As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF AND GEAR RETRACTION, HEARD PULSATING NOISE AND FELT PULSATING THROUGH RUDDER PEDALS, AFTER GEAR EXTENSION PULSATING SUBSIDED. R & R HEAT EXCHANGER DUE TO EXCESSIVE VIB FAN TO HSG LEAK CKD GOOD IAW AMM 27-11-42. INSP A/C FOUND NO OTHER DEFECTS. (K)