About VREF

VREF Aircraft Value Reference, Appraisal & Litigation Consulting Services was founded in 1994 and is based in Buffalo Grove, Illinois, with representation in over 40 global locations.

VREF provides industry-leading aircraft valuation data through online subscription services (SaaS), published quarterly books, and is the largest aircraft appraisal firm worldwide, completing over 20,000 valuations a month.

VREF provides appraisals and advisory services to a worldwide client base of aviation professionals, including every major OEM, financial institutions, broker/dealer, and insurance underwriters, as well as the general consumer. VREF is the official Valuation Service and Appraisal company for the AOPA and the only aircraft appraisal software endorsed by the American Society of Appraisers (ASA).

Meet the VREF Team

Jason Zilberbrand, ASA, CAA, ISA AM, AOA AM, MRAeS

President & CTO

312-961-0934 | [email protected] | Linkedin ProfileCurriculum Vitae

Jason Zilberbrand is the President of VREF Aircraft Value Reference & Appraisal Services. He is a Accredited Senior Aircraft Appraiser with the American Society of Appraisers (ASA), and an Accredited Member of the Appraisers National Association (ANA), and he is also an Accredited Member of the International Society of Appriasers (ISA),  Expert Witness,  broker,  inventorying dealer, acquisition agent, aircraft owner, aircraft operator, contract negotiator, consultant, teacher, conference speaker, and author. Jason spent over 15 years as an inventory aircraft dealer with a $300-million-dollar credit facility, and over $4.5 billion in aircraft transactions.

After spending 25 years in General Aviation working directly with aircraft owners, operators, and owning and operating his own aircraft, Jason knows the international aviation marketplace. He is considered an expert in aircraft valuations and aircraft transactions, and his background is diverse with knowledge in technology and aviation.

Areas of aviation expertise include:
• Business aviation transactions
• Breach of contract disputes
• Corporate breach of contract
• Back to back disputes
• Agent agreements
• Aircraft valuation
• Aircraft diminution of value, post-accident damage, insurance claims
• Aircraft Depreciation, historical depreciation
• Engine maintenance programs, Airframe Maintenance Programs, Power by the hour programs contracts, and standards
• Statistical analysis of aircraft values
• Aircraft resale, aircraft import/export

Jason graduated in the top 1% of his class with National Honors from Roosevelt University in Chicago as well as a lifetime member of The Franklin Honor Society and a member of the Royal Aeronautical Society. Jason is an avid Triathlete, marathon runner, swimmer, and cyclist and enjoys spending time with his family. Jason is currently the Director of Public Relations for ASA Chicago Chapter 33.

Ken Dufour, ASA, MAM, ATP, CFI


815-633-1684 | [email protected] | Linkedin Profile

Mr. Kenneth Dufour, ASA is the CFO of VREF and was appointed as Alumni-At-Large Trustee for Embry-Riddle Aeronautical University in October 1998. He now serves as the Chair of the Student Life Committee and is a member of the Development and Flight Safety and Education committees. Mr. Dufour is also the Chair of the Alumni Advisory Council. Mr. Dufour is an accredited senior appraiser with the American Society of Appraisers (ASA).

Dufour’s aviation career spans more than 30 years of involvement. He has held positions as regional vice president, area manager, and regional marketing manager for leading industry companies like Gulfstream Aerospace, Honeywell, BF Goodrich Aerospace, AlliedSignal, and Litton Aero Products.

Dufour earned a bachelor’s degree in professional Aeronautics and a Master of Aviation Management degree from Embry-Riddle Aeronautical University in Daytona Beach, Florida. He is a licensed Airline Transport Pilot and a Certified Flight Instructor for Single-Engine, Multi-Engine and Instruments. Dufour is a member of the American Society of Appraisers, where he holds the designation of Accredited Senior Appraiser (ASA). Previously representing the National Aircraft Finance Association on its Board of Directors, Dufour now serves as an active member of the organization.

Leo V. Heidemann, ASA

Senior Aircraft Appraiser

815-519-7311 | [email protected] | Linkedin Profile | Curriculum Vitae

Leo Heidemann, ASA,  is a senior aircraft appraiser, and he has over 30 years of experience in aviation. He has been a full-time aircraft appriaser since 2001 and he has completed thousands of appraisals for fixed wing aircraft including piston, light sport, experimental, museum, war birds and business jets. Previously to becoming an aircaft apprisaer, Leo was a Support Equipment Engineer with Pratt & Whitney Aircraft Government Products Division and he developed ground support equipment for the F100 and TF30 enignes. Leo is a member of the Ameican Society of Appraisers and he holds a Accredited Senior Apraiser designation in  Machinery and Technology Specilities.

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