AD/MU-2/65 Amdt 1 Engine Torque Indication System (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/MU-2/65 and issues the following AD under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Mitsubishi MU-2 Series Aeroplanes

AD/MU-2/65 Amdt 1 Engine Torque Indication System 4/2007 DM

Applicability:	Model MU-2B, -10, -15, -20, -25 and -26 aeroplanes, serial number (S/N) 008 through 347 (except for S/N 313 and 321) and Model MU-2B-30, -35 and -36 aeroplanes S/N 501 through 696 (except S/N 652 and 661).
Requirement:	1.For MU-2B, -10, -15, -20 and -30 aeroplanes:
a.     If not previously accomplished in accordance with the original issue of this Directive, inspect the torque indication system in accordance with Mitsubishi Heavy Industries (MHI) MU-2 Service Bulletin (SB) No. 233A dated 14 January 1999 or later revision approved by the Japan Civil Aviation Bureau (JCAB).
b.    If, during the Requirement 1 inspection, the errors in the torque indication system are found to exceed the allowable limit specified in the SB, repair or replace the torque transmitter in accordance with the SB.
2.    For MU-2B-25, -26, -35 and -36 aeroplanes:
a.     If not previously accomplished in accordance with the original issue of this Directive, inspect the torquemeter in accordance with MHI SB No. 233A or later revision approved by the Japan Civil Aviation Bureau (JCAB).
b.    If, during the Requirement 1 inspection, the errors in the torque indication system are found to exceed the allowable limit specified in the SB, repair or replace the torquemeter in accordance with the SB.
c.     If not previously accomplished in accordance with the original issue of this Directive, inspect the torque transducer in accordance with MHI SB No. 233A or later revision approved by the Japan Civil Aviation Bureau (JCAB).
d.    If, during the Requirement 3 inspection, the torque transducer output voltage is found to exceed the allowable limit specified in the SB, adjust the torque transducer output voltage in accordance with the SB.

3.    Accomplish a ground check of the engines in accordance with paragraph 3 of MHI SB No. 233A or later revision approved by the Japan Civil Aviation Bureau (JCAB).
Note 1:  The holder of a Certificate of Registration of an Australian aircraft is required under Civil Aviation Regulation 55 to ensure that the Aircraft Flight Manual (AFM) is amended to the current approved revision.
4.    Repair any discrepancies noted during the Requirement 1 check.
Note 2:  JCAB AD TCD-4889-1-2006 refers.
Compliance:	For Requirement 1.a. - Within 100 hours time in service (TIS) after the effective date of this Amendment.
For Requirement 1.b. - Before further flight after the Requirement 1.a. inspection.
For Requirement 2.a. - Within 100 hours TIS after the effective date of this Amendment.
For Requirement 2.b. - Before further flight after the Requirement 2.a. inspection.
For Requirement 2.c. - Within 100 hours TIS after the effective date of this Amendment.
For Requirement 2.d. - Before further flight after the Requirement 2.c. inspection.
For Requirement 3 - Within 100 hours TIS after the effective date of this Amendment.
For Requirement 4 - Before further flight after the Requirement 3 check.
This Amendment becomes effective on 9 March 2007.
Background:	MHI reports that some torque transmitter or transducers have been found significantly out of calibration.  This can result in an actual power mismatch that is not indicated on the engine instruments.  Mismatched power and resulting trim may result in degraded performance or handling qualities.
The original issue of this Directive required the inspection and, if necessary, the repair, replacement or calibration of the torque indication system.
This amendment introduces a ground check of the engines following the inclusion of a Power Assurance Chart in the AFM.

The original issue of this Directive became effective on 10 March 1999.

David Punshon
Delegate of the Civil Aviation Safety Authority

28 February 2007