As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 2 ENGINE, MULTIPLE STALLS AT TAKEOFF. DIVERTED TO LHR. *S/D* ENGINE EXPERIENCED A GROUPE 3 SURGE EVENT. GROUPE 3 SURGES ARE THE RESULT OF EXCESSIVE BLADE TIP CLEARANCES IN THE REAR STAGES OF THE HIGH PRESSURE COMPRESSOR. ENGINE WAS REMOVED FOR HIGH PRESSURE COMPRESSOR REFURBISHMENT.