Document ID: chunk:federal_register_of_legislation:F2006B04638:body:0:p2
Version: federal_register_of_legislation:F2006B04638
Segment Type: other
Provision Reference: 
Character Range: 2964–5209

Revision A.

c.         Effective 30 September 2004; as detailed in Table 2 of BHTC ASB 407-04- 63 Revision A.

d.        Effective 30 September 2004; as detailed in Table 2 of BHTC ASB 407-04- 63 Revision A.

Requirement 3: Tail Rotor Segmented Drive Shaft Bearings:

                  1. Unless previously accomplished, within 200 flight hours from the effective date of this Directive or no later than 30 September 2004, whichever comes first and as detailed in Table 1 of BHTC ASB 407-04-63 Revision A.

b.        Effective 30 September 2004; as detailed in Table 2 of BHTC ASB 407-04- 63 Revision A.

c.         Effective 30 September 2004; as detailed in Table 2 of BHTC ASB 407-04- 63 Revision A.

d.        Effective 30 September 2004; as detailed in Table 2 of BHTC ASB 407-04- 63 Revision A.

            This Amendment becomes effective on 15 September 2004.

            Background: This Directive was issued in response to reports of the tail rotor drive and oil cooler blower bearing failures in Bell 407 helicopters. In certain operating conditions, hot exhaust gases can be ingested into the aft fairing area resulting in high temperatures in the tail rotor drive bearing zones. In addition to this, a differential pressure across these bearings was extruding the grease from the bearings. This can lead to failure of the tail rotor drive bearings and possible loss of control of the helicopter.

            This amendment has been issued to mandate the installation of oil cooler airflow modifications and to reflect the release of further amendments to the requirement documents. Previous amendments, in part, introduced an additional replacement bearing P/N 407-340-339-107. This amendment requires the replacement of P/N 407-430-339-101 and -103 bearings at all tail rotor hanger bearing locations, including the oil cooler blower locations, and the installation of a revised lubrication decal.

            The original issue of this Airworthiness Directive became effective on 3 October 2002 and superseded AD/BELL 407/21 Amdt 2.

 James Coyne
 Delegate of the Civil Aviation Safety Authority 10 September 2004

 The above AD is notified in the Commonwealth of Australia Gazette on 15 September 2004.