Applicability: SAAB SF340A-004 through -159, SAAB 340B-160 through -339.

Effective date: September 09, 1999.

Compliance: Required as indicated in SAD 1-145.

Remarks: Where applicable, the requirements of this AD must be integrated into the Aircraft's Logbook(s). 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.

AIRCRAFT TYPE: SAAB SF340A and SAAB 340B

SERIAL No's AFFECTED: SAAB SF340A-004 through -159, SAAB 340B-160 through -339

SUBJECT: Hydraulic Power- Introduction of New Swivel Brackets

BACKGROUND: A misalignment of the downlock or brake swivels in the MLG dragbrace and MLG shock strut trunnions has, due to excessive loads during extension/retraction of landing gear, resulted in abnormally high failure rate of the hydraulic swivels.

A brake swivel failure causes loss of:

- Inboard or outboard brakes

A downlock swivel failure and LDG selected "UP" causes loss of:

- Hydraulic fluid in the main hydraulic system

- Nose wheel steering operation

- Extension and retraction of landing gears

- Extension and retraction of the flaps

- Propeller brake (if installed)

In flight if the downlock swivel fails, you must perform an emergency extension of the landing gear.

This SAD introduces new swivel brackets with a supporting datum shoulder that will prevent misalignment of the downlock and the brake swivels.

REFERENCE DOCUMENTS: Saab Aircraft AB Mandatory Service Bulletin SAAB 340-29-009 revision 2 dated 2 July, 1999.

ACTIONS: Perform actions described in Saab Aircraft AB Mandatory Service Bulletin SAAB 340-29-009 revision 2 dated 2 July, 1999 or later revision.

COMPLIANCE TIME: To be performed within 12 months from release of this SAD

EFFECTIVE DATE: 2 July, 1999