Section 121.433 - Training required(a)Initial training. No certificate holder may use any person nor may any person serve as a required crewmember on an airplane unless that person has satisfactorily completed, in a training program approved under subpart N of this part, initial ground and flight training for that type airplane and for the particular crewmember position, except as follows: (1) Crewmembers who have qualified and served as a crewmember on another type airplane of the same group may serve in the same crewmember capacity upon completion of transition training as provided in § 121.415 .(2) Crewmembers who have qualified and served as second in command or flight engineer on a particular type airplane may serve as pilot in command or second in command, respectively, upon completion of upgrade or conversion training, as applicable, for that airplane as provided in § 121.415 .(b)Differences training. No certificate holder may use any person nor may any person serve as a required crewmember on an airplane of a type for which differences training is included in the certificate holder's approved training program unless that person has satisfactorily completed, with respect to both the crewmember position and the particular variation of the airplane in which the person serves, either initial or transition ground and flight training, or differences training, as provided in § 121.415 .(c)Recurrent training.(1) No certificate holder may use any person nor may any person serve as a required crewmember on an airplane unless, within the preceding 12 calendar months- (i) For flight crewmembers, the person has satisfactorily completed recurrent ground and flight training for that airplane and crewmember position and a flight check as applicable;(ii) For flight attendants and dispatchers, the person has satisfactorily completed recurrent ground training and a competence check; and(iii) In addition, for pilots in command the person has satisfactorily completed, within the preceding 6 calendar months, recurrent flight training in addition to the recurrent flight training required in paragraph (c)(1)(i) of this section, in an airplane in which the person serves as pilot in command in operations under this part.(2) For pilots, a proficiency check as provided in § 121.441 of this part may be substituted for the recurrent flight training required by this paragraph and the approved FFS course of training under § 121.409(b) of this part may be substituted for alternate periods of recurrent flight training required in that airplane, except as provided in paragraphs (d) and (e) of this section.(d) Notwithstanding paragraph (c)(2) of this section, a proficiency check as provided in § 121.441 may not be substituted for the extended envelope training required by § 121.423 or training in those maneuvers and procedures set forth in a certificate holder's approved low-altitude windshear flight training program when that program is included in a recurrent flight training course as required by § 121.409(d) .Doc. No. 9509, 35 FR 95, Jan. 3, 1970, as amended by Amdt. 121-91, 37 FR 10729, May 27, 1972; Amdt. 121-199, 53 FR 37697, Sept. 27, 1988; Amdt. 121-366, 78 FR 67840 , Nov. 12, 2013; Amdt. 121-382, 85 FR 10925 , Feb. 25, 2020 85 FR 10925 , 4/27/2020; 89 FR 51428 , 7/18/2024