I am trying to find a source for a full explanation of this subject (MTBUM). Could anyone direct me? Thanks ahead of time.
As ou have identified, MTBUM is an acronym for Mean Time Between Unscheduled Maintenance Action. MTBUM is simply the total number of operating hours divided by the total number of unscheduled maintenance events. A description of this metric and related metrics is available in AFOTEC Pamphlet 99-104, Operational Suitability Test & Evaluation, paragraph 18.104.22.168.3. Logistics Reliability. The pamphlet can be viewed on-line at http://web.deskbook.osd.mil/reflib/DAF/007GW/001/007GW001DOC.HTM If you have any additional questions, feel free to contact me.
Your URL http://web.deskbook.osd.mil/reflib/DAF/007GW/001/007GW001DOC.HTM does not appear to work, has it been redirected / deleted?
Yes, the link has apparently been broken. Here is a definition for MTBUM form the Reliability, Maintainability, and Availability for Logisticians Text Book, which can be found at this link: https://acc.dau.mil/GetAttachment.aspx?id=215093&pname=file&aid=35378&lang=en-US
Mean Time Between Unscheduled Maintenance (MTBUM): The total operating time divided by the total number of incidents requiring unscheduled maintenance.
This text book, along with other to OSD related Reliability, Availability and Maintainability information can be found on the follow site: