49 C.F.R. § 175.705 Inspection of aircraft for contamination by Class 7 (radioactive) materials.
Title 49 - Transportation
(a) Aircraft used routinely for the carriage of Class 7 (radioactive) materials shall be periodically checked for radioactive contamination. The frequency of checks shall be related to the likelihood of contamination and the extent to which Class 7 (radioactive) materials are carried. (b) An aircraft must be taken out of service if the level of contamination exceeds that provided in §175.700(b). [Amdt. 175–25, 47 FR 54824, Dec. 6, 1982, as amended by Amdt. 175–47, 55 FR 52687, Dec. 21, 1990]
Title 49: Transportation
PART 175—CARRIAGE BY AIRCRAFT
Subpart C—Specific Regulations Applicable According to Classification of Material
§ 175.705 Inspection of aircraft for contamination by Class 7 (radioactive) materials.

