EMC Personality Profile


Doug with the remaining USAF CT-43A during ground testing at Ramstein AFB April 1996.

Having heard Doug Hughes’ 2001 DOD E3 Program Review Paper Aircraft E3 Upsets in Las Vegas, I knew he had been involved with several interesting and high profile aircraft safety and accident investigations. I had occasion to hear some details recently when I stopped in his Alion office in Annapolis since we were working on the same Department of Defense Ultra Wideband study. As Doug and I talked about his work, I realized that he would be a good candidate for the EMC Personality Profile column. I thought that our readers would be interested in some of his high profile endeavors. References are provided at the end of this article for those readers that may be interested in obtaining more information.
Doug didn’t choose EMC as a career. It chose him. He obtained his first amateur radio license while attending a high school in a small Missouri Ozarks town. He has held K0LGZ, W0JBK, W3EWP, and is currently W3HO. Ham radio, electronics, and playing the trumpet were his passions during high school. Jazz trumpet players normally starve, while electronic engineers don’t, so his educational direction was easy. Doug admits his trumpet skills are limited, even today.

Doug Hughes, USAF CT-43A Accident Investigation, Flight Test Technical Director, over Croatia, May 1996.

The University of Missouri at Rolla was within budget and commuting distance for Doug and it had a great ham station W0EEE, so he obtained his BSEE there in 1963. That university didn’t have the EMC reputation it has today, but at least four of Doug’s classmates ended up doing EMC work professionally. Bill Hord went on to receive a PhD from Rolla and make his fame in the radar field, but he was Doug’s EM theory teacher while a graduate assistant. Even Bill couldn’t make Doug understand Maxwell’s equations. It was Doug’s most-hated course and would become his nemesis. What goes around, etc.
Like many UMR graduates, Doug went to St. Louis to work for McDonnell Aircraft, eventually McDonnell-Douglas, and now Boeing. Mr. Mac probably rolled over in his grave after the Boeing takeover/merger (many say that MacAir took over Boeing, but that is out of scope for this profile).
Assignment to MacAir’s excellent EMC group on the first day out of the three-week drafting school was a stroke of good (or bad, depending on outlook) fortune for Doug. He was trained by the St. Louis EMC experts: Gus Weinstock, Phil McBrayer, Walt McKerchar, and UMR classmates Dick Shimamoto and Cliff Skouby.
Doug did a lot of interface wiring design, subcontractor monitoring trips, aircraft testing, proposal writing, and future technology work while with MacAir. He also met and married a student nurse named Sandy.
One of the most enduring of the MacAir educational experiences dealt with the RF susceptibility of position-transducer-fed flight control avionics. The Phantom II (F/RF-4) aircraft was in production during that era and included an Aileron-Rudder Interconnect (ARI) circuit. Signals from position transducers on each aileron were added, amplified, and used to control a hydraulic valve to add a small amount of rudder when turning. The Wright Brothers had a mechanical method to do the same to connect their wing warp and rudder on the original Wright Flyer. The hip cradle controlled it – they literally flew by the seat of their pants.
Emissions from on-board communications transmitters would couple into the wiring between the aileron position transducers and the ARI amplifier at the vertical stabilizer base. It even happened once during an important sales flight when the Shah of Iran came to St. Louis to purchase some F-4s. He was flying the back seat of an RF-4 and noted controls for the high-frequency (HF) radio. The Shah received permission from the pilot to operate aeronautical mobile on the HF ham bands using his ham radio license. It was embarrassing when his ham transmission caused the rudder to move.

CT-43A Crash Position Indicator Signal Coverage Diagram as predicted by JSC/Alion staff Linda Sparks, Richard Albus, and David Quasny.

Doug was taught that there is no such thing as an uncommanded flight control surface movement. Increased wire shielding and ARI amplifier filtering fixed the problem. Doug participated in the ARI and nine additional air safety investigations during his five years at MacAir. He didn’t know Dick Ford back then, but both had a part in the Forrestal Fire investigation. Doug was asked to perform the circuit analysis of the LAU-10 rocket launcher pod to determine the possibility of CVN-59 on-board radar emissions to cause inadvertent missile launch from a MacAir product F-4B parked on deck 29 July 1967. The missile hit a parked A-4 and knocked off the center fuel tank starting a fire with 134 fatalities. John McCain (now Senator McCain) was in the A-4, but escaped, only to be shot down and captured a few weeks later.

Doug and Sandy Hughes.

Doug was directly involved with resolving a fatal EMI problem with the F/RF-4 lower UHF communications antenna coupling to the nose-gear steering electro-hydraulic system. Again, it was RF susceptibility of signals from position transducers.
Another interesting safety investigation while at MacAir involved EMI between F-4 and RF-4 radars that were allocated to the same frequency band. Doug was assigned to be the liaison engineer for a study to be done by John Wibbe at the DOD Electromagnetic Compatibility Analysis Center (ECAC) in Annapolis. This led Doug to join the ECAC/IITRI staff in late 1968 “for just two years.” Doug was planning to spend the time learning everything about EMC at ECAC and then return to share it at MacAir. Doug is now with Alion at the DOD Joint Spectrum Center, so only the names have changed, the job is still about the same 36 years later. Doug has said he never returned to St. Louis because he never learned everything about EMC.
Upon moving to the Annapolis area, Doug resumed his graduate studies at George Washington University and received a MSEE in Communications Theory in 1971. He and I took the Coherent Communications (phase-locked-loop) course from Vitirbi’s book together. We ended up teaching the professor more than he taught us. Doug had actually built a phase-locked loop in a ham radio frequency synthesizer.
EMC engineering at ECAC/JSC/ IITRI/Alion is anything but dull. Doug, like many of his colleagues, has been called upon to do a large variety of important projects. He has defined and performed EMC tests; helped to develop the center’s major Cosite Analysis Model; performed many analyses of densely packed radiating/receiving electronics; spent eight years doing personnel and project management including hiring, development, training, project production, etc; platform equipment placement studies; DOD equipment technical database development and spectrum certification; electronic warfare EMI fratricide deconfliction; developed EMC analysis methods for low-observable platforms: frequency management studies of frequency-agile DOD systems; frequency sharing studies of civil and DOD systems with common frequency allocations; and involvement with the on-going ultra wideband decisions.
But Doug is most proud of his work with air safety studies, including combat search and rescue. Since 1997, Doug has supported the development of the Combat Survivor Evader Locator (CSEL) system. CSEL will save many downed airmen’s lives in the future.
During the mid 1990’s, Doug noted the literature mentioning that the commercial Boeing 737 airliner had problems with erratic rudder movement. He suspected EMI, and the DOD has small fleets of B737 derivative aircraft, so he arranged an EMI-Lessons-Learned brief to be given to the staff of the US National Transportation Safety Board (NTSB) in early February 1996. That presentation led to Doug being called upon to participate in many accident investigations as an EMC subject matter expert. The lessons learned were many and beyond this profile. A number of URLs are appended to this profile for readers to study independently. Doug is also available to answer specific questions via his home e-mail at isasim4415@aol.com.

Doug and Sandy with family.

Many readers already know of the JSC involvement with the USAF IFO 21 (Ron Brown Department of Commerce Mission to Croatia) and TWA 800 accident investigations. Doug and Rich DeSalvo were called upon to go to Ramstein AFB Germany and to Croatia as JSC’s on-site representatives to the USAF Accident Investigation Board for the IFO 21 CT-43A accident of April 3, 1996 in Croatia. Rich and Doug had both served on the RTCA’s SC-177 study of portable electronics EMI aboard aircraft, and there was a suspected mobile telephone use during the critical approach flight phase. Doug, Rich, and a large group of support staff back in Annapolis and with the FAA in DC and Atlantic City investigated this and 13 additional E3 issues. A major finding was due to JSC’s analysis of why the Crash Position Indicator signal could only be detected by search and rescue aircraft to the northwest of the accident site. Both the mountain and aircraft vertical stabilizer shielded the radiation in other directions. Results of the JSC work were included in the Board’s briefing, which was given to President Clinton and Vice President Gore on June 6, 1996. Interested readers are encouraged to down load the excellent summary published by the Flight Safety Foundation. A link is presented below.
Doug and fellow JSC/Alion staff member Martin Macrae performed the TWA 800 and subsequent Swiss Air 111 and Egypt Air 990 EMC analyses for the NTSB and Canadian Transportation Safety Board. Rich DeSalvo provided the JSC interface. An English professor at Harvard had written a series of papers calling into question the need to study the possibility of RF emissions from DOD transmitters causing EMI to these three aircraft. Her work received wide distribution, and she was even interviewed by Katie Couric on the NBC Today Show.
The NTSB spent approximately $1M on the TWA 800 EMI investigation, including full-scale ground testing in New Mexico of a B747-100 and center fuel tank wiring. Applicable links are presented below. No EMI source was found to be causal, but switching transients were measured within an order of magnitude of the 0.25 mJ HERF threshold. An order of magnitude below switching transients as an EMI source were portable electronics, and yet another order below portable electronics were sources from the external electronic environment, the original hypothesis of the Harvard professor, Dr. Elaine Scarry. The EMC analysis material appears on pp. 159-164 of the NTSB TWA 800 report. Doug wrote the last paragraph on page 160.
The external EM environments were predicted for TWA 800, Swiss Air 111, and Egypt Air 990. Potential EMI causes of an 18-minute Swiss Air 111 VHF communications blackout were also postulated for the Canadian TSB.

The three Michigan grandsons with their game faces.

Doug is a full member of the International Society of Air Safety Investigators (https://www.isasi.org) having performed the mandatory ten investigations by 1967. He has participated in a total of 29 investigations, two of which were in support of American Airlines.
Doug’s wife Sandy is a Registered Nurse working in a private OB/GYN practice. They have a daughter and son, both of whom are married to their college sweethearts. Their daughter Laura is also a Registered Nurse, works at the University of Michigan Hospital in Ann Arbor, married to an industrial engineer, and mother to three active hockey-playing boys. Their son Darren is an English PhD candidate at the University of Tennessee, a web site developer, and is married to a famous forensic artist.
Doug and Sandy hope to retire to Michigan in early 2005 to be closer to the grandsons and to “the child who will pick their assisted-living home” in the distant future. Doug plans to continue building a model railroad in the Michigan basement and to be on call for interesting air safety investigations involving those weird radio frequency signals and EMI. A quote of his is popular with fellow practitioners in the small air safety investigation community – “EMI leaves no scratch marks.”
Selected URLs
Joanna & Darren Hughes
Doug’s Model Railroad
CVN 59 Forrestal Fire (7/29/67)
IEEE SPECTRUM - September 1996
IFO 21 (4/3/96)
https://www.flightsafety.org/pubs/fsd_1996.html (Flight Safety Digest, July-August 1996: pp 1-25, CPI coverage page 15, E3 pp 18-19)
https://www.rvs.uni-bielefeld.de/publications/ Incidents/DOCS/ComAndRep/Dubrovnik/summary-T43.html
TWA 800 (7/17/96)
https://www.ntsb.gov/events/TWA800/exhibits_web.htm (Systems Group Reports in .PDF)
Korean Airlines 801 (8/6/97)
AAL 1340 (2/9/98)
Swiss Air 111 (9/2/98)
Thai Airways International Tg261 (12/11/98)
Global Hawk vehicle went out of control over the China Lake, CA range due to an inadvertent command-destruct signal from the Tonopah, NV range and was destroyed.
Egypt Air 990 (10/31/99)
AAL 1291 (11/20/00)
Thai Airways International Ltd fatal B737-400 fuel tank explosion at Bangkok, Thailand (3/3/01)
AAL 587 (11/12/01)
TWA 800, Egypt Air 990, Swiss Air 111, and Electromagnetic Interference (Dr. Elaine Scarry of Harvard theory)
© 2004 Douglas J. Hughes
Used by permission EMC

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