14 CFR §137.53

1. (a)General. No person may operate an aircraft over a congested area except in accordance with the pilot and aircraft rules of this section.
2. (b)Pilots. Each pilot in command must have at least—
   1. (1)25 hours of pilot-in-command flight time in the make and basic model of the aircraft, at least 10 hours of which must have been acquired within the preceding 12 calendar months; and
   2. (2)100 hours of flight experience as pilot in command in dispensing agricultural materials or chemicals.
3. (c)Aircraft.
   1. (1)Each aircraft must—(i) If it is an aircraft not specified in paragraph (c)(1)(ii) of this section, have had within the preceding 100 hours of time in service a 100-hour or annual inspection by a person authorized by part 65 or 145 of this chapter, or have been inspected under a progressive inspection system; and
      1. (ii)If it is a large or turbine-powered multiengine civil airplane of U.S. registry, have been inspected in accordance with the applicable inspection program requirements of § 91.409 of this chapter.
   2. (2)If other than a helicopter, it must be equipped with a device capable of jettisoning at least one-half of the aircraft's maximum authorized load of agricultural material within 45 seconds. If the aircraft is equipped with a device for releasing the tank or hopper as a unit, there must be a means to prevent inadvertent release by the pilot or other crewmember.