Division Fokker F50 (F27 Mk 50) Series Aeroplanes - AD/F50/88 Amdt 1 - Power Plant - Feathering Pump - Fokker F50 (F27 Mk 50) Series Aeroplanes

Fokker F50 (F27 Mk 50) Series Aeroplanes

AD/F50/88 Amdt 1	Power Plant - Feathering pump	13/2007 TX

Applicability:	Model F.27 Mk.50, 0502 and 0604 aeroplanes all serial numbers, unless the engines that are installed have previously been modified in accordance with Fokker Service Bulletin (SB) SBF50-61-024 Revision 1 dated 4 July 2007.
Requirement:	1. Visually inspect both engines externally in two specific areas for any indication of oil leakage in accordance with the instructions detailed in Fokker Services All Operator Message AOF50.037 (ref TS04.57535) dated 2 November 2004.The pilot may carry out Requirement 1 of this AD provided the pilot has completed an approved training program.Note 1: Fokker Services All Operator Message AOF50.037 includes graphics to show the specific areas that need to be inspected.2. If any indication of oil leakage is found during the inspection as detailed in Requirement 1 of this AD, perform a detailed inspection for oil leakage at the feathering pump of the affected engine in accordance with Part 1 of the Accomplishment Instructions of Fokker Services SB F50-61-023 Revision 1 dated 4 July 2007 or later NAA approved revision.3. Perform a detailed inspection for oil leakage at the feathering pump on both engines in accordance with Part 1 of the Accomplishment Instructions of Fokker Services SB F50-61-023 Revision 1 dated 4 July 2007 or later NAA approved revision.4. If during the inspection as detailed in Requirement 2 or 3 of this AD, oil leakage is found at the feathering pump mounting pad of an engine, replace bobbin part number (P/N) 638005614 with bobbin P/N 638005637 and install a gasket on the feathering pump of that engine in accordance with the Accomplishment Instructions of Fokker Services SB F50-61-025 dated 4 July 2007 or later NAA approved revision.5. Replace bobbin P/N 638005614 with bobbin P/N 638005637 and install a gasket on the feathering pump of that engine in accordance with the Accomplishment Instructions of Fokker Services SB F50-61-025 or later NAA approved revision.

Applicability:

Model F.27 Mk.50, 0502 and 0604 aeroplanes all serial numbers, unless the engines that are installed have previously been modified in accordance with Fokker Service Bulletin (SB) SBF50-61-024 Revision 1 dated 4 July 2007.

Requirement:

1. Visually inspect both engines externally in two specific areas for any indication of oil leakage in accordance with the instructions detailed in Fokker Services All Operator Message AOF50.037 (ref TS04.57535) dated 2 November 2004.The pilot may carry out Requirement 1 of this AD provided the pilot has completed an approved training program.Note 1: Fokker Services All Operator Message AOF50.037 includes graphics to show the specific areas that need to be inspected.2. If any indication of oil leakage is found during the inspection as detailed in Requirement 1 of this AD, perform a detailed inspection for oil leakage at the feathering pump of the affected engine in accordance with Part 1 of the Accomplishment Instructions of Fokker Services SB F50-61-023 Revision 1 dated 4 July 2007 or later NAA approved revision.3. Perform a detailed inspection for oil leakage at the feathering pump on both engines in accordance with Part 1 of the Accomplishment Instructions of Fokker Services SB F50-61-023 Revision 1 dated 4 July 2007 or later NAA approved revision.4. If during the inspection as detailed in Requirement 2 or 3 of this AD, oil leakage is found at the feathering pump mounting pad of an engine, replace bobbin part number (P/N) 638005614 with bobbin P/N 638005637 and install a gasket on the feathering pump of that engine in accordance with the Accomplishment Instructions of Fokker Services SB F50-61-025 dated 4 July 2007 or later NAA approved revision.5. Replace bobbin P/N 638005614 with bobbin P/N 638005637 and install a gasket on the feathering pump of that engine in accordance with the Accomplishment Instructions of Fokker Services SB F50-61-025 or later NAA approved revision.

6. The replacement of a modified engine with an unmodified (i.e. pre-SBF50-61-024 or pre-SB F50-61-025) engine is no longer authorised.7. Do not install a replacement engine or QEC unit on any aircraft unless it has been modified in accordance with the Accomplishment Instructions of Fokker Services SB F50-61-025 or later NAA approved revisions.After accomplishment of the modification in accordance with Fokker Services SB F50-61-025 on both engines of the aircraft the repetitive visual and detailed inspections in Requirements 1, 2 and 3 of this AD may be discontinued.Note 2: EASA AD 2007-0203 dated 1 August 2007 refers. This AD supersedes CAA Netherlands AD (BLA) 2003-089/2 and BLA 2004-129.

Compliance:	1. Prior to each take-off after the effective date of this AD.2. Before further flight.3. At the intervals specified in the requirement document.4. Before further flight.5. At the next scheduled or unscheduled aircraft maintenance opportunity with sufficient aircraft downtime but no later than 15 August 2009.6. After accomplishment of the modification in accordance with Fokker Services SB F50-61-025.7. From the 15 August 2009.
	This Amendment becomes effective on 26 October 2007.
Background:	This AD was originally in addition to those requirements previously detailed in AD/F50/85. That AD required replacement of certain parts. This action has not been satisfactory in addressing the unsafe condition. There have been several incidents involving in-flight shut down or aborted take-offs due to oil leakage at the feathering pump. It has been determined that such leakage can be readily identified at the intervals specified in this AD to allow timely rectification of any defects discovered and prevent the unsafe condition from occurring.This amendment supersedes the requirements of AD/F50/85 Amdt 1. This AD now requires in addition to the existing inspections, the fitment of an improved version of the gasket and bobbin, which interface the feathering pump to the engine. Once fitted to both engines the inspections currently required by this AD may be discontinued.

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