Bell Helicopter Textron Canada (BHTC) 206 and Agusta Bell 206 Series Helicopters

AD/BELL 206/153 Amdt 1 Tail Rotor Blade Trailing Edge Skin Cracks 7/2004 TX

Applicability: Model 206A and 206B helicopters, equipped with tail rotor blade, part numbers 206-016-201-131 or 206-016-201-133, and Model 206L series helicopters equipped with tail rotor blade, part number 206-016-201-131; with serial numbers identified in Model 206A and 206B Alert Service Bulletin (ASB) 206-04-100 Revision A, or Model 206L Series ASB 206L-04-127 Revision A, as applicable. Agusta-Bell Model AB206A/B helicopters, equipped with tail rotor blades, part numbers 206-016-201-131 or 206-016-201-133; with serial numbers identified in Model AB206A/B Alert Bolletino Technico (ABT) 206-237.

Requirement: Part A: Identification of Affected Tail Rotor Blades
1. Verify if the rotorcraft is equipped with tail rotor blades identified in the "Component Affected" or "Helicopters Affected" section of the applicable ASB or ABT, listed in the Applicability part of this Directive. If the rotorcraft is equipped with an affected blade, enter the part number and serial number into the journey logbook. If not equipped with an affected blade, indicate that the rotorcraft is not equipped with blades affected by this Directive.
2. If any spare blade is listed in the “Component Affected” or “Helicopters Affected” section of the applicable ASB or ABT, the blade is to be identified with a “Blue Diamond” decal as per Part II, of the applicable ASB or ABT.
Part B: Initial and Recurring Check for Tail Rotor Blade Cracks
Check the affected tail rotor blade for cracking in accordance with the instructions in Part I of the applicable ASB or ABT listed in the Applicability part of this Directive. If a crack is found, before further flight, replace the affected blade.
Part C: Schedule 100 hour / Annual Inspection For Tail Rotor Blade Cracks
Perform a detail visual inspection of the tail rotor blade using a magnifying glass, in accordance with Part II of the applicable ASB or ABT listed in the Applicability part of this Directive. If a crack is found, before further flight, replace the affected blade.

Note: Transport Canada AD CF-2004-05 refers.

Compliance: Part A.1. Before further flight after 6 May 2004, unless already accomplished.
Part A.2. Before the installation of a spare blade.
Part B. Before further flight after 6 May 2004, unless the initial inspection is already accomplished. Repeat thereafter at intervals specified in applicable ASB or ATB.
Part C. At the next, and recurring, 100 hour scheduled inspection or annual inspection after 6 May 2004, whichever occurs first. This Directive shall be entered on the Maintenance Release as maintenance required. The Requirement Part A.1.action, and Requirement Part B. "Recurring 3-Flight Hour Check," identified in the applicable ASB or ABT listed in Applicability part of this Directive, may be performed and certified by the Pilot in Command who has been trained to do the Requirement Part A.1. action and Requirement Part B. inspection by an appropriately qualified person. In this case, a copy of the applicable ASB or ABT and this Directive is to be carried in the aircraft. This Amendment becomes effective on 6 May 2004.

Background: Transport Canada received reports of three occurrences of skin cracks originating near the tail rotor blade trailing edge balance weight. Two of the occurrences resulted in loss of the weight and a strip of material along the trailing edge, leading to an imbalance, which caused fracture of three of the four tail rotor gearbox attachments. One of these occurrences resulted in the gearbox shifting that caused failure of the drive shaft, which resulted in loss of yaw control.

FMI: http://casa.gov.au/avreg/aircraft/ad/ADfiles/Rotor/bell206/bell206-153.pdf