Professional competitiveness of tertiary education graduates is of top priority for English for Specific Purposes (ESP) curricular at technical universities. The article justifies the process-genre approach as an effective systematic synthetic method of teaching technical writing at Bauman Moscow State Technical University (BMSTU). The goal of the study is to analyze its implementation in the ESP courses at BMSTU and describe the second language (L2) students' proficiency in technical writing. Four-stage technical writing teaching model is introduced aiming at writing skills development: clarity, conciseness, accessibility, recognizing the audience, and accuracy. The findings of blending instructions and feedback by means of apprenticeship models in encouraging collaborative learning process are traced. The results of the study demonstrate improvements in 108 students' writing scores after they were involved in the experimental teaching program. BMSTU students reveal high proficiency in observing the clarity of a technical document (93.5%), its accessibility (100%), and recognizing the audience (100%). 17.6% of unsatisfactory points received for conciseness and 51%-for accuracy can be explained by still insufficient knowledge of the English language functioning in professional and academic discourses. The collected data help reveal and measure the most problematic features of L2 communicative competence in order to further improve ESP course syllabus.