This Special Airworthiness Information Bulletin (SAIB) informs you, owners or operators, of an airworthiness concern regarding possibility of separation of the cabin door while in flight for the following Schweizer Models: 269A, TH-55A, 269A-1, 269B, 269C, serial numbers 001 through 1917, 269C-1, serial numbers 0001 through 347, and 269D, serial numbers 0001 through 0073.