Part 450 Transition Checklist: A Practitioner's Guide for Legacy License Holders

The March 10, 2026 deadline is approaching faster than most operators appreciate.

On that date, every legacy launch and reentry license issued under Parts 415, 417, 431, and 435 expires.

No extensions. No grandfather clauses. If you haven't transitioned to Part 450 by then, you don't launch.

This guide provides a systematic approach for operators currently holding legacy licenses to plan and execute their Part 450 transition. It's based on published FAA guidance, lessons learned from early Part 450 applicants, and the regulatory requirements themselves.

Understanding What Actually Changes

Part 450 represents a fundamental shift from prescriptive to performance-based regulation.

Under legacy rules, the FAA told you how to demonstrate safety. Under Part 450, you propose your means of compliance—and then prove it works.

The key structural differences that affect your documentation:

Single license structure. Part 450 consolidates what previously required separate licenses into a single vehicle operator license.

This license can cover multiple launch sites, multiple vehicle configurations, and both launch and reentry operations.

The upside: fewer licenses to maintain. The complexity: your application must comprehensively address all intended operations.

Methodology descriptions replace prescriptive requirements. Section 450.115 requires you to describe the methodology used for flight safety analysis.

This isn't a formality—AST will evaluate whether your methodology can actually demonstrate compliance with the quantitative risk criteria in §450.101.

If your legacy approach relied on range-provided tools and standardized methods, you now need to document and defend those choices explicitly.

Uncertainty treatment is now explicit. Section 450.117(a) requires demonstration that you've appropriately handled variability and uncertainty in your flight safety analysis.

The FAA's published guidance ("Handling Variability and Uncertainty in Flight Safety Analysis") provides a framework, but you must document how your specific analysis addresses each source of uncertainty.

Gap Analysis: Mapping Legacy Documentation to Part 450 Requirements

Start by inventorying your existing documentation against Part 450 Subpart C requirements.

The FAA publishes a Part 450 Application Compliance Checklist (available on the AST website) that maps each requirement to expected documentation.

Documentation You Likely Have

• Flight Safety Analysis results (debris, toxic, blast hazards)
• Flight Termination System design and test documentation
• Ground safety plans and procedures
• Launch site operator agreements
• Environmental documentation (EA, EIS, or CatEx)

Documentation You Likely Need to Create or Substantially Revise

• Flight safety analysis methodology descriptions per §450.115
• Uncertainty treatment documentation per §450.117
• Hazard control strategy determination per §450.107
• Flight abort rule development (if applicable) per §450.108
• Collision avoidance analysis per §450.169

The Pre-Application Process: Use It

The FAA strongly encourages pre-application consultation, and for good reason.

Early engagement with AST allows you to identify potential compliance issues before you've committed to a particular approach in your formal application.

The Pre-Application Opportunity Planning Tool (POPT) is optional but valuable. It structures your initial engagement and helps AST understand your intended operations before formal submission.

Information provided in the POPT can be incorporated into your eventual application.

Key pre-application activities:

1. Schedule an initial consultation to discuss your transition timeline and identify major compliance questions
2. Submit draft methodology descriptions for informal review before finalizing your approach
3. Identify any novel compliance approaches early—these require more extensive review
4. Clarify how Federal range services map to Part 450 requirements per the FAA's determinations

Timeline Reality Check

The FAA has 180 days from acceptance of a complete application to issue a licensing determination.

Note the qualifier: complete application. Incomplete submissions don't start that clock.

Working backward from March 10, 2026:

• To ensure license issuance by deadline: submit complete application by September 2025
• To allow for application revisions: begin formal submission process by June 2025
• To complete pre-application consultation: engage AST by early 2025
• To complete gap analysis and documentation development: start now

The FAA has indicated that experienced operators with well-established operations should be able to transition efficiently.

However, "efficiently" assumes your documentation is in order and your compliance approaches align with published means of compliance.

If you're proposing alternative approaches or have complex multi-site operations, build in additional time.

Advisory Circulars: Your Primary Reference

The Part 450 Means of Compliance Table (published on the AST website) lists accepted means of compliance for each performance-based requirement in Subpart C.

This table also shows which Advisory Circulars are published versus pending.

Critical ACs for transition planning:

• AC 450.107-1: Hazard Control Strategies Determination
• AC 450.108-1: Flight Abort Rule Development
• AC 450.115-1: Flight Safety Analysis Methodology (when issued)
• AC 450.143-1: Flight Safety System design, test, and documentation

Where ACs haven't been published, you may propose alternative means of compliance—but expect more extensive review and discussion with AST.

Bottom Line

The transition from legacy regulations to Part 450 isn't merely administrative.

It requires operators to explicitly document and defend compliance approaches that may have been implicit under prescriptive rules.

Start your gap analysis now, engage AST in pre-application consultation, and build your timeline backward from March 2026.

The FAA has provided substantial guidance—use it.

The operators who struggle will be those who underestimate the documentation effort required to demonstrate compliance under a performance-based regime.