Document ID: chunk:federal_register_of_legislation:F2005L03582:body:0:p2
Version: federal_register_of_legislation:F2005L03582
Segment Type: other
Provision Reference: 
Character Range: 3875–6977

MEB05-1 dated21 February 2005 and the applicable maintenance manual.
                 If the P/N is CM3589-50, 593-250-101, 593-250-102, W31-X2M5A-50 or
                 W31-X1000-50 and the date code is 0434 or later; then no further action is required.
                 2. If the P/N is CM3589-50, 593-250-101, 593-250-102, W31-X2M5A-50 or
                 W31-X1000-50 and there is no date code, replace the avionics bus circuit breaker switch with a P/N CM3589-50 that has a date code of 0434 or later in accordance with the following:
                   a. For Models 425 and 441 aeroplanes - SB CQB05-2, dated 21 February 2005 and the applicable maintenance manual.
                   b. For all other affected aeroplane models - SB MEB05-1 dated21 February 2005 and the applicable maintenance manual.

                3. If the P/N is CM3589-50, 593-250-101, 593-250-102, W31-X2M5A-50 or
                W31-X1000-50 and the date code is earlier than 0434, the part has a safe life limit of 1,000 hours time in service (TIS) and must be replaced within the 1,000 hour time limit with a P/N CM3589-50 that has a date code of 0434 or later in accordance with the following:
                  a. For Models 425 and 441 aeroplanes - SB CQB05-2, dated 21 February 2005 and the applicable maintenance manual.
                  b. For all other affected aeroplane models - SB MEB05-1 dated21 February 2005 and the applicable maintenance manual.
                4. Avionics bus circuit breaker switches P/N CM3589-50, 593-250-101,
                593-250-102, W31-X2M5A-50 or W31-X1000-50 that do not have a date code or have a date code earlier than 0434 may not be installed as a replacement spare.
             Later revisions of the above SB(s), approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2005-20-25, are considered acceptable for compliance with the equivalent Requirements of this Directive.
             Note:  FAA AD 2005-20-25 Amdt 39-14321 refers.
Compliance:  For Requirement 1 - Within the next 200 hours TIS, the next 12 months or at the next scheduled inspection, after the effective date of this Directive, whichever occurs first.
             For Requirement 2 - Before further flight after the Requirement 1 inspection.
             For Requirement 3 - Within the 1,000-hour TIS safe life limit.
             For Requirement 4 - As of the effective date of this Directive.
             This Airworthiness Directive becomes effective on 22 December 2005.
Background:  The FAA has received failure reports of certain Tyco Electronics circuit breaker switches installed on the master avionics bus of Cessna Model 400 aeroplanes.
             Analysis of the circuit breaker switch revealed the copper braid inside the switch had frayed.  Continued use causes an internal short.  The internal short could result in the internal switch components or external wiring melting because it is no longer protected by the circuit breaker.  The affected circuit breaker switches have a date code earlier than 0434 or do