Special Conditions: Bell Helicopter Textron Canada Model 427 Helicopters, High Intensity Radiated Fields

This special condition is issued for Bell Helicopter Textron Canada (Bell) Model 427 helicopters. These helicopters will have a novel or unusual design feature associated with the installation of electronic systems that perform critical functions. The applicable airworthiness regulations do not contain adequate or appropriate safety standards to protect systems that perform critical control functions, or provide critical displays, from the effects of high-intensity radiated fields (HIRF). This special condition contains the additional safety standards that the Administrator considers necessary to ensure that critical functions of systems will be maintained when exposed to HIRF.