Remarks: The compliance of this AD must be recorded in Aircraft Logbook, where applicable the requirements of this AD must be integrated into Aircraft Technical Documentation. Address inquiries concerning this AD to: Civil Aviation Authority, Airworthiness Division, Ruzyne Airport, 160 08 Prague 6, Czech Republic, tel: 420 2 33320922, fax: 420 2 20562270.

(formerly Fokker Aircraft B.V.)

RLD Type Certificate Nr.: A22F

The cruise lock system, as currently installed on Fokker Model F.27 series aircraft, was originally developed to prevent inadvertent reduction of propeller blade pitch below the cruise lock position (32 degrees). As operational experience accumulated, the modes of drive disconnect became known, and two improvements to the engine were introduced to prevent this. Despite the fact that experience has demonstrated that this failure mode is now extremely unlikely to recur, several cruise lock hang-ups have occurred as a result of a malfunction of the automatic cruise lock withdrawal system, combined with aircrew failure to manually disconnect the system by selecting the High Pressure Cock (HPC) lever to the lockout position in accordance with proper Airplane Flight Manual (AFM) procedures. The resulting engine burnouts have led to a number of incidents and some accidents. To address this problem, RLD issued Airworthiness Directive (BLA) 1996-130 that requires the AFM to be amended for operation with the HPC lever in the lockout position during the entire flight. Recently, an F.27 operator reported that strict adherence to Fokker Services' instructions as described in Manual Change Notification - Operations (MCNO) F27-001 (which covers the same Flight Manual (FM) and Airplane flight Manual (AFM) changes as required by BLA 1996-130) would result in incorrect procedures being introduced into the Flight Manual. To remedy the perceived possibility of operation introducing invalid emergency procedures into their Flight Manuals, Fokker Services issued MCNO F27-008 dated March 1, 2000 that includes instructions to (re)introduce the correct "Manual Feathering", "Unfeathering & Relighting" and "Propeller Overspeed" procedures in the Flight Manual. Since a potentially unsafe condition has been identified that may exist or develop on other aircraft of the same type design, this Airworthiness Directive (BLA) requires a verification check of the affected Flight Manuals and correction, as necessary.

Applicability: Fokker Aircraft B.V. Model F.27 Mk.200, Mk.400, Mk.400M, Mk.500, Mk.500CRF and Mk.600 aircraft, which are equipped with Rolls-Royce Dart 7 engines, having serial numbers in the range from 10102 through 10504 (which were delivered with a Flight Manual; subsequent a/c were delivered with an Airplane Flight Manual).

Effective date: May 20, 2000

Compliance: Required as indicated, unless accomplished previously.

Before June 1, 2000, verify that the affected Flight Manual procedures agree with Fokker MCNO F27-008 and, if deviations are found, correct the affected Flight Manual procedures in accordance with the instructions of Fokker MCNO F27-008 dated March 1, 2000. This may be accomplished by inserting a copy of Fokker MCNO F27-008 into the Flight Manual.

Remarks:

- Operators of the affected aircraft may obtain copies of the referenced service information upon request directly from Fokker Services B.V., Technical Services Dept., P.O.BOX 231, 2150 AE Nieuw-Vennep, The Netherlands, telephone (31) 252-627-350, facsimile (31) 252-627-211.

- Compliance with this AD must be recorded in the proper Aircraft Log Book(s).