Commonwealth legislation

AD/B737/99 - Main Rudder Power Control Unit (PCU)

RepealedCTH

This Act has been repealed and is no longer in force. It is retained for historical reference.

Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

2/10 complexity

This mandatory Airworthiness Directive requires all Boeing 737 owners/operators to perform Boeing’s specified test of the main rudder Power Control Unit at the first opportunity and then every 250 flight hours, and to replace any unit that shows abnormal results before the next flight. It addresses a discovered internal jam that can make the rudder deflect opposite pilot input, posing a serious loss-of-control risk.

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Current sections

Direct links to the current provisions in AD/B737/99 - Main Rudder Power Control Unit (PCU).

AD/B737/99 - Main Rudder Power Control Unit (PCU)

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Boeing 737 Series Aeroplanes

AD/B737/99 Main Rudder Power Control Unit (PCU) 1/97

Applicability: All Boeing 737 models.

Requirement: 1. Perform a test on the main rudder power control unit (PCU) in accordance with Boeing Alert Service Bulletin (ASB) 737-27A-1202 dated 01 November 1996 to verify proper operation.

If, as a result of Requirement 1, the test gives unusual results as described in the referenced ASB, replace the main rudder PCU and perform the test of Requirement 1.

Note: FAA AD T96-23-51 refers.

Compliance: 1. For Requirement 1, prior to 14 November 1996 and there after at intervals not to exceed 250 hours time in service.

For Requirement 2, before further flight.

Background: Recent tests on the main rudder PCU conducted by Boeing demonstrated a potential failure scenario that was previously unknown. These tests revealed that rudder pedal can cause deformation in the linkage leading to the primary and secondary slides of the servo valve of the main rudder PCU if the secondary slide of the PCU jams in certain positions. This situation could result in rudder motion in the opposite direction of the rudder command.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/B737/99 - Main Rudder Power Control Unit (PCU)