# JASC 6321: Main Rotor Brake

- Type: JASC system/component code (FAA)
- ATA chapter: 63 Main Rotor Drive
- Title in the code table: MAIN ROTOR BRAKE
- Service difficulty reports: 275
- FAA code table: https://www.faa.gov/sites/faa.gov/files/JASC_Code.pdf#page=57
- Page: https://openairdocs.org/jasc/6321

## What it covers

The system which reduces rundown time or stops rotor rotation during engine power off conditions. Typical parts are brake, caliper, lining, seal, check valve, etc.

## Service difficulty reports (275, newest 50)

- [SDR 4DSR20251023002](https://openairdocs.org/sdr/4DSR20251023002), Oct 23, 2025: Snias AS350B3. BRAKE. OUT OF TOLERANCE. DURING A SCHEDULED 12YR INSPECTION, THE MGB ROTOR BRAKE WAS FOUND TO BE OUT OF TOLERANCE/LOOSE AND REQUIRED REPLACEMENT. (N613TC)
- [SDR 454A0110100922](https://openairdocs.org/sdr/454A0110100922), Feb 11, 2025: Bolkms BK117C2. BRAKE CALIPER. CRACKED. FOUND CRACKING ON EACH BRAKE CALIPER PISTON. WEAR PLATES DO NO COMPLETELY SPAN PISTON. FOUND ABNORMAL WEAR ON HOUSING FR (N529MD)
- [SDR 2023FA0000029](https://openairdocs.org/sdr/2023FA0000029), Jan 16, 2023: Bell 407. MOUNT BRACKET. CRACKED. THE RIGHT AFT MAIN ROTOR BRAKE TURN BUCKLE MOUNT WAS FOUND CRACKED AT THE AFT SIDE OF THE BOLT HOLE BORE. (N412UH)
- [SDR 2022FA0000646](https://openairdocs.org/sdr/2022FA0000646), Oct 26, 2022: Agusta AW139. AXLE. CORRODED. CUSTOMER REPORTED ROTOR BRAKE INOPERATIVE ON ARRIVAL AT REPAIR STATION FOR SCHEDULED INSPECTION. TROUBLESHOOTING REVEALE (N9NJ)
- [SDR QR9R20211029004](https://openairdocs.org/sdr/QR9R20211029004), Oct 29, 2021: Bolkms BK117C2. SWITCH. FAULTY. ACFT RESTRICTED FROM ROTOR BRAKE USE DUE TO ROTOR BRAKE CAUTION DOES NOT ILLUMINATE ON CAD WHEN BRAKE IS ENGAGED. REPLAC
- [SDR AC2A2021102913901](https://openairdocs.org/sdr/AC2A2021102913901), Oct 28, 2021: Agusta AW139. ACTUATOR. STUCK. ROTOR BRAKE INOP, FOUND ROTOR BRAKE ACTUATOR WILL NOT ACTUATE (STUCK) (N639MC)
- [SDR QR9R20210902003](https://openairdocs.org/sdr/QR9R20210902003), Sep 2, 2021: Bolkms BK117C2. PAD. FAILED. ROTOR BRAKE FAILED TO STOP ROTOR SYSTEM IN ALLOWED TIME. AIRCRAFT RESTRICTED FROM ROTOR BRAKE USE.
- [SDR QR9R20210901004](https://openairdocs.org/sdr/QR9R20210901004), Sep 1, 2021: Bolkms BK117C2. PAD. UNRELIABLE. ROTOR BRAKE FOUND TO BE INEFFECTIVE (CAUTION ADVISORY ON CAD INDICATED THAT IT WAS ENGAGING). ROTOR BRAKE CHECK PERFORME
- [SDR HDNA20210822005](https://openairdocs.org/sdr/HDNA20210822005), Aug 22, 2021: Bell 407. CALIPER. BROKEN. THE LEFT ROTOR BRAKE CALIPER LOWER MOUNTING EAR BROKE IN ADDITION TO THE TURN BUCKLE ATTACHMENT AT THE CALIPER WAS COMPR (N414UH)
- [SDR AC2A2021072213901](https://openairdocs.org/sdr/AC2A2021072213901), Jul 21, 2021: Agusta AW139. ACTUATOR. STUCK. ROTOR BRAKE CAS FAIL MESSAGE ILLUMINATED ON SHUTDOWN, ACTUATOR STUCK IN UP POSITION. (N639DS)
- [SDR AC2A2020111413901](https://openairdocs.org/sdr/AC2A2020111413901), Nov 13, 2020: Agusta AW139. CONTROL MODULE. DEFECTIVE. ROTOR BRAKE WILL NOT BUILD PRESSURE. ROTOR BRAKE CONTROL MODULE WAS FOUND TO BE DEFECTIVE. MODULE WAS PREVIOUSLY REPAIRE (N639DS)
- [SDR QMLA2018101218111](https://openairdocs.org/sdr/QMLA2018101218111), Oct 9, 2018: Snias AS350B3. BRAKE ASSY. DAMAGED. UPON DISASSEMBLY OF ROTOR BRAKE. BRAKE ASSEMBLY DRIVE FLANGE AND HYDRAULIC DRIVE COUPLING HAD EXTREME HEAT DAMAGE AND ME (N397LG)
- [SDR KBTR201901280002](https://openairdocs.org/sdr/KBTR201901280002), Jul 26, 2018: Bell 407. BRACKET. CRACKED. DURING 3600 HOUR OVERHAUL FOUND BRAKE CALIPER MOUNTING BRACKET CRACKED, STARING AT LOWER CENTER CORNER EXTENDING AROUND  (N407LF)
- [SDR KBTR201901280001](https://openairdocs.org/sdr/KBTR201901280001), Jul 26, 2018: Bell 407. BRACKET. CRACKED. DURING 3600 HOUR OVERHAUL FOUND BRAKE CALIPER MOUNTING BRACKET CRACKED, STARING AT LOWER CENTER CORNER EXTENDING AROUND  (N407LF)
- [SDR KBTR201901280003](https://openairdocs.org/sdr/KBTR201901280003), Jun 5, 2018: Bell 407. BRACKET. CRACKED. DURING 3600 HOUR OVERHAUL FOUND BRAKE CALIPER MOUNTING BRACKET CRACKED, STARING AT LOWER CENTER CORNER EXTENDING AROUND  (N808MT)
- [SDR QMLA2018040418040](https://openairdocs.org/sdr/QMLA2018040418040), Apr 4, 2018: Urocop EC135P2. PAD. WORN. ABOUT 18 MINUTES INTO FLIGHT, ROTOR BRAKE CAUTION LIGHT ILLUMINATED WITH AN ACCOMPANYING ODOR. LANDED AIRCRAFT AND SHUTD (N530LN)
- [SDR KBTR2018102355371](https://openairdocs.org/sdr/KBTR2018102355371), Mar 29, 2018: Bell 407. BRACKET. BROKEN. AFTER PERFORMING A 3600 HOUR ROTOR BRAKE CALIPER OVERHAUL ON CALIPER P/N:427-340-352-113, S/N: 656 THE CALIPER WAS SENT  (N766MT)
- [SDR KBTR201810235537](https://openairdocs.org/sdr/KBTR201810235537), Mar 29, 2018: Bell 407. BRACKET. BROKEN. AFTER PERFORMING A 3600 HOUR ROTOR BRAKE CALIPER OVERHAUL ON CALIPER P/N:427-340-352-113, S/N: 644 THE CALIPER WAS SENT  (N766MT)
- [SDR 7AJA2015031500001](https://openairdocs.org/sdr/7AJA2015031500001), Mar 15, 2015: Beech C90A. BRAKE. BROKEN. AIRCRAFT TOOK OFF FROM AIRPORT WITH NO INDICATION OF ANY DIFFICULTIES IN FLIGHT AND UNEVENTFUL LANDING. UPON PARKING ACF (N587PB)
- [SDR QMLA2014041614038](https://openairdocs.org/sdr/QMLA2014041614038), Apr 16, 2014: Urocop AS365N3. PLANETARY GEAR. UNSERVICEABLE. DURING A6031RT, MAST INSPECTION, UPON SEPARATION OF THE MAST & MGB, SEVERAL METALLIC FERROUS FLAKES WAS LOCATED ON & ARO (N546AM)
- [SDR CA140127011](https://openairdocs.org/sdr/CA140127011), Jan 10, 2014: Agusta AW119MKII. FLANGE. DAMAGED. (CAN) AFTER SHUTDOWN, DURING ROTOR BRAKE APPLICATION, CREW REPORTED GRINDING NOISE COMING FROM TRANSMISSION AREA, AND EX
- [SDR CA130812008](https://openairdocs.org/sdr/CA130812008), Aug 12, 2013: Bell 407. BOLT. SHEARED. (CAN) WHILE PERFORMING INSPECTION, ACCORDING WITH BHT-407-MM1, CH 5-00-00, PARA 5-20 & DOC B0223-OM4, PARA 1.2. ROTOR BR
- [SDR AC2A201304150001](https://openairdocs.org/sdr/AC2A201304150001), Apr 8, 2013: Bell 427. BRAKE. FALSE INDICATION. ROTOR BRAKE CAS MESSAGE APPEARED SHORTLY AFTER TAKEOFF. FOLLOWED EMERGENCY PROCEDURES AND RETURNED TO DEPARTURE. TESTED  (N427HV)
- [SDR ALGA201202141208](https://openairdocs.org/sdr/ALGA201202141208), Feb 14, 2012: Bell 407. HOUSING. CORRODED. ROTOR BRAKE HOUSING CORRODED BEYOND LIMITS. (N647AL)
- [SDR ALGA201202141207](https://openairdocs.org/sdr/ALGA201202141207), Feb 14, 2012: Bell 407. HOUSING. CORRODED. ROTOR BRAKE HOUSING CORRODED BEYOND LIMITS. (N647AL)
- [SDR ALGA201202141206](https://openairdocs.org/sdr/ALGA201202141206), Feb 14, 2012: Bell 407. HOUSING. CORRODED. ROTOR BRAKE HOUSING CORRODED BEYOND LIMITS. (N647AL)
- [SDR ALGA201202141205](https://openairdocs.org/sdr/ALGA201202141205), Feb 14, 2012: Bell 407. HOUSING. CORRODED. MAIN ROTOR BRAKE HOUSING CORRODED BEYOND LIMITS. (N647AL)
- [SDR GAKA2012F00040](https://openairdocs.org/sdr/GAKA2012F00040), Jan 20, 2012: Bell 429. CALIPER. OUT OF ADJUST. MADE AN UNSCHEDULED LANDING AFTER DEPARTURE, PILOT NOTICED A CAS MESSAGE "ROTOR BRAKE". THERE WERE NO ADVERSE INDICATION (N428SL)
- [SDR 2011FA0000652](https://openairdocs.org/sdr/2011FA0000652), Sep 21, 2011: PAD. CRACKED. ROTOR BRAKE PAD EDGES CRACKED OR CHIPPED FROM NEW. WHEN INSTALLING ON DISK PAD COMES APART AT EDGE. VIBRATION OF RIVET G
- [SDR PG92011F00010](https://openairdocs.org/sdr/PG92011F00010), Sep 21, 2011: Urocop EC130B4. BRAKE. CRACKED. ROTOR BRAKE PAD CRACKED FROM NEW. EDGES FALLING APART WHILE INSTALLED ON ACFT. R & R WITH ONLY 94.7 HRS PART TT. PROBABL (N893PA)
- [SDR CA101110007](https://openairdocs.org/sdr/CA101110007), Nov 8, 2010: Aerosp AS355N. NUT. LOOSE. (CAN) PILOT MADE PRECAUTIONARY LANDING SHORTLY AFTER TAKEOFF FROM BASE IN AIRPORT INFIELD DUE TO A SUDDEN ABNORMAL VIBRA
- [SDR QMLA2010102510071](https://openairdocs.org/sdr/QMLA2010102510071), Oct 25, 2010: Bell 222UT. DISC. UNSERVICEABLE. DURING LIFT OFF, ROTORBRAKE WARNING LIGHTS ILLUMINATED, FOLLOWED BY TRANSMISSION CHIP LIGHTS AND TRANSMISSION OIL PRESSU (N220LN)
- [SDR JBZA2010F00100](https://openairdocs.org/sdr/JBZA2010F00100), Apr 20, 2010: Urocop EC135P2. DISC. CRACKED. PILOT REPORTED "ROTOR BRAKE CHATTER DURING USE". MECHANIC FOUND ROTOR BRAKE DISK HAD (2) CRACKS, ONE 1.1250" LONG, ONE 1 (N38RX)
- [SDR CA081204004](https://openairdocs.org/sdr/CA081204004), Dec 3, 2008: Bolkms BO105S. HANDLE. DAMAGED. (CAN) DURING CRUISE, THE ROTOR BRAKE HANDLE DOWN WARNING LIGHT TURN ON INTERMITTENTLY. THE WARNING LIGHT SWITCH IS ADJUS
- [SDR QML2008F00016](https://openairdocs.org/sdr/QML2008F00016), Oct 16, 2008: Bell 222U. BRAKE. OUT OF ADJUST. ON REPOSITION FLIGHT, APPROX 6 MILES FROM LANDING, ROTOR BREAK AND MASTER CAUTION ILLUMINATED. THIS IS A LAND AS SOON AS (N402MA)
- [SDR CA071130012](https://openairdocs.org/sdr/CA071130012), Nov 30, 2007: Urocop EC120B. BRAKE. DAMAGED. (CAN) MECHANICAL DAMAGE TO ROTOR BRAKE GRID ASSEMBLY, DUE TO IMPROPER OPERATION. TRIGGER WAS NOT DEPRESSED PRIOR TO ENGA
- [SDR U0GA113886](https://openairdocs.org/sdr/U0GA113886), Jan 23, 2007: Agusta A119. DAMPER. SHEARED. PILOT FELT VIBRATION WHEN ROTOR BRAKE WAS ENGAGED AFTER LANDING AND SHUTDOWN. POSTFLIGHT INSPECTION REVEALED THE DAMPER  (N822MM)
- [SDR AC2A110523](https://openairdocs.org/sdr/AC2A110523), Jul 22, 2006: Bell 206L3. CALIPER. LEAKING. FOUND CALIPER LEAKING / REPLACED CALIPER (N7159J)
- [SDR KBM2006F00222](https://openairdocs.org/sdr/KBM2006F00222), Jun 21, 2006: Snias AS350B2. BRAKE DISC. WORN. MAIN ROTOR BRAKE DISK, WORN BEYOND LIMITS, REMOVED AND REPLACED. (K) (N230SH)
- [SDR KBM2006F00157](https://openairdocs.org/sdr/KBM2006F00157), Apr 15, 2006: Snias AS350B2. BRAKE CABLE. SEIZED. ROTOR BRAKE CABLE, UNIT SEIZED, REMOVED AND REPLACED. (K) (N345SH)
- [SDR CA060310006](https://openairdocs.org/sdr/CA060310006), Mar 10, 2006: Skrsky S61A. FLANGE. FAILED. ATTEMPTED TO REPLACE A PART DAMAGED BEYOND REPAIR. A PART WAS LOCATED AND ACQUIRED TO REPLACE DAMAGED UNIT. PART WAS DEL
- [SDR AC2A108368](https://openairdocs.org/sdr/AC2A108368), Feb 12, 2006: Bell 427. PUCK. CHIPPED. DURING AN INSPECTION THEY FOUND THE ROTOR BRAKE PUCK CHIPPED/ THE CALIPER WAS REPLACED. (N427GT)
- [SDR CA060216002](https://openairdocs.org/sdr/CA060216002), Jan 24, 2006: Bolkms BO105C. CALIPER. BINDING. (CAN) PISTON DOES NOT RETRACT INTO CALIPER HOUSING AFTER BRAKING CAUSING ROTOR BRAKE PAD TO REMAIN IN CONTACT WITH BRAKE
- [SDR CA060130001](https://openairdocs.org/sdr/CA060130001), Jan 16, 2006: Robsin R44RAVENII. SPRING. BROKEN. DURING THE FIRST 100 HR INSPECTION CARRIED OUT ON THE AIRCRAFT, IT WAS NOTICED THAT THE ABOVE SPRING WAS BROKEN. IT APPE
- [SDR ALG2005F00079](https://openairdocs.org/sdr/ALG2005F00079), Oct 15, 2005: Bell 206L4. CALIPER. LOOSE. DURING DAILY INSPECTION THE MECHANIC FOUND ROTOR BRAKE BOLTS LOOSE AND A PAD WAS MISSING, REMOVED AND REPLACED BOTH CALI (N265AL)
- [SDR ALGA106433](https://openairdocs.org/sdr/ALGA106433), Sep 22, 2005: Bell 412. BEARING. FAILED. TRANSMISSION ASSY MAKING METAL, DISSEMBLED FOUND ROTOR BRAKE QUILL DUPLEX BEARING BEARING BREAKING DOWN. / REMOVEN AND R
- [SDR ALG2005F00066](https://openairdocs.org/sdr/ALG2005F00066), Aug 21, 2005: Bell 206L4. BOLT. DEFECTIVE. DURING MAINTENANCE SERVICE CHECK, THE LT ROTOR BRAKE CALIPER WAS FOUND TO BE DEFECTIVE. THE FOLLOWING ITEMS WERE REMOVED (N265AL)
- [SDR YTRR104408](https://openairdocs.org/sdr/YTRR104408), Jun 30, 2005: Bell 407. CALIPER. CRACKED. ON ROUTINE INSPECTION FOUND CALIPER HOUSING CRACKED AT MOUNTING FLANGE ON ROTOR BRAKE. (N595RL)
- [SDR ERAA096629](https://openairdocs.org/sdr/ERAA096629), May 25, 2004: Bolkms BO105S. OIL COOLER. LEAKING. LEAK AT TOP OF NR 2 COOLING AREA. SENT TO DRAKE AIR FOR REPAIR. CLEANED, FLUSHED, REPAIRED/OVERHAULED, TESTED AND INSPEC (N129EH)
- [SDR CA040420001](https://openairdocs.org/sdr/CA040420001), Apr 15, 2004: Bolkms BO105S. STRUCTURE. DAMAGED. (CAN) THE COLLECTIVE FRICTION ASSEMBLY WAS REPORTED FEELING LOOSE. LOOSENESS WAS TRACED TO THE BRAKE BOX, WHICH WAS MOUN

All 275: https://openairdocs.org/jasc/6321/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 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 6340](https://openairdocs.org/jasc/6340): Rotor Drive Indicating System (265 reports)
- [JASC 6397](https://openairdocs.org/jasc/6397): Main Rotor Drive System Wiring (17 reports)

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