What was found
IAD - FLT 2724 - ON CLIMB OUT FROM IAD, CAPTAIN HEARD A POP FOLLOWED BY SOME VIBRATION. THE AIRCRAFT SEEMED NORMAL OTHERWISE. AFTER WHAT WAS BELIEVED TO BE A BIRD STRIKE, FLIGHT RETURNED TO FIELD AT IAD AS PRECAUTION. FLIGHT LANDED WITHOUT FURTHER INCIDENT. NO EMERGENCY WAS DECLARED. MAINTENANCE FOUND THE RIGHT NOSE GEAR DOOR LINKAGE BROKEN. REMOVED AND REPLACED THE RIGHT NOSE GEAR DOOR LINKAGE AND RIGGED PER MM 32-22-11. PERFORMED SATISFACTORY RETRACTION TEST. (M)