AERO MECHANIC: When Mopa starts you should be ready to inspect every one of the 500 odd flights which will land and take off in a week at the airport due to be commissioned by 2022

The first of a series of lessons on how to maintain and repair aircraft. The Mopa airport was commissioned three years and from now do not give GMR an opportunity to refuse jobs to Goans claiming that they are not qualified. You can also get jobs not only in airlines but at ground level by getting experience with one of the ground handling companies like Freedom Holidays which takes care of all the English charters coming to Goa…..

Basics of Aircraft Maintenance Reserve Development & Management


Most operating leases provide that the lessee is liable for the ongoing costs related to maintaining an aircraft to the required standard. In the event that an aircraft is forcibly repossessed due to a default by the airline, the aircraft may require expensive investment in outstanding maintenance work before it is in a condition to be re-leased or sold to another airline/investor. Therefore, a lessor’s primary risk in relation to maintenance is one where the lessee fails to pay, in whole or in part, for the maintenance utility they consumed. To mitigate maintenance exposure most lessors have independent credit departments to evaluate the creditworthiness of lessees. Evaluation of an operator’s credit standing generally involves the establishment of some financial test, the failure to meet which would invoke an obligation to establish more stringent collateral security in the form of security deposits and payment of maintenance reserves. Maintenance reserves are payments made by the lessee to the lessor to accrue for those scheduled major maintenance events that require significant aircraft grounding time and/or turn-around time for certain major component overhauls. Put another way, maintenance reserves are payments for maintenance utility¹ consumed and can be expressed as follows for a particular maintenance event: A lease agreement will specify what maintenance events are to be covered through payment of reserves and for which the lessee may draw down against the accrued amounts. Areas of maintenance typically covered by reserves are as follows:
• Airframe Heavy Structural Inspections
• Landing Gear Overhauls
• Engine Performance Restoration
• Engine Life Limited Parts (LLPs)
• Auxiliary Power Unit (APU) Restoration The contractual position relating to maintenance reserve is always a subject of intense negotiation. Many airlines have sufficient credit stature that their prominence in the marketplace means they can reject paying maintenance reserves. On the other hand, lessors will show less flexibility for weaker credit lessees and require these operators to pay maintenance reserves. Maintenance reserve payments are calculated on flight hour, flight cycle, and/or calendar basis and are usually paid on a monthly basis in arrears. Accumulated reserves are reimbursed (subject to limitations) after major maintenance events are completed. see Appendix A for summary of Maintenance Utilit
Therefore, at the time an aircraft is taken out of service for maintenance, the lessor should already have funds to cover the cost of outstanding maintenance. More importantly, in the event of default, maintenance reserve provides lessor with value protection throughout the lease. In general, reserves become the property of the lessor immediately upon payment. Customarily, the lessee will cause the required maintenance to be completed and then claim reimbursement for the qualified portion of the work from the reserve account held by the lessor. Repayment takes place only if payment into the reserve account is fully up to date, and only up to the amount held in the specific reserve account. Thus if a particular event is carried out, and the cost of that work exceeds the total in the specific reserve account, the excess cost is the responsibility of the lessee. Funds generally cannot be transferred from other reserve accounts for the same aircraft to cover any shortfall incurred. So, for example, a lessee cannot siphon a fund used for engine maintenance and funnel those proceeds to subsidize the cost of airframe heavy check. In the event a lessee negotiates to not pay maintenance reserves they may still be required to provide collateral security in the form of an End of Lease Financial Adjustment or through a Letter of Credit (LOC). Under an End of Lease Financial Adjustment structure, if a certain maintenance event is returned at the end of a lease in a worse than stipulated condition, the lessee must make an end of lease payment to the lessor. Conversely, if a certain maintenance event is returned in a better than stipulated state, the lessor is obliged to pay the lessee. There are two types of end-of-lease payment structures:
• Mirror-In / Mirror-Out A mirror adjustment can either be one-way, where the Lessee is required to pay an adjustment when a certain maintenance event is returned with less time remaining than at delivery, or a two-way mirror whereby lessor may have to pay the lessee if a certain maintenance event is returned in better condition than at delivery.
• Zero-Time or Full-Life A payment whereby the lessor receives payment for time used since last overhaul or since new. A maintenance Letter of Credit (LOC) is bank guarantee that lessee will return the asset to the lessor in the condition required by the lease. Often, LOC amounts are reconciled on periodic basis – typically annually or semi-annually – to reflect maintenance utility consumed and performed.


Most lessors analyze cost data to come up with baseline maintenance reserve for each aircraft and engine model. Reserve rates (particularly engine rates) are often adjusted to account for key factors such as age, average flight length, and environment. Once sufficient reported cost data is available, baseline reserves are benchmarked to actual reported data to ensure consistent and unbiased cost metrics. To develop baseline costs, lessors make use of internally available sources as well as industry sources. The three primary maintenance cost data sources available to lessors are derived from internally generated reserve claims, industry publications, and manufacturer published cost data. i. Reserve claims – as a lessor accumulates sufficient maintenance reserve claims the degree of variability between baseline costs and actual costs diminishes. Many lessors develop costs reports that provide individual airline specific maintenance costs.
Information extracted from an engine performance restoration claim will yield a host of maintenance data (i.e. removal cause, time between performance restoration, flight leg, build goal, restoration and LLP costs, and the associated cost per flight-hour).
ii. Industry publications – the following industry publications provide detail analysis of both aircraft and engine types spread across numerous airlines, and are useful for establishing maintenance cost and performance interval benchmarks. a. Aircraft Commerce b. International Bureau of Aviation (IBA) – Maintenance Cost Journal c. Aircraft Technology & Engineering Maintenance

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