After a First Officer informs the Captain of a large nick in one of the propeller blades on #2 engine of their DHC-8-300; four mechanics determine the aircraft should not be release for revenue service. They were overridden and aircraft was released.

Narrative

After the First Officer completed his aircraft walkaround; he brought to my attention a large nick in one of the #2 engine propeller blades. Accordingly; a maintenance logbook entry was made. Shortly thereafter; 4 mechanics arrived at the aircraft to inspect the damaged propeller. After inspecting and re-inspecting the propeller blade; the 4 mechanics individually and collectively concluded the affected propeller blade most likely exceeded maintenance limitations or at least not willing to allow this aircraft back into revenue service. Some 50 minutes later and after lengthy discussions; the decision was made to ferry the aircraft to ZZZ for repair. One of the mechanics left to get the ferry permit and returned to the aircraft within 10 minutes. Upon his return; without any additional information or further inspection; someone decided the aircraft is airworthy for revenue flight contrary to 4 experienced mechanics saying otherwise; and he was comfortable with this assessment and would be able to endorse the maintenance logbook stating such. I then call my Supervisor and explained the situation and circumstances. He stated that he would do some research and get back with me. A pilot supervisor showed up and I explained once again the situation and more importantly expressed my concerns as to how and why certain decisions were made. Dubiously; within the next 30 minutes; after clearly stated apprehension of 4 experienced mechanics and some apprehension of the Regional Chief Pilot and the already-made decision that the aircraft was not airworthy for revenue service by stating to ferry the aircraft; the aircraft was cleared for revenue service. Maintenance log entry; Maintenance was notified. At some point; PROP struck FOD. Callback conversation with Reporter revealed the following information: Reporter stated the damaged area was at the blade trailing edge and approximately 6-8' inches from the outboard tip of the blade. The props are a Kevlar type composite blade. The DHC-8-300 was released for continued service after someone in maintenance; who had not seen the nick damage; overrode the four mechanics decision to ferry the aircraft. Reporter stated his concern was how this person concluded that the nick was 'OK'. He later heard there were disagreements on the interpretation of the damage and the damage limits. The DHC-8 finished the remaining three trips that day and went to the hangar.