MB,
You cannot train, study or work on a tourist visa.
In any event, a business visa is ONLY appropriate if you are an employed current commercial pilot, going for recertification or to maintain an existing rating, and there is no classroom work.
Yes you can undertake flying training, under certain circumstances, on business/pleasure visa (B1/B2). Those falling into this category shall be undertaking part-time (ie fewer than 18 or 22 hours per week, subject as defined in the INA) vocational study (flying training) which is
incidental to those primary purposes establishing admissibility under B1/B2 visas. The JAR-FCL NQ is an obvious example - someone taking the family on holiday to Florida and squeezing in a NQ if he has the time. Another example, same circumstances, might be the undertaking of a full JAR-FCL PPL.
That is the opinion of the Office of the Inspector General in its report dated 20th May 2002,
Special Report
See FN10 to Ch. 2.3:
The academic student is defined as a "bona fide student qualified to pursue a full course of study and who seeks to enter the United States temporarily and solely for the purpose of pursuing such a course of study consistent with section 214(l) at an established college, university, seminary, conservatory, academic high school, elementary school, or other academic institution or in a language training program in the United States." The vocational student is defined as "an alien having a residence in a foreign country which he has no intention of abandoning who seeks to enter the United States temporarily and solely for the purpose of pursuing a full course of study at an established vocational or other recognized nonacademic institution (other than in a language training program) in the United States." 8 USC § 1101(a)(15)(f) and (m). A "full course of studies" is defined separately for academic and vocational students. For vocational students, a "full course of studies" is defined as at least 12 semester hours if the school is a community college or junior college, 12 hours per week if it is a postsecondary vocational or business school, 18 clock hours of attendance a week if the dominant part of the course consists of classroom instruction in a vocational school, and 22 clock hours of attendance a week if the dominant part of the course of study consists of "shop or laboratory work." 8 CFR § 214.2(m)(9). For academic students, the hours required for a "full course of studies" depend on the type of program (e.g., postgraduate, undergraduate, language school) that the student is taking. 8 CFR § 214.2(f)(6). Students who do not meet these hourly requirements do not qualify for an M-1 or F-1 visa. However, they can be admitted under a B-1/B-2 visa if the inspector determines that their course of study is incidental to their primary purpose of pleasure or for a business related purpose.