Document ID: chunk:federal_register_of_legislation:F2006L01029:body:0:p3
Version: federal_register_of_legislation:F2006L01029
Segment Type: other
Provision Reference: 
Character Range: 5548–7376

P/N 46500-7 up-lock assemblies.

                2. Initially, before the up-lock assembly accumulates 2500 hours air time or 3000 flight cycles, whichever occurs first, thereafter at intervals not exceeding 2500 hours air time or 3000 flight cycles, whichever occurs first.

                3. Within 30 calendar days from the effective date of this AD, unless previously accomplished.

                4. Prior to the up-lock assembly accumulating 2500 hours air time or 3000 flight cycles, whichever occurs first; and thereafter, at intervals not exceeding 400 hours air time or 480 flight cycles, whichever occurs first.
             This Airworthiness Directive becomes effective on 11 May 2006.
Background:  A DHC-8 Series 400 aircraft experienced difficulties in extending the right main landing gear.  The cause is attributed to failure of the gear up-lock unit to disengage. Investigation of the up-lock hook revealed a groove in the lower jaw due to premature wear. In addition, it was found that the low friction liner was omitted on a batch lot of up lock rollers, including the incident aircraft.  These factors may result in the inability to extend the main landing gear.

             A modified up-lock assembly, P/N 46500-5, has been introduced as a substitute for P/N 46500-3 which is no longer in production.  However, the design of the modified up-lock assembly is very similar to P/N 46500-3 and could be subjected to the same failure.  A modified up-lock assembly, P/N 46500-7, has been introduced as a substitute for P/N 46500-3 or 46500-5 and is terminating action to this directive.  The applicability section of this directive is also revised to reflect production aircraft that have incorporated the terminating action.

James Coyne
Delegate of the Civil Aviation Safety Authority

17 March 2006