As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIRCRAFT WAS BEING TROUBLESHOT FOR POOR ENGINE PERFORMANCE AND WAS BEING FERIED BACK TO MAINTENANCE BASE. DURING CRUISE THE PILOT AND ENGINEER FELT A SUDDEN SURGE AT A CONSTANT POWER SETTING. POWER WAS REDUCED AND ALL ENGINE INDICATIONS WERE NORMAL.POST FLIGHT INSPECTION SHOWED UNUSUAL WEAR ON THE COMPRESSOR BLEED VALVE AND FOUND THE DIAPHRAGM WAS RUPTURED.