scope:

Scope and Applicability.

This instruction and the attached enclosures will be the definitive document and foundation for determining and developing inventory requirements for Navy and Marine Corps engine and module stocking levels at supported locations, as well as quantities to support the repair pipeline and the total stock level requirements. The outputs governed by this instruction will be used as a baseline in determining applicable procurement, retention and disposal budget submissions during the Program Objective Memorandum process.

a. Material Management. Reference (a) prescribes procedures for the uniform management of Department of Defense material. The Department of Defense components must establish and pursue the goal of provisioning sufficient support items to meet end item readiness objectives at minimum investment cost.

b. Spare Engine and Module Requirements. Data elements needed to compute spare aircraft engine and module requirements within the Repairable Integrated Model for Aviation (RIMAIR) model will be obtained from the Propulsion Management Board.

(1) Site Data. The most current Aircraft Planning Data File (APDF) is the primary document used to obtain the number and distribution of operating aircraft at a base, ship or supported sites. The weapon system planning document is a basic policy and planning document, published by Commander, Naval Air Systems Command (COMNAVAIRSYSCOM) and is produced to provide direction and guidance for program planning, budgeting and execution in the development, acquisition, operation and logistics support of aircraft and airborne weapons and equipment. The weapon system planning document and other sources of data may be used to support APDF information and validate repair and support sites. If information in the APDF conflicts with other source documents, an official determination will be made by Director, Air Warfare (OPNAV N98).

(2) Flight Hours. The most current Executable Requirement OP20 (Budget Exhibit Analysis of Flying Hours Program) is used for RIMAIR engine and module Baseline Assessment Memorandum (BAM) requirement calculations and engine and module retention calculations.

(3) Utilization Rate.

(a) Peacetime Rates. Capture the monthly hours per aircraft associated with the Master Aviation Plan and operational presence requirements. The peacetime utilization rates are derived from the Type/Model/Series (TMS) Required Flight Hours depicted in the selected ER OP20 and established aircraft site data from the selected APDF. For cases where there is significant variation between Budgeted and Required Flight Hours for a specific TMS, OPNAV N98 will coordinate with NAE stakeholders to determine the appropriate flight hour basis.

(b) Wartime Rates. Capture an increase to the peacetime rates associated with increased operational requirements in a major combat operation. The wartime utilization rates are provided by OPNAV N98.

(4) Protection Level. Protection level represents the probability that the RIMAIR modeled output quantity of engines or modules will be sufficient to meet the total uninstalled spare inventory requirements. These requirements are determined by varying the protection levels from 50% to 90% during separate RIMAIR modeling runs. The 50% protection level value model run, determines the baseline quantity of inventory needed to support the repair pipeline (quantity required for inventory in repair or in-transit status) requirements. The 90% protection level value model run is used to validate the module or engine inventory quantity required to support peacetime demand (current operations pool) per the engine and module readiness goal requirements detailed in reference (c).

c. Repair Pipeline Standards. Baseline repair pipeline standards and associated transportation times are coordinated and validated through the Propulsion Management Board (PMB). Baseline values should not account for inefficiencies within the logistics systems. Additional sparing requirements are not computed to mask or compensate for these inefficiencies (i.e. transportation, awaiting parts, manpower, tooling, etc.) and are not permitted absent in OPNAV N98 authorization.

(1) Mean Engine Flight Hours Between Removal (MEFHBR). MEFHBR is the primary metric used for both RIMAIR BAM calculations and retention runs. The source for the MEFHBR is the PMB.

(2) Transportation Times. Transportation times are governed by the Uniform Material Movement and Issue Priority System. Baseline transportation times are maintained by Commander, Naval Supply Systems Command (COMNAVSUPSYSCOM). Deviations to baseline transportation times may be authorized by OPNAV N98.

(3) Modular Type Spare Engine Requirements. Engines are designed for disassembly into major sub-components that allow for rapid return of the whole engine to ready for issue (RFI) status. Although modular engines offer more rapid repair turnaround times (RTAT) than conventionally configured engines, aircraft operational availability requirements dictate that a level of built-up spare engines be maintained for immediate installation in aircraft in addition to spare engine modules. Spare engine and module requirements are computed based upon the parameters outlined in this instruction.

Purpose.

a. To implement policy and procedures governing the requirements development process for the procurement, budgeting and retention of spare engines and modules.

b. This version incorporates the retail inventory management guidance provided in reference (a), commonly referred to as the "Super-Reg," and reference (b). This instruction is a complete revision and should be reviewed in its entirety.