AD Number: AD/PR/35 Amdt 3
Subject: Propeller Hub Wall Cracking 12/2005 TX
Applicability: R334/4-82-F/13, R333/4-82-F/12, R324/4-82-F/9, and R321/4-82-F/8 propellers with hub part number (P/N) 660709201.

Note 1: These propeller hubs may be installed on, but not limited to, CASA 212, Metro III, Merlin IVC, Metro IIIC, Jetstream Series 3100 and 3200 aircraft.

Requirement: For CASA 212 aircraft:
1. Inspect for cracks in the rear wall of the propeller hub assemblies in accordance with Dowty Service Bulletin (SB) 61-1119 Revision 4, and report all findings of cracking to Dowty Propellers.
2. For hub assemblies P/N 660709201, other than zero time assemblies, assembled in propellers held in storage, inspect in accordance with paragraph 3 (accomplishment instructions) of Dowty SB 61-1119 rev 4 or any later EASA approved revision.
4. For hub assemblies P/N 660709201, other than zero time assemblies, held in storage, inspect in accordance with paragraph 3 (accomplishment instructions) of Dowty SB 61-1119 rev 4 or any later EASA approved revision.
6. Remove from service any propeller or hub that does not satisfy the acceptance criteria for further operation.
For Jetstream 3100 and 3200, Merlin IVC/Metro III, and aircraft, Merlin IIIC
aircraft:
7. Inspect for cracks in the rear wall of the propeller hub assemblies in accordance with Dowty SB 61-1124 Revision 1, SB 61- 1125 Revision 1 or SB 61-1126 Revision 1 as is applicable, and report all findings of cracking to Dowty Propellers.
8. Remove from service any propeller or hub that does not satisfy the acceptance criteria for further operation.

Note 2: CAA UK AD's G-2005-0027, 009-05-2002, 010-05-2002, and 011-05-2002.
and EASA Approval No 2005-6230 refers.

Note 3: CAA UK AD G-2005-0027 supersedes 003-11-2001. This Directive applies
to the R334/4-82-F13 propeller installed on CASA 212 aircraft.
Compliance: 1. Within 10 flight hours or 20 calender days from the effective date of this Directive; or Within 300 flight hours or 300 flight cycles from the previous inspection whichever occurs earlier, where the inspection has been previously accomplished within the last 300 flight hours and 300 flight cycles prior to the effective date of this Directive. Thereafter repeat the inspection at intervals not to exceed 300 flight hours or 300 flight cycles whichever occurs earlier.
2. Prior to installation on an aircraft.
3. Prior to installation on an aircraft.
4. Before further flight.
5. Remains unchanged as detailed in the amendment 2 of this Directive as: For propellers with 950 hours time in service since the effective date of the applicable referenced service bulletin; prior to reaching 1000 hours propeller time in service. Thereafter, at intervals not to exceed 1000 hours propeller time in service. For propellers in excess of 950 hours time in service since the effective date of the applicable reference service bulletin, within 50 hours from the hours accumulated at 26 March 2003 (the effective date of amendment 2 of this directive). Thereafter, at intervals not to exceed 1000 hours propeller time in service.
6. Before further flight.

This Amendment becomes effective on 26 September 2005.

Background: There has been a report of cracks originating from around the threaded insert holes of the rear half hub. In one instance this resulted in a complete separation from the engine flange. This Directive requires the inspection of the rear wall of the propeller for cracks.

Amendment 3 decreases the inspection interval for the propeller installed on the CASA 212 aeroplane. This change has been prompted by a hub separation on a CASA 212 aeroplane. Amendment 2 included additional propeller models and a change to compliance requirements. Amendment 1 of this Directive included the addition of extra propeller models using the same hub part number. The original issue of this Airworthiness Directive became effective on 28 November 2002.

Amendment 1 of this Airworthiness Directive became effective 20 March 2003.

Amendment 2 of this Airworthiness Directive became effective 26 March 2003.

FMI: www.casa.gov.au