(a) This section applies to propeller-driven, small airplanes having
standard airworthiness certificates that are designed for "agricultural
aircraft operations" (as defined in §137.3 of this chapter, as effective
on January 1, 1966) or for dispensing fire fighting materials.
(b) If the Airplane Flight Manual, or other approved manual material
information, markings, or placards for the airplane indicate that the
airplane has not been shown to comply with the noise limits under part 36
of this chapter, no person may operate that airplane, except --
(1) To the extent necessary to accomplish the work activity directly
associated with the purpose for which it is designed;
(2) To provide flight crewmember training in the special purpose
operation for which the airplane is designed; and
(3) To conduct "nondispensing aerial work operations" in accordance
with the requirements under §137.29(c) of this chapter.