Narrative:

During the takeoff roll; above 100 KTS; the left eng prv EICAS message illuminated with a left engine bleed light and an associated left eng prv status message. Followed QRH procedure and turned off the left engine bleed air switch. Called dispatch; talked to maintenance control and decided to continue to destination. Two hours into the flight while at FL340 the right eng hpsov EICAS message illuminated with an associated right eng hpsov status message. Right pneumatic duct pressure remained normal at 39 psi. The QRH procedure directed to turn the right engine bleed air switch off. I elected to leave the right engine bleed air switch on to prevent an unwanted depressurization and I declared an emergency and began to descend and divert to a nearby airport while we started the APU as a backup pneumatic source below 17;000 ft. Called dispatch and maintenance control again and maintenance advised that; with normal duct pressure; the now intermittent right eng hpsov message was probably an indication problem. He also advised taking the aircraft back to our departure airport due to superior maintenance capability. With dispatch concurrence; I decided to return. Following descent below 17;000 ft MSL we followed the QRH procedure and turned the right engine bleed switch off. We landed uneventfully and below max landing weight upon arrival.

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Original NASA ASRS Text

Title: A B767-300ER ultimately returned to their departure airport after experiencing EICAS pneumatic system bleed anomalies on both engines.

Narrative: During the takeoff roll; above 100 KTS; the L Eng PRV EICAS message illuminated with a left engine BLEED light and an associated L Eng PRV status message. Followed QRH procedure and turned off the left engine bleed air switch. Called Dispatch; talked to Maintenance Control and decided to continue to destination. Two hours into the flight while at FL340 the R Eng HPSOV EICAS message illuminated with an associated R Eng HPSOV status message. Right pneumatic duct pressure remained normal at 39 PSI. The QRH procedure directed to turn the right engine bleed air switch off. I elected to leave the right engine bleed air switch on to prevent an unwanted depressurization and I declared an emergency and began to descend and divert to a nearby airport while we started the APU as a backup pneumatic source below 17;000 FT. Called Dispatch and Maintenance Control again and Maintenance advised that; with normal duct pressure; the now intermittent R Eng HPSOV message was probably an indication problem. He also advised taking the aircraft back to our departure airport due to superior maintenance capability. With Dispatch concurrence; I decided to return. Following descent below 17;000 FT MSL we followed the QRH procedure and turned the right engine bleed switch off. We landed uneventfully and below max landing weight upon arrival.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.