# JASC 2311: UHF Communications System - Type: JASC system/component code (FAA) - ATA chapter: 23 Communications - Title in the code table: UHF COMMUNICATION SYSTEM - Service difficulty reports: 69 - FAA code table: https://www.faa.gov/sites/faa.gov/files/JASC_Code.pdf#page=18 - Page: https://openairdocs.org/jasc/2311 ## What it covers The system parts and circuitry including the receiver, transmitter, and antenna used exclusively for ultra high frequency (UHF) communications. ## Service difficulty reports (69, newest 50) - [SDR YENA2026101600985](https://openairdocs.org/sdr/YENA2026101600985), Oct 15, 2026: Airbus A321271NX. COMMS UNIT. FAULTED. FLT # 353, BOS-DUB. (ETOPS) "CA RMP ENTERES 3 WHEN 1 SELECTED OF RADIO FREQ ( RADIO MANAGEMENT PANELS (RMP) RMP 1 RMP 1 (N2193J) - [SDR I5PA2026091588804](https://openairdocs.org/sdr/I5PA2026091588804), Sep 15, 2026: Boeing 757230. COUPLER. INOPERATIVE. ETOPS, LEFT HF ON MEL - REPLACED LH HF COUPLER PER AMM (N888LT) - [SDR I5PA2026083188807](https://openairdocs.org/sdr/I5PA2026083188807), Aug 31, 2026: Boeing 757230. COUPLER. INOPERATIVE. ETOPS SIGNIFICANT REPORT, LT HF INOPERATIVE. ON MEL. REPLACED THE LT HF COUPLER IAW APPLICABLE AMM (N888LT) - [SDR ASAA2026082666545](https://openairdocs.org/sdr/ASAA2026082666545), Aug 26, 2026: Airbus A330243. COUPLER. UNSERVICEABLE. ATB. HF NR 1 UNABLE TO TRANSMIT. TRIED NUMEROUS TIMES, NUMEROUS FREQUENCIES AND ALL 3 RNPS UNSUCCESSFUL. GROUNDED - YES. (N381HA) - [SDR UIEA2026082300786](https://openairdocs.org/sdr/UIEA2026082300786), Aug 22, 2026: Boeing 74787UF. TRANSCEIVER. INOPERATIVE. RIGHT HF INOPERATIVE. NO HF CAPABILITY, LT & RT UNABLE TO TRANSMIT. R & R HF ANTENNA COUPLER IAW AMM 23-11-03. R & R RT (N851GT) - [SDR QR9R2026072400001](https://openairdocs.org/sdr/QR9R2026072400001), Jul 24, 2026: Bolkms BK117C2. ANTENNA. FAULTY. RT 5000 TRANSMISSIONS UNREADABLE WHEN TWIST GRIPS WERE IN FLT. AT IDLE, RADIO WAS BARELY READABLE WITH GROUND AND TWR. R - [SDR QR9R2026012000001](https://openairdocs.org/sdr/QR9R2026012000001), Jan 20, 2026: Bolkms BK117C2. TRANSCEIVER. FAILED. #4 RADIO WOULD NOT XMIT MORE THAN 1 MILE WHEN IN FLIGHT. ON GROUND AT AIRFIELD, RADIO OPERATES OK. AFTER TAKEOFF, WAS UN - [SDR QR9R2025092400002](https://openairdocs.org/sdr/QR9R2025092400002), Sep 24, 2025: Bolkms BK117C2. TRANSCEIVER. FAILED. UHF RADIO FAILURE IN FLIGHT. TEST FLIGHT EVAL FOUND TRANSMISSION ON WULFSBERG 5000 UNREADABLE. RX PART ON WOLFSBERG WORK - [SDR I5PA2025090859302](https://openairdocs.org/sdr/I5PA2025090859302), Sep 6, 2025: Boeing 757223. TRANSCEIVER. INOPERATIVE. RIGHT HF INOPERATIVE. R & R RT HF TRANSCEIVER IAW AMM, OPS CHECK NORMAL. (N193AN) - [SDR I5PA2025083119302](https://openairdocs.org/sdr/I5PA2025083119302), Aug 31, 2025: Boeing 757223. TRANSCEIVER. FAULTY. RIGHT HF INOPERATIVE. R & R RT HF TRANSCEIVER IAW AMM, OPS CHECK NORMAL. (N193AN) - [SDR I5PA2024071088803](https://openairdocs.org/sdr/I5PA2024071088803), Jul 10, 2024: Boeing 757230. TRANSCEIVER. INOPERATIVE. LEFT HF INOPERATIVE, REPLACED LH HF TRANSCEIVER (N888LT) - [SDR YENA2024070100924](https://openairdocs.org/sdr/YENA2024070100924), Jun 28, 2024: Airbus A321231. SMOKE DETECTOR. FALSE ACTIVATION. FLT#81, JFK-RNO. (AIRCRAFT DECLARED AN EMERGENCY AND DIVERTED TO DEN). ' AFT AVIONICS SMOKE IND IN CRUISE QRH COMPLETED (N969JT) - [SDR HALA2023121108267](https://openairdocs.org/sdr/HALA2023121108267), Dec 3, 2023: Airbus A330243. UNKNOWN. UNKNOWN. ETOPS - #2 HF WILL NOT TUNE AND TX #1 HF HAS DIFFICULTY TUNING . WORKS INTRMITTENT. REMOVED AND REPLACED #2 HF TRANCEIVE (N392HA) - [SDR YENA2023112201443](https://openairdocs.org/sdr/YENA2023112201443), Nov 20, 2023: Airbus A321271N. TRANSCEIVER. FAILED. FLT#44, LGW-JFK. (ETOPS) ' HF2 TUNING TONE PREVENTS TRANSMITTING WHEN PTT IS DEPRESSED; REMOVED AND REPLACED HF TRANSCEI (N4076J) - [SDR GTIA2023102737563](https://openairdocs.org/sdr/GTIA2023102737563), Oct 25, 2023: Airbus A320232. HF COMM. FAULTED. HF 1 TRANSMITS BUT DOES NOT RECEIVE ( HIGH FREQUENCY (HF) COMMUNICATION SYSTEM ATSU/ACARS AND VHF OPERATE NORMALLY )-- (N652NK) - [SDR NACA2023070900001](https://openairdocs.org/sdr/NACA2023070900001), Jul 9, 2023: Boeing 767323. TRANSCEIVER. INTERMITTENT. HF #1 INTERMITTENT TX, RX OK. REMOVED AND REPLACED #1 TRANSCEIVER IAW AMM 23-11-03, OPS CHECK GOOD. NO TRAX INFO AVAILAB (N379CX) - [SDR NACA2023070800002](https://openairdocs.org/sdr/NACA2023070800002), Jul 8, 2023: Boeing 767323. UNKNOWN. UNKNOWN. LEFT HF RADIO DOES NOT TX, JUST GOT STATIC OR SIDETONE WHEN TRY TO TX. PERFORMED LH HF OPS CHECK PER AMM 23-11-00, OPS C (N379CX) - [SDR YENA2023032200274](https://openairdocs.org/sdr/YENA2023032200274), Mar 21, 2023: Airbus A321271N. UNKNOWN. UNKNOWN. FLT#1620, BOS-LHR. (ETOPS) 'HF RADIO 1 IN INTERMITTENT WORKED EARLY IN FLIGHT BUT TRANSMISSIONS ARE INTERMITTENT BY 30 D (N4073J) - [SDR UIEA2023031000243](https://openairdocs.org/sdr/UIEA2023031000243), Mar 9, 2023: Boeing 74747UF. TRANSCEIVER. UNKNOWN. ATB-RH HF RADIO NOT TRANSMITTING.(

REMOVED AND REPLACED RH HF TRANSCEIVER PER AMM 23-11-00. OPS CHECK GOOD

) (N493MC) - [SDR CALA2023022000498](https://openairdocs.org/sdr/CALA2023022000498), Feb 20, 2023: Boeing 7378. COUPLER. NONE. BOTH HF RADIOS INOP. PERFORMED T/S ON HF RADIOS IN REF AVO10462. ALL WIRING AND CONTACTED SFO ON HF1 AND HF2 AT FREQ. 5. (N77520) - [SDR CALA2023010900059](https://openairdocs.org/sdr/CALA2023010900059), Jan 9, 2023: Boeing 737824. HF COMM. INOPERATIVE. HF RADIOS WILL NOT TRANSMIT BITE BOTH NUMBER 1 AND NUMBER 2 TRANSCEIVERS, BITE TEST OK. GROUND OPS CHK NUMBER 1 AND 2 HF (N77520) - [SDR ABXA2023010102](https://openairdocs.org/sdr/ABXA2023010102), Jan 1, 2023: Boeing 767338. TRANSCEIVER. WEAK. RIGHT HF WAS WEAK ON GROUND BUT WORKS IN FLIGHT WHEN IRO OR CAPT TRIED TO XNIT NO TRANSMISSION OVERRED AND NO SIDE TONE (N371CM) - [SDR HALA2022101100271](https://openairdocs.org/sdr/HALA2022101100271), Oct 10, 2022: Airbus A330243. NONE. NONE. ETOPS - #2 HF RADIO WILL NOT TUNE. BITE TEST PASS PER AMM 23-11-00. DUE TO MULTIPLE WRITES UP OF HF #2, REMOVED & INSTAL (N379HA) - [SDR HALA2022100500267](https://openairdocs.org/sdr/HALA2022100500267), Oct 5, 2022: Airbus A330243. NONE. NONE. HF 1 RADIO WOULD NOT TUNE AND IS INOP. REMOVED & REPLACED HF #2 COUPLER PER AMM 23-11-36. OPERATIONAL CHECK OK. COUPLER, (N384) - [SDR YENA2022090500870](https://openairdocs.org/sdr/YENA2022090500870), Sep 4, 2022: Airbus A321271N. COUPLER. FAULTY. FLT#7, JFK-LHR. (ETOPS) 'REF TSI MDDR#484335 REPLACE HF 1 COUPLER; PER TSI WO#1201122 REMOVED & REPLACED HF1 (4RE1) IAW (N4062J) - [SDR SIMA20220725004](https://openairdocs.org/sdr/SIMA20220725004), Jul 25, 2022: Emb ERJ170200LR. RMU. INOPERATIVE. THROUGH 8000' RMU 1 OUT - ELECTRICAL BURNING SMELL IN THE COCKPIT. TROUBLESHOT PER FIM 21-20-00-210-801-A. DETERMINED CA (N661JA) - [SDR I5PA2022040375701](https://openairdocs.org/sdr/I5PA2022040375701), Apr 3, 2022: Boeing 75729J. TRANSCEIVER. INOPERATIVE. RH HF INOP IN FLIGHT. RH HF TRANSCEIVER FOUND DEFECTIVE AND REPLACED. (N757QM) - [SDR I5PA2022032588802](https://openairdocs.org/sdr/I5PA2022032588802), Mar 22, 2022: Boeing 757230. COUPLER. UNSERVICEABLE. IN REF. TO LP 52417 LEFT HF INOP. REMOVED AND REPLACED LEFT HF COUPLER IAW AMM 23-11-01. (N888LT) - [SDR I5PA2022030388801](https://openairdocs.org/sdr/I5PA2022030388801), Mar 3, 2022: Boeing 757230. COUPLER. UNSERVICEABLE. IN REF. TO LP 52411 ITEM 2 FOR MEL 23-11-01-02A, LEFT HF INOP. REMOVED AND REPLACED LEFT HF COUPLER IAW AMM 23-11-01. (N888LT) - [SDR P5CA2021112200423](https://openairdocs.org/sdr/P5CA2021112200423), Nov 22, 2021: Boeing 7673JHF. COUPLER. NONE. LEFT HF INOP.(

T/S PER FIM 23-11-00. REMOVED/REPLACED LH HF COMM ANTENNA COUPLER AMM 23-11-01. MDDR 156972 CLEARED UP. (N643GT) - [SDR UIEA2021090601959](https://openairdocs.org/sdr/UIEA2021090601959), Sep 6, 2021: Boeing 74745E. TRANSCEIVER. FAULTED. AIR TURNBACK DUE TO INABILITY TO ESTABLISH HF CONTACT.(

 REMOVED AND REPLACED R/H HF TRANSCEIVER. OPS CK GOOD IAW (N473MC) - [SDR HALA2021033100040](https://openairdocs.org/sdr/HALA2021033100040), Mar 31, 2021: Airbus A330243. HF COMM. INOPERATIVE. ETOPS - UNABLE TO TUNE HF RADIOS 1 AND 2. HOURS LATER DURING FLIGHT RADIO 1 DID CORRECT ITSELF WITHOUT ANY RESET AND TUN (N388HA) - [SDR HALA2021021900021](https://openairdocs.org/sdr/HALA2021021900021), Feb 18, 2021: Airbus A330243. TRANSCEIVER. DEFECTIVE. ETOPS - HF NR 2 RADIO INOP. REMOVED AND REPLACED HF 2 TRANSCEIVER PER AMM 23-11-00, OPS CK GOOD. OK FOR SERVICE. TRANSCE (N370HA) - [SDR I5PA2021020188801](https://openairdocs.org/sdr/I5PA2021020188801), Feb 1, 2021: Boeing 757230. COUPLER. FAULTY. DISCREPANCY R HF INOPERATIVE. CORRECTIVE ACTION R & R R HF COUPLER IAW AMM 23-11-01. OPS CHECK OK. (N888LT) - [SDR HALA2020111200203](https://openairdocs.org/sdr/HALA2020111200203), Nov 11, 2020: Airbus A330243. TRANSCEIVER. DEFECTIVE. ETOPS-HF RADIOS TUNING INTERMITTENT. NORMAL TOWARDS END OF FLIGHT. REMOVED & REPLACED HF 2 TRANSCEIVER, PER A330 AMM 23- (N396HA) - [SDR DALA2020061202466](https://openairdocs.org/sdr/DALA2020061202466), Jun 12, 2020: Boeing 737832. ANTENNA. DELAMINATED. FOUND NR 2 AIRPHONE ANTENNA DELAMINATED. RMVD NR 2 AIRPHONE ANTENNA PER AMM 23-19 (488979) AND C/W EA 12-477283-14 AMD E (N3739P) - [SDR HALA2019101000407](https://openairdocs.org/sdr/HALA2019101000407), Oct 9, 2019: Airbus A330243. TRANSCEIVER. MALFUNCTIONED. ETOPS SIGNIFICANT SYSTEM - #1 HF RADIO WILL NOT TUNE. // TROUBLESHOT #1 HF RADIO REF A330 TSM 23-11-00-810-819-A. REMOVE (N395HA) - [SDR AALA201908069002](https://openairdocs.org/sdr/AALA201908069002), Aug 2, 2019: Boeing 737823. CONTROL UNIT. FAILED. AIRCRAFT WAS GROUNDED: PILOT REPORTS BOTH HF #1 AND HF #2 RADIOS INOP. UNABLE TO TRANSMIT OR RECIEVE ON SEVERAL DIFFEREN (N950AN) - [SDR QXEA2019072500282](https://openairdocs.org/sdr/QXEA2019072500282), Jul 23, 2019: Bombdr DHC8402. UNKNOWN. MALFUNCTIONED. POSSIBLE FAILURE OF BOTH RADIOS FOR XMIT ONLY TO TOWER FREQS 119.9 & 120.95. TOWER ONLY COULD NOT HEAR US. ALL OTHER AIR (N404QX) - [SDR QXEA2018091700334](https://openairdocs.org/sdr/QXEA2018091700334), Sep 15, 2018: Bombdr DHC8402. TRANSCEIVER. INOPERATIVE. BOTH CAPTAIN AND FIRST OFFICER WERE UNABLE TO BE HEARD BY TOWER ON NR 1 RADIO. WE COULD BOTH HEAR TOWER ON RADIO NR 1. C (N441QX) - [SDR QXEA2016052500346](https://openairdocs.org/sdr/QXEA2016052500346), May 25, 2016: Bombdr DHC8402. ANTENNA. MALFUNCTIONED. NR 1 COMM UNUSEABLE ON 126.6 MHZ. NR 2 OK ON 126.6. RETURNED TO FIELD, LANDING UNEVENTFUL. REPLACED NR 1 VHF COMM ANTENN (N430QX) - [SDR FDEA201507162269](https://openairdocs.org/sdr/FDEA201507162269), Jul 16, 2015: Boeing 757236. CIRCUIT BREAKER. TRIPPED. CAPTAIN'S O2 MASK DOES NOT TRANSMIT. PDX R RESET COMM CB AT CAPTAIN`S O2 BOX IAW AMM 35-11-4. OPERATIONS CHECKED NORMAL. (N978FD) - [SDR PNSA2015062605](https://openairdocs.org/sdr/PNSA2015062605), Jun 26, 2015: Saab 340B. ELECTRONIC UNIT. MALFUNCTIONED. COMM NR 2 INTERMITTENTLY FAILS TO RECEIVE OR TRANSMIT AND MAKES TOGGLE CHANNEL CHANGE BEEP TONES DURING FAILURE. R & R R (N677PA) - [SDR UIEA2014071800338](https://openairdocs.org/sdr/UIEA2014071800338), Jul 18, 2014: Boeing 74787UF. ANTENNA. DAMAGED. LIGHTNING STRIKE AT 12 O'CLOCK POSITION. PRELIMINARY INSPECTION IAW AMM 05-51-13 201 FOUND MULTIPLE BURN MARKS AROUND RI (N856GT) - [SDR UALA2012042502492](https://openairdocs.org/sdr/UALA2012042502492), Apr 25, 2012: Boeing 747422. SMOKE DETECTOR. FAULTED. FOUND FAULT IN CARGO AFT-3 LOOP-A. MESSAGE NR 26164. REPLACED SMOKE DETECTOR 3A I IN AFT PIT PER MM26-16-01 AND IPC 26-1 (N181UA) - [SDR I5PA030809](https://openairdocs.org/sdr/I5PA030809), Mar 8, 2009: Boeing 727200. TRANSCEIVER. MALFUNCTIONED. AIRCRAFT, AIR RETURNED DUE TO NR 1 AND NR 2 HF'S WOULD NOT TRANSMIT OR RECEIVE. CLEANED AND RESEATED BOTH TRANSCEIVERS, (N319NE) - [SDR CA080523005](https://openairdocs.org/sdr/CA080523005), May 16, 2008: Snias AS350BA. TRANSCEIVER. INOPERATIVE. (CAN) RADIO WOULD NOT TRANSMIT, REMOVED AND INSTALLED SERVICABLE RADIO. - [SDR HALA0800471](https://openairdocs.org/sdr/HALA0800471), Mar 31, 2008: Boeing 7673G5. TRANSCEIVER. MALFUNCTIONED. ETOPS SIGNIFICANT SYSTEM, L HF TRANSMITTER UNABLE TO TRANSMIT OR RECEIVE. REMOVED AND REPLACED LT HF TRANSCEIVER IAW AMM (N586HA) - [SDR RAIA00701008](https://openairdocs.org/sdr/RAIA00701008), Jan 5, 2007: Emb EMB145LR. CONTROL MODULE. UNKNOWN. FLT NR 7897-MDT-CAPTAIN AND FO'S RADIO LOCKED UP AND WERE UNABLE TO CHANGE FREQUENCIES. MAINTENANCE REMOVED AND REINSTAL (N823HK) - [SDR HALA0600478](https://openairdocs.org/sdr/HALA0600478), Jun 26, 2006: Boeing 717200. ANTENNA. CRACKED. VHF ANTENNA HAS A CRACK ON THE LEADING EDGE. REMOVED AND REPLACED ANTENNA PER AMM 23-12-02, OPERATIONAL CHECK PER AMM 23 (N476HA) All 69: https://openairdocs.org/jasc/2311/reports.md ## Other codes in chapter 23 - [JASC 2300](https://openairdocs.org/jasc/2300): Communications System (1,971 reports) - [JASC 2310](https://openairdocs.org/jasc/2310): HF Communications System (1,684 reports) - [JASC 2312](https://openairdocs.org/jasc/2312): VHF Communications System (1,271 reports) - [JASC 2320](https://openairdocs.org/jasc/2320): Data Transmission Auto Call (106 reports) - [JASC 2330](https://openairdocs.org/jasc/2330): Entertainment System (802 reports) - [JASC 2340](https://openairdocs.org/jasc/2340): Interphone/Passenger Announcement (PA) System (755 reports) - [JASC 2350](https://openairdocs.org/jasc/2350): Audio Integrating System (628 reports) - [JASC 2360](https://openairdocs.org/jasc/2360): Static Discharge System (104 reports) - [JASC 2370](https://openairdocs.org/jasc/2370): Audio/Video Monitoring (219 reports) - [JASC 2397](https://openairdocs.org/jasc/2397): Communications System Wiring (430 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.