Caravan Undifferentiated
Maintenance Airframe; Maintenance Nondestructive Testing (NDT); Maintenance Powerplant
Maintenance Inspector 14; Maintenance Lead Technician 28; Maintenance Technician 10
Communication Breakdown; Confusion; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Manuals; Human Factors; Chart Or Publication
On review of aircraft records; after replacement of both Number 1 and Number 2 Avionics' Master Switches; an issue with the Part Numbers (P/N) was noted. The switches removed were P/N CM3589-30 (Alternate (ALT) P/N W31-X1000-30) and P/N W31-X2M1G-30. When the part numbers were researched for replacement the Illustrated Parts Catalog (IPC) indicated that the proper P/N was CM3589-30 for this Serial Number (S/N) aircraft. That P/N was no longer valid by Cessna; nor was the W31-X1000-30 Alternate. The P/N W31-X2m1G-30 was recognized and that part was installed. The only P/N that was noted by Cessna was for a later Airframe S/N; that P/N was 7270-5-30. After contacting Cessna support; they provided information dated December 2012; stating that in February 1997; Cessna Engineering replaced the CM3589-30 Switch with the 7270-5-30. None of this is found in any of the Cessna C-208 Series Airframe IPC; Service Bulletins (S/Bs); Avionics Install Manual or the Wiring Manual. Cessna Parts stated to verify the P/N on the aircraft and install what was removed. The correction would be that the current manuals are updated when a change is made to them. This revision was 15 years old. Any change an operator makes must be updated within a very short time. Manufacturers are not required to do that.
Reporter stated he works as a Quality Assurance Manager for a Part 135 Cargo Operator that flies Cessna C-208 Caravans. A recent smoke in the cockpit incident required replacement of the original Number 1 and Number 2 Avionics Master Switches identified as P/N CM3589-30. The -30 represents 30-Amp load capacity. One of the Master switches had welded 'open' and burnt-up in flight. Not knowing what was burning; the Pilot had disconnected all the Avionics equipment; including communications; but managed to land safely.Reporter stated there was no legal cross-reference in the Illustrated Parts Catalog (IPC) allowing the installation of the newer Master Switch with P/N 7270-5-30; as a replacement for the original CM3589-30 switch that Cessna noted was no longer valid; even though the IPC indicated CM3589-30 was the correct replacement part. There is however; an after market Master switch available; that is a PMA part for the CM3589-30.Reporter stated that 2011 is the latest Revision of Cessna's C-208 IPC. That revision still does not include the information noting that Cessna Engineering had replaced the CM3589-30 switch with the newer P/N 7270-5-30 switch back in 1997. He questions how many other Operators of C-208 aircraft that have; or may be required to replace the same Master Switches; are faced with similar legal concerns for installing a switch that does not have any cross-reference for installation approval.
A Maintenance Quality Assurance Manager for a Cargo Operator report the lack of updated information in Cessna's 208 Series Airframe Illustrated Parts Catalog (IPC); Service Bulletins; Avionics Installation Manual and Wiring Manuals. Data from 1997 for Avionics Master Switches; CM3589-30; still had not been incorporated in the revised 2011 IPC Manual resulting in an incorrect part installation.