EAS425 Tutor-Marked Assignment Report: Arrow Airways Case in Flight Line Management, Singapore

Arrow Airways is a small airline based in Singapore. It operates a fleet of eight Airbus A319 passenger aircraft to provide commercial passenger services within the Asia Pacific region. The flight data for the aircraft fleet, status as at 31 May 2025, is shown in Table Q1a. With no in-house engineering and maintenance setup within the airline, Arrow Airways has outsourced all its maintenance requirements to a SAR-145 approved aircraft maintenance service company, Mission MRO Services.

Question 2

Arrow Airways has also appointed Mission MRO Services to manage the inventory of its aircraft fleet. One of the routine responsibilities is to review the adequacy of aircraft rotable spares to support the service level targets demanded by Arrow Airways.

Five aircraft rotables (see Table Q2) are flagged for routine spare review. These rotables were highlighted by the Line Maintenance in Mission MRO Services for review due to increased failure rate and/or non-fulfilment of the part demands in the recent weeks. These aircraft rotables have no established repair capabilities in Singapore and need to be shipped to the authorised repair centres located overseas for all repair and maintenance services.

MPN – The material part number (MPN) is the unique reference number used to identify an aircraft part and is used to track all its part procurement and repair / services activities.

QPERAC – This is the number of units of an aircraft rotable effective on the aircraft type in which it is installed.

Flight Tasking – This is the number of flight hours per day of revenue flights that each aircraft of an aircraft type is assigned by the airline to fly. This is the average figure derived for the respective aircraft type in the prevailing month.

Field MTBR – The Mean Time Between Removals (MTBR) indicates the frequency in which an aircraft rotable is expected to be removed from the aircraft and hence the need for a replacement spare unit. The field MTBR of a rotable is the average figure derived from the removal data collected over the preceding 12 months from the effective aircraft fleets.

Repair TAT – This is the expected turnaround time (TAT) taken to send an unserviceable aircraft rotable to the repair workshop for repair and servicing and be returned back to the airline’s storage warehouse. TAT will include the lead-time to repair and service the part, the total transportation time to and fro the repair workshop, including cross-border customs delay where applicable. A set of standard TAT figures of 30-days, 45-days, 60-days or 90-days are pre-set in the rotable spare analysis, based on the geographical locations of the authorised repair centres for the respective aircraft rotables. These repair TAT figures are pre-set in the initial spare provisioning plan agreed between the airline and the OEMs. They are not indicative of the repair TAT performance of the existing overseas repair centres.

Essentiality Code (ESS) – The aircraft manufacturer will provide the airline the Master Maintenance Essential List (MMEL) which lists the aircraft parts that are critical to aircraft flight operations, including details regarding how the aircraft may or may not be operated with the part inoperative. The essentiality code (ESS) essentially represents the criticality level of an aircraft part to the airline’s operation.

Arrow Airways has categorised the criticality of the aircraft rotables into three categories and defined the target service level for the respective category as follows:

Target Service Levels

• Essentiality Code 1 = 95%
• Essentiality Code 2 = 90%
• Essentiality Code 3 = 85%

Using the data provided in Table 1, apply the spare provisioning methodology stated in the IATA Guidance Materials for Inventory Management to evaluate the annual demand and pipeline demand for the five components and hence analyse if their current stock holding is adequate to support the target service levels demanded by Arrow Airways. Design the follow-up actions to address and improve any stocking shortfall.

(20 marks)

Question 3

Appraise the scope of the maintenance tasks in the RCM Methodology, stating an example for each as illustration.

(6 marks)

Question 4

Using a relevant example, analyse the issuing organisation for each of the following documents and the condition(s) that need to be met before each document could be issued.

Question 5

By stating the objective and organisation that issue a Airworthiness Directive (AD), evaluate how the information provided by the document provides.

(7 marks)

Question 6

Table Q6 summarises the accumulated flight hours of a fleet of six Airbus A319 aircraft operated by an airline and the respective number of hours that each aircraft is tasked to fly per month. Analyse the potential risks on the aircraft availability for the aircraft fleet 4-months from now and design a plan to mitigate the risks identified.

(10 marks)

Question 7

The annual demand for an aircraft hardware is 38,820 units and each unit is priced at $60. The minimum stock level equivalent to 2-month of demand is to be maintained at all time. The local hardware supplier typically delivers the goods 3 days after receiving the purchase order. Appraise the term Re-Order Point (ROP) and evaluate the ROP value for this aircraft hardware.

(5 marks)

Question 8

Analyse the underlying assumptions and principles used for rotable spare review to identify THREE (3) potential scenarios that could affect the accuracy of the rotable review.

(10 marks)