AD/EMB-145/19 Horizontal Stabilizer Actuator Clutch Key Washer (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (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.

Embraer EMB-135 and EMB-145 Series Aeroplanes

AD/EMB-145/19 Horizontal Stabilizer Actuator
Clutch Key Washer 9/2008

Applicability:

Embraer EMB-145( ) aircraft.

Requirement:

1.    Verify the Part Number (P/N) and Serial Number (S/N) of the Horizontal Stabilizer Actuator (HSA) units installed on the affected aircraft and perform the following in accordance with instructions and procedures to detailed in Embraer Service Bulletin No.145-27-0088, original issue, or later revisions approved by the CTA.

(a)   If the P/N of the installed unit is 362200-1011 or 362200-1013, and the unit S/N is included among the following: 0390 through 0408, 0413 through 0439, 0441 through 0487, 0489 through 0504, 0506 through 0508, 0510, 0512 through 0531 or 0534 through 0548, perform a visual inspection of the clutch assembly to verify that at least one of the locking tabs on the key washer is bent against the clutch nut; if none of the locking tabs on the key washer is bent, replace the HSA with a serviceable unit; if at least one of the locking tabs on the key washer is bent, no corrective action is necessary; and

(b)   If the unit installed is not included among the affected units, according to the list on item (a) above, no additional action is necessary.

2.    No HSA unit included in the list detailed in Requirement 1(a) above should be installed on an aircraft unless the required inspection in such item is previously performed.

Note:  DEPARTAMENTO DE AVIAÇÃO CIVIL AD 2002-04-01 refers.

Compliance:

For Requirement 1 - Within 30 days after the effective date of this AD, unless previously accomplished.

For Requirement 2 - From the effective date of this AD.

This Airworthiness Directive becomes effective on 28 August 2008.

Background: There has been a case of looseness of the horizontal stabilizer actuator primary system clutch nut due to incorrect procedures at key washer installation, which caused the loss of both pitch trim control channels.

James Coyne
Delegate of the Civil Aviation Safety Authority

17 July 2008