Hubungan Jam Terbang, Usia Dan Index Masa Tubuh Terhadap Kejadian Nyeri Punggung Bawah Pada Pilot Fixed-Wing Penerbangan Komersial Di Indonesia. (Studi Dengan Kuesioner Oswestry Disability Index) = ASSOCIATION BETWEEN LOW BACK PAIN AND FLIGHT HOURS, AGE, AND BODY MASS INDEX AMONG FIXED WING COMMERCIAL FLIGHT PILOT IN INDONESIA (STUDY WITH OSWESTRY DISABILITY INDEX QUESTIONNAIRE)