# JASC 7711: Engine Pressure Ratio (EPR)

- Type: JASC system/component code (FAA)
- ATA chapter: 77 Engine Indicating
- Title in the code table: ENGINE PRESSURE RATIO (EPR)
- Service difficulty reports: 456
- FAA code table: https://www.faa.gov/sites/faa.gov/files/JASC_Code.pdf#page=66
- Page: https://openairdocs.org/jasc/7711

## What it covers

The system which sense, measures, and indicates the engine pressure ratio (EPR) of an turbine engine. The system measures the difference between the compressor inlet pressure and the turbine discharge pressure. Typical parts are sensor, transducer, transmitter, probe, etc.

## Service difficulty reports (456, newest 50)

- [SDR AALA202610107756](https://openairdocs.org/sdr/AALA202610107756), Oct 8, 2026: Airbus A321231. RELAY. FAULT MESSAGE. AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT DIVERTED TO MIA DUE TO THE FLIGHT CREW REPORTING ENGIN (N910AU)
- [SDR AALA202610106569](https://openairdocs.org/sdr/AALA202610106569), Oct 8, 2026: Airbus A321231. PROBE. FAULT MESSAGE. AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT DIVERTED TO MIA DUE TO THE FLIGHT CREW REPORTING ENGIN (N910AU)
- [SDR YENA2026082600710](https://openairdocs.org/sdr/YENA2026082600710), Aug 26, 2026: Airbus A320232. PROBE. DAMAGED. FLT # 1380, FLL-GUA (AIRTURN BACK TO FLL). ENG 2 EPR MODE FAULT; FOUND #2 ENG P2/T2 PROBE WITH DEBRI FROM BIRD STRIKE. R (N594JB)
- [SDR AALA202607166702](https://openairdocs.org/sdr/AALA202607166702), Jul 13, 2026: Airbus A321231. PROBE. FAULT MESSAGE. AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED INTO ABQ DUE TO THE FLIGHT CREW REPORTING AT CRUISE ALTITUDE RECEIVED E (N120EE)
- [SDR AALA202607166207](https://openairdocs.org/sdr/AALA202607166207), Jul 13, 2026: Airbus A321231. RELAY. FAULT MESSAGE. AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED INTO ABQ DUE TO THE FLIGHT CREW REPORTING AT CRUISE ALTITUDE RECEIVED E (N120EE)
- [SDR 2026FA0000475](https://openairdocs.org/sdr/2026FA0000475), May 30, 2026: Airbus A320251N. SENSOR. UNSERVICEABLE. DURING TAKE OFF ENG 2 N2 OVERLIMIT 117.0% DURING 5 SECONDS. DUE TO PFR MESSAGES AND FOLLOWING TSM 73-21-00-810-B46-A REV (N963AV)
- [SDR WX0A2025091232561](https://openairdocs.org/sdr/WX0A2025091232561), Sep 12, 2025: Airbus A319111. ENGINE. MULTIPLE FAIL. (AIRCRAFT GROUNDED) (EMERGENCY DECLARED) AFTER TO DURING CLIMB THE N1 BEGAN BEING VERY ERATIC THROUGH FL 180 FOLLOWED BY (N329NV)
- [SDR DALA2025071605350](https://openairdocs.org/sdr/DALA2025071605350), Jul 16, 2025: Airbus A319114. CABLE. SHEARED. SHIP 3161-ATB-RETURNED TO BIS DUE TO RIGHT ENGINE EGT OVER LIMIT. EMERGENCY WAS DECLARED. EGT LIMIT WAS NOT REACHED. MTC (N361NB)
- [SDR UIEA2025010400003](https://openairdocs.org/sdr/UIEA2025010400003), Jan 4, 2025: Boeing 7474H6. WARNING MESSAGE. ACTIVATED. LOW SPEED RTO PRIOR TO 40 KIAS, #1 EPR INDICATION DISAPPEARED.(<P>REF MEL 73-21-01 DMI 223505 OPERATION NOTE #4 FOR EPR  (N718BA)
- [SDR YENA2024110801441](https://openairdocs.org/sdr/YENA2024110801441), Nov 5, 2024: Airbus A320232. BLEED VALVE. UNKNOWN. FLT#787, JFK-SXM. "DESCENDING THROUGH 10,000 INFLIGHT CALLED TO INFORM A DIRTY SOCK SMELLIN THE CABIN COMMING FROM ROW 1 (N563JB)
- [SDR FDEA202407090975](https://openairdocs.org/sdr/FDEA202407090975), Jul 9, 2024: Doug MD11F. ENGINE. VIBRATION. NR 3 ENGINE HIGH VIBE 5.0 & ABOVE.VERBAL FROM FLIGHT CREW. REF ER 24-01792 COMPLETED #3 ENGINE INSTALLATION REF WIC 7100 (N610FE)
- [SDR AALA202404016063](https://openairdocs.org/sdr/AALA202404016063), Mar 31, 2024: Airbus A321231. SENSE LINE. LOOSE. AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO CLT DUE TO #2 ENGINE EPR FAULT, FLIGHT CRE (N582UW)
- [SDR CALA2024020900371](https://openairdocs.org/sdr/CALA2024020900371), Feb 7, 2024: Boeing 757224. HOSE. MISSING. R ENG EPR INCREASED AS ALT INCREASED W/ LOW FUEL FLOW. FOUND P1 FLEX HOSE MISSING, REPLACED FLEX HOSE REF. AMM 77-11-01  (N14115)
- [SDR CALA2024020900370](https://openairdocs.org/sdr/CALA2024020900370), Feb 7, 2024: Boeing 757224. HOSE. MISSING. R ENG EPR INCREASED AS ALT INCREASED W/ LOW FUEL FLOW. FOUND P1 FLEX HOSE MISSING, REPLACED FLEX HOSE REF. AMM 77-11-01  (N14115)
- [SDR QR9R2023121900001](https://openairdocs.org/sdr/QR9R2023121900001), Dec 19, 2023: Bolkms BK117C2. SENSOR. WARNING LIGHT. ENGINE #2 OVERSPEED FAIL CAUTION ON START RUN-UP. REMOVED AND REPLACED DOUBLE SENSOR IAW ARRIEL 1 E2 MM 77-14-00-900-802
- [SDR AALA202311028343](https://openairdocs.org/sdr/AALA202311028343), Oct 26, 2023: Airbus A320232. PROBE. DEFECTIVE. AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT DIVERTED TO STL. FLIGHT CREW REPORTED THAT DURING CRUI (N657AW)
- [SDR AALA202302024822](https://openairdocs.org/sdr/AALA202302024822), Jan 28, 2023: Boeing 737823. SENSOR. LEAKING. AIRCRAFT WAS GROUNDED: RIGHT AFTER TAKEOFF NOTICED DIRTY SOCK SMELL IN CABIN AND FLIGHT DECK. SMELL DISAPPEARED SHORTLY  (N801NN)
- [SDR AALA202302021170](https://openairdocs.org/sdr/AALA202302021170), Jan 28, 2023: Boeing 737823. PACKING. DETERIORATED. AIRCRAFT WAS GROUNDED: RIGHT AFTER TAKEOFF NOTICED DIRTY SOCK SMELL IN CABIN AND FLIGHT DECK. SMELL DISAPPEARED SHORTLY  (N801NN)
- [SDR AALA202301174822](https://openairdocs.org/sdr/AALA202301174822), Jan 13, 2023: Airbus A321231. INDICATOR. INOPERATIVE. AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO FLL AFTER THE FLIGHT CREW REPORTED LOOSING (N561UW)
- [SDR DALA2022111507358](https://openairdocs.org/sdr/DALA2022111507358), Nov 12, 2022: Airbus A330223. PROBE. FAULTED. SHIP 3353 -ATB- SHORTLY AFTER TAKEOFF FLIGHT CREW RECEIVED LEFT ENGINE EPR MODE FAULT AND N1 WENT INTO DEGRADED MODE. LE (N853NW)
- [SDR CALA2022080801978](https://openairdocs.org/sdr/CALA2022080801978), Aug 5, 2022: Airbus A300*. NONE. NONE. CREW WRITE UP,"AT CRUISE THE FO SCREENBLANKED OUT. ENG2 N1DEGRADED MODE. RAN EC AMADIRUS ON BAT." BUS 2 SPLY BREAKER WAS (N809UA)
- [SDR YENA2022072600716](https://openairdocs.org/sdr/YENA2022072600716), Jul 25, 2022: Airbus A321271N. NONE. FAILED. FLT#44, LGW-JFK. (ETOPS) ' REF TSI ON WO 1190881, REPLACE N1 SPEED PROBE; REMOVED AND REPLACED OF ENG 2 N1 SPEED PROBE I (N4058J)
- [SDR F3LA2022061300059](https://openairdocs.org/sdr/F3LA2022061300059), Jun 11, 2022: Airbus A320251N. NONE. NONE. DISCREPANCY: REFERENCE LP 210431 ENG 1 STALL CAUTION MSG. ENGINE PARAMETERS NORMAL AFTER CAUTION WENT AWAY. CORRECTIVE A (N328FR)
- [SDR QR9R20220422002](https://openairdocs.org/sdr/QR9R20220422002), Apr 22, 2022: Bolkms BK117C2. SENSOR. INTERMITTENT. DURING FLIGHT, THE N2 RPM NEEDLE FOR THE #2 ENGINE ON THE TRIPLE TACH MOVED TO ZERO INTERMITTENTLY. AT AIRSPEEDS SLOWER 
- [SDR QR9R20220413002](https://openairdocs.org/sdr/QR9R20220413002), Apr 13, 2022: Bolkms BK117C2. SENSOR. WARNING LIGHT. ENGINE #2 N2 TACHOMETER READING FELL TO ZERO AFTER 2 HOURS OF FLIGHT. REMOVED AND REPLACED SPEED SENSOR IAW 77-12-00-900
- [SDR YENA2022022800102](https://openairdocs.org/sdr/YENA2022022800102), Feb 25, 2022: Airbus A320232. BLEED VALVE. FAILED. FLT # 1691, JFK-LIR(DIVERTED TO MCO). ENGINE 1 STALL AT CRUISE 34000, LOUD SHAKE NO ECAM PRESENT DIVERT TO MCO; PER TSM  (N613JB)
- [SDR YENA2021120600828](https://openairdocs.org/sdr/YENA2021120600828), Dec 5, 2021: Airbus A321271N. SENSOR. FAILED. (ETOPS) FLT # 44, LGW-JFK. ENG 2B-0448-N1 SPEED SNSR FAIL ; RAR ENG#2 N1 SPEED SNSR IAW EMM TASK 77-11-21-520-000. PERFO (N4058J)
- [SDR K11A2020121800034](https://openairdocs.org/sdr/K11A2020121800034), Dec 18, 2020: Boeing 7272M7. CIRCUIT BREAKER. TRIPPED. ON TAKEOFF NR 1 EPR INOPERABLE, REJECTED TAKEOFF. CORRECTIVE ACTION & OTHER PERTINENT INFORMATION: RESET NR 1 EPR CIRCUI (N726CK)
- [SDR UOIA2020111300002](https://openairdocs.org/sdr/UOIA2020111300002), Nov 12, 2020: Bnorm BN2AMK3. GOVERNOR. DAMAGED. LOSS OF RPM ON TAKEOFF. (N920GD)
- [SDR AALA202010209017](https://openairdocs.org/sdr/AALA202010209017), Oct 19, 2020: Airbus A321231. SENSOR. DEFECTIVE. AIRCRAFT WAS GROUNDED. ENGINE 1 EPR MODE FAULT N1 DEGRADED MODE. APPLIED THE PROCEDURE AND USED MANUAL THRUST. AN EMERGE (N993AN)
- [SDR ABXA202006296099](https://openairdocs.org/sdr/ABXA202006296099), Jun 26, 2020: Boeing 767281. SENSOR. DEFECTIVE. LEFT ENGINE SLOW TO SPOOL WITH SOME STRANGE INDICATION COMPARED TO RIGHT ENGINE WITH N1'S MATCHED N2 (LEFT ENGINE) IS 10 (N767AX)
- [SDR AALA202003169019](https://openairdocs.org/sdr/AALA202003169019), Mar 13, 2020: Boeing 7572B7. TRANSMITTER. FAULTY. AIRCRFT IN BASE VISIT: DURING CLIMB TO FL380 WITH THROTTLES MATCHED L CRD EPR 1.77 R EPR 1.71 WHEN EPR MATCHED THROTTLES (N206UW)
- [SDR YENA2019120280685](https://openairdocs.org/sdr/YENA2019120280685), Nov 28, 2019: Airbus A320232. RELAY. FAILED. FT # 1416, LGB-AUS. RETURNED TO FIELD. ENG 2 EPR MODE FAULT ON CLIMBOUT; R & R RELAY BOX 4100KS ENG #2 AS PER AMM 71-51- (N613JB)
- [SDR ASAA2019091330673](https://openairdocs.org/sdr/ASAA2019091330673), Sep 13, 2019: Airbus A321253N. SENSOR. FAULTED. SMR FAULTS FOUND ON ENG 2 CHANNEL A. DISPLAYED SMR FAULT IS 0343-N2 SENSOR. ATA 771120. DATE 1507. WHEN THIS/THESE SMR F (N926VA)
- [SDR AALA201909109009](https://openairdocs.org/sdr/AALA201909109009), Sep 9, 2019: Airbus A321231. SENSE LINE. LOOSE. AIRCRAFT WAS GROUNDED: FLIGHT AIR RETURNED TO DFW ON ACCOUNT OF #2 ENGINE EPR FAULT. EMERGENCY WAS DECLARED. MAINTENANCE (N119NN)
- [SDR IPXA2019070844195](https://openairdocs.org/sdr/IPXA2019070844195), Jul 3, 2019: Boeing 75724APF. SENSE LINE. LOOSE. INSPECTION TYPE:N/A DIVERSION - DURING CRUISE FLIGHT @ FL 390, M.79, OAT -51C) ENGINE INDICATIONS BECAME ABNORMAL FOR PH (N474UP)
- [SDR GTIA2019031803224](https://openairdocs.org/sdr/GTIA2019031803224), Mar 18, 2019: Airbus A319132. EPR SYSTEM. MALFUNCTIONED. A+ CRUISE FL360 ENGINE NR 2 EPR MODE FAULT DEGRADE MODE PER COM TURNED ON N1 MODE FOR ENGINE 1AND 2-PERFORMED TSM 73-22- (N525NK)
- [SDR ASAA2018101126447](https://openairdocs.org/sdr/ASAA2018101126447), Oct 11, 2018: Airbus A321253N. WARNING SYSTEM. FALSE ACTIVATION. ENG 1 MINOR FAULT GROUNDED - YES. PERFORMED TSM 77-11-00-810-839-A, FAULT APPEARED PHASE 9, NO MAINTENANCE ACTION NECESS (N928VA)
- [SDR HALA2018100800480](https://openairdocs.org/sdr/HALA2018100800480), Oct 8, 2018: Airbus A330243. CONTROL UNIT. MALFUNCTIONED. ETOPS SIGNIFICANT SYSTEM, AFTER ENG START ENG NR 2 EPR MODE FAULT. PERFORMED TSM 73-21-71-810-843-A. REPLACED NR 2 ENG P (N378HA)
- [SDR AALA201808319032](https://openairdocs.org/sdr/AALA201808319032), Aug 29, 2018: Boeing 757223. TRANSMITTER. FAULTY. AIRCRAFT WAS GROUNDED: REJECTED TAKEOFF AT 75 KNOTS, MAXIMUM GROUND SPEED 90 KTS DUE TO ENGINE PRESSURE RATIO. RIGHT ENG (N196AA)
- [SDR AALA2018090629006](https://openairdocs.org/sdr/AALA2018090629006), Aug 28, 2018: Boeing 757223. TRANSMITTER. FAILED. AIRCRAFT ABORTED TAKEOFF FOR AN EPR MESSAGE ON RIGHT ENGINE. RIGHT ENGINE EPR BLANKED AT 70 KTS. IAW E-58 9768713, TROUB (N196AA)
- [SDR HALA2018062500300](https://openairdocs.org/sdr/HALA2018062500300), Jun 23, 2018: Airbus A330243. SENSE LINE. UNSECURE. ATB - ETOPS SIGNIFICANT SYSTEM - ENG 1 EPR MODE FAULT REPEAT WRITE UP. REMOVED AND REINSTALLED PROBE ACCESS PANEL FOR T/ (N390HA)
- [SDR HALA2018062500301](https://openairdocs.org/sdr/HALA2018062500301), Jun 22, 2018: Airbus A330243. PROBE. FAULTY. ATB - ETOPS SIGNIFICANT SYSTEM - ON CLIMB OUT ECAM: AUTO FLT A-THR OFF WNG 1 EPR MODE FAULT MAN THR. ADJUST FUEL 2FW 2FC (N390HA)
- [SDR FDEA201804241109](https://openairdocs.org/sdr/FDEA201804241109), Apr 24, 2018: Boeing 75728A. TUBE. DAMAGED. PDIS 928 76-00 6718 24APR18 BNA OPEN U LOGPAGES:2252904 AT CRUISE NOTICED L EPR PEGGED. FUEL FLOW AT 1.5. LOTS OF RIGHT  (N928FD)
- [SDR FDEA201802010285](https://openairdocs.org/sdr/FDEA201802010285), Feb 1, 2018: Boeing 75728A. TUBE. LEAKING. DURING CLIMB THROUGH FL 270, THE LEFT ENGINE INDICATED N1 OF 82% VS N1 95%, FOR THE RIGHT ENGINE. LEFT EGT WAS 120DEG. L (N928FD)
- [SDR HALA2017120300266](https://openairdocs.org/sdr/HALA2017120300266), Dec 1, 2017: Airbus A330243. PROBE. FAILED. ATB BACK TO HNL DUE TO THE NR 2 ENGINE EPR MODE FAULT ECAM MESSAGE APPEARED. N1 MODE ONLY. LOST BOTH EPR'S. RECOVERY FAI (N373HA)
- [SDR AALA20170802005](https://openairdocs.org/sdr/AALA20170802005), Aug 1, 2017: Boeing 757223. TRANSMITTER. INOPERATIVE. AIRCRAFT WAS GROUNDED, EMERGENCY DECLARED. RETURNED TO JFK. DURING CRUISE THE RIGHT ENGINE EPR INDICATION BLANKED. REMOV (N191AN)
- [SDR AALA201707119013](https://openairdocs.org/sdr/AALA201707119013), Jul 9, 2017: Doug MD83. TRANSMITTER. FAULTY. AIRCRAFT WAS GROUNDED. TUS-DFW FLIGHT ABORTED TAKEOFF AT 15 KNOTS ACCOUNT LEFT ENGINE PRESSURE RATIO INDICATION. REMOVED (N9622A)
- [SDR AALA201706099037](https://openairdocs.org/sdr/AALA201706099037), Jun 7, 2017: Doug MD83. B-NUT. LOOSE. THE AIRCRAFT WAS GROUNDED. LEFT ENGINE SLOW TO ACCELERATE ON TAKE OFF. THE N1 EVENTUALLY ACHIEVED 90%, BUT EPR REMAINED  (N9626F)
- [SDR AALA20170105015](https://openairdocs.org/sdr/AALA20170105015), Jan 1, 2017: Doug DC982. INDICATION SYS. MALFUNCTIONED. AIRCRAFT NOT GROUNDED. WHILE ADVANCING POWER FOR TAKEOFF, RIGHT ENGINE PRESSURE RATIO DISPLAY STOPPED AND RED BAR APPEAR (N33502)

All 456: https://openairdocs.org/jasc/7711/reports.md

## Other codes in chapter 77

- [JASC 7700](https://openairdocs.org/jasc/7700): Engine Indicating System (705 reports)
- [JASC 7710](https://openairdocs.org/jasc/7710): Power Indicating System (191 reports)
- [JASC 7712](https://openairdocs.org/jasc/7712): Engine BMEP/Torque Indicating (1,239 reports)
- [JASC 7713](https://openairdocs.org/jasc/7713): Manifold Pressure (MP) Indicating (77 reports)
- [JASC 7714](https://openairdocs.org/jasc/7714): Engine RPM Indicating System (1,357 reports)
- [JASC 7720](https://openairdocs.org/jasc/7720): Engine Temperature Indicating System (695 reports)
- [JASC 7721](https://openairdocs.org/jasc/7721): Cylinder Head Temperature (CHT) Indicating System (62 reports)
- [JASC 7722](https://openairdocs.org/jasc/7722): Engine EGT/TIT Indicating System (1,198 reports)
- [JASC 7730](https://openairdocs.org/jasc/7730): Engine Ignition Analyzer System (52 reports)
- [JASC 7731](https://openairdocs.org/jasc/7731): Engine Ignition Analyzer (15 reports)
- [JASC 7732](https://openairdocs.org/jasc/7732): Engine Vibration Analyzer (237 reports)
- [JASC 7740](https://openairdocs.org/jasc/7740): Engine Integrated Instrument System (53 reports)
- [JASC 7797](https://openairdocs.org/jasc/7797): Engine Indicating System Wiring (592 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.