摘要
航空發動機主要為航空器提供動力，是攸關飛行安全的重要部件，更可稱做是航空器的心臟。其維修品質不僅可確保飛行安全，維修時間還會直接影響到航空公司的航班與航機調度規劃、航空公司的運營以及成本的管理。因此航空發動機維修廠更需要有周全的生產規劃以滿足航空公司的需求。雖然維修品質已有國際標準規範，但飛機引擎維修產業類似於訂單式生產，每月維修訂單數量與維修所需的時數都不固定；一有新產品開發完成還要開發新的維修製程。若維修廠在接下訂單後，卻無法如期完成或品質無法滿足顧客需求，終將造成客戶流失。所以透過精準預測航空產業的維修需求以及人力和機台的產能，將能極大化人力與機台效能。然而如何儘早預測航空產業的維修需求，以配合調整個案公司的人力與機台產能，會是一大挑戰。在預設航空產業需考慮的變因包括：
(1)大量湧入延後保養的發動機，造成人機負荷困難，
(2)在飛航市場需求蓬勃的情況下，但新機交機不順利導致繼續延用原來需要汰換的發動機，
(3)發動機需根據零件磨耗情況進行基本(Minimum)、中度(Performance)、或重度翻修(Overhaul)，維修時間不易掌控。甚至預期要翻修的零件因磨耗嚴重而報廢。
(4)客戶因其它考量，把發動機零件維修訂單轉送到其它維修廠。
因此本個案採用總體計劃的規劃方法，以AC個案公司為例建立一個可根據客戶需求產能變化進行分析的平台，來了解目前公司設備和人員是否可以滿足客戶的訂單要求，並了解個案公司是否還有多餘產能增加訂單銷售，是否需要增加人員或機台以及進行人員的技能培訓，以避免人機閒置、加班超出法規或人員技能無法滿足客戶維修需求的風險管控。
關鍵詞：總體計劃、需求預測、風險管理、航空發動機、維修

ABSTRACT
An aircraft engine is the propulsion system that generates thrust for an aircraft. It is one of the most significant element related to the aviation safety and can be consider as a heart of an aircraft. The safety and quality of Aircraft MRO (MRO=Maintenance, Repair, Overhaul) have the highest priority and must comply with the international aviation safety regulation. The turnaround time, AKA (TAT), directly affects to airline’s schedule reliability、operations and costs management. Hence, the repair shop of MRO must have good planning and scheduling for civil aircraft engine maintenance. The MRO quality is well controlled by international aviation safety regulation, but aircraft maintenance business model is similar to make-to order. Every month the quantity of repair order or demand will be different; after new repair launch or new repair process developed. If the repair shop is not able to fulfill customer requirement, finally the business will be lost. Therefore, through the accurate forecasting of the aviation engine repair demand、manpower and machine capacity, it can maximize the manpower and machine performance. So, how to get the accurate forecast in aircraft engine MRO business, so as to ensure the repair shop manpower and machine capacity able to meet the customer requirement, it will be a big challenge. There are some forecasting factors have to be considered by repair shop as follow::
1. A large number of repair parts sent to repair shop within a short period of time, causes the manpower and machine over-loaded.
2. Even though the influx of new aircraft into Asia is occurring rapidly, the old air plane retirements are in service due to the delayed delivery of new aircrafts in year 2017 - 2018.
3. There are three kind of repair scenarios are different, e.g. 1. Minimum Repair, 2. Performance Restoration Repair 3, Overhaul, that the repair time is different for each scenarios. Some worse condition is the part at as-receive condition determined as a scrap part.
4. Due to some reasons, customer cancels the sale order or sends the repair to other competitor.
The purpose of this paper took an aircraft repair shop (AC) as a sample, for the introduction of the Aggregate Planning (AP) method according to customer demand forecast to understand the existing manpower and equipment utilization able to satisfy customer demand or do we have any extra resources for new product either a new customer demand. Also according to the analysis result we can understand the necessity increasing in manpower and equipment or providing additional training plan to exiting manpower in order to prevent the idle of machine and manpower or high overtime rate but still fails to fulfill customer requirement.

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