On February 21, 1994, at 0737 hours mountain standard time, a Piper PA-31-350, N4109D, right engine compartment caught fire during the landing roll-out on runway 08R at Phoenix Sky Harbor Airport, Phoenix, Arizona. The pilots were completing a visual flight rules scheduled commuter flight under Title 14 CFR Part 135. The airplane, operated by Arizona Pacific Airlines, Prescott, Arizona, sustained minor damage. The two flight crewmembers and one passenger were not injured. Another passenger fractured his ankle during the evacuation process. Visual meteorological conditions prevailed. The flight originated at Ernest J. Love Field, Prescott, Arizona, at 0712 hours. Both pilots reported in the Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2, that the local controller informed them of the fire shortly after touchdown. When the pilot-in-command (PIC) applied the brakes, he noticed that the right brake was ineffective. The PIC executed a left 180-degree turn to stop the airplane. After the airplane stopped, the second-in-command (SIC) assisted the passengers evacuate the airplane through the main cabin door. The PIC evacuated the airplane through the left front door. Messrs. Paul Texter and Dean Hennies, Aviation Safety Inspectors, Federal Aviation Administration (FAA), Scottsdale [Arizona] Flight Standards District Office, conducted the on-scene investigation. Inspector Texter reported that the origin of the fire was in the firewall area next to the main fuel line. He also said that Inspector Hennies found the right main fuel line "B" nut loose, and that both engines were replaced on February 18, 1994.