# JASC 6340: Rotor Drive Indicating System

- Type: JASC system/component code (FAA)
- ATA chapter: 63 Main Rotor Drive
- Title in the code table: ROTOR DRIVE INDICATING SYSTEM
- Service difficulty reports: 265
- FAA code table: https://www.faa.gov/sites/faa.gov/files/JASC_Code.pdf#page=58
- Page: https://openairdocs.org/jasc/6340

## What it covers

The indicators, sensors/transmitters and associated systems which indicate operation or activation of rotor systems. Typical parts are tachometer, transmitter, circuit breaker, wiring harness, light, switch, indicator, needle, etc.

## Service difficulty reports (265, newest 50)

- [SDR QR9R2026091000001](https://openairdocs.org/sdr/QR9R2026091000001), Sep 10, 2026: Bolkms BK117C2. TRANSDUCER. FLUCTUATES. #2 XMSN PRESSURE INDICATION ON CPDS ERRATIC DURING GROUND RUN. INDICATION FLUCTUATED BETWEEN 0.0 AND 5.0 BAR RANDOMLY. R
- [SDR QR9R2026082400001](https://openairdocs.org/sdr/QR9R2026082400001), Aug 24, 2026: Bolkms BK117C2. TRANSMITTER. FAULTED. NO OIL PRESSURE OBSERVED ON TRANSMISSION NR 2 AFTER REACHING STABILIZED GROUND IDLE AFTER START OF ENGINE NR1. ABORTED T
- [SDR QR9R2026060400001](https://openairdocs.org/sdr/QR9R2026060400001), Jun 4, 2026: Bolkms BK117C2. INDICATOR. STUCK. TRIPLE TACH WOULD NOT MOVE AT IDLE DURING START RUN-UP. REMOVED AND REPLACED TRIPLE TACH IAW AMM 62-41-00, 4-3; MOC SUCC
- [SDR QR9R2026052900001](https://openairdocs.org/sdr/QR9R2026052900001), May 29, 2026: Bolkms BK117C2. TRANSDUCER. FAULTY. NO RISE IN #1 TRANSMISSION OIL PRESSURE AFTER STARTING. ONLY DISPLAYED STATIC INDICATION OF .2. REMOVED AND REPLACED #1 
- [SDR QR9R2026043000001](https://openairdocs.org/sdr/QR9R2026043000001), Apr 30, 2026: Bolkms BK117C2. TRANSDUCER. FAULTED. NR 1 TRANSMISSION OIL PRESSURE .4 BAR, RESET, INDICATED 1.4 AND IMMEDIATELY DROPPED DOWN TO .4 AGAIN DURING START RUN-UP
- [SDR QR9R2025121700001](https://openairdocs.org/sdr/QR9R2025121700001), Dec 17, 2025: Bolkms BK117C2. TRANSMITTER. FAILED. PILOT REPORTED MAST MOMENT EXCEEDANCE ABOVE 90% WHILE IN LEVEL FLIGHT AND STEADY SPEED. REPORTED MM MONITORING SYSTEM JU
- [SDR QR9R2025112500001](https://openairdocs.org/sdr/QR9R2025112500001), Nov 25, 2025: Bolkms BK117C2. TRANSMITTER. FAILED. DURING ENG #1 START, MM INDICATION BEGAN TO MOVE PAST 77% REACHING THE MM EXCEEDANCE ONCE THE ENG REACHED IDLE. A TEST F
- [SDR QR9R2025101700001](https://openairdocs.org/sdr/QR9R2025101700001), Oct 17, 2025: Bolkms BK117C2. SPU. UNRELIABLE. MAST MOMENT INDICATION UNRELIABLE DURING START RUN-UP. UNABLE TO REDUCE BELOW 8% WHEN CENTERED, ALSO JUMPED AROUND WHEN 
- [SDR QR9R2025070200001](https://openairdocs.org/sdr/QR9R2025070200001), Jul 2, 2025: Bolkms BK117C2. INDICATOR. STUCK. TRIPLE TAC FAILED IN FLIGHT. NR STUCK IN POSITION AND WOULD NOT MOVE. BOTH N2 NEEDLES DID MOVE. REMOVED AND REPLACED TRI
- [SDR QR9R2025052900002](https://openairdocs.org/sdr/QR9R2025052900002), May 29, 2025: Bolkms BK117C2. TRANSDUCER. FAILED. #2 TRANSMISSION OIL PRESSURE GUAGE REDUCED TO 1.0 IN FLIGHT. REMOVED AND REPLACED #2 PRESSURE TRANSDUCER IAW AMM 63-41-0
- [SDR QR9R2025052000001](https://openairdocs.org/sdr/QR9R2025052000001), May 20, 2025: Bolkms BK117C2. INDICATOR. STUCK. #1 ENGINE N2 STUCK AT 96%. SHUTDOWN ENGINES AFTER LANDING AND THE NEEDLE REMAINED AT 96%. ALL OTHER ENGINE INDICATIONS W
- [SDR QR9R2025043000001](https://openairdocs.org/sdr/QR9R2025043000001), Apr 30, 2025: Bolkms BK117C2. INDICATOR. STUCK. #1 ENGINE TRIPLE TAC POINTER STUCK IN POSITION AT ABOUT 101%. REMOVED AND REPLACED TRIPLE INDICATOR RPM IAW AMM 62-41-00
- [SDR QR9R2025040900002](https://openairdocs.org/sdr/QR9R2025040900002), Apr 9, 2025: Bolkms BK117C2. TRANSDUCER. FAULTY. #1 TRANSMISSION OIL PRESSURE DROPPED BELOW 1.0 BAR DURING TAKEOFF. REMOVED AND REPLACED TRANSDUCER IAW AMM 63-41-00, 4-4
- [SDR QMLA2025032120038](https://openairdocs.org/sdr/QMLA2025032120038), Mar 21, 2025: Bell 407. WARNING LIGHT. ILLUMINATED. TRANSMISSION CHIP LIGHT ILLUMINATED (N775AL)
- [SDR QR9R2025031400004](https://openairdocs.org/sdr/QR9R2025031400004), Mar 14, 2025: Bolkms BK117C2. TRANSDUCER. FAULTY. #1 TRANSMISSION OIL PRESSURE DROPPED TO ZERO IN FLIGHT. REMOVED AND REPLACED TRANSDUCER IAW AMM 63-41-00, 4-4; MOC SUCCE
- [SDR QR9R2025031100002](https://openairdocs.org/sdr/QR9R2025031100002), Mar 11, 2025: Bolkms BK117C2. TRANSDUCER. FAULTY. AT IIDLE (70% N1 + - 2) #2 TRANSMISSION OIL PSI WAS LESS THAN 1.0 BAR. TROUBLESHOOTING REVEALED #2 TRANSMISSION OIL PRES
- [SDR QR9R2025030700002](https://openairdocs.org/sdr/QR9R2025030700002), Mar 7, 2025: Bolkms BK117C2. TRANSMITTER. FAILED. MAST MOMENT READING ON VEMD LANE 1 INOP DURING START RUN-UP. TROUBLESHOOTING FOUND THE SSTU FAILED DYN.KAL ON FUNCTIONAL
- [SDR QR9R2025011700001](https://openairdocs.org/sdr/QR9R2025011700001), Jan 17, 2025: Bolkms BK117C2. TRANSDUCER. FLUCTUATES. FOUR SEPARATE EVENTS OF #2 XMSN OIL PRESSURE FLUCTUATION IN FLIGHT BELOW 1.5 BAR AND AS LOW AS 0.7. NO ASSOCIATED WARNIN
- [SDR QR9R2024101000004](https://openairdocs.org/sdr/QR9R2024101000004), Oct 10, 2024: Bolkms BK117C2. TRANSDUCER. FLUCTUATES. IN FLIGHT, #2 TRANSMISSION OIL PUMP PRESSURE FLUCTUATED DOWN TO .3 BAR AND THEN BACK TO NORMAL. FLUCTUATED MULTIPLE TIME
- [SDR QR9R2024071600001](https://openairdocs.org/sdr/QR9R2024071600001), Jul 16, 2024: Bolkms BK117C2. TRANSMITTER. FAILED. SENSOR SIGNAL TRANSMITTING UNIT WAS RECEIVED NEW FROM AIRBUS. DURING MAST MOMENT PART 2 ADJUSTMENT- UNABLE TO MAINTAIN M
- [SDR QR9R2024020600001](https://openairdocs.org/sdr/QR9R2024020600001), Feb 6, 2024: Bolkms BK117C2. PICKUP. FAILED. TRIPLE TACH ROTOR INDICATED 0% RPM AFTER REACHING GROUND IDLE CONDITIONS. REMOVED AND REPLACED SPEED PICK-UP. MOC COMPLE
- [SDR QR9R2023092000001](https://openairdocs.org/sdr/QR9R2023092000001), Sep 20, 2023: Bolkms BK117C2. TRANSDUCER. FLUCTUATES. IN FLIGHT, #2 TRANSMISSION OIL PRESSURE WILL FLUCTUATE BETWEEN NORMAL, DOWN TO LESS THAN 1.5 BAR, THEN RETURN TO NORMAL.
- [SDR QR9R20220914002](https://openairdocs.org/sdr/QR9R20220914002), Sep 14, 2022: Bolkms BK117C2. NONE. FLUCTUATES. #2 TRANSMISSION OIL PRESSURE SYSTEM FAILED DURING FLIGHT. DISCONNECTED, INSPECTED, CLEANED AND RESEATED TRANSMISSION PRE
- [SDR JBZA20220801001](https://openairdocs.org/sdr/JBZA20220801001), Jul 29, 2022: Urocop EC135P2. TRANSMITTER. INOPERATIVE. CRUISE FLIGHT 1500' MSL MAIN TRANSMISSION OIL PRESSURE STARTED FLUCTUATING BETWEEN 1.1 & 2.8, MOMENTS LATER PRESSURE DRO (N315RX)
- [SDR QR9R20220629001](https://openairdocs.org/sdr/QR9R20220629001), Jun 29, 2022: Bolkms BK117C2. TRANSDUCER. LOW PRESSURE. NO POSITIVE TRANSMISSION OIL PRESSURE AT GROUND IDLE ON ENGINE NUMBER 1. REMOVED AND REPLACED PRESSURE TRANSDUCER IAW AM
- [SDR QR9R20220428002](https://openairdocs.org/sdr/QR9R20220428002), Apr 28, 2022: Bolkms BK117C2. NONE. FAILED. DURING AVIONICS CONFIGURATION OF THE RUN-UP PROCEDURES, WITH ENGINES AT IDLE, THE MAST MOMENT INDICATOR DRIFTED OFF THE 
- [SDR QR9R20220422001](https://openairdocs.org/sdr/QR9R20220422001), Apr 22, 2022: Bolkms BK117C2. NONE. PRESSURE LOSS. START ABORTED DUE TO TRANSMISSION OIL PRESSURE WAS AT 0.0 BARS AFTER STARTING #1 ENGINE. REMOVED AND INSTALLED NEW PRESS
- [SDR QR9R20220401001](https://openairdocs.org/sdr/QR9R20220401001), Apr 1, 2022: Bolkms BK117C2. TRANSDUCER. PRESSURE LOSS. #2 TRANSMISSION OIL PRESSURE REMAINED AT ZERO AFTER ENGINE START. REMOVED AND REPLACED #2 TRANSMISSION OIL PRESSURE TRAN
- [SDR QR9R20220223001](https://openairdocs.org/sdr/QR9R20220223001), Feb 23, 2022: Bolkms BK117C2. TRANSDUCER. FAILED. DURING FLIGHT, # 2 XMSN OIL PRESSURE WENT TO ZERO. REMOVED AND REPLACED NO. 2 TRANSMISSION OIL PRESSURE TRANSDUCER. MOC 
- [SDR QR9R20211029008](https://openairdocs.org/sdr/QR9R20211029008), Oct 29, 2021: Bolkms BK117C2. NONE. FAULT MESSAGE. FLT #1, WHILE CONDUCTING NORMAL HOVER FLIGHT ON HOVER TAXI LANE, MAST MOMENT EXCEEDANCE MESSAGE RECEIVED. MM INDICATED V
- [SDR QR9R20211021002](https://openairdocs.org/sdr/QR9R20211021002), Oct 21, 2021: Bolkms BK117C2. CHIP DETECTOR. FAULT MESSAGE. TRANSMISSION CHIP CAUTION LIGHT ILLUMINATED IN FLIGHT. MAINTENANCE REPLACED MAIN TRANSMISSION RH CHIP DETECTOR IAW AMM 6
- [SDR QR9R20210930003](https://openairdocs.org/sdr/QR9R20210930003), Sep 30, 2021: Bolkms BK117C2. TRANSDUCER. FAULTY. #2 XMSN PRESSURE INDICATION STAYED AT 0.0 ONCE ENGINE WAS STARTED RESULTING IN AN ABORTED TAKEOFF. #2 PRESSURE TRANSDUCE
- [SDR 8HBR20211012033](https://openairdocs.org/sdr/8HBR20211012033), Sep 29, 2021: Robsin R22BETA. DUAL TACHOMETER. FLUCTUATES. ENGINE SIDE OF DUAL TACHOMETER HAD INTERMITTENT INDICATION ISSUES. (N8340S)
- [SDR 8HBR20210920027](https://openairdocs.org/sdr/8HBR20210920027), Sep 11, 2021: Robsin R22BETA. DUAL TACHOMETER. FLUCTUATES. ENGINE SIDE OF DUAL TACHOMETER HAD INTERMITTENT INDICATION ISSUES. (N7155W)
- [SDR 8HBR20210920029](https://openairdocs.org/sdr/8HBR20210920029), Sep 9, 2021: Robsin R22BETA. DUAL TACHOMETER. FLUCTUATES. ENGINE SIDE OF DUAL TACHOMETER HAD INTERMITTENT INDICATION ISSUES. (N351JD)
- [SDR 8HBR20210920028](https://openairdocs.org/sdr/8HBR20210920028), Sep 8, 2021: Robsin R22BETA. DUAL TACHOMETER. FLUCTUATES. ENGINE SIDE OF DUAL TACHOMETER HAD INTERMITTENT INDICATION ISSUES. (N779SH)
- [SDR YV3R2020111900392](https://openairdocs.org/sdr/YV3R2020111900392), Nov 13, 2020: Robsin R44. HORN. INOPERATIVE. CUSTOMER REPORTED HORN ASSEMBLY P/N: B320-6 IS INOPERATIVE.
- [SDR FKEA202008040353](https://openairdocs.org/sdr/FKEA202008040353), Jul 31, 2020: Bolkms BK117C2. INDICATOR. INOPERATIVE. AIRCRAFT WAS HOVERING WHEN PILOT NOTICED THERE WAS NO ROTOR RPM INDICATION WITH NO WARNING INDICATION AIRCRAFT WAS LANDE (N240SF)
- [SDR 2020F00343](https://openairdocs.org/sdr/2020F00343), Jul 17, 2020: Bolkms BK117C2. INDICATOR. INOPERATIVE. AIRCRAFT WAS PULLED INTO A HOVER AND THE LOW ROTOR WARNING SOUNDED AND THE ROTOR RPM READ ZERO. AIRCRAFT LANDED AND FLIG (N440SF)
- [SDR HEER20200604815](https://openairdocs.org/sdr/HEER20200604815), Jun 3, 2020: Skrsky S92A. CHIP DETECTOR. ACTIVATED. CHIP SYSTEM FAULT CAUTION LIGHT ILLUMINATED IN FLIGHT. CHECKED DRIVE TRAIN HUMS NR 2 INPUT CHIP. (N935PH)
- [SDR YV3R2020051800260](https://openairdocs.org/sdr/YV3R2020051800260), May 1, 2020: Robsin R44. HORN. INOPERATIVE. CUSTOMER REPORTED HORN ASSEMBLY P/N: B320-6 IN INOPERATIVE. (N888SN)
- [SDR YV3R2020052000263](https://openairdocs.org/sdr/YV3R2020052000263), Apr 29, 2020: Robsin R44. WARNING HORN. INOPERATIVE. CUSTOMER REPORTED LOW WARNING R.P.M WARNING HORN P/N: B320-6 WAS INOPERATIVE. (N888SN)
- [SDR M3XA2020042303](https://openairdocs.org/sdr/M3XA2020042303), Apr 22, 2020: Urocop EC135P2. SENSOR. DIRTY. PILOT REPORTED DURING CRUISE FLIGHT MAIN GEARBOX OIL PRESSURE INDICATED 0.1 BAR. MECHANIC TROUBLESHOT SYSTEM, CLEANED OI (N456MT)
- [SDR YV3R2020052000261](https://openairdocs.org/sdr/YV3R2020052000261), Apr 21, 2020: Robsin R44. WARNING HORN. INOPERATIVE. CUSTOMER REPORTED LOW R.P.M WARNING HORN P/N: B320-6 WAS INOPERATIVE. (N888SN)
- [SDR AC2A2020012483901](https://openairdocs.org/sdr/AC2A2020012483901), Jan 18, 2020: Agusta AB139. RING. UNSTAKED. DURING DAILY INSPECTION, NOTICED RIGHT SIDE MAIN GEARBOX CHIP DETECTOR NOT FULLY ENGAGED. UPON INVESTIGATION, FOUND RETE (N139FW)
- [SDR QMLA2019091019074](https://openairdocs.org/sdr/QMLA2019091019074), Sep 10, 2019: Urocop EC135P2. CHIP DETECTOR. CONTAMINATED. SUPPLEMENTAL INFORMATION. WHILE ENROUTE TO HOSPITAL THE TRANSMISSION CHIP LIGHT CAME ON. A LANDING WAS CONDUCTED WITHOUT (N135AN)
- [SDR YV3R2019032300054](https://openairdocs.org/sdr/YV3R2019032300054), Mar 12, 2019: Robsin R44RAVENII. WARNING HORN. DEFECTIVE. CUSTOMER REPORTED LOW RPM WARNING HORN P/N: B320-6 WILL NOT WORK UNTIL TAPPED WHEN TESTING.
- [SDR O84A2018F00155](https://openairdocs.org/sdr/O84A2018F00155), Dec 3, 2018: Bolkms BK117C2. CHIP DETECTOR. CONTAMINATED. M/R GEARBOX CHIP LIGHT ILLUMINATED DURING HOVER. MECHANIC INSPECTED CHIP PLUGS AND FOUND NORMAL FUZZ PER MM. CLEANED CHI (N240SF)
- [SDR M3XA2017092210](https://openairdocs.org/sdr/M3XA2017092210), Sep 22, 2017: Bell 407. WARNING LIGHT. FALSE ACTIVATION. PL FOR TRANSMISSION CHIP LIGHT INDICATION. REMOVED, CLEANED, AND INSPECTED. ALL TRANSMISSION CHIP DETECTORS, NO CHIPS FO (N242MT)
- [SDR M3XA2017081205](https://openairdocs.org/sdr/M3XA2017081205), Aug 12, 2017: Bell 407. PRESSURE SWITCH. DEFECTIVE. ON SHORT FINAL TO THE HOSPITAL THE PILOT HAD A TRANSMISSION OIL PRESSURE WARNING LIGHT ILLUMINATE ON THE CAUTION WARNING (N762MT)

All 265: https://openairdocs.org/jasc/6340/reports.md

## Other codes in chapter 63

- [JASC 6300](https://openairdocs.org/jasc/6300): Main Rotor Drive System (637 reports)
- [JASC 6310](https://openairdocs.org/jasc/6310): Engine/Transmission Coupling (772 reports)
- [JASC 6320](https://openairdocs.org/jasc/6320): Main Rotor Gearbox (1,930 reports)
- [JASC 6321](https://openairdocs.org/jasc/6321): Main Rotor Brake (275 reports)
- [JASC 6322](https://openairdocs.org/jasc/6322): Rotorcraft Cooling Fan System (213 reports)
- [JASC 6330](https://openairdocs.org/jasc/6330): Main Rotor Transmission Mount (603 reports)
- [JASC 6397](https://openairdocs.org/jasc/6397): Main Rotor Drive System Wiring (17 reports)

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