FRONTIER AIRLINES, INC.

Operated by Frontier Airlines (per NTSB report)

Operated by Frontier Airlines (per NTSB report)

Operated by Frontier Airlines (per NTSB report)

Operated by Frontier Airlines (per NTSB report)

Operated by Frontier Airlines (per NTSB report)

Operated by FRONTIER AIRLINES INC (per NTSB report)

Operated by Frontier Airlines (per NTSB report)

Operated by Frontier Airlines (per NTSB report)

Operated by Frontier Airlines (per NTSB report)

Operated by FRONTIER AIRLINES INC (per NTSB report)

Operated by FRONTIER AIRLINES INC (per NTSB report)

Operated by Frontier Airlines (per NTSB report)

DURING SCHEDULED HEAVY CHECK EPSU TEST FOUND 10WL FAILED TEST. AIRCRAFT WAS NOT GROUNDED. REMOVED AND REPLACED 10WL EPSU BATTERY IAW AMM 33-51-38-400-002-A OPS TEST GOOD. A/C OK FOR SERVICE. AIRCRAFT WAS RETUNED TO SERVICE.

AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. FOUND CRACK ON LH SHEAR PLATE AND REQUIRES REPLACEMENT AS PER A320N SRM 51-72-11 REV 49. PERFORMED REPLACEMENT OF L/H SHEAR PLATE AS PER SRM 51-72-11 REV 49 MX ACTION IS ACCEPTABLE. /END/.

AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. FOUND CRACK ON RH SHEAR PLATE AND REQUIRES REPLACEMENT AS PER A320N SRM 51-72-11 REV 49. PERFORMED REPLACEMENT OF R/H SHEAR PLATE AS PER A320N SRM 51-72-11 REV 49. MX ACTION IS ACCEPTABLE. /END/.

AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. FOUND CORROSION ON RT AFT DOOR SILL CORRODED REQUIRES TO BE EVALUATED AS PER SRM 53-41-14-283-002 REV 49. CORROSION WAS REMOVED AND REPAIR WAS PERFORMED ON DOOR SILL FROM FR.67 TO FR.68 IAW SRM 53-41-14-283-002 REV 49. MX ACTION IS ACCEPTABLE.

NR 1 EPSU BITE TEST FAILED 12WL BATTERY. AC WAS NOT GROUNDED FOR THIS EVENT IT WAS SCHEDULED MX. REMOVED AND REPLACED EPSU BATTERY AT 12WL REF AMM 33-51-38-400-002-A. AC OK FOR SERVICE.

FUME EVENT DESCENDING THRU 17,000 - 18,000 DIRTY SOCK SMELL DETECTED THEN DISAPPEARED. RETURNED AT 10,560 FEET MUCH STRONGER DIRTY SOCK SMELL. CHECKLIST PROCEDURE CALLED FOR PACK 1 OFF. UNKNOWN IF ODOR PERSISTED DUE TO OXYGEN USE TO GATE. COMPLIED WITH W/O 603333 NR 1 ENGINE REMOVED AND REPLACED IAW TASK CARDS MP71042-05 AND MP71042-06. AC RETURNED TO SERVICE. ORIGINAL SUBMISSION DATE: 06/10/2026

REFERENCE LP 557839 #2 AT ABOUT 4000' MSL, UNCOMMANDED ROLL WHILE GOING FLAPS 1 TO FLAPS 2 WITH SPEED BRAKE DEPLOYED. AUTO PILOT WAS OFF. OBSERVED ON FLIGHT CONTROL. SD PAGE LEFT AIL HALF DOWN, RIGHT AIL HALF UP. FELT REDUCED ROLL AUTHORITY WHILE TURNING. AC WAS GROUNDED. AIRBUS & TECH SERV STATED NO ABNORMALITY. C/W AMM 27-96-00-710-023-A NO FAULTS FOUND. AC RETURNED TO SERVICE.

DURING HEAVY CHECK EPSU BATTERY (1001WL) FWD L FAILED EMER TEST. AIRCRAFT WAS GROUNDED. REMOVED AND REPLACED EPSU BATTERY (1001WL) FWD L IAW AMM 33-51-38-000-003-A/33-51-38-400-003-A. OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.

LAV SERVICE DOOR MISSING. INBOUND FLIGHT NUMBER 3022. FOUND DURING WALKAROUND INSPECTION. AC WAS NOT GROUNDED. PLACED ON CDL 52-01B. AC WAS OK FOR SERVICE.

DURING SCHEDULED HEAVY CHECK EPSU BATTERY 10WL FWD L FAILED EMER TEST. AIRCRAFT WAS NOT GROUNDED AS A RESULT OF THE SDR REPORTABLE EVENT. REMOVED AND REPLACED EPSU BATTERY 10WL FWD L IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A. OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.

DURING SCHEDULED HEAVY CHECK EPSU BATTERY 12WL EXT R FAILED EMER TEST. AIRCRAFT WAS NOT GROUNDED. REMOVED AND REPLACED EPSU BATTERY 12WL EXT R IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A. OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.

AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. FOUND CRACK ON LT SHEAR PLATE AFT WET AREA AND REQUIRES REPLACEMENT IAW SRM 51-72-11 REV 49. PERFORMED REPLACEMENT OF LT SHEAR PLATE IAW SRM 51-72-11 REV 49. MX ACTION IS ACCEPTABLE.

AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. FOUND CORROSION ON RT AFT DOOR SILL. REQUIRES TO BE EVALUATED IAW SRM 53-41-14 REV 49. CORROSION WAS REMOVED AND REPAIR WAS PERFORMED ON DOOR SILL AT FR. 68 IAW SRM 53-41-14 REV 49. MX ACTION IS ACCEPTABLE.

AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. FOUND CRACK ON RH SHEAR PLATE AFT WET AREA AND REQUIRES REPLACEMENT IAW SRM 51-72-11 REV 49. PERFORMED REPLACEMENT OF RT SHEAR PLATE IAW SRM 51-72-11 REV 49. MX ACTION IS ACCEPTABLE.

DURING HEAVY CHECK EPSU BATTERY 12WL EXT R FAILED EMER TEST. AIRCRAFT WAS NOT GROUNDED. REMOVED AND REPLACED EPSU BATTERY 12WL EXT R IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.

DURING HEAVY CHECK EPSU TEST FOUND AFT EPSU (13WL) FAULTING FOR INTERIOR AND EXTERIOR LIGHTS. AIRCRAFT WAS GROUNDED. REMOVED AND REPLACED R4 DOOR SLIDE IAW AMM 25-62-44-400-803-A. OPS TEST GOOD. RE-TESTED EPSU BATTERY TEST IAW AMM 33-51-38-400-002-A. OPS TEST GOOD. NO FURTHER FAULTS DETECTED. AIRCRAFT WAS RETURNED TO SERVICE.

ACFT WAS ON SCHEDULED MAINTENANCE REFERENCE LP477858 #3 EPSU 10WL TEST FAIL BATTERY FAULT. REMOVED AND REPLACED EPSU BATTERY AT 10WL REF AMM 33-51-38-400-002-A. A/C OK FOR SERVICE. /END/.

ACFT WAS ON SCHEDULED MAINTENANCE REFERENCE LP477859 #1 EPSU 13WL TEST FAIL BATTERY FAULT. REMOVED AND REPLACED EPSU BATTERY AT 13WL REF AMM 33-51-38-400-002-A. A/C OK FOR SERVICE.

ACFT WAS ON SCHEDULED MAINTENANCE REFERENCE LP477859 #2 EPSU 16WL TEST FAIL BATTERY FAULT. REMOVED AND REPLACED EPSU BATTERY AT 16WL REF AMM 33-51-38-400-002-A. A/C OK FOR SERVICE.

LG RETRACTION NOSE GEAR NEVER HAD UPLOCK. RECYCLED GEAR, STILL NO NOSE GEAR UPLOCK. GEAR STAYED DOWN & 3 GREEN ENTIRE TIME. W/O GEAR DOORS CLOSED. REF TSM 32-31-00-810-808-A REMOVED AND REPLACED RELAY 62GA IAW ESPM 20-46-50. OPS CHECK GOOD. A/C OK FOR SERVICE.

REFERENCE LP682927 #3 DURING SCHEDULED HEAVY CHECK EPSU BATTERY 12WL EXIT R FAILED TEST. AIRCRAFT WAS NOT GROUNDED AS A RESULT OF THE SDR REPORTABLE EVENT. REMOVED AND REPLACED EPSU BATTERY 12WL IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.

REFERENCE LP541811 #3 DURING SCHEDULED HEAVY CHECK EPSU BATTERY 10WL FAILED TEST. AIRCRAFT WAS NOT GROUNDED. REMOVED AND REPLACED EPSU BATTERY 10WL IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.

REFERENCE LP541812 #1 DURING SCHEDULED HEAVY CHECK EPSU BATTERY 16WL FAILED TEST. AIRCRAFT WAS NOT GROUNDED. REMOVED AND REPLACED EPSU BATTERY 16WL IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.

PERFORMED EPSU TEST AND 12WL & 13WL FAULTED ON THE TEST. AC WAS NOT GROUNDED AS A RESULT OF THIS SDR REPORTABLE EVENT, AC WAS ON SCHEDULED MX.. REMOVED AND REPLACED THE EPSU BATTERY ON POSITIONS 12WL & 13WL PER AMM REF 33-51-38-000-002-A AND 33-51-38-400-002-A. PERFORMED OPS CHECK. OPS CHECK GOOD. AC OK FOR SERVICE. /END/.

REFERENCE LTPR NR 5001479408-0010 AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. FOUND CRACK ON LH SHEAR PLATE AND REQUIRES REPLACEMENT AS PER A320N SRM 51-72-11 REV.48. RERFORMED REPLACEMENT OF LT SHEAR PLATE AS PER A320N SRM 51-72-11 REV. 48 MX ACTION IS ACCEPTABLE.

REFERENCE LTPR NR 5001479409-0010 AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. FOUND CRACK ON RH SHEAR PLATE AND REQUIRES REPLACEMENT AS PER A320N SRM 51-72-11 REV.48. PERFORMED REPLACEMENT OF R/H SHEAR PLATE AS PER A320N SRM 51-72-11 REV. 48 MX ACTION IS ACCEPTABLE.

REFERENCE LTPR NR 5001480168-0010 AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. DURING INSPECTION FOUND CABIN FLOORBEAM Y-765 IN FR68 CORRODED. REQUIRED REPLACEMENT IAW SRM 53-41-14 REV 48. FLOORBEAM Y-765 IN FR 68 REPLACED IAW SRM 53-41-14 REV 48. MX ACTION IS ACCEPTABLE.

REFERENCE LTPR NR 5001479406-0010 AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. FOUND CORROSION ON L/H AFT DOORSILL. REQUIRES TO BE EVALUATED AS PER A320N SRM 53-41-14-283-002 REV 48. CORROSION WAS REMOVED AND WAS FOUND IN ALLOWABLE LIMITS (CAT-A) RE-PROTECTION IS REQUIRED AS PER SRM 53-41-14-283-002-REV.48 MX ACTION IS ACCEPTABLE.

REFERENCE LTPR NR 5001479407-0010 AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. FOUND CORROSION ON R/H AFT DOORSILL. REQUIRES TO BE EVALUATED AS PER A320N SRM 53-41-14-283-002 REV 48. CORROSION WAS REMOVED AND REPAIR WAS PERFORMED ON DOORSILL FROM FR.67 TO FR.68 AS PER SRM 53-41-14-300-001 REV.48 MX ACTION IS ACCEPTABLE.

EPSU BATTERY 11WL EMER L FAILED TEST, AIRCRAFT WAS NOT GROUNDED AS A RESULT OF THE SDR REPORTABLE EVENT, SCHEDULED HEAVY CHECK. REMOVED AND REPLACED EPSU BATTERY (11WL) IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A. OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.

NR 3 EPSU BATTERY 10WL FWD L FAILED TEST, AIRCRAFT WAS NOT GROUNDED, SCHEDULED HEAVY CHECK. REMOVED AND REPLACED EPSU BATTERY (10WL) IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A. OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.

NR 1 FUME EVENT RETURNED UPON DECENT INTO DENVER, AC WAS GROUNDED. NO CHANGE FROM PREVIOUS EXPERIENCES, PRIOR TO APU MEL. STRONG DIRTY SOCK ODOR. PERFORMED INSPECTION OF APU IN REF TSM 05-50-00-810-831-A, NO ODORS OR SMELLS NOTED AT THIS TIME. DURING WALK AROUND DID NOTE ENG NR 1 SPINNER CONE LEAKING OIL. MX CONTINUED ON LP701407 #2. LP701407 ITEM #2 FOUND ENG #1 SPINNER CONE LEAKING OIL. PERFORMED REPLACEMENT OF THE #1 ENGINE FAN SHAFT COVER SEAL IN REF AMM 72-15-00-960-801-A. T/W F9TAB11302C DD 06/30.2026. IDLE TEST OK, NO LEAKS NOTED AT THIS TIME. A/C OK FOR SERVICE.

NR 1 EPSU BATTERY (11WL) FAILED TEST, AC WAS NOT GROUNDED. SCHEDULED RON HEAVY CHECK. REMOVED AND REPLACED EPSU BATTERY (11WL) IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A. OPS CHECKED GOOD. AIRCRAFT WAS RETURNED TO SERVICE.

DISCREPANCY: REFERENCE LP178762 #1 EPSU BATTERY (12WL) FAILED TEST. AIRCRAFT WAS NOT GROUNDED AS A RESULT OF THE SDR REPORTABLE EVENT, SCHEDULED RON HEAVY CHECK. CORRECTIVE ACTION: REMOVED AND REPLACED EPSU BATTERY (12WL) IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A. OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE. /END/.

ACFT WAS GROUNDED AS A RESULT OF ODOR EVENT DURING DESCENT QRH PROCEDURE INDICATES PACK 1 MAY BE THE SOURCE. AC WAS GROUNDED AS A RESULT OF THE SDR REPORTABLE EVENT. REFERENCE LP580465 #1 FOUND SOURCE OF ODOR TO BE ENG 1. ENG 1 HAS BEEN REPLACED, PERFORMED LEVEL B REMOVAL OF THE CONTAMINATION OF ECS REF AMM 21-00-00-645-503-A. NO DEFECTS NOTED AT THIS TIME. REF LP580465 #2 FOR REPLACEMENT OF ENG 1. ACFT OK FOR SERVICE.

NR 2 EPSU BATTERY (11WL) EMERGENCY LIGHT FAILED TO TEST, ACFT WAS NOT GROUNDED. SCHEDULED RON MAINTENANCE HEAVY CHECK. REMOVED AND REPLACED EPSU BATTERY (11WL) EMERGENCY LIGHT IAW AMM 33-51-38-000-002-A, & 33-51-38-400-002-A. OPS CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE.

NR 3 EPSU BATTERY (12WL) FAILED TO TEST, ACFT WAS NOT GROUNDED, SCHEDULED RON MAINTENANCE HEAVY CHECK. R & R THE EPSU BATTERY (12WL) IAW AMM 33-51-38-000-002-A, & 33-51-38-400-002-A. OPS CHECKED GOOD. ACFT RETURNED TO SERVICE.

REFERENCE NR5001472996-0010. AC WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. DURING INSPECTION FOUND L/H SHEAR PLATE FR69-70 CRACKED. REQUIRES REPLACEMENT AS PER A320N SRM 51-72-11 REV 47. PERFORMED REPLACEMENT OF L/H SHEAR PLATE BETWEEN FR 69-70 AS PER A320N SRM 51-72-11 REV 47. MX ACTION IS ACCEPTABLE.

REFERENCE NR5001472996-0010. AC WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. DURING INSPECTION FOUND R/H SHEAR PLATE FR69-70 CRACKED. REQUIRES REPLACEMENT AS PER A320N SRM 51-72-11 REV 47. PERFORMED REPLACEMENT OF R/H SHEAR PLATE BETWEEN FR 69-70 AS PER A320N SRM 51-72-11 REV 47. MX ACTION IS ACCEPTABLE.

REFERENCE LP147381 #2 EMERGENCY POWER SUPPLY UNIT L (11WL) FAULT. AC WAS NOT GROUNDED AS A RESULT OF THIS SDR REPORTABLE EVENT, IT WAS A RON SCHEDULED MAINTENANCE VISIT. REPLACED EPSU FIN 11WL REF AMM TASK 33-51-38-000-001-A, AMM 33-51-38-400-001-A. BITE TEST OK, AC OK FOR SERVICE. /END/.

AIRCRAFT GROUNDED. ODOR EVENT DURING DESCENT. DURING FLT TO DTW USED ELIMINATION OF ODOR CHECKLIST DURING DESCENT WITH FLT CREW USING O2 MASK. AFTER DETECTING ODOR, AFTER PACK 1 WAS OFF FOR 5-10 MINS, DURING APPROACH & LANDING, ODOR DISSIPATED. DURING TAXI, PACK 1 ON & STRONG ODOR OF DIRTY SOCKS, IN COCKPIT & CABIN. PACK 1 OFF & ODOR DISSIPATED, DURING POST FLT, 1ST OFF NOTICED STRONG ACRID ODOR, PLASTIC ODOR FROM INTERIOR OF FRONT OF ENG 1, NO ODOR FROM NR 2. BOTH ENGS, NORMAL INDS, ALL PHASES OF FLT & TAXI. ACFT RFS. PACK 1 REQUIRES DEFERRAL. PLACED ON MEL 21-52-01B, PLACARDS INSTALLED. ACFT OK FOR SERVICE. R & R PACK 1, TESTED, NO DISCREPANCIES NOTED IAW AMM 21-52-41-000-001-A & 21-52-41-400-001-A.

REFERENCE LP702388 #1 EPSU BATTERY (13WL) AFT L FAILED TEST FAILED EPSU SYS TEST. AC WAS NOT GROUNDED AS A RESULT OF THIS SDR REPORTABLE EVENT, IT WAS A RON SCHEDULED HEAVY CHECK. REMOVED AND REPLACED EPSU BATTERY (13WL) IAW AMM 33-51-38-000/400-002-A. OPS CHECK GOOD. AC OK FOR SERVICE.

REFERENCE LP702387 #3 EPSU BATTERY (11WL) EMERG L FAILED TEST FAILED EPSU SYS TEST. AC WAS NOT GROUNDED AS A RESULT OF THIS SDR REPORTABLE EVENT, IT WAS A RON SCHEDULED HEAVY CHECK. REMOVED AND REPLACED EPSU BATTERY (11WL) IAW AMM 33-51-38-000/400-002-A. OPS CHECK GOOD. AC OK FOR SERVICE. /END/.

REFERENCE LP702387 #2 EPSU BATTERY (10WL) FWD L FAILED TEST FAILED EPSU SYS TEST. AC WAS NOT GROUNDED AS A RESULT OF THIS SDR REPORTABLE EVENT, IT WAS A RON SCHEDULED HEAVY CHECK. REMOVED AND REPLACED EPSU BATTERY (10WL) IAW AMM 33-51-38-000/400-002-A. OPS CHECK GOOD. AC OK FOR SERVICE.

DISCREPANCY: REFERENCE LP514643 #3 CIDS 1 EPSU TEST 13WL AFT BATTERY FAILED. AC WAS NOT GROUNDED AS A RESULT OF THIS SDR REPORTABLE EVENT, IT WAS A RON SCHEDULED MAINTENANCE VISIT. CORRECTIVE ACTION: REMOVED AND REPLACED EPSU BATTERY IN REF AMM 33-51-38-000-002-A AND AMM 33-51-38-400-002-A. OPS TEST GOOD, AC OK FOR SERVICE. /END/.

EPSU BATTERY (11WL) FAILED EMERGENCY LIGHT TEST. ACFT WAS NOT GROUNDED. REMOVED AND REPLACED EPSU BATTERY (11WL) IAW AMM 33-51-38-000/400-002-A. OPS CHECK GOOD. AC OK FOR SERVICE.

EPSU BATTERY (13WL) FAILED EMERGENCY LIGHT TEST. AC WAS NOT GROUNDED. REMOVED AND REPLACED EPSU BATTERY (13WL) IAW AMM 33-51-38-000/400-002-A. OPS CHECK GOOD. AC OK FOR SERVICE.

DISCREPANCY: REFERENCE LP532313#3 EPSU BATTERY (12WL) FAILED EMERGENCY LIGHT TEST. AC WAS NOT GROUNDED AS A RESULT OF THIS SDR REPORTABLE EVENT, IT WAS A RON SCHEDULED HEAVY CHECK. CORRECTIVE ACTION: REMOVED AND REPLACED EPSU BATTERY (12WL) IAW AMM 33-51-38-000/400-002-A. OPS CHECK GOOD. AC OK FOR SERVICE. /END/.

BURNING ELECTRICAL SMELL FROM FORWARD LAV. AC WAS GROUNDED AS A RESULT OF THIS SDR REPORTABLE EVENT. PERFORMED ISOLATION/DEACTIVATION OF FWD WATER HEATER, SMELL DISSIPATED AFTER TIME PER AMM 05-50-00-510-831-A. LP680661 ITEM #1 PLACED ON MEL 38-10-01B CN 1245050 DD 03/22/26 PER MCC #437027 MX ACTION CW. NR 1 REF LP680661 C/N 1245050 MEL 38-10-01B DD 03/22/26 FWD LAV WATER HEATER-PERFORMED OPS CHECK IAW 38-12-00-710-004-A. NO DEFECTS NOTED AT THIS TIME. AC OK FOR SERVICE. THIS CLEARS MEL 38-10-01B C/N 1245050 PLACARDS REMOVED.

DISCREPANCY: REFERENCE LP520272 #1 EPSU BATTERY (17WL) FAILED EPSU SYS TEST. AC WAS NOT GROUNDED AS A RESULT OF THE SDR REPORTABLE EVENT IT WAS A SCHEDULED RON HEAVY CHECK. CORRECTIVE ACTION: REMOVED AND REPLACED EPSU BATTERY (17WL) IAW AMM 33-51-38-000/400-002-A. OPS CHECK GOOD. AC OK FOR SERVICE. /END/.