Summary
We propose to adopt a new airworthiness directive (AD) for all Fokker Services B.V. Model F.28 Mark 1000, 2000, 3000, and 4000 airplanes. This proposed AD was prompted by a design review, that revealed a hot spot may develop in the main fuel tank under certain failure conditions of the solenoid of the level control pilot valve, the reed switch of the main tank overflow valve, the level float switch of the collector tank, or the solenoid of the main tank fueling shut- off valve. This proposed AD would require installing fuses in the wiring of the solenoid of the level control pilot valve, the reed switch of the main tank overflow valve, the level float switch of the collector tank, and the solenoid of the main tank fueling shut-off valve, as applicable. This proposed AD would also require accomplishing concurrent actions and revising the airplane maintenance or inspection program, as applicable, by incorporating fuel airworthiness limitation items and critical design configuration control limitations (CDCCLs). We are proposing this AD to prevent an ignition source in the main fuel tank vapor space, which could result in a fuel tank explosion and consequent loss of the airplane.