July 2013 - Wright-Patterson Air Force Base

DISTRIBUTION A. Approved for public release; distribution unlimited. (WP Public Affairs Case Number 88ABW-2013-3177) 

Director’s Comments 

I’m sure I’m not alone in feeling that this 

is the longest fiscal year of my Air Force 

career. Budget uncertainty has certainly 

sharpened our planning skills and helped 

us focus on the core functions of our 

business. Air Force civil servants have 

been notified that furloughs, if enacted, 

will start the second week of July. We 

will follow AFLCMC guidance to focus 

furlough days on Fridays. If this comes 

to pass, it will affect the staff’s productivity. 

We will do everything possible to 

overcome the 20 percent reduction in 

collective man-hours by reducing 

extraneous meetings, projects, and 

distractors so the staff stays focused on 

our number one priority, customer 

support for field issues. Give us as much 

notice as possible, be patient, and follow 

up if you don’t hear from us. 

Across the spectrum of operations, the 

Air Force is looking for ways to reduce 

costs and directing the MAJCOMs to fall 

in line. Inspection oversight is a 

high-interest area. Changes to Inspector 

General programs are looming that will 

affect how PMELs are assessed in the 

future. Chief McKinnon is providing 

further details. 

Thus far, we have weathered the 

Sequestration budget cuts with most 

requirements funded. Our AFPSL 

contractor enacted austerity measures 

that stretched the budget, and we 

appreciate efforts of our MAJCOM 

MFMs and Node Managers to scrutinize 

every N49/59/64 calibration item. We 

are managing our shortage in CAM 

equipment funding by deferring what we 

can to future years. Help us by taking a 

July 2013 

Volume 33, Issue No. 3 

AFMETCAL 

NEWSLETTER 

Colonel Victoria H. Reed 

Director, Air Force Metrology and 

Calibration 

hard look at what you need in the future 

and when. Please join us in advocating 

to your MAJCOM/A4s for funding for 

MFMs to travel to Heath for a face-toface 

Advisory Group meeting in the fall, 

because working issues in that forum 

maximizes effectiveness. 

I will end with a personal word of thanks 

and farewell to departing MAJCOM 

Functional Managers: Chief John Leary 

from ACC, SMSgt Rod Hartwig from 

USAFE, SMSgt Greg Johnson from 

PACAF and MSgt Greg Earp from 

AFGSC. They have served their 

MAJCOM leadership and the PMEL 

Calibration Network well and will be 

missed. But change is good, and we 

welcome the new eyes and fresh perspective 

of new Functionals. And as always, 

thanks to every member of our 1800- 

person network for doing your job with 

AIR FORCE 

METROLOGY 

Special Points of Interest: 

Process Review Culture (pg. 5) 

PPC3 Changed from N40 to 

Cal & Return (pg. 7) 

ADC-2500 Inspection 

Procedure (pg. 9) 

Releasing Hidden Value 

Streams in PMEL (pg. 13) 

NSCS Runtime Errors (pg. 14) 

Gage Blocks 101 (pg. 16) 

Importance of Calibrating 

Spectral Purity (pg. 17) 

Fittings for New Vacuum Cal 

System pg. (22) 

 

Inside This Issue: 

Director’s Comments 1 

Chief’s Corner 3 

News and Notes 5 

From the Bench 14 

AFMETCAL 

Personnel Changes 

Coming Events: 

23 

professionalism and cheerful 

good humor in the face of an 

uncertain future. See you 

around the Network! 

Colonel Reed 

AFMETCAL Advisory Group/ 

PAMS-CCB/PIWG/RNI 

Meetings 

(5-6 November 2013) 

DISTRIBUTION A. Approved for public release; distribution unlimited. (WP Public Affairs Case Number 88ABW-2013-3177)

Page 2 

AFMETCAL NEWSLETTER 



The views and 

opinions expressed 

herein, unless 

otherwise specifically 

indicated, are those of 

the individual author. 

They do not purport to 

express the views of 

the U.S. Government, 

the Department of 

Defense, Department 

of the Air Force or 

HQ AFMC. 

Disclosure & Editorial Policy 

Disclosure: The Air Force Metrology and 

Calibration (AFMETCAL) Program Newsletter 

is published on a triannual basis (Mar, 

Jul, Nov) by the AFMETCAL Division 

(AFLCMC/WNM), Plans & Analysis Section 

(AFLCMC/WNMRX), 813 Irving-Wick 

Drive W, Heath, Ohio 43056-1199. 

The views and opinions expressed herein, 

unless otherwise specifically indicated, are 

those of the individual author. They do not 

purport to express the views of the U.S. 

Government, the Department of Defense, 

Department of the Air Force or HQ AFMC. 

Information contained in the AFMETCAL 

Newsletter is for informational purposes and 

is not directive in nature. Photographs are 

the property of the United States Air Force 

unless otherwise stated. 

The appearance of hyperlinks does not constitute 

endorsement by the U.S. Air Force of 

the respective web site or the information, 

products or services contained therein. The 

U.S. Air Force does not exercise any editorial 

control over the information found at those 

locations. 

Editorial Policy Statement: The AF- 

METCAL Quarterly Newsletter is the AF- 

METCAL Director’s forum to share insights 

into policy and emerging trends, personnel 

news, technical and other information of interest 

to the Air Force metrology community 

at large. Newsletter articles cover many topics: 

technical issues; clarifications of policies/procedures; 

process improvements; and 

items of general interest about Air Force metrology 

community members. 

Submissions: We encourage readers to submit 

articles for the following categories: 

From the Bench (technical), About People 

(field personnel news), News & Notes 

(general information). Submissions should 

be in Microsoft Word, Times New Roman 12 

font, accompanied whenever possible by 

digital photos in JPEG format. Native photo 

file sizes less than 2MB per image are preferred. 

Photos must be accompanied with 

caption information which fully identifies all 

individuals depicted, including rank, title 

or office, and event. Note that all text and 

photo submissions are subject to editing 

for content, cropping and/or size. All submissions 

that are technical in nature are 

reviewed by the AFMETCAL Engineering 

Branch (AFLCMC/WNME) for accuracy 

and appropriateness. Publication of any 

submission, regardless of subject matter, 

will be approved by the AFMETCAL Division 

and submission does not guarantee 

publication. All submissions are reviewed 

for compliance with Privacy Act, FDO, 

STINFO, OPSEC and other information 

security requirements as applicable. 

How to Make a Submission: The AF- 

METCAL Newsletter editor transmits 

quarterly calls for inputs through the 

PMEL MAJCOM Functional Managers 

and other significant metrology program 

POCs to the respective PMEL managers 

and/or program functional offices. Normal 

submissions are in response to these data 

calls. Authors should submit their article 

inputs via e-mail through their respective 

chain of command to the AFMETCAL 

Newsletter editor. Authors may submit 

inputs out of cycle, but should use the 

same channels for those submissions. 

Deadline for submissions is the 15th of the 

month prior to the scheduled quarterly 

newsletter publication (publication months 

are March, July and November). Do not 

submit copyrighted material. 

Director, Air Force Metrology & 

Calibration 

Colonel Victoria H. Reed 

Editor: 

Bob Nappier 

Assistant Editor: 

Lee Wood

Page 3 

Chief’s Corner 




The Six Degrees of PMEL Change 

Wow, the AFMETCAL whirlwind tour continues. The past four 

months were fast and furious, driven by a multitude of concurrent 

budget constraints and transformation initiatives. While challenging to 

say the least, it also offered an incredible and rare opportunity to affect 

positive change on our program. One thing for sure, we are all 

connected in one way or the other by the upcoming changes to the 

PMEL landscape. I’ll call it the six degrees of PMEL change. Changes 

ranging from Repair Network Integration implementation; the soon to 

be vetted/released 2P manpower standard; significant changes to both 

AFI 21-101 and TO 00-20-14; results of sequestration on our day-today 

budgets/operations/civilian furloughs; and last but not least, significant 

changes to the Air Force Inspection System (AFIS) impacting the 

AFMETCAL Certification Team and ultimately, you. Since announcement 

of the Air Force’s “White Space” initiative and changes to the 

AFIS, the AFMETCAL PMEL Assessment and Certification Program 

experienced a multitude of modifications. Folks, put on your seat belt, 

because there’s more on the way. Tomorrow’s sight picture of the 

AFMETCAL Certification Team will be significantly different from 

today’s and that’s my focus; to provide some vision and insight on 

where we are heading regarding AFIS. But for some perspective, let’s 

cover a little of where we were and are. 

Chief Master Sergeant 

Martin McKinnon 

Chief, Laboratory Certification Branch 

Prior to the White Space initiative, AFMETCAL was the process owner for all assessment scheduling, criteria, notification, 

duration, result determination, certification, and finally reporting. We inspected for both capability/performance 

and compliance. Subsequently, the “White Space” and the initial phase of AFIS changes came down the pipe. A few of 

you have already experienced the results of this phase: Consolidated Unit Inspections (CUI)/(Tier 0, 1, 2), the tool used 

by the IG to combine required/desired functional inspections into 1- or 2- week inspection blocks. CUIs would include 

teams from LCAP, NSI, HSI, ORI, and/or AFMETCAL to name a few. While we aligned under the CUI concept, not 

much really changed regarding the AFMETCAL Certification process. 

The primary impact of the CUI concept to our AFMETCAL Assessment and Certification Program drove changes to 

when and how we perform our on-site assessments. Now, 95% of the assessment schedule is synchronized with the IG 

schedule. Notification flows through the IG to your wing/base Gatekeeper and not directly from AFMETCAL. 

NOTE: I need to foot stomp this one folks. AFMETCAL Certification Team members are considered trusted agents and 

we are not authorized to provide scheduled assessment dates. Please refrain from calling the team to request our on-site 

dates. We are not authorized to release this information to you until after official notification is released so hold fast for 

your official notification; it can be as short as 45 days depending on your MAJCOM’s notification policy. 

The term “synchronized” does a good job in describing how we are currently aligned with the IG’s schedule. We go 

when they go but we still currently operate somewhat independent of the IG. We have our own reports and in/out-briefs, 

we make our own travel arrangements and usually don’t wear the IG badge. Some other significant changes brought 

about by this phase included: on-site footprint was reduced to 5 duty-days, reduced/altered the Quality Program and 

Management System interview process, and we reduced assessment of some preliminary calibration steps. 

Finally, the meat of my message: Where are we heading? To frame this, I think I need to provide some key SAF/IGI 

changes that are driving this end state. There will be two major components to the new AFIS. First, the Wing 

Commander’s Inspection Program (CCIP) will be responsible for all compliance inspections at that wing. CCIP is the 

foundation of the AFIS and has two primary components: a wing inspection program and a self-assessment inspection 

(Continued on page 4)

Page 4 




Chief’s Corner (continued) 

(Continued from page 3) 

program. The wing IG, with support from subject-matter experts, will execute the wing inspection program to inspect 

Groups, Squadrons and other organizations below the Wing level. The self-assessment program, enabled by the 

Management Internal Control Toolset (MICT), will capture and report unit performance data to the chain of command 

and appropriate staffs. 

The second key element of the new AFIS is the Unit Effectiveness Inspection (UEI). The UEI is a significant change in 

focus for MAJCOM IGs. The UEI validates and verifies a wing CC’s inspection program and offers the MAJCOM CC 

an independent assessment of the unit’s discipline, effectiveness, efficiency and readiness. The UEI includes a 24-30 

month continual inspection cycle for Active-Duty and AFRC units/48-60 months for ANG and on-site IG visits to 

conduct focus groups, interviews, task evaluations, audits and observations. No later than 1 Oct 14, AFMETCAL will 

be fully integrated into the IG UEI. With this, you should expect the following changes to the current AFMETCAL 

assessments: 

1) AFMETCAL Assessment Team will inspect each PMEL during their UEI. Not all wing/base units or organizations 

will be assessed by the IG, but due to PMEL’s inherent risk associated with a break in safety, accuracy, reliability or 

traceability of measurements, PMEL will most assuredly be evaluated. 

2) PMEL assessment will consist of only performance based observations/task evaluations. We will no longer look at 

the facility, environment, Management System, or Proficiency Testing. We will focus only on the Measurement 

Capability Assessment and Quality Program Effectiveness pieces of the current assessment program. All the compliance 

based items will be passed on to the CCIP and MICT checklists. 

3) AFMETCAL Assessment Team members will become official IG Inspectors, but will no longer certify the PMEL. 

The MAJCOM IGs do not certify and we will be augmenting the MAJCOM IGs. Additionally, expect only IG in/outbriefs 

and reports. The AFMETCAL in/out-briefs and reports will no longer be necessary. 

4) Results will not be pass/fail. The IG/AFMETCAL will use elements of the 5-tier rating system. 

5) If significant problems exist, we won’t be dealing with certification withhold, we will be dealing with Corrective 

Action Plans (still worked through MAJCOM Functionals) with revisits still a viable option. 

While these changes are necessary in order to comply with new Secretary of the Air Force requirements and directives, 

they also come with the hope we can streamline the oversight process and place process ownership/compliance 

validation in the proper hands. The manpower utilized to “paint the grass” or ramp up for another inspection should now 

be utilized to strengthen day-to-day compliance. The wave of change is upon us and it’s time we embrace it and make 

the best of it. The delivery mechanism may have changed, but we will safeguard the ability to evaluate safe, accurate, 

reliable and traceable measurements and that’s what it’s all about. The six degrees of change will not impact the 

fundamental and underlying principle all of us are committed to – every step; every item; every day! 

MARTIN B. MCKINNON, CMSgt, USAF 

Chief, Laboratory Certification Branch/2P Career Field Manager 

AF Metrology and Calibration Division, AFPEO Agile Combat Support

Page 5 




News and Notes 

A Process Review Culture... 

Recently, I completed a lengthy analysis of the assessed PMEL quality trends from 2007-2012. This analysis involved 

the review of more than 250 assessment reports and over 60,000 data points. What did I find? Short story…the Process 

Review is KING! Below is the semi-longer story. 

To preface the results of this analysis, I would like to overview the value a process review (PR) and quality review (QR) 

provide to a PMEL. A PR provides a microscopic view into a specified area(s) of a process. This may highlight potential 

errors that could be passed on to effect end of line product quality. The knowledge gained from a PR is preventative 

and may identify areas of improvement. The actions resulting from process nonconformities are proactive in nature and 

should be used to continuously improve the production system. A QR is a complete review of an item at the end of a 

process chain within a production system. The knowledge gained from a QR is minimal as more data/information is 

usually required to determine cause. The actions resulting from quality nonconformities are reactive and require a PR to 

accurately determine how the nonconformity was caused. What does this overview have to do with the analysis? 

When looking at the data from 2007 to 2012, a clear pattern developed with respect to lab assessment pass ratings. 

Further investigation revealed that the culture of our PMELs was starting to change. In 2007, TO 00-20-14 (20071030) 

changed to include this statement, “All K-stamp holders shall participate in at least two PRs every 12 months.” As 

PMELs changed the way quality programs implemented this new requirement, the data received from the assessments 

began to show positive trends in assessment results. One way to highlight these trends was the creation of the PR/QR 

Ratio. The PR/QR Ratio is generated by dividing a lab’s PR count by QR count within a specified period. Example – If 

a lab has a PR/QR Ratio of 0.2, then the lab performs 1 PR for every 5 QRs. 

As seen in Figure 1, from 2007 to 2012, there is an increase in the average PR/QR Ratio per year for labs assessed. 

Figure 2 goes a step further and breaks out the average PR/QR Ratio for successful labs and unsuccessful labs. If this 

information doesn’t completely sell the value of PRs, Figure 3 (next page) may help. 

(Continued on page 6) 

Figure 1 - PR_QR Ratio for all assessments from 2007-2012 

Figure 2 - PR_QR Ratio Pass/Fail Comparisons

Page 6 




News and Notes (continued) 


A Process Review Culture…(continued) 

Figure 3 

PR/QR Probability 

Plot 

Figure 3 is a probability plot. A probability plot is typically used for estimation. However, in this manner, it is used as a 

qualitative tool providing a comparison from successful labs ( ) to unsuccessful labs ( ). With this in mind, 

the X axis is the PR/QR Ratio and Y Axis is the probability in percent. As we move up the Y axis to 50%, the two data 

populations cross the X axis at 0.25 PR/QR Ratio. This figure starts to paint a great picture on the effects PRs have on 

the lab measurement capability assessment (MCA) success at around the 97.5% mark on the Y axis. As can be seen, 

there is not a lab with a 0.45 PR/QR Ratio or higher that has failed an assessment to date. Additionally, the labs with 

greater success have higher PR/QR Ratios than most of the population of assessed labs. 

I know some readers are questioning how successful labs with a 0.2 PR/QR Ratio can pass while some unsuccessful labs 

have equal to or higher PR/QR Ratios. The answer to this question comes down to talent and hard work. After reading 

more than 250 assessment reports, I found the sole factor that determined a successful lab from an unsuccessful lab was 

the results of the MCA. Now some managers are nodding “Yes” as it has been stated over the years that the more PRs 

performed will most likely yield greater benefits to the calibration process. This data validates that a PR centered quality 

program may garner more successful assessment results and more importantly, increased end of line product quality. 

In conclusion, I would like to highlight some of the main takeaways from this analysis. First, the more process reviews a 

lab performs, the better chance it has to pass the MCA portion of an assessment and most importantly, the better the end 

of line product quality. Second, the difference between successful and unsuccessful labs comes down to the results of 

the MCA. The use of the PR is extremely valuable when this statement is taken to heart. As a technician, supervisor, or 

manager, you do not want to be blindsided with process issues that could have been caught during a PR. Lastly, if there 

is a technician, process, or capability that management wants to look harder at, use targeted PRs. Do not increase QR 

rates in hopes to identify QNCs that will ultimately generate a PR. Bottom line, dollar for dollar, the PR will make you 

more money in the long run. 

If you have any questions or comments about the analysis provided, please do not hesitate to contact me at 

charles.holman@afmetcal.af.mil or DSN 312-366-5096. 

MSgt Charles Holman 

Laboratory Certification Branch 

AFLCMC/WNMQ

Page 7 





PPC3 Low Pressure Secondary Standard Changed 

from N40 to Cal & Return 

The PPC3 (i.e. PPC3-200K BG15KP (W) DVU, WUC: WXSB0) was purchased by AFMETCAL from FY05 to FY08 

as a low pressure exchange standard. The AFPSL recently identified that the PPC3 exchange pool assets are too low to 

continue this effort due to many units being damaged. Because of spending cuts, AFMETCAL is unable to repair these 

units and therefore will be changing the PPC3 listing from Exchange to Cal & Return. Accordingly, damaged units will 

be repaired at the local PMEL level. These items have been in the field for many years and shipped from every PMEL to 

the AFPSL for calibration. While a few of the units were damaged by shipping, most of the units’ transducers have gone 

bad due to over-pressurizing and incorrect set up or use. 

Shipping issues were mainly attributed to excessive vibration which caused the loosening of the three screws that fasten 

the transducer bracket to a solid steel block inside the unit, in turn causing the transducer to be tossed around during 

shipping and ultimately being damaged. 

Picture of a unit with a damaged transducer during shipping due to a loose bracket. 

Over-pressurization can be caused by one of the following scenarios: 

 

Technician sets a pressure without the proper pressure or vacuum input sources applied (disconnected or turned off) 

to the PPC3. When realized, the technician tries to correct the problem without first venting the PPC3. This can over 

-range the transducer. 


Page 8 






 

 

PPC3 Low Pressure Secondary Standard Changed 

from N40 to Cal & Return (continued) 

Technician sets a pressure and then realizes there is a leak in the system. The technician tries to fix the leak without 

first venting the PPC3. This can over-range the transducer. 

The PPC3 is used as a monitor, and an external controller can easily over-pressurize the PPC3 and damage the 

transducer. 

To ensure the PPC3 does not get over-pressurized, warning statements will be added to the calibration procedures in 

which the standard is used. There are currently 21 calibration Technical Orders which utilize this item and they will be 

the ones addressed with these statements. The statements will be as follows: 

 

 

 

 

Ensure all proper connections are connected and opened before operating the PPC3. 

Always vent the PPC3 before fixing any leaks or calibration set-up. 

Never connect a pressure supply greater than 20% over the maximum control pressure of the PPC3. Only connect 

the pressure supply to the SUPPLY port. 

The PPC3 is a Pneumatic Pressure Controller. Do not use it as an indicator. Do not apply pressure to both the TI and 

the PPC3 Controller at the same time. If not strictly observed, could result in damage to, or destruction of, 

equipment or loss of mission effectiveness. 

George Ephrem 

Mechanical Engineering Section 

AFLCMC/WNMEM

Page 9 





ADC-2500 Inspection Procedure 

In the course of providing calibration support for an ADC-2500 Air Data Calibration Test Set, we noted what appeared 

to be shipping damage to the unit. We could hear a “rattling noise” when we moved the item within our PMEL—and 

that’s never a good thing. 

An inspection of the item revealed that the Power Supply and a Filter had become unsecure and damaged several connectors 

on a circuit board. We had noted a loose Power Supply assembly in another unit in the past—but simply reasoned 

it was an “isolated incident”—after all, we had never noted a similar problem before. However, now that we’ve 

identified another unit with the same issue, we reasoned that there might be a systemic problem with the assembly of 

the unit. 

Flipping the Power Supply assembly over, we noticed nothing out of the ordinary. A review of the maintenance data 

on the item revealed no specifications for torque of the screws holding the assembly to the chassis. However, there 

was no Loctite sealant or adhesive on the screws in question—this would certainly aid in keeping the unit secure. 

Therefore, we put together this small presentation to help you prepare your unit for shipment when calibration is necessary. 

If you’ll follow the enclosed instructions for each of your units prior to shipment, you can significantly increase the 

chances that your unit will arrive without damage and ready for us to calibrate. 

After the initial application of Loctite (or some other sealant/adhesive) to the screws in question, any future actions 

should be limited to a quick internal inspection prior to shipment—simply make sure the Power Supply and Filter 

Capacitor are securely attached to the chassis. 

Please direct any questions to our Production Supervisor, Mr. Steve Gordon or our Technical Expert in this area, Mr. 

Joshua Strickler at DSN 226-7011. 

Steve Gordon/RAF Feltwell PMEL 

Remove ADC-2500 top cover and locate Power Supply Assembly and Filter Capacitor 

Power 

Supply 

Filter 

Capacitor 

Continued on page 12

Page 10 





Continued from page 11 

ADC-2500 Inspection Procedure (continued) 

Remove the six screws securing the Power Supply Mounting Plate to the Chassis 


Page 11 







Rotate the Power Supply Assembly Mounting Plate so you can see the bottom surface 

Verify the four screws attaching the Power Supply Assembly to the plate are present and secure. It not already treated, loosen each 

screw in turn and apply Loctite or a similar adhesive to the screw. Then tighten each screw. Carefully re-position the mounting plate 

and secure to Chassis with the six screws previously removed. 

Power Supply Assembly attaching screws 


Page 12 







Verify the Filter Capacitor is tightly secured to the Chassis with screws on each side 

Replace Cover on ADC-2500. Ship at your convenience!!

Page 13 





Releasing Hidden Value Streams in the PMEL: A Shift in Perspective 

How invisible is your PMEL operation to your customer? For the 

PMEL, this question may bear significantly upon your customer’s 

satisfaction level. Finding value within an inspection activity can be an 

elusive endeavor, because a PMEL has a counterintuitive value-add 

structure inherent to its activities. Consider this: If the PMEL brings in a 

piece of equipment, tests the equipment, and the equipment meets its 

specification, the cost of calibration is sunk. The PMEL process 

contains very little value-add activity, beyond regulatory compliance, 

when product is conforming upon receipt. Historically, this is the 

paradigm in the Air Force laboratory, but a shift in perspective may 

unleash the potential for the PMEL to operate under a new paradigm 

that unleashes the hidden value streams within the PMEL calibration 

process. 

First, consider the implications of using automation beyond a simplistic 

assembly-line type increase in productivity. What if you went to the 

doctor and the only record your doctor kept was “Healthy” or “Sick”? 

How valuable are these records? These types of records are equivocal to 

the level of insight gained through most traditional calibration processes 

in use to date. The detailed records of a piece of TMDE’s health 

Mr. Michael Meggs 

coupled with the ease with which a computer amasses these records 

makes automation an integral development in the PMEL community. When faced with the decision between performing 

an automated or manual calibration process, the automated procedure should automatically garner preference solely on 

the basis of its data mining capabilities. These capabilities translate into reduced customer visibility by allowing the 

PMEL to isolate peculiar calibration conditions, such as measurements that are biased but that are consistently in tolerance 

over time. Without the capability to see the value of the measurement over time, the likelihood of an unnecessary 

adjustment will increase, thus resulting in increased turnaround times. Also, the PMEL will be able to predict calibration 

failure times by viewing measurements that are in tolerance across calibration intervals but that are drifting towards 

specification limits and plan accordingly through the production control process. Automation turns the sunk cost of 

inspection into an asset, namely the record of the TMDE’s quantitative condition rather than its qualitative condition, 

and this will unlock additional revenue streams over time as the laboratory explores new ways to interpret the data 

collected through automated calibration. 

Second, consider the value of your metrics from the perspective of the customer. PMEL technicians feel the pain of 

backlog, but do customers feel this same pain? Consider this: If you have a backlog of one million widgets with the 

capability to calibrate one million widgets with a one day turn-around, will your customers be dissatisfied? While the 

scenario is hyperbolic, its intent is to show the importance of production control’s duty of balancing inputs and outputs. 

With the assumption of a zero-day backlog at the outset, a perfectly balanced input and output from the PMEL results in 

no residual. One can see how the classical paradigm of more-is-better for production control does not fit the PMEL 

invisibility paradigm; rather, balanced-is-better is the name of the new game. The PMEL should strive to match its 

average daily output to its average daily input, else it becomes a bottleneck operation, either pushing unnecessary 

product to the customer or pulling unnecessary product into the lab. The time required for calibration must receive due 

consideration, and once more computer information systems prove invaluable in determining mean calibration time and 

the standard deviation of that time, in order to quantify the most economical point in time to bring the equipment into 

the laboratory. Operations management principles can be rigorously applied to quantify lead times with a fair amount of 

accuracy. 


Page 14 





Releasing Hidden Value Streams in the PMEL: A Shift in Perspective 

(continued) 


Finally, consider the impact of unleveled production extrapolated over time on the inventories of your customers. Backlog 

goes up in the PMEL, and the customer compensates with new inventory. The new inventory creates higher workload 

on the PMEL, and turnaround times increase further, ad nauseam, creating a flywheel effect on the calibration 

equipment inventory. How well do you know your customer’s requirements for TMDE? If true demand for quantitative 

measurement triggers the purchase of new TMDE, the PMEL should operate as the vanguard for the new acquisition, 

meaning the attrition of obsolete equipment that is being replaced by the new standard should be coordinated through 

the PMEL. The PMEL must also work to standardize TMDE across the maintenance complex, striving to provide 

TMDE with evidence of reliability through longer calibration intervals to customers with identical requirements. How 

many different brands of 200 inch pound torque wrenches with a 4% uncertainty are supported by your PMEL? One 

could argue that any answer other than one is not optimal, because standardization decreases training hours, changeover 

times, and ultimately turn-around time. 

Effectively using automation, production control, and standardization will allow the PMEL to increase customer 

satisfaction by decreasing the amount of time customer equipment spends in PMEL possession. This paradigm shift is 

not without obstacles, and customers must be convinced that letting go of excess safety stock will work to their 

advantage, so know what you do and why you do it. 

Michael Meggs 

Columbus AFB, MS 

From The Bench 

Noise Source Calibration System “Runtime Errors” 

Recently, during a capability assessment, we ran into an issue with our TA110000-622. 

While attempting to perform the system “Self Test”, we kept receiving either a 

“RUNTIME ERROR 9” or “RUNTIME ERROR 13”. After talking to other colleagues, I 

received mixed results. One base was sending their Noise Sources for lateral support 

because their NSCS kept giving errors and they had given up on trying to fix the system. 

Another base had no problems with using the NSCS. 

After a couple of days of head scratching, we got the system to work fully. What was the 

common denominator? We had been entering the values manually, meaning: via the 

keyboard, when changing Runs, Averages, etc in TO 33K4-4-729-1 for the values instructed 

to change. The last attempt, we used the drop down boxes to change the values the T.O. 

instructed us to change. The user MUST use the drop down options, when they are 

available, or else the system will Error out. We asked the base that was having no 

Pictured at left: Noise Source Calibration System 


Page 15 


From The Bench (continued) 



Noise Source Calibration System “Runtime Errors” (continued) 

Drop Down Box 


problems using their system to manually enter the values….they were now receiving RUNTIME ERRORS. 

Problem solved. We hope yours is too. 

Richard Curley 

Senior Metrologist, Kirtland AFB 

Pictured at left: 

Mr. Richard Curley

Page 16 



Gage Blocks 101 



The ability to wring Gage Blocks together is a source of pride for most seasoned Phys/D technicians. With a practiced 

hand, an individual can construct Gage Block stacks as easily as a child can snap building blocks together; however 

without this experience and practice, a new or rusty technician can just as easily drop or score these instruments 

making them unsuitable for use. How often have we encountered a Gage Block set that is missing the .110” block, or 

been working and heard the telltale sound of a block falling on the floor or worse yet, bouncing off of the support 

beams of a surface plate? Some of my favorites that were taught to me include: using oil from your skin to help the 

blocks wring together (but only if you need to) and using a calibrated surface plate to remove a burr from a gage block 

that was just dropped on the floor. Both of these statements are incorrect, but it is still commonplace to see them. We 

conduct training based on training plans, technical data, technical orders and AFMETCAL “white papers”; the notes, 

handbooks, and papers listed in the appropriate sections’ Functional Area on METWEB is simply another method of 

getting metrology concepts and methodology disseminated to the field and should be periodically reviewed. The 

purpose of the following article is to discuss how to wring two or more Gage Blocks together. 

What actually causes Gage Blocks to “wring” together though? According to The Gauge Block Handbook by Ted 

Doiron and John Beers, Dimensional Metrology Group, Precision Engineering Division, National Institute of Standards 

and Technology, Appendix B: Wringing Films it is stated that “it is probable that wringing is due to a number of 

forces…” which include the force of the atmosphere (101 KPa or 14 psi), metal to metal contact (causing a rather 

insignificant metallic bond) and the average wringing film thickness which depends on the fluid in the wringing film 

as well as the surface finish of the wrung surfaces. “The fluid between blocks seems to provide much of the cohesive 

force. No matter how a block is cleaned, there will be some small amount of adsorbed water vapor. The normal 

wringing procedure, of course, adds minute amounts of grease which allows a more consistent wringing force.” With 

the adhesive force between blocks measuring up to 300 Newtons (75 lbs) this “wringing film” constitutes a very large 

part of the ability for two or more Gage Blocks to be wrung together. 

Now that we’ve touched on the mechanics of why Gage Blocks adhere, let’s discuss how to ensure we have a 

consistent wringing layer. Assuming that all other factors have been addressed (cleaning, inspection, etc.) we start by 

placing a single drop of oil on the previously cleaned surface of the Gage Block to be wrung and rub the oil around it 

to coat the entire surface. The surface is then wiped dry using a lint-free cloth. What is left behind is a very thin 

microfilm of oil. This remaining microfilm of oil will allow the blocks to be wrung. Both surfaces being wrung 

together are cleaned using air or a camel hair brush if required. Two 

corners of the gage blocks are first brought together and then the block is 

brought into its final position in a rotating fashion so that once completed, 

the gaging points of the blocks are aligned. Slight pressure is applied on 

the top block and carefully slid over the bottom block. There should be a 

grabbing or adhesion feeling between blocks during this process. The 

entire procedure is well documented in “The Gage Block Handbook” as 

written by Kevin John at AFMETCAL which is available at the Length 

Measurement Engineering Support page on the Metrology & Calibration 

functional area, METWEB. 

DANIEL L. CLARK, TSgt, USAF 

PMEL Quality Assurance Evaluator 

96 MXS/MXMD, Eglin AFB

Page 17 



Importance of Calibrating Spectral Purity 



Have you ever driven down the road listening to the radio, and one radio station is overpowering the stations on either 

side of its channel? The Spectral Purity of the transmitter’s generator is most often the culprit. 

A little bit of research on the part of the calibration lab will ensure that the customer does not get a limitation that 

could potentially hinder their setups. The customer might unwittingly accept a limitation even though most work 

center PMEL monitors don't know how the generator under test is used, and some end-users do not know how spectral 

purity will affect the setup or test being performed. 

Phase Noise, Residual FM, and Spurious signals can impact any modulated signal, and can be detrimental to RADAR 

and Electronic Warfare (EW) applications. In the lab, a bad generator can impact your modulation test and give you 

false failures (or false accepts, depending on the situation). In the field, phase noise on the AM signals can impact 

VOR, ILS, GS, and other navigation signals. Digital communications could have packet loss from the phase noise 

jitter. Phase noise on RADAR may cause clutter and mask the small return of targets. 

Spurious signals are generally created through the process of mixing signals within the generator to get the final 

carrier wave. Often times, a Spurious Response is an integer multiple of the YO Frequency (harmonically related 

spurious). Other spurs can be the result of power line feed-through, induced from fan rotation, or the result of fluorescent 

lights. While most of the mixed components are filtered out, some signals do get through. In wireless communications 

systems, high levels of spurious signals can be a problem when they fall inside the channel. Generators can be 

within spurious specifications and still exhibit a problematic spur if it just happens to fall in a sensitive region for a 

specific test. I’ve seen many customers send in a generator with a note indicating a failure during their tests. Most 

often, the spurs pass calibration (even at the specific frequencies and settings the customer is using it), but are too high 

for their specific tests. 


Page 18 






Importance of Calibrating Spectral Purity (continued) 

Most phase noise is generated within the local oscillator(s). AC ripple from the power supplies may not be filtered 

entirely, and is subsequently transferred into the oscillator. This noise is amplified as the signal is fed through 

different stages and loops within the generator. This creates a band of noise surrounding the carrier wave. At times, 

this noise can spread over several kHz, masking nearby channels or transmissions. 

In AM transmissions, close-in phase noise may be denoted by a hum(s) in the transmission. This noise can overpower 

the modulation wanted within the system. Close-in phase noise (1Hz-1kHz) can play a significant role in VOR/ILS 

setups, interfering with transmissions to the aircraft avionics. 

In FM and PM transmissions, phase noise can cause channels to overlap. In today’s world of communications, more 

and more signals are filling the airwaves. As the available spectrum continues to decrease, so does channel 

spacing. This makes clean signals critical to the FM and PM transmissions. Phase noise in the pedestal region (1kHz 

to 100kHz) will impact channel spacing. Close-in phase noise will be heard by the receiver as static in the transmission 

over the audio. 

Effects of high phase noise on Channel Spacing 

In digital communications, highly stable oscillators are required to maintain multiple digital modulations simultaneously 

on the same carrier. Broadband generators built into the synthesized generators produce multiple carrier 

frequencies that are modulated, that are in-turn modulated on the source carrier. Phase Noise on any of the modulated 

carriers can cause jitter, resulting in lost packets of data. This can cause dropped calls by your cellular phone provider, 

missed transmissions for satellite links, or lost data packets carrying flight course information being transmitted to a 

drone flying over Afghanistan. 


Page 19 







In RADAR, systems continue to demand greater resolution of targets. This puts higher requirements for spectral purity 

on local oscillators/signal generators. For example, airborne and over-the-horizon radars want to detect slow moving, 

low altitude targets. They must detect very low level return signals, which have very small Doppler shifts. High phase 

noise will mask out the return of smaller signals. 

Phase Noise System 

Common measurement flaws: One of the issues with the phase noise measurement system is that you are mixing the 

generator under test against an “ideal, noise free” generator. Since there is no such real world device, you must either 

mix it against something you know is much better than the unit under test and assume that the ‘reference’ injects no 

noise. Another option is to mix against something that is equivalent to the unit under test, and assume equal 

contribution from both generators. Both of these methods are inherently flawed. By mixing against something better 

you are assuming no degradation from the reference. 

If you do have a reference that is 10 times better (i.e. 10dBc cleaner than your unit under test) the effects are minimal 

but there is still degradation in your measurement. By mixing against an equal source and assuming equal 

contribution, you should add 6dB to your target (if the specification at the 1kHz offset is -121dBc, verify the 

unit under test is below -127dBc), which allows you to accept results which really exceed the intended 


Page 20 







specification because there is another noise source. However, how do you really know that they are equal, and in fact 

most times they are not equal? One source will have better noise characteristics than the other and this creates 

ambiguous data. To solve this issue, when testing generators that have equal specifications, you should perform a 

3-source comparison. A 3-source comparison will allow you to isolate individual generators better within the system 

to improve the reliability of your measurement results. 

Some failures encountered may be unrelated to specific instrument being tested. Outside influence will often affect 

your spectral purity measurements as well. Power supplies from computers, monitors, and other test equipment can 

and will add additional noise to your phase noise measurements (as depicted in the two images below). Minimize the 

equipment located within the area of your setup for those ultra-low (-140dBc) measurements and reduce the faulty 

spurs. 

TCXO with monitor running 

TCXO with monitor off 


Page 21 







Remember that generators with poor specifications or degraded performance are unusable for some applications, such 

as testing radar and Electronic Countermeasure receivers and EW systems where the high level of spurious will appear 

as ghost (false) signals or threats. Generators with poor phase noise will not work for noise sidebands tests on 

spectrum analyzers. Generators with high spurious emissions can cause significant error with very high-speed timing 

tests, such as excessive jitter on the Agilent-Sampling Oscilloscope mainframe. 

Properly calibrating the spectral purity on generators will ensure that the pilot can see the targets on the radar, can talk 

to the other aircraft, and trust that the avionics will help him/her land safely when the job is done. 

Harry E. Burnsworth Jr. 

Technical Writer 

AFPSL 

Donald Sheppard 

K3/K4 Electronics Technician 

Wright Patterson AFB 

Pictured above: Mr. Harry Burnsworth Jr. 

Pictured above: Mr. Donald Sheppard

Page 22 



Fittings for New Vacuum Calibration System 

(969-8221M003/TPS COMPACT) 



The new vacuum system makes achieving high vacuum much easier than before while using the old VR300 cart. 

However, depending on your lab’s fittings, you might need to purchase a few adaptors to connect the PG7601 

Platform, vacuum exchange standards, etc. The fittings on the calibration spool are slightly larger (NW40) compared 

to the VR300 (NW16) or the PG7601’s platform (NW25). Fortunately all the adaptors can be purchased from Key 

High Vacuum and cost about $950 depending on your current inventory/needs. 

To adapt the spool to the GPH-320 sensor and SPC-935-G1 manometers you will need to purchase a few compression 

adaptors. The fitting for the manometers is a (KSA-3540) ½”. Two fittings are needed if you wish to use the 1 Torr 

and 100 Torr manometers simultaneously. To connect the GPH-320 sensor use a (KSA-3540-1) ¾”. To connect the 

PG7601 platform to the spool use two reducers (KSA-4825). This reduces the calibration spool’s flange from NW40 

to NW25 and will allow connection of the 1 Torr manometer and vacuum hose to the platform tee-fitting as outlined in 

33K6-4-3583-1. Please consult the Key High Vacuum website at www.keyhigh.com for current pricing. The site has 

a price lookup feature but contact them directly for shipping prices. 

Remember these are ONLY the minimum fittings required to connect the vacuum exchange standards and the PG7601 

to the calibration spool; more adaptors may be required depending on the items supported at your base. 

SSgt Nathan Layel 

Joint Base Langley-Eustis, VA

Page 23 


AFMETCAL Personnel Changes 

Assessment Team’s Latest Volunteers Welcomed 



MSgt Mark Reese MSgt Todd Meyer MSgt Chad Brown 

The AFMETCAL assessment team would like to welcome its newest volunteers: MSgt Mark Reese, 

MSgt Todd Meyer, MSgt Chad Brown, and their families. Each brings a diverse background and an 

exceptional metrology skill set from Shaw AFB, Ramstein AB, and Nellis AFB respectively. Their desire to 

gain added field perspectives and to contribute to the AFMETCAL Program has brought them to the team. 

We’d like to take this opportunity to say thanks to all three for stepping-up for this demanding assignment and 

for living their commitment to the Air Force and the Air Force Metrology Program. Please join us in 

congratulating them on their decision to join a great team. 

Darrell DeChon, MSgt, USAF 

Metrology Laboratory Evaluator

Page 24 




We’re On The Web! 

http://www.wpafb.af.mil/library/ 

factsheets/factsheet.asp? 

id=19755 

USAF METROLOGY 

AFLCMC/WNM 

813 Irving-Wick Drive W 

Heath, Ohio 43056-1199 

 

 

 

 

 

Some of the articles to look for in the next edition: 

Comments from the AFMETCAL Director 

Words of Wisdom from the Chief of the Laboratory 

Certification Branch 

News & Notes from AFMETCAL, the AFPSL and 

PMELs in the field 

Interesting articles From the Benches of PMELs 

throughout the world 

And much, much more! 

Submissions: We encourage readers to submit articles for the following categories: From the Bench 

(technical), About People (field personnel news), News & Notes (general information). Submissions should 

be in Microsoft Word, Times New Roman 12 font, accompanied whenever possible by digital photos in JPEG 

format. Native photo file sizes less than 2MB per image are preferred. Photos must be accompanied with 

caption information which fully identifies all individuals depicted, including rank, title or office, and event. 

Note that all text and photo submissions are subject to editing for content, cropping and/or size. All 

submissions that are technical in nature are reviewed by the AFMETCAL Engineering Branch (AFLCMC/ 

WNME) for accuracy and appropriateness. Publication of any submission, regardless of subject matter, will 

be approved by the AFMETCAL Division and submission does not guarantee publication. All submissions 

are reviewed for compliance with Privacy Act, FDO, STINFO, OPSEC and other information security 

requirements as applicable. 

How to Make a Submission: The AFMETCAL Newsletter editor transmits quarterly calls for inputs through 

the PMEL MAJCOM Functional Managers and other significant metrology program POCs to the respective 

PMEL managers and/or program functional offices. Normal submissions are in response to these data calls. 

Authors should submit their article inputs via e-mail through their respective chain of command to the 

AFMETCAL Newsletter editor. Authors may submit inputs out of cycle, but should use the same channels for 

those submissions. Deadline for submissions is the 15th of the month prior to the scheduled quarterly newsletter 

publication (publication months are March, July and November). Do not submit copyrighted material.

July 2013 - Wright-Patterson Air Force Base

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