On June 23, 2002, at 1215 mountain daylight time, a Beech BE-58, twin-engine airplane, N8245H, was substantially damaged following the collapse of the nose landing gear during the landing roll at the Four Corners Regional Airport (FMN), near Farmington, New Mexico. The airplane was owned and operated by San Juan Pilot Training, Inc., dba Mesa Airlines Pilot Development, at Farmington, New Mexico, under Code of Federal Regulations Part 91. The flight instructor and the private pilot/multiengine student were not injured. Visual meteorological conditions prevailed for the instructional flight, for which a company visual flight rules (VFR) flight plan was filed. The local flight departed Farmington at 1100. On the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) the flight instructor reported that when the main landing gear retracted a "pop-bang was heard." The two green main landing gear indicator lights and the red in-transit indicator light remained illuminated. The pilot's recycled the landing gear; however, they could not get a down and locked indication for the nose landing gear. The pilots established radio communication with the company dispatcher who notified the chief pilot. During a low approach over the active runway, the chief pilot and mechanics observed the nose landing gear was not locked in the down position and was at a 45 degree angle. Subsequently, the nose landing gear collapsed during the landing roll on runway 23 at FMN. The FAA inspector, who responded to the accident site, reported the failure of the plunger assembly for the nose landing gear. Substantial damage was found at the cabin bulkhead. The operator reported that the nose landing gear plunger assembly, part number 35-825094-4, had accumulated 10,872.5 hours. The nose landing gear plunger assembly was forwarded to the NTSB for examination. The NTSB Investigator-in-Charge (IIC) examined the nose landing gear plunger assembly utilizing the stereoscopic microscope. The nose landing gear plunger assembly was forwarded to Raytheon Aircraft Company, Wichita, Kansas, for metallurgical examination. Metallurgical examinations revealed a fatigue fracture.