TECHNICAL BULLETIN June 2011 Revision A, 1 August 2011 SUBJECT: MAIN ROTOR BLADE P/N /-149 / -151 /-153, INTRODUCTION OF

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1 TECHNICAL BULLETIN June 2011 Revision A, 1 August 2011 MODEL AFFECTED: 206A/B (TH-67) SUBJECT: MAIN ROTOR BLADE P/N /-149 / -151 /-153, INTRODUCTION OF HELICOPTERS AFFECTED: COMPLIANCE: Serial number 4 and subsequent equipped with blades P/N /-133 /-137 /-139 and -141 At customer s option DESCRIPTION: Bell Helicopter has investigated two recent events of main rotor blade tell-tale weight separation. This one inch square by one half inch thick lead weight is bonded inside the blade spar at blade station The investigations revealed that in both cases the telltale weight has sheared off leaving lead material still bonded to the blade spar. After separation, the tell-tale weight migrated inside the spar towards the tip cap causing damage to the tip cap retention hardware holes rendering the blades unserviceable. At time of conception of the Bell 206, there was enough uncertainty in the adhesive bonding process that the tell tale weight was included in the design to provide an early warning of pending mid-span weight bond joint separation. Modern adhesives and bonding process used in the assembly of main rotor blades are now considered to be controlled enough that an early warning indicator is no longer needed. This Bulletin introduces a new main rotor blade design (Table 1) without the tell-tale weight and also provides the instructions to upgrade the existing main rotor blades by removing the subject weight. Applicability of this Bulletin to any spare part shall be determined prior to its installation on an affected aircraft. Revision A of this bulletin is to inform operators that in addition to Bell Helicopter Textron and Associated Companies, all Bell Helicopter Textron Approved Blade Repair Facilities can also accomplish the intent of the bulletin. Page 1 of 5

2 APPROVAL: The engineering design aspects of this Bulletin are Transport Canada Civil Aviation (TCCA) approved. CONTACT INFO: For any questions regarding this Bulletin, please contact: Bell Helicopter Product Support Engineering - Light Helicopters Tel: / / pselight@bellhelicopter.textron.com MANPOWER: Approximately 3 man-hours are required to complete this Bulletin. This estimate is based on hands-on time, and may vary with personnel and facilities available. WARRANTY: There is no warranty credit applicable for parts or labor associated with this Bulletin. MATERIAL: Required Material: Consumable Material: SPECIAL TOOLS: WEIGHT AND BALANCE: Not affected. ELECTRICAL LOAD DATA: Not affected. REFERENCES: BHT-206A/B-SERIES-IPB Illustrated Parts Breakdown, Chapter 62. BHT-206A/B-SERIES-MM Maintenance Manual, Chapter 18 and 62. Page 2 of 5

3 PUBLICATIONS AFFECTED: BHT-206A/B-SERIES-IPB Illustrated Parts Breakdown, Chapter 62. Information Letter Rev A ACCOMPLISHMENT INSTRUCTIONS: -NOTE- Owners / Operators have the opportunity to select from two options in order to accomplish this modification. Bell Helicopter is estimating that 10 percent of the affected blades have excess of adhesive surrounding the subject weight that will prevent it to be removed by the technician. Preliminary evaluation and coordination with the Blade Facility is required prior to initiate the accomplishment of this Technical Bulletin. OPTION 1: On site assistance by a Bell Helicopter Textron s technician. OPTION 2: Returning the affected blade to Bell Helicopter Textron Inc. In either case, contact the Bell Helicopter Textron facility or associated companies listed below for scheduling. Bell Helicopter Textron Inc 580 St Etienne Road Broussard, Louisiana Tel: (337) Fax: (337) sales@rotor-blades.com Associated Companies: RBI Hawker Limited LIU FZS1 BD06/07, JAFZ (South) P. O. Box Dubai, UAE Tel: Fax: Rotor Blades Limited Unit 5B, Roman Way Crusader Park, Warminster BA12 8BT, Wiltshire Tel: United Kingdom Page 3 of 5

4 As an alternate you may contact your closest Bell Helicopter Approved Blade Repair Facility, refer to the annual Customer Support and Services Directory or contact Bell Helicopter Product Support Engineering - Light Helicopters. ACCOMPLISHMENT INSTRUCTIONS (Cont): 1. Remove main rotor hub and blade assembly from helicopter, (BHT-206A/B-SERIES- MM, Chapter 62). 2. Remove blade from main rotor hub and blade assembly, (BHT-206A/B-SERIES-MM, Chapter 62). -NOTE- As an alternative to shipping the blade to one of the Repair Facilities listed above, the subject modification may be performed on site by a Repair Facility Representative. Contact Repair Facility to arrange on-site modification. 3. Prepare main rotor blade for shipment: Refer to Information Letter GEN 04-98, Rev C for shipping instructions. 4. Send main rotor blade, with historical card, to shipping address as instructed on the Return Material Authorization (RMA). The main rotor blade will be modified and reidentified in accordance with Table Once received, install modified main rotor blade onto hub assembly, (BHT-206A/B- SERIES-MM, Chapter 62). 6. Install main rotor hub and blade assembly to helicopter, (BHT-206A/B-SERIES-MM, Chapter 62). 7. Verify the main rotor assembly vibration level and adjust as necessary, (BHT- 206A/B-SERIES-MM, Chapter 18). 8. Make an entry in helicopter historical service records indicating compliance with this Technical Bulletin. Page 4 of 5

5 Table 1. New Main Rotor Blades Without a Tell Tale Weight Part Number Description Notes Standard White High visibility (black and white) High visibility (orange and white) All black 1. Refer to Information Letter Rev A, Main Rotor Blades useable on 206A/B models. Table 2. Re-identified modified Main Rotor Blade Part Number Description Notes FM FM Standard White Standard White FM High visibility (black and white) FM High visibility (orange and white) FM All black 1 1. Refer to Information Letter Rev A, Main Rotor Blades useable on 206A/B models. Page 5 of 5