The Royal Malaysian Air Force (RMAF) has faced difficulties in achieving and sustaining at least 70% of its aircraft availability (Av) in order to support its operational requirements. The head start for this research is to discuss with a focus group (FG) which comprise of eight officers and one moderator and supported by observation on the field. The FG highlighted that the low Av was due to the ineffectiveness and inefficiency of the through life cycle support (TLCS) as a result of weaknesses in the acquisition conceptual framework (ACF). Three research questions were put forward; Q1: Why has the RMAF not achieved its aircraft Av as its desired objectives? Q2: How do the RMAF's present acquisition practices given a significant impact to Av? And Q3: What is the recommended ACF to be used to ensure higher aircraft Av? The mix mode method (quantitative and qualitative) data collection was used. The literature review focused on critical success factors (CSFs) in terms of acquisition, terms and definition, and present practices in the Royal Malaysian Army (RMA), the Royal Malaysian Navy (RMN), the Malaysian public sector, the Department of Defence of the United States of America (DoD USA), the Ministry of Defence of United Kingdom (MoD UK) and the Australian Defence Force (ADF). Based on the CSFs from the literature review, a preliminary ACF I was developed. The RMAF case study had focused on Type A, Type B, Type C and Type D aircraft. Data on aircraft status for FY 2011 to 2015 was gathered from the Air Support Command Headquarters (ASHQ). The survey was achieved through 16 self-administered structured questionnaires which are close-ended involving 120 out of 150 respondents from the Worker Group (WG). The interviewer collected qualitative data using 21 semi-structured questionnaires with open-ended answers on 20 respondents from the Management Group (MG). The survey and interview results were presented in a matrix table and categorized in accordance with themes and their relationships. Based on the results of the case study, the preliminary ACF I was modified to ACF II. Then, ACF II was validated by four experts who comprise of two senior officers and two senior managers from the aviation industry. After validation, the ACF II was modified to ACF III (final) and was proposed for implementation. Three project objectives were put forward. Objective 1: To identify the cause of low Av. Finding 1: Av for Type A, Type B, and Type C aircraft for FY 2011 to 2015 is approximately 43% (target ≥70% Av). The low Av is due to aircraft downtime waiting for spare parts at the RMAF's facilities (AWP) 23.5% (target ≤10%), waiting for spare parts at the second line or contractor facilities (CONT) 25% (targeted ≤10%), and under work by RMAF Technicians (IWRK) 9% (within target ≤10%). Objective 2: To identify the RMAF's present ACF and its significant impact to Av. Findings: 2: The weaknesses of CSF's integration in the present ACF which is based on an ad-hoc basis have caused ineffective and inefficient TLCS, higher AWP and...