The CF6-80C engines on the 767 have two different versions of door opening systems that open the thrust reverser halves for access to the engine during maintenance.

• Power Door Opening System (PDOS) with thrust reverser power opening pack connected to aircraft power operated with a switch on the thrust reverser.
• Manual Door Opening System (MDOS) with thrust reverser handpump quick release connector.

This change is done to prepare installation of engines with PDOS system on aircraft that is not provisioned for PDOS system, therefore the MDOS procedure can only be used for opening and closing of the thrust reversers halves for maintenance access.

The CF6-80C engines on the 767 have two different versions of door opening systems that open the thrust reverser halves 

for access to the engine during maintenance.  

- Power Door Opening System (PDOS) with thrust reverser power opening pack connected to aircraft power operated with a switch on the thrust reverser.  

- Manual Door Opening System (MDOS) with thrust reverser handpump quick release connector. 

Recore of Janitrol/Grimes IDG Oil Cooler, P/N 35E38-5, in accordance with Honeywell LORI Sealed Drawing List SDL3796-1, Revision A, dated 11 October 2005 or later FAA approved revision.

Recore of Hamilton Standard Air Supply Precoolers, Part Numbers 792940-4 and 792940-5, in accordance with the requirements of Honeywell LORI Sealed Drawing List SDL3499-1, Revision B, dated 10 October 2005 or later FAA approved revision.

Replace core assembly of Hamilton Standard Air Supply Precooler, Part Number 773287-3 and 773287-5

Replace core assembly of Hamilton Standard Air Supply Precooler, part number 792930-4 and 792930-5

Replace core assembly of AiResearch APU Oil Cooler, part number 160176-1

Replace core assembly of Hamilton Standard bleed air precooler P/N 77516-2 and -3.

: Install fireproof blankets on the engine fan-reverser intermediate seal core area replacing the fireproof insulating coating (MA255) in accordance with United Air Lines, DAS-1-WE, Approved Drawing List No. 5994 dated August 30, 1994, or later FAA approved revisions.

Modifies the aircraft to install a one way check valve in the yaw damper actuator hydraulic return port. The installation is in accordance with DAS-1-WE Approved United Air Lines Drawing List No. 5990 dated April 27, 1994, or later FAA approved revisions.