As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON CLIMB THROUGH 15 000 FT NR 4 ENGINE BEGAN TO SURGE WITH ASSOCIATED FLUCTUATIONS IN TORQUE, ITT AND FUEL FLOW. WHEN THE FLIGHT CREW CLOSED THE NR 4 AIRFRAME BLEED VALVE AND REDUCED POWER THE ENGINE STABILIZED. NO FURTHER ISSUES WERE NOTED FOR THE REST OF THE FLIGHT. THE NR 4 ENGINE WAS REPLACED.