- Parabolic Arc
- November 29, 2023
Executive Summary of Scaled Composites Submission to NTSB
Submission to NTSB by Scaled Composites
Regarding the October 31, 2014
May 29, 2015
Scaled Composites (Scaled) is an aerospace and specialty composites development company located in Mojave, California. Since its founding by Burt Rutan thirty-three years ago, Scaled has successfully designed, built, and flight tested over 30 unique manned aircraft and spacecraft for the United States Government, national defense contractors, and other commercial customers. Scaled specializes in unique aircraft design, rapid prototyping, and flight testing. Scaled focuses on developing proof-of-concept aircraft using novel and creative approaches to solve difficult technical challenges presented by its customers.
Scaled has been recognized for its ability to safely and efficiently develop breakthrough air and spacecraft. For example, in 2000, Scaled’s Proteus airplane set an altitude record for its class, reaching over 63,000 feet, and in 2005, Scaled’s GlobalFlyer airplane set the record for the fastest time around the world unrefueled. Scaled’s SpaceShipOne, which debuted in 2004, pioneered a number of design firsts and captured the Ansari X Prize, awarded to the first nongovernmental organization to launch a reusable manned vehicle into space, and the National Aeronautic Association’s Collier Trophy, awarded annually for the greatest achievement in aeronautics or astronautics in America, with respect to improving the performance, efficiency, and safety of air or space vehicles, the value of which has been thoroughly demonstrated by actual use during the preceding year.
Scaled tailors its customized designs to meet government and commercial customer specifications. The company brings creative solutions to unique design challenges, and builds and tests prototypes efficiently and safely based on those designs. Scaled’s engineers and test pilots, along with its other employees, are carefully selected. They bring to the company great talent and a wide-ranging mix of cross-disciplinary expertise that enables them to participate in various aspects of Scaled’s flight programs. This multidisciplinary approach allows members of Scaled project teams to develop a comprehensive understanding of different aircraft systems and to participate in what Scaled believes to be a safer, more efficient manner than may be possible under the “siloed” approach of more traditional companies in which each employee is assigned a narrower set of roles and responsibilities. Safety and quality have always been paramount values at Scaled, and Scaled’s transparent, nonhierarchical culture enhances both. Scaled’s approach is best expressed by one of Burt Rutan’s oft-repeated mottos: “Question, don’t defend.” This means that it is every employee’s responsibility to enhance quality and safety by openly and continually probing all aspects of their projects.
SpaceShipTwo was the second manned, privately-funded spacecraft prototype designed and built by Scaled. The SpaceShipTwo program originated in 2006 to create a prototype for Virgin Galactic. The prototype would be used as an initial model for Virgin Galactic to develop a vehicle to carry private passengers into space and back to earth as part of a Virgin Galactic commercial space program. The SpaceShipTwo prototype evolved from SpaceShipOne, after years of additional design, development, manufacture, and testing by Scaled.
On the morning of October 31, 2014, the SpaceShipTwo prototype was on a rocket-powered test flight mission over the Mojave Desert with an experienced flight crew. It had previously completed over 50 successful test flights. Shortly after the aircraft released from its carrier plane, known as WhiteKnightTwo, and was accelerating, a catastrophic accident occurred. The evidence indicates that the accident happened when the feather reentry system deployed early because it was unlocked by the copilot prematurely, outside the sequence set forth in the flight test card and Normal Procedures.1 When the feather system was unlocked, it was subjected to aerodynamic loads that caused the feather to open early, during a phase of flight when it was supposed to remain retracted. The early opening of the feather caused the SpaceShipTwo prototype to break apart, resulting in the loss of the aircraft. The accident resulted in serious injury to the pilot and the tragic death of the copilot. The reason for the copilot’s premature unlocking of the feather locks is unknown.
Since the October 31, 2014 accident, Scaled has been extensively supporting the accident investigation conducted by the National Transportation Safety Board (NTSB). As a party to the investigation, in accordance with NTSB procedures, and consistent with its active cooperation, Scaled is making this submission to provide its analysis of the facts and probable cause of the accident, its proposed findings and recommendations, and a summary of safety actions that Scaled has already taken since the accident.
As explained more fully below, Scaled believes the facts demonstrate that:
- SpaceShipTwo’s crew were well-qualified and well-trained. The SpaceShipTwo test pilots were fully qualified and properly licensed and trained for the flight. The test pilots had each logged thousands of hours of flight time, including in experimental test aircraft, and each had successfully piloted or copiloted SpaceShipTwo on a number of prior occasions. They were both highly credentialed aerospace engineers who were familiar and involved with the design of the vehicle and aware of its operating limitations. Both had an active role in developing test flight and safety procedures. They both had participated in numerous formal and informal SpaceShipTwo flight simulations during which they repeatedly practiced flight procedures, including the proper and timely unlocking of the feather system.
- The SpaceShipTwo prototype was carefully designed in accordance with industry recognized procedures and Scaled’s design processes. The SpaceShipTwo prototype’s design, including its unique feather reentry system, was carefully considered and designed based on years of research, development, and analysis. The design evolved from that of the successful SpaceShipOne program and used simple, proven technologies as a means to limit failure modes. SpaceShipTwo’s systems, including the feather system, were tested and regularly inspected and maintained; functioned successfully on dozens of flights; and were reviewed and improved upon over time by Scaled engineers. Detailed data review and analysis show that, during the October 31 test flight, until the premature unlocking of the feather, SS2’s systems and structures functioned as designed.
- Procedures for the feather system were tested and analyzed for safety, and disseminated and discussed among SpaceShipTwo program team members. Scaled’s procedures include assessing and mitigating identified risks, and it followed these procedures with respect to SpaceShipTwo. The design of and procedure for unlocking the feather system were fundamental aspects of the aircraft design and of the flight test plan. The flight test procedures provided for the feather to be unlocked at a specific speed (measured by a Mach number) that Scaled had selected to permit a safety margin both before and after the unlocking procedure. Scaled documented this feather unlocking procedure in numerous sources, including as a part of the flight test card, which test pilots follow during practice in simulated flight sessions, carry with them, and use as their guide to test flight procedures, including on the October 31 test flight. Throughout the design process, program engineers and test pilots discussed that unlocking the feather system at the wrong time could have catastrophic effects.
- Scaled has a robust safety process and culture. Scaled’s culture of “question, don’t defend” calls for all employees to understand design choices on the aircraft and to question, analyze, and respond to safety concerns rather than simply defend current designs or procedures. Scaled subjected SpaceShipTwo to a seven-year systems safety assessment – using industry-recognized methods – that encompassed identifying potential hazards, analyzing the likelihood of those hazards, and employing design or procedural mitigations as needed. Scaled routinely revised and updated this systems safety assessment as systems were modified. Through Scaled’s flight test procedures, test pilots and engineers regularly reviewed and analyzed the design of the vehicle, flight procedures, and potential hazards, including the risk of human error. This review took many forms and took place in many forums, including program-wide “Flight Readiness Reviews.” In these reviews, program team members and independent subject matter experts discussed potential hazards and were required by Scaled’s procedures to determine those hazards were adequately mitigated before flights could occur. One such Flight Readiness Review was held only days before the October 31 test flight.
- SpaceShipTwo complied with regulatory requirements and at the time of the October 31 test flight was appropriately permitted with an Experimental Permit duly issued by the FAA. Throughout its systems safety assessment and testing process, Scaled worked closely with the FAA. Both before and at the time of the accident, the SpaceShipTwo program was operating with the proper FAA permits and with the proper regulatory authority. The FAA had issued Scaled an Experimental Permit to operate SpaceShipTwo as a reusable suborbital rocket, and Scaled flew SpaceShipTwo in compliance with that permit.
- Scaled is committed to learning from this accident and continuing to enhance even further the safety of its procedures for vehicle design, manufacture, and testing. Scaled will incorporate learning from this accident into its flight procedure review and safety assessment in future projects. Scaled will expand the documentation of training and testing further to promote safety, including with emphasis on the challenges inherent in rocket flight. Scaled will regularly review and evaluate this data and documentation to ensure that lessons learned and procedural rationales are disseminated and reinforced. Scaled will enlist the services of human performance experts to provide further input on crew workload, in-flight conditions, and simulator training. In addition to implementing these recommendations, Scaled hopes the industry as a whole can learn from the accident in order to further improve the safety of experimental flight testing.
Space travel is a culmination of mankind’s dream of conquering flight. Revolutionary advancements in aviation, from the Apollo program, to the Space Shuttle, to SpaceShipOne, are inspiring to so many in our country in part because of the unparalleled challenges and potential rewards they present. But the history of American aviation and space travel demonstrates that with those historic challenges come potential risks to and extraordinary sacrifices by some of the people most dedicated to and passionate about the endeavor. Recognizing those challenges, sacrifices, and the importance of the enterprise to the industry and to the nation, Scaled is committed to learning everything it can from this accident, doing all in its power to prevent similar tragedies, and continuing to build on its reputation for innovation, quality, and safety.
1 Test flight documentation of flight crew procedures, including the flight test card and Normal Procedures, is discussed in more detail in Part III.C, infra.