Airworthiness Directives; Boeing Model 727-200 and 727-200F Series Airplanes; 737-200, 737-200C, 737-300, and 737-400 Series Airplanes; 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747SR, and 747SP Series Airplanes; 757-200 and 757-200PF Series Airplanes; and 767-200 and 767-300 Series Airplanes
This document extends the comment period for the above- referenced NPRM, which proposes the adoption of a new airworthiness directive (AD) that applies to certain Boeing transport category airplanes. The NRPM would require replacing any insulation blanket constructed of polyethyleneteraphthalate (PET) film, ORCON Orcofilm[supreg] AN-26 with a new insulation blanket. The NPRM results from reports of in-flight and ground fires on certain airplanes manufactured with insulation blankets covered with AN-26, which may contribute to the spread of a fire when ignition occurs from sources such as electrical arcing or sparking. This extension of the comment period is necessary to ensure that all interested persons have ample opportunity to submit any written relevant data, views, or arguments regarding the NPRM.
Special Conditions; West Star Aviation, EFIS on the Cessna 441; Protection of Systems for High Intensity Radiated Fields (HIRF)
These special conditions are issued to West Star Aviation, 796 Heritage Way, Grand Junction, CO 81506, for a Supplemental Type Certificate for the Cessna 441 Conquest. This airplane will have novel and unusual design features when compared to the state of technology envisaged in the applicable airworthiness standards. These novel and unusual design features include the installation of an electronic flight instrument system (EFIS) in the form of two digital altimeters. The digital altimeters will be Honeywell/Ametek AM-250 models, one on the pilot side and one on the copilot side, for which the applicable regulations do not contain adequate or appropriate airworthiness standards for the protection of these systems from the effects of high intensity radiated fields (HIRF). These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to the airworthiness standards applicable to these airplanes.