SF 340B
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Aircraft Equipment Problem Less Severe
General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
During preflight; detected areas of possible corrosion that need to be addressed by Maintenance. I have seen it on several rudder assemblies on various aircraft and consider it a general defect that could lead to airworthiness issues to the entire Saab 340 fleet.Hearing the word 'corrosion' from Maintenance is similar to hearing the word 'cancer' from your physician. They're both scary; but I am only talking corrosion in this narrative. I recommended reading Advisory Circular AC-43-4A entitled 'Corrosion Control for Aircraft;' from the FAA (Federal Aviation Administration) website; www.FAA.gov. According to the document; there are seven forms of corrosion that occur on airframes. It would be best finding all hidden corrosion on aging airframes and have it removed.
Reporter stated seeing the corrosion around the rudder trim tab and the attaching fasteners while accomplishing the preflight walk around. The paint appeared to be bubbling up around the fastener heads. This is the fourth airplane that he has seen this on. After notifying the Company of his observation on these airplanes; they were taken out of service and repaired. He said he was not aware of a comprehensive inspection program to look for this problem on all the airplanes in the fleet.
Saab 340 First Officer reported finding areas of possible corrosion on the airplane rudder near the trim tab during preflight inspection. Aircraft was removed from service and repaired.