McClellan AFB | Ultrasonic C-Scan Gantry System | 1984

McClellan Air Force base was heavily invested in NDT. They had real-time X-ray equipment from Ridge, which most facilities still used film, also lot’s of Eddy Current, hand held Ultrasonic Instruments and thickness gages, Magnaflux and Penetrant areas. Their in house maintenance of honeycomb structures was upgraded in 1984-1985 for automated Ultrasonic Bondtesting. McClellan was responsible for many fixed wing and rotary aircraft maintenance dating back to 1935, and they were closed in 1995 due to Federal Government budget cut backs. McClellan did all the bond repairs, structure and routine maintenance on aircraft like the F-111. This testing and maintenance which during the 1980’s as one inspector named this aircraft “The Flying Crack”- due to the numerous fatigue cracking issues in the air frame. The F-111 fighter was historically used back to the Vietnam War time period and still being maintained in the 1980’s.

Automation / Sperry worked with McClellan AFB to upgrade their facility. A large MIDUS digital controlled robotic gantry c-scan system was installed at the base in Sacramento, California for performing through-transmission Ultrasonic squirter inspection of various control surfaces that were removed from the aircraft being maintained. Previously, many of the manual inspections utilized the NDT Instruments 2100 bond tester, however for more thru-put of inspection Ultrasonic C-Scan was implemented.

This large system included a remote control panel inside the control room where what we called the “Star Trek” console was installed. At the time, the color graphic display was basically CGA like screen resolution- however the software was custom. Licensed from Boeing and Wayne Woodmansee’s group in Renton, Washington- the unique 1mm .040″ x 0.60″ sample points were represented when plotted on a Benson X-Y plotter in digital numbers from 0 to 9, with the grey scale pattern designed in these fonts. Boeing developed their own data acquisition c-scan software since the commercial manufacturers did not offer much at the time. Many of the designs were patented by their group. The computer used hardware for data acquisition, was a Data General Mini Computer running RDOS, which was a very cryptic command line operating system. Each scan line that was sampled and was stored as file on removable platter hard disk- ranging from a measly 5-10 Megabytes! The X- Axis robotic scanner with servo-step motors was fast-as I recall ramped up to at least 24 inches per second. The Automation designed MIDUS Digital Multi-processor board design was very unique at the time, as it used separate boards running Intel series 8000 microprocessors. Several boards were custom 8 layer PCB’s and had their own CPU’s so it was distributing processing and the system board software was in firmware- held on a re writable EEProm chip set of 8. The boards were stacked in an Intel I-bus rack and a central clock was used to sync the system. The MIDUS Software when printed on a line printer, the code itself stacked up roughly 18″-24″ from the floor, and was several years in development.

Ultrasonic NDT Research Laboratory

In order to develop inspection procedures and perform R & D in support of various large Aerospace programs, the NDT Labs at North American Rockwell had a long history and large inventory of various pioneering Ultrasonic Systems.

In the 1960’s in order to inspect the Apollo Command Module, specialized water jet squirters were designed and perfected for non-contact, non-immersion Ultrasonic NDT inspection. The only earlier usage were with the Krautkramer Bros. in Germany for steel plate inspection. This technique was copied throughout industry and then became standard within the Aerospace industry and Commercial Testing of Composite Materials and remains today.

Automation Industries US-642 Scanning bridge, US-950D C-scan recorder, 6′ tank with immersion turntable. The workhorse, industry leading 640 series featured high speed X or Y axis scanning for both through transmission and pulse echo inspections. It also was configured with dual 741 manipulators for independent control, all digital logic, servo step control designed around then reliable 7400 series IC’s.
NDT Testing Laboratory fully equipped for Ultrasonic R & D, show with computer tape controlled curve following module and the dry paper polar drum c-scan recorder (right)

Apollo 11 Command Module

Apollo 11 Command Module at Rockwell International in Downey, California
Apollo Command Module on display after engineering evaluations at the Contractor’s facility in California after being returned from space.

Once the Command Module was returned from space, it was evaluated in depth at the Rockwell Space Division facility in Downey, California. This was a one use design, unlike the future Space Shuttle. Especially of engineering evaluation post mission, was the bottom of the Apollo command module thermal protective ablative heat shield, that protected the Astronauts during the extreme temperatures experienced during reentry into the Earth’s atmosphere.

Real size mock-up of the first Space Shuttle at Rockwell Space Division in Downey, CA, the major prime contractor for NASA.

Automation Industries SR Series C-Scan Systems

The SR series were the first commercial product line available, and designed for Ultrasonic immersion inspections. This standard product c-scan system was manufactured in Chatsworth, California. Sold for both Research and Development as well as Production testing, they represented Automation Industries attempt at standardizing the Ultrasonic C-Scan system with interchangeable components- such as the US-710 Manipulator. The scanning axis traversed Y axis the width of the tank and the scanning bridge indexed along the X axis.

Produced from the 1960’s- they were used through the early 1980’s for military and commercial hardware immersion inspection production c-scan immersion inspections. The Alden “Wet Paper” recorder produced basic line scans of black and white (No grey scale) and came in rolls and indexed forward in sync with the X-Y axis scanning bridge indexing. The original application was in transmission of weather reporting data across the US, and it was adapted for use in NDT.

McDonnell Douglas 1988- Long Beach

Douglas Aircraft operated between 1921 through 2015 as a major prime contractor of Aircraft and systems.

Douglas Aircraft which started in 1921 at the Santa Monica Airport, was one of the largest private employers in the Southern California South Bay area, Douglas Aircraft led the US through many decades of manufacturing both Military and Commercial Aircraft. This particular brochure was printed in 1988 and covers a lot of area about Quality management, Internal Customers, Company Culture and other things.

For 65 Years, Douglas produced both Commercial and Military Aircraft. The facilities for production for both markets grew from 1.42-2.0 million square feet. Aircraft at it’s peak being produced included the C-47 in WWII and employing over 160,000 employees.

Later through the Korean and Vietnam Wars- the B-17 Bomber, B-66, C-124 were built there. Economic cycles came and went, in 1977 Military refueling tankers were built from modified from DC-10’s which first production for commercial passenger transport. Thanks to Jimmy Carter, this program was cancelled and thousands were unemployed. The 1980’s although were a boom period, required that Douglas Employees train Chinese visitors on all various aspects of manufacturing- in a trade for the purchase of Commercial Jets in China.

The 1990’s saw many changes to Southern California with manufacturing- the peak internal employment was estimated to be 44,000 workers. However, over 500,000-750,000 good paying jobs were eliminated during the Aircraft and Aerospace Industry contracted in So Cal.- this includes the myriads of local subcontractors supplying sub assemblies, to rivets. Small manufacturing suppliers such as Machine shops simply disappeared.

Boeing who merged in 1997 with McDonnell Douglas, eliminated duplicate jobs, duplicate products, extinguished it’s rival and sold off it’s property around the Long Beach Airport and Bldg 54 remained through the contract ending with the C-17 Military program finalized in 2015.

Historical NDT Imaging- CRT

For the first time on the internet, these historical images of various scans were made of brazed titanium test panels. 7-7a and 7-7b shown at different intensities. The uneven pattern imaging the honeycomb I believe was due to a variety of possible variables in the inspection process- off axis scanning, internal excessive braze material or alternative imaging methods. These were produced in 1956, and no specific notations were available from the research lab.

Automation-Sperry C-Scan-Midus-Robotic Scanning

1971 Forged Turbine Disk caused 1989 Crash

1989 Headline “Forging of flawed fan disk in 71′ spawned 89′ Crash” The Sioux City Iowa crash of the Douglas DC-10, United Flight 232 was a miracle. The 290 lb. disk manufactured at Titanium Metals Corporation of America in Henderson, Nevada, failed. The GE Engine built in Evendale, Ohio plant. Human error of switching serial numbers that trace each and every part had somehow been switched from a good part to a bad one. Disk MPO00385. Lot’s of finger pointing went on between GE, the FAA, NTSB, the Ultrasonic Inspection Lab, The disk manufacturer, etc.

The pilot Alfred Haynes did his best to emergency land the DC-10, without Engine 2 and hydraulics which were ripped apart by the exploding disk, but 112 people died that day in Sioux City. Read the entire original news article below that I archived years ago. Alfred Haynes has passed away at 87 years old, August 26, 2019 and saved the lives of 184 passengers and crew.

Normally, NDT is never mentioned- but in this case after a tragedy, it was. Ultrasonic Inspection is mentioned, as the public is not aware, but all Aircraft high speed rotating components go through in depth Ultrasonic, Eddy Current, Penetrant and Visual inspections. The turbine disks hold the turbine blades and are crucial to the engineering marvel of the gas turbine engine- we take for granted each time we fly.

Apollo Space Program 1964

Apollo Command Module Ultrasonic C-Scan System 1964- Budd Company

Behind the scenes, the Apollo Spacecraft in it’s entirety required rigorous physical testing, proof testing, fatigue, pressure and stress testing, visual inspections and re-inspections, many steps to insure all systems and sub components functioned perfectly. Many of those tests perhaps say software, or electrical wiring harness testing are well understood by many. However, still until now most obscure to the general public in quality assurance, and remain without much publicity-yet huge responsibility for safety behind the scenes were those in NDT.

Non Destructive Testing- or NDT, NDI or NDE to many people somehow has remained a small niche industry for many years. Steam boiler explosions in the East Coast were some of the earliest adopters of NDT. Companies such as Hartford Steam boiler in the early days went to embark into testing for corrosion and wall thickness measurements.

Occasionally, the mainstream news media will mention “X-Ray” but rarely anything regarding the use of Ultrasound for the inspection of materials for internal defects. Usually, in the course of investigating an air crash where an internal defect caused internal cracking which lead to a turbine to fly apart as in the famous Iowa United Flight 232 crash in 1989

1956, Earliest Ultrasonic C-Scan Images from Hughes Memotron Storage scope

The earliest Ultrasonic C-Scan Inspections were developed in Paramount, California using a Hughes Memoscope- which was a storage oscilloscope and each X-Y planar view scan once completed was documented with a simple black and white photo. The scanning equipment and instrumentation was developed by (3) business partners Lee Furon, Don Modispacher and Nat Jeffras worked at Automation Instruments. Using their equipment at Automation Instruments, Cal Kammerer in 1956 provided the earliest known C-Scan recordings for Industry. Later the company grew into Automation Industries which many of us in the NDT Equipment industry worked for until the late 1980’s when it was purchased by Staveley in England, then closed.

Reduced Turntable drum C-Scan inspection using the squirter technique to inspect the Apollo Command Module Phenolic and composite structure
Apollo Command Module Ultrasonic Squirter NDT C-Scan Inspection 1964, Cal Kammerer (Left), Dan Norris (Right) Note empty area- which was the trapezoid shaped section was the entry door for the Astronauts to enter into the command module.
1965 photo of the Apollo Command Module being inspected at North American. This mechanically synchronized ultrasonic c-scan reduced model (left side) recorded the ultrasonic data while the Command Module (right) in production after bonding was inspected for internal defects with through transmission 2.25Mhz opposing water squirters. This was the first large scale system with a turntable c-scan system ever developed- at the time Budd Company, previously Automation Instruments. Dan L. Norris is seen controlling the inspection.

Sonic Testing and Engineering 1977

Founded in the 1970’s by the Torkelson twin brothers- Dean and Dale (Eugene), and later brought in Dan L. Norris operated one of the most busy, successful and “can-do” NDT Testing Laboratories on the US West Coast. Located in South Gate, California near the corner of Imperial Highway and Garfield Ave.

I was fortunate enough to learn the specialized trade of Ultrasonic Non Destructive Testing working for this company in the late 1970’s. As a commercial testing laboratory STE had at the time had the most Ultrasonic C-Scan capability including turntable c-scan equipment. Though they did not have solid state scanners yet, the AI SR-150 series scanners used vacuum tubes and were surplused by local prime contractor companies were purchased or loaned. Dan Norris was responsible for bringing C-Scan Inspection into STE, which until his arrival STE focused mostly on manual Ultrasonic Inspection methods such as contact, immersion hand scanning and immersion manual scanning for wrought materials and rolled aluminum plate and bar stock. Dan had worked with my father Cal Kammerer together at North American during the Apollo program, where they innovated and perfected Ultrasonic Through Transmission Squirter Inspection for the various structures and components most notably the Apollo Command Module. Sonic Testing and Engineering also lead the market among all the other Los Angeles area test labs not only in equipment, but in problem solving, creating true reference standards with EDM notches and flat bottom holes in materials which were difficult to machine with conventional tooling and carbide drills. The hands-on engineering and providing NDT solutions that other Prime contractors could not or would not do themselves- was their market niche as so few people in the USA actually had experience in this small niche industry. During this time such large companies who did not have in house personnel or equipment necessary for specialized NDT- outsourced it. Sub Contractor companies now long gone from Southern California such as Ladish Pacific, Reisner Forge, Schlosser Forge, Martin Marietta Aluminum (Later International Light Metals), Alcoa, employed roughly 500,000 people at it’s peak in time.

During this booming era prior to the pre-cold war ending in 1989, STE lead the NDT market and was one of the most capable labs located in the greater Los Angeles area. Many NDT Technicians were apprentices (Level 1 or Level 2 Technicians) at this Company and went on to work for large prime contractors such as Rockwell, Northrup in Hawthorne, General Dynamics, Rohr Industries, Grumman, Douglas Aircraft or founded their own NDT companies in various niche markets such as in the lucrative field inspection in the Wilmington area Oil Refineries, Los Angeles Harbor Shipyard work or as in my case NDT Equipment sales and manufacturing. During this time, many local Southern California companies actually provided the bulk of the materials and process technologies in support of the Aerospace and Aviation industries. Southern California had a large concentration of many manufacturing jobs at this time- 1000’s of small machine shops to larger rolled aluminum plate and tubing manufacturers, hand forgings, and forged high temperature alloy high speed rotating parts for General Electric and Pratt and Whitney. High nickel content non-corrosive exotic alloy materials such as Waspalloy, Astrolloy were routinely inspected completely after being machined in-house or locally, then the surface preparation onsite by grinding was done on site, then surface etching, ID’s and then with Liquid Penetrant and many directions of coverage of Ultrasonic Longitudinal and Shear wave inspections. The late 70’s also saw the mass adoption for Aerospace the graphite epoxy and graphite polyimide composites. Many parts that were under inspection at this time were for the F-18, was one area that STE contracted to inspect many compound curved and complicated shaped honeycomb parts were outsourced from Northrup (the McDonnell Douglas subcontractor as well).

This period of the late 1970’s-early 1980’s and this industry was a lucrative one to be in at the time. The owners were also generous with their profit sharing programs. I started right out of high school at $3.00 an hour doing heavy forging hand scanning work and kept getting trained and received hourly increases until reaching $11.50 5 years later as a certified NDT Level 2 technician and concentrating on doing c-scan work- mainly for the F-18 program. This experience was not taught in any University anywhere, you could not get a degree in NDT anywhere in the world- at least one that meant anything. Sure some NDT was taught for aircraft inspection and Embry Riddle, but nothing like working for Sonic Testing and Engineering which was a daily learning experience with all sorts of complex applications from inspection of electron beam welds for the Space Shuttle to Squirter UT Composite inspections- on various honeycomb materials. Competition was not that much compared to other “regular” industries and the volume of work was available for everyone in the true competing testing labs- such as General Inspection in nearby Cudahy, California who also had been around for many years and operated by John Barriatua who also worked with AI in the early days. General Inspection while they did casting inspections which were not done at STE- General did rolled plate, bar and c-scan work they concentrated on X-ray work, which Sonic Testing never entered.

STE was actually located within a few miles of where the Ultrasonic C-Scan was developed at Automation Instruments in Paramount, California in 1956. This early work was in support of the XB-70 bomber program which used brazed titanium honeycomb structure and needed pulse echo and thru-transmission inspections. Prior to the Apollo program in the 1960’s.

STE- also did their own surface treatment via grinding to bring the material surfaces within specs for near surface resolution- eliminating rough machining grooves, and sand blasting. Other services included Liquid Penetrant, Magnaflux (Magnetic Particle), Eddy Current Conductivity, and rough machining of exotic ring alloys. Off site, STI- known as Surface Treatment and Inspection did Acid etching and chem milling and operated as a subsidiary to STE, until local regulations on pollution control required it be closed.

STE was sold and merged with other test labs after the industry contracted, shrank and changed, but the billions of dollars of critical military and commercial hardware that was inspected and still some in use today, the careers and wealth that was built around it remain a legacy.

Upper 2 photos and Lower right: F-18 composite inspection with Ultrasonic Squirter Thru transmission, Automation SR-150 Scanning Bridge, North American Aviation Squirter design, 2.25Mhz Transducers, Automation Immerscope 725- Lower Left: Author at work in 1978 on General Electric High Speed Turbine disk turntable inspection.