Dan Hrehov has over 30 years of experience in flight testing for virtually every Boeing model. The first third of his career focused on planning and conducting avionics and automatic flight control testing. The second third, he was a lead flight test engineer responsible for a group testing navigation and communication equipment. The final third comprised special assignments in flight test safety and helping set up the FAA's Delegated Organization. He has authored several papers on topics like electromagnetic compatibility, flight test safety and risk assessment, and certification of flight test instrumentation.

1. Dan Hrehov Career Highlights
With over thirty years flight testing experience covering virtually every Boeing model, my career can be
logically split into thirds, the first third planning and conducting many avionics and automatic flight
controls testing. This included autopilot, FMC, autothrottle, Nav and Comm radios, WXR, Displays,
EPGWS, Ground Prox, TCAS, FDR, CVR, IFE equipment etc. The second third devoted to being a lead
flight test engineer responsible for the Nav/Comm Analysis group of twelve engineers which planned,
conducted and reported on the testing listed above. And the final third comprised many special
assignments primarily in the flight test safety and regulatory areas in setting up a FAA Delegated
Organization. Below is a summary of selected accomplishments. Many of those accomplishments
resulted in authoring the seven papers or presentations prepared for SFTE symposiums. Copies of the
abstracts are available upon request.
Electromagnetic Compatibility/Interference (EMC/EMI) Pertaining to Flight Test
EMI had been a topic not very well understood in the flight test community both at the FAA and here at
Flight Test. It was a source of much confusion as to who was responsible for finding compliance to the
FAR 25.1431c. I saw this as an opportunity and partnered with the FAA Chief Scientist on EMC who
shared my concern and co-developed a training class on EMC. I tailored an EMC class for flight test
pilots and engineers and then presented it to all of flight test and then at several SFTE symposiums across
the country. After ten years I still teach this class to flight test pilots and engineers here at Boeing which
has resulted in a better understanding of how flight test crews test for EMC.
Flight Test Safety and Instrumentation Safety Focal
In the early 90's I was on the original team formed to develop a Flight Test Risk assessment process for
Boeing Flight Test. This team developed the process to identify flight test risks, assign likelihood and
consequences and then develop alleviations to minimize the risk. This was later adopted by the FAA and
with some enhancements became the FAA Order 4040.26 for flight test risk management.
I am responsible for evaluating and approving the installation and use of carry-on test equipment, such as
oscilloscopes and laptops, on test aircraft. This included a Safety-of-Flight evaluation that included
structural, environmental, EMC and operational considerations. My experience as a Systems and
Equipment AR provided good insight in this area. I prepared a SETP workshop presentation on the
unintended consequences with instrumenting airplanes and how to alleviate the risk.
FAA Delegated Organization and AR Advisor
Boeing became delegated organization in 2004 and I was very involved from the beginning in setting up
the flight test processes and procedures and documenting them in our Procedures Manual. These are
some of the tasks and responsibilities as an AR Advisor.
 Creating and revising sections of the procedure manual related to flight test that govern the
operation of the delegated organization
 Responsible for re-current training of the flight test Authorized Representatives (AR).
 Created the training plan for prospective flight test ARs.
 Conducted the evaluation panel for prospective AR and those wanting an expansion in
responsibilities.
 Conducted annual performance evaluations for over 20 ARs.
 Acted as intermediary between flight test and design engineering ARs when disputes arose.

2. Flight Analyst AR
As a Flight Analyst AR for the delegated organization I reviewed certification plans, prepared and
approved flight test plans, witnessed airplane ground and flight testing and wrote and approved flight test
reports. This is in the area of Avionics and Autoflight.
Systems and Equipment AR
As a Systems and Equipment AR for the delegated organization I was responsible for the certification of
flight test data systems that could be installed and used on customer airplanes in revenue service. These
small data systems recorded both digital and analog data and were certified to Part 25 requirements. I was
responsible for the certification of this equipment that included preparation of certification plans,
preparing and approving qualification test plans, witnessing qualification tests, preparing test reports,
preparing safety analysis that included failure analysis and FMEA studies, and reviewing and approving
service bulletins on the data system installations.
Lightning Protection of Instrumentation
In certifying the portable flight test data system for in-service use after becoming a Systems and
Equipment AR, I recognized the need for a better understanding of lightning protection for
instrumentation wiring for the normal flight test airplanes. In the process of getting through lightning
qualification testing, it became apparent lightning protection knowledge amongst the Instrumentation
engineers was not very sophisticated. Through my research I was able to make recommendations to that
group to better protect both the airplane and data system from the hazards associated with lightning. I
reviewed their drawings and made recommendations for better protection. That organization now takes
ownership of lightning protection and now does a fine job. I wrote a SFTE paper on this topic that won a
Best of Session award.