• 06 Jul 2025 06:55 AM
• 0

Q&A With Buddy Denham, Joby Aviation

By Alex Scerri

James “Buddy” Denham is Joby Aviation’s chief test pilot. He joined Joby in 2019 after retiring from Naval Air Systems Command, where he was recognized as an Esteemed Fellow. For the Navy, he focused on the research, development, test and evaluation of advanced flight controls and flight dynamics for a wide variety of aircraft. He led the research and development of the Unified Control Concept (UCC) — a joint US and UK project — that was successfully integrated into the F-35B Lightning II short takeoff and vertical landing (STOVL) variant. Subsequently, he pioneered a new flight control concept for aircraft carrier landings, called Precision Landing Mode (PLM), that dramatically increased touchdown precision, lowered pilot workload and increased safety for carrier landings on the US Navy’s F/A-18E/F/G and F-35C aircraft.

With the recent increased visibility of Joby’s flight testing of its S4 electric vertical takeoff and landing (eVTOL) prototype, Vertiflite dug into the details with Denham. This discussion has been lightly edited.

Vertiflite: On average, what is the pace of Joby’s flight testing?

Denham: Our aircraft fly nearly every day at our Marina, California, facility. Since 2017, we have flown more than 40,000 miles across our fleet of five aircraft — showcasing hover, high-speed cruise and a number of other capabilities.

What milestones did you need to check off before a pilot-on-board flight test?

We began flying with a pilot on board in 2023, completing initial tests including free thrustborne hovers and forward transitions to semi-thrustborne flight. During these tests, we assessed the aircraft’s performance on tasks pilots would be required to perform during normal operations, such as accelerating and transitioning to forward flight.

What additional data did you need before the crewed transition?

Before progressing to test piloted transition flights, we completed a series of tests where we purposely failed batteries, motors and other aspects of the aircraft’s tilt mechanism to ensure our team could transition back to a vertical landing in case of any major incident or failure mode. All tests were demonstrated successfully and our aircraft continued safe flight.

How would you describe the flight experience and specifically pitch change for the transition to forward flight?

By integrating Unified Control into our aircraft, we build on the learnings from the F-35B and VAAC [Vectored thrust Aircraft Advanced flight Control] Harrier programs, developed through joint US and UK aeronautical research. This set the foundation for the F-35B STOVL variant — which our implementation closely mirrors. It gives the pilot direct command and control of flight path, speed and direction, and each axis is decoupled so the pilot can, for example, set a flight path and command a speed change. In comparison, current aircraft have coupled axes that require pilots to manually adjust thrust and pitch attitude to maintain their flight path. Lowering the pilot workload increases the overall situational awareness of the pilot to focus on other related tasks, such as navigation, traffic awareness and communications with air traffic controllers.

The cabin is described as very quiet. Can you share any noise measurements?

The Joby aircraft was intentionally designed to have a low noise profile when flying overhead and be as least disruptive as possible to cities and neighborhoods. From the ground, it’s 100 times quieter than a [legacy] helicopter, and during a study with NASA, [the S4] was found to produce just 65 dB of noise from 330 ft [100 m] away. When sitting in the cabin, the noise is comparable to the sound of wind in trees.

What is the significance and challenge of having two aircraft flying together?

Flying two aircraft at once was a significant achievement for our team and demonstrates the maturity of our test flight program. Being able to fly multiple aircraft in tandem plays a critical role in scaling the types and amount of tests we can run, accelerating our path to certification.

Did you need the two-ship flight for some specific test points?

We utilized two-ship operations to test our telemetry systems and ensure we had adequate frequency separation, allowing us to conduct concurrent flight testing for multiple aircraft.

The US Federal Aviation Administration (FAA) officials have said that the “FAA is ready for powered lift.” Does this energize the team?

The FAA is the gold standard regulator, and we look forward to continuing to work closely with them to certify our aircraft and bring them to market. They’ve set the expectation that the US will lead the world in ushering in this new era of aviation, and we’re extremely grateful for their support, excitement and the foundation they’ve laid to make eVTOL technology a reality.

How far along the test flight program are you at this time, and how does it tally with starting passenger operation in Dubai, in the United Arab Emirates (UAE), in early 2026?

Joby is flying more aircraft with greater capabilities than ever before. These recent achievements demonstrate the maturity of our flight test program and are crucial milestones toward starting TIA [Type Inspection Authorization] flights with FAA pilots onboard the aircraft — the final phase of certification. Joby continues to lead the industry in FAA certification of our aircraft, and we are more than halfway through the fourth of five stages of type certification.

Additionally, we are on track to begin flight testing in Dubai by the middle of this year, which will prepare us for carrying our first passengers in 2026.

When will you introduce commercial customer pilots to the aircraft?

We are well on the way to building out our pilot pipeline with the development of our Joby Aviation Training Center and Joby Aviation Academy [collocated in Watsonville, California]. Our Aviation Academy provides aspiring pilots access to a low-cost, high-quality training where they can complete all certificates needed to become a commercial pilot. Our Aviation Training Center trains commercial pilots to fly our aircraft in just six weeks.

Is the academy a Part 141 school, training for type under "powered lift" category or is there another specific name for the rating? 

Joby Aviation Academy is a Part 141 pilot school and provides flight training for individuals pursuing pilot ratings in the single-engine airplane category, including private, instrument, commercial, and certified flight instructor ratings. 

In the future, graduates of Joby Aviation Academy hired by Joby will receive type training specific to the Joby aircraft, authorizing them to fly for Joby in commercial operations.

How will this be handled in practice considering the single-pilot configuration?

Our training program is focused on multiple modules completed in Flight Simulation Testing Devices (FTSDs), designed to provide exceptional, immersive learning opportunities. Before embarking on this portion of the program, trainees will be given a thorough technical training via classrooms and virtual-reality realms. Following that, and during their FTSD modules, students will experience flight firsthand in one of our aircraft. They’ll start with observation of operations and maneuvers, and build up to solo flights with instructors observing from the ground.

Will the training vary whether the candidate pilot has fixed- or rotary-wing experience?

Yes, rotary-wing pilots entering the training program with no fixed-wing rating will need to receive one through completion of the Joby Aviation Academy before further progressing.

Do you expect any surprises when flying the aircraft in the UAE?

Our aircraft is designed to operate in a variety of conditions, and the purpose of in-market testing is to deeply understand how the aircraft performs and how we will need to operate it ahead of starting commercial service. We’ve already been testing an aircraft for nearly two years at Edwards Air Force base which is a hot, desert environment. In Dubai, we’ll have the opportunity to put the aircraft through its paces with ongoing, real-world testing, in the environment in which we plan to operate.

Will operations in the UAE be based on FAA or European operational rules?

Joby’s operations in Dubai will be based on the GCAA’s [UAE’s General Civil Aviation Authority’s] operational framework, which builds on the FAA’s standards.

Will the first flights be commercial or do you plan some non-revenue flying at the outset?

After FAA certification, we'd expect our first passengers to be Joby flight test engineers alongside our test pilots, followed by paying customers as we deploy in markets.

About the Author

Alex Scerri started his aviation career in 1994 flying for Air Malta. He joined Emirates in 2006, flying several aircraft types, including the Airbus A380 as captain, and worked in the fleet technical office. He is currently flying the A350 for French Bee in Paris. He has been writing on advanced air mobility (AAM) and aviation safety since 2020, including for Vertical Magazine.