With regard to control forces, very small, light airplanes like the 601 are often said to be "fingertip airplanes," and this is praise, not criticism. Low control forces in pitch are potentially a cause for concern, however, because they might allow a pilot to overstress the airplane by a sudden stick movement. The FAA conceded that the 601's pitch force "gradient" — the rate of change of stick force with speed or G-loading — was well-behaved but added, somewhat tentatively, that "flight test data from foreign authorities indicate at aft center of gravity conditions the stick forces do become light." None of the witness accounts mentioned a sudden pull-up, however, and so the low stick forces, while worthy of mention, are not unique to the 601 and do not necessarily rise to the level of a design flaw. The FAA did suggest, however, that the American Society for Testing and Materials (ASTM) "consensus standard" under which the 601 was certified as an LSA ought to specify minimum stick forces for limit G-loads, as federal airworthiness standards do.