTY SOCK SMELL AT GEAR DOWN THRU ENGINE SHUTDOWN, ODOR CAME AND WENT IN THE FRONT, BACK FA'S REPORTED SIMILAR ODOR AT 8000 AGL. FOUND APU OIL OVERSERVICED. DRAINED OIL IAW AMM 49-90. INSPECTED APU BLEED DUCT, NO OIL WETTING NOTED - [SDR DALA2026080404500](https://openairdocs.org/sdr/DALA2026080404500.md): Oil Cap · leaking · Aug 1, 2026 · N375DN · Airbus A321211 > DIRTY SOCK ODOR, 6000-4000FT DEEMED TO DISSIPATE AFTER A MINUTE. FOUND OIL SEEPING THROUGH APU OIL FILLER CAP. REMOVED AND REPLACED APU FILLER CAP ROLLER AND BOLT IAW CMM 49-27-27. CLEANED AREA AND CHECKED FOR LEAK. NO LEAKS NOTED. (LP 8780332, 1731517 - AI - [SDR AALA202608049301](https://openairdocs.org/sdr/AALA202608049301.md): Vent Line · leaking · Aug 1, 2026 · N9011P · Airbus A319115 > AIRCRAFT WAS GROUNDED: STRONG DIRTY SOCKS; MUSTY ODOR ON FLUGHT DECK. LESSENING WITH PACK 1 OFF. MAINTENANCE REPLACED THE APU AIR OIL SEPERATOR AND THE APU VENT TUBE *AALA202608145149* - MAINTENANCE ACCOMPLISHED A DECONBTAMINATION OF THE ENVIRONEMTAL CONTRO, - [SDR I5PA2026072819301](https://openairdocs.org/sdr/I5PA2026072819301.md): Solenoid Valve · faulted · Jul 28, 2026 · N193AN · Boeing 757223 > APU FAILED TO START DURING LANDING. R & R APU DEOIL SOLENOID VALVE IAW AMM. - [SDR DALA2026073004411](https://openairdocs.org/sdr/DALA2026073004411.md): O-Ring · leaking · Jul 28, 2026 · N414DZ · Airbus A330941 > ODOR IN CABIN DURING FLIGHT. REPLACED APU FILLER CAP O-RING PER A330 AMM 49-91. OK FOR SERVICE. (9202395) AIRCRAFT WAS GROUNDED. - [SDR YENA2026072800628](https://openairdocs.org/sdr/YENA2026072800628.md): Oil System · leaking · Jul 25, 2026 · N944JT · Airbus A321231 > FLT 524, LAX-JFK. TAXI OUT OIL ODOR WITH APU BLEED, DISSAPATED & ODOR RETURN ON DESCENT THRU 16000 FT FOLLOWED FROM ODORIZED RECOGNITION & ISOLATION PROCEDURE; FOLLOWED INFO NOTICE & TSM 05-50-00-810-831-A FOUND ODOR TO BE TYPE 1 & COMING FROM APU FOUND APU OI - [SDR UIEA2026072300640](https://openairdocs.org/sdr/UIEA2026072300640.md): Apu · odor · Jul 23, 2026 · N418MC · Boeing 74747UF > BACK TO BLOCK DUE TO EICAS MESSAGE SMOKE CREW REST AND UNUSUAL SCENT DETECTED IN UPPER DECK. PERFORM FIRE TEST, NO SMOKE PRESENT IN CABIN. OIL SCENT COMING FROM APU. SUSPECT APU BEARING OIL LEAK ENTERING CABIN. REMOVED AND REPLACED APU IAW ATLAS WORK CARD 49- - [SDR YENA2026070700523](https://openairdocs.org/sdr/YENA2026070700523.md): Oil System · leaking · Jul 3, 2026 · N618JB · Airbus A320232 > FLT # 375, PHL-FLL. INFLIGHT NOTICED DIRTY SOCK ODOR IN CABIN AFTER APU BLEED TURNED ON; COMPLIED WITH I/N 2017-T015-M. INDENTIFIED SOURCE OF ODOR TYPE 1 APU OIL SATURATION. PERFORMED LVL A ECS DECON. AIR QUALITY CK GOOD. - [SDR YENA2026070700520](https://openairdocs.org/sdr/YENA2026070700520.md): Oil System · leaking · Jul 2, 2026 · N923JB · Airbus A321231 > FLT #316, SFO-JFK. DIRTY SOCK SMELL OUTOF 20,000 ON DESCENT IN FORWARD SECTION OF AIRCRAFT APU OFF.; PER INFO NOTICE 2017-TO15M PERFORMED VISUAL INSP. OF APU FOUND SIGNS OF OIL ON AIR INLET. SURROUNDINGS. REF LOG PAGE 472187 ITEM 2.REF EC NO. A4917122-01 FOR S - [SDR DALA2026070603931](https://openairdocs.org/sdr/DALA2026070603931.md): Oil System · leaking · Jul 2, 2026 · N372DA · Boeing 737832 > APU, PRIOR TO PUSH BACK WITH PACKS ON. A SMELL OF SMOKE ACCOMPANIED WITH A BANGING NOISE IT TAIL. AND VISIBLE SMOKE OBSERVCED BY GROUND CREW. NO ABNORAMAL INDICATIONS IN FLIGHT DECK.: R & R RECIRCULATION AIR FILTERS IAW AMM 21-25. REMOVED AND REPLACED APU, P - [SDR AALA202608127582](https://openairdocs.org/sdr/AALA202608127582.md): Separator · coked · Jun 23, 2026 · N908AA · Airbus A321231 > AIRCRAFT WAS GROUNDED: ON DESCENT, FLIGHT ATTENDANTS REPORTED A STRONG ODOR IN THE AFT HALF OF THE CABIN. IT WAS LIKENED TO THE ODOR OF EXHAUST. IT DISSIPATED AFTER LANDING. NO ODORS WERE SMELLED IN THE FLIGHT DECK OR FORWARD HALF OF CABIN. MAINTENANCE FOUND - [SDR AALA202608129232](https://openairdocs.org/sdr/AALA202608129232.md): Tube · coked · Jun 23, 2026 · N908AA · Airbus A321231 > AIRCRAFT WAS GROUNDED: ON DESCENT, FLIGHT ATTENDANTS REPORTED A STRONG ODOR IN THE AFT HALF OF THE CABIN. IT WAS LIKENED TO THE ODOR OF EXHAUST. IT DISSIPATED AFTER LANDING. NO ODORS WERE SMELLED IN THE FLIGHT DECK OR FORWARD HALF OF CABIN. MAINTENANCE FOUND - [SDR AALA202608124014](https://openairdocs.org/sdr/AALA202608124014.md): Module · leaking · Jun 23, 2026 · N908AA · Airbus A321231 > AIRCRAFT GROUNDED, DURING DESCENT, FLT ATTENDS REPORTED A STRONG ODOR IN AFT HALF OF CABIN. LIKENED TO ODOR OF EXHAUST. DISSIPATED AFTER LANDING. NO ODORS IN FLT DECK OR FWD HALF OF CABIN. MAINTENANCE FOUND THE APU FCU & LUBE MODULE LEAKING OIL OUT OF THE AF - [SDR DALA2026061503566](https://openairdocs.org/sdr/DALA2026061503566.md): Oil System · overserviced · Jun 12, 2026 · N356NW · Airbus A320212 > SMOKE/FUME EVENT AFT GALLEY (10K THROUGH LANDING). C/A: PERFORMED INITIAL INSPECTION OF NR 1, NR 2 ENG AND APU COMPARTMENT NO EXTERNAL LEAKS NOTED. (WIP D.P 098218). PERFORMED W/C 0550- 2001, LOGGED DATA WITH PTRAK, RESULTS SUBMITTED TO SMOKE AND FUMES GROUP - [SDR DALA2026061103520](https://openairdocs.org/sdr/DALA2026061103520.md): Control Valve · contaminated · Jun 9, 2026 · N346NB · Airbus A319114 > FO SMELLED WET SOCK SMELL ON TAXI - IN WHEN SWITCHING TO APU BLEED. SMELLED IN FLIGHT DECK ONLY NOT IN CABIN. REMOVED LOAD CTL VLV PER A319 AMM 49-51 INSP FOUND OIL CONTAMINATE. CLEANED AND REINSTALLED (KH 384158) PERFORMED LEVEL B DECONTAMINATION WITH REF TO - [SDR SWAA2026060810070](https://openairdocs.org/sdr/SWAA2026060810070.md): Line · leaking · Jun 7, 2026 · N8790Q · Boeing 7378 > PREVIOUS CREW REPORTS POSSIBLE SMOKE IN COCKPIT AFTER LANDING APU OIL SUPPLY LINE LEAKING AT THE LINE.<[01] OK TO CONTINUE PER MEL 49-11-01 SP1 SP2. FOUND OIL LEAKING FROM APU OIL COOLER SUPPLY LINES. REMOVED AND REPLACED APU OIL COOLER SUPPLY LINES IAW AMM 49 - [SDR AALA202606082338](https://openairdocs.org/sdr/AALA202606082338.md): Module · leaking · Jun 7, 2026 · N904AA · Airbus A321231 > AIRCRAFT WAS GROUNDED: INBOUND CABIN CREW REPORTED A DIRTY SOCK / ROTTEN EGG SMELL ON DEPARTURE AND ARRIVAL BELOW 10K FEET. MAINTENANCE FOUND THE APU OIL LUBE MODULE LEAKING AND REPLACED IT PER AMM 49-91-45. A DECONTAMINATION OF THE ENVIRONMENTAL CONTROL SYST - [SDR DALA2026060903441](https://openairdocs.org/sdr/DALA2026060903441.md): Oil System · leaking · Jun 4, 2026 · N937AT · Boeing 717200 > DIRTY SOCK ODOR ON GROUND AT GATE FROM BOTH PACKS INDEPENDENTLY ON APU AIR. T/S PER FIM 49-50 FOUND OIL INSIDE THE APU PLENUM. R & R COELESSOR BAGS IAW AMM 21-54 OLD BAGS SMELLED LIKE OIL (8655364) (AIRCRAFT GROUNDED) - [SDR DALA2026060403384](https://openairdocs.org/sdr/DALA2026060403384.md): Oil System · leaking · May 31, 2026 · N589DT · Airbus A321271NX > FUMES - DESCENDING THRU FL190, CREW NOTICED A DIRTY SOCKS SMELL. O2 MASKS WERE DONNED AND AN EMERGENCY DECLARED. CORRECTIVE ACTION: INITIAL T/S FOUND OIL BEHIND NR 1 ENGINE SPINNER. NR 1 ENGINE FOAM WASH PERFORMED. FOLLOW UP BORESCOPE WAS GOOD. LEVEL C DECONTA - [SDR DALA2026060203346](https://openairdocs.org/sdr/DALA2026060203346.md): Oil System · leaking · May 31, 2026 · N937AT · Boeing 717200 > FLIGHT ATTENDANTS REPORTED A MUSTY OR MILDEW SMELL DURING FLIGHT IN THE MID-CABIN. FOUND APU COMPARTMENT CONTAMINATED WITH OIL. REPLACED APU PER AMDS W/C 4900-9901. (8655352) (AIRCRAFT GROUNDED) - [SDR AALA202605283511](https://openairdocs.org/sdr/AALA202605283511.md): Pressure Switch · faulted · May 26, 2026 · N116AN · Airbus A321231 > AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT DIVERTED TO PHL DUE TO THE FLIGHT CREW REPORTING WITH THE LEFT ENGINE IDG INOPERATIVE AND ON MEL, THAT DURING CLIMB THROUGH FL 240 THE APU AUTO SHUTDOWN. THE AIRCRAFT LANDED SAFELY AT PHL AND TA - [SDR AALA202605252810](https://openairdocs.org/sdr/AALA202605252810.md): Oil Cooler · leaking · May 20, 2026 · N768US · Airbus A319112 > AIRCRAFT WAS GROUNDED: DIRTY SOCK ODOR IN COCKPIT ON DESCENT WITH POWERS AT IDLE. DISSIPATES WHEN THRUST COMES BACK IN. FA'S DID NOT SMELL ANY ODOR INTHE CABIN. MAIBNTENANCE REPLACED OIL COOLING FAN PER JC 26L000021002 AND AMM 49-52-51. - [SDR DALA2026052103097](https://openairdocs.org/sdr/DALA2026052103097.md): Oil System · leaking · May 20, 2026 · N356NW · Airbus A320212 > CREW REPORTS MUSTY HAZE IN CABIN, APU RUNNING PACKS OFF. TURNED ON PACKS, MADE ISSUE WORSE. WOULD NOT DISSAPATE UNTIL PACKS AND APU SHUT DOWN. OPENED APU ACCESS DOORS FOR INSPECTION IAW AMM 52-41. INITIAL VISUAL INSPECTION, FOUND LARGE QTY OF OIL IN APU INLET Next page: https://openairdocs.org/jasc/4990/reports.md?page=2 ## 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 = '4990' ORDER BY difficulty_date DESC ``` This list as a web page: https://openairdocs.org/jasc/4990/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.