Candid voices: metrics in Air Force Calibration Laboratories: a case study

Air Force Journal of Logistics, Spring, 2006 by William L. Maitland

Introduction

Under the direction of the Air Force Metrology and Calibration (AFMETCAL) Program, the Air Force employs a network of 75 calibration laboratories across the country and overseas to support its inventory of test measurement and diagnostic equipment (TMDE). Some of the laboratories, known as precision measurement equipment laboratories (PMEL), are operated by government employees--military, civil service, or a combination thereof. The remaining labs are contractor operated. A summary of the geographic location and who operates the PMELs can be found in Table 1. The overseas figures include PMELs located in Alaska and Hawaii.

The TMDE supported by PMELs is defined as

   ...those devices used to maintain, evaluate, measure, calibrate,
   test, inspect, diagnose, or otherwise examine materials, supplies,
   equipment, and systems to identify or isolate actual or potential
   malfunctions, or decide if they meet operational specifications
   established in technical documents (1).

Well maintained and accurate TMDE plays a key role in ensuring aircraft are able to fly when needed, navigate and communicate as necessary, and deliver their payload with precision. When examining the skills mix of a PMEL, one finds a majority of personnel found in a PMEL are metrologists. (2) They perform calibration and repair work on TMDE. Typically there may also be several support personnel assigned to accomplish tasks such as scheduling and supply. PMELs are most commonly seen as a function within the aircraft maintenance complex.

TMDE requires periodic calibration to ensure it meets its specified parameters. "Calibration is a comparison between equipment items, one of which is a measurement standard of known accuracy, to detect, correlate, adjust and report any variation in the accuracy of the other item(s)." (3) Calibration of TMDE is a crucial element in maintaining system accuracy and reliability.

This case study examines how the use of metrics might help PMELs manage the TMDE workload with a goal of reducing equipment downtime. Shortening the time TMDE is unavailable to the owners or users could cut the cost of TMDE support to the Air Force, improve customer service, and free up resources that could be used elsewhere.

Defining the Problem

Since the early 1990's the Air Force has explored ways to cut the cost of maintaining calibrated TMDE. Most of the effort was focused on outsourcing TMDE workloads, privatization of calibration facilities and their associated workloads, eliminating weapon system specific PMELs, and allowing torque calibrations to be performed outside a PMEL by nonmetrology personnel. The process the organization uses to deliver TMDE to the PMEL, the workflow through the PMEL, and the means to return equipment to the customer was only given a cursory look. Little effort was expended measuring or determining an adequate measurement to gauge the efficiency of PMEL operations. Measuring backlog, the one metric that has been used for 30 years, does little to measure the actual performance of a PMEL. The Air Force supports 608,000 items of TMDE and performs 754,000 maintenance actions involving TMDE calibration each year. Because of the number of items supported, the costs associated with the workflow are significant and warrant further investigation.

The major objectives for this study are as follows.

* Review existing metrics used by PMEL managers

* Develop notional metrics for the PMEL function

* Identify the advantages and disadvantages of each proposed metric

Literature Review

The literature review for this project is divided into two categories--government documentation and commercial standards. The government documentation section is comprised of Air Force instructions, Air Force technical orders, government reports, and contract statements of work. All instructions, technical orders and contractual documents require compliance by the user while the other documents offer guidance unless specified otherwise.

Government Documents

In December 2001 the Air Force Logistics Management Agency published the handbook Maintenance Metrics US Air Force. In the foreword, the Director of Logistics, Air Force Materiel Command, Lieutenant General Terry L. Gabreski states:

   Aircraft maintenance metrics are important. Don't let anyone tell
   you differently! They are critical tools to be used by maintenance
   managers to gauge an organization's effectiveness and efficiency.
   In tact, they are roadmaps that let you determine where you've been,
   where you're going, and how (or it) you're going to get there. Use
   of metrics allows you to flick oft your organizational autopilot and
   actually guide your unit. But they must be used correctly to be
   effective. Chasing metrics for metrics' sake is a bad thing and
   really proves nothing. A good maintenance manager will not strive to
   improve a metric but will use it to improve the performance of the
   organization. (4)

Air Force Instruction 21-113, Air Force Metrology and Calibration (AFMETCAL) Program, is the primary governing document for the AFMETCAL Program. It defines the purpose of the program and recognizes Air Force Metrology and Calibration Detachment 1 as the technical authority on metrology issues. "PMELs are owned and operated by their respective MAJCOM [major command] or FOAs (field operating activity) to provide calibration and maintenance support to TMDE operated by users within a specified geographic region." (5) Air Staff responsibilities include establishing "policy for managing and operating the AFMETCAL Program." (6) The publication does not include any production standards for managing a PMEL.