What was found
LEFT ENGINE TRAILING SMOKE. RETURNED TO SFO. FOUND OIL IN BREATHER TUBE. REPLACED OIL BREATHER CARBON SEAL. LEFT ENGINE RUN UP OPS CHECKS GOOD IAW MM 72-20-00.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
LEFT ENGINE TRAILING SMOKE. RETURNED TO SFO. FOUND OIL IN BREATHER TUBE. REPLACED OIL BREATHER CARBON SEAL. LEFT ENGINE RUN UP OPS CHECKS GOOD IAW MM 72-20-00.