Otto Aerospace has reached a major certification milestone for its Phantom 3500 clean-sheet business aircraft programme after securing closure of the G-1 Issue Paper, establishing the aircraft’s Certification Basis with the Federal Aviation Administration (FAA) under 14 CFR Part 23.

The agreement defines the regulatory framework under which the Phantom 3500 will be certified and follows Otto’s decision to pursue certification under Part 23 after becoming an FAA applicant in September 2025.

The company says the milestone provides alignment with the FAA on certification requirements and enables the programme to progress into its next phase.

“This is a huge moment for the entire Otto team and a really exciting milestone for the Phantom 3500,” says Scott Drennan, president and chief executive officer of Otto Aerospace. “Now that the certification basis is in place, the programme moves into a higher gear on execution. We have alignment with the FAA on what we need to demonstrate and that gives us real momentum as we move toward first flight and entry into service.”

Otto is also working with the FAA East Certification Branch to close the G-2 Issue Paper, which will define the means of compliance for the certification programme.

The FAA has continued engagement with Otto’s transonic laminar flow technology and Supernatural Vision cabin concepts, while the company has recently completed Preliminary Design Review and advanced testing activities.

“We appreciate the FAA’s continued engagement in reaching this milestone,” adds Kerri Hinton, director of test and certification at Otto Aerospace. “Our commitment to safety is unwavering, and we look forward to continuing our work together as we advance the Phantom 3500 through certification.”

Otto has already begun advanced material testing and continues supplier development activities as it works towards a planned first flight in 2027 and entry into service in 2030.

Flight testing will be conducted from Cecil Airport in Jacksonville, Florida.

The programme is backed by a firm order from Flexjet for 300 aircraft valued at more than $5 billion, one of the largest commitments in business aviation.