Target of this article is to consider particularities of human factor influence in professional activity of aviation maintenance specialists. In consequence of theoretic analysis of studying of this problem were discovered preconditions and recent trends of development of human factor at specialists of this activity area as well as were identified structural components of mentioned phenomenon. According to that, the authors made a description of defining characteristics of manifestation of human factor in professional activity of aviation maintenance specialists: psychophysiological particularities of employees, professional requirements for carrying out of this activity and work conditions of those specialists. All this, at the opinion of authors, is one of determinants of human factor manifestation at aviation maintenance specialists. As to the improvement of professional activity level of specialists of this field, following levels of human factor manifestation at aviation maintenance specialists with precise hierarchic structure of its development were identified: sensory-perceptual level (work of human analyzer system), personal level (value-motivational aspect of carrying out of professional activity) and professional level (development of professional competence of personnel). At the basis thereof it was elaborated authors functional three-stage hierarchic model of human factor of aviation maintenance specialists. In order to decrease the risk of mistakes making by specialists during solving professional problems at any level of their committing, it was suggested a number of activities for improvement of human factor in professional activity of aviation maintenance specialists, which are directed to the development of sensory-perceptual, personal and professional levels.