Special Conditions: Boeing Model 747SP; NASA Stratospheric Observatory for Infrared Astronomy (SOFIA); Cryogenic Systems Using Liquid Nitrogen and Liquid Helium

These special conditions are issued for the Boeing Model 747SP airplane. This airplane, as modified by L-3 Communications/Integrated Systems, of Waco, Texas, will have novel and unusual design features associated with cryogenic systems using liquid nitrogen and liquid helium. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.