The subject of this comment is a pioneering early study of parachute stability [1]. Although published almost 50 years ago, it continues to be cited by current researchers in the field. Its nonlinear time-domain simulations may have been superseded by more recent computations, but the insight provided by its linearized formulation remains valuable.

Unfortunately, the paper as published contains some inconsistencies in the formulas describing the “longitudinal” (symmetric) motions of the gliding parachute. This comment aims to establish whether these are simply typographical errors or mistakes that affect the reliability of the results. It is intended to be read in conjunction with the original publication