Lesson Info:

• Lesson Number: 1413
• Lesson Date: 2004-03-18
• Submitting Organization: JSC
• Submitted by: Steven G. Labbe

Subject:

Abstract:

The NASA Engineering & Safety Center (NESC) received a dissenting opinion describing aerodynamic concerns leading to a potential loss of vehicle control that would result in a failure to achieve mission objectives. Working in conjunction with the X-43A project, the NESC ensured that the aerodynamic issues were properly addressed through the existing independent Flight Readiness Review (FRR) process. The role of the NESC was to confirm that the independent FRR committee adequately reviewed, investigated and responded to the dissenting opinion.

Description of Driving Event:

The X-43A is a prototype, hypersonic aircraft mounted on a modified Pegasus booster rocket that accelerates the X-43A to its test speed and altitude. The modified Pegasus/X-43A (or Hyper X Launch Vehicle) stack is launched from the NASA B-52B aircraft. The initial X-43A flight resulted in a mishap and loss of vehicle and mission. Subsequent return-to-flight activities conducted by the program to prepare for the 2nd flight test resulted in a dissenting opinion being submitted.

NESC involvement was initiated by receipt of the dissenting opinion through e-mail. The dissenting opinion raised three potential overarching transonic aerodynamics issues that were not being addressed sufficiently by the program during return to flight activities. 1) Incomplete aerodynamic analysis of Flight 1 (a failure to quantify all contributing factors); 2) The need to develop and/or validate scaling laws for ground test to flight databases supporting Flight 2; and 3) The need to correct known errors & deficiencies in ground based experimental & computational data sets.

The NESC Director negotiated with the X-43A Return-to-Flight (RTF) Manager to have these issues addressed through the existing independent X-43A Flight Readiness Review (FRR) process with NESC monitoring and evaluation.

Lesson(s) Learned:

When dissenting opinions based on good engineering judgment are brought to the attention of an effective advocate/champion, increased safety assurance in affected programs is enhanced.

1. The X-43A Flight Readiness Review (FRR) process defined in Dryden Handbook DHB-X-001, Airworthiness and Flight Safety Review, Independent Review, Mission Success Review, Technical Brief and Mini-Tech Brief Guidelines, appears to be an excellent FRR process that

• Provides an alternative approach to the more traditional single meeting method
• Avoids the potential for the large data dump and “rubber stamp” type review
• Allows for FRR initiated actions, necessary response time and appropriate follow up on the identified technical issues.
• Provides a mechanism for dissenting opinions via Request For Action (RFA)
• Is independently established from outside the program
• Can draw on the necessary expertise and skills from across the agency as required
• Reports independently to the Airworthiness and Flight Safety Review Board (AFSRB) on a programs flight readiness
  

2. The Agency needs a strategy for addressing dissenting opinions. It is in NASA's best interest to create an environment that encourages dissenting opinions within its programs. It takes courage and conviction to openly present and defend a dissenting opinion to a program or organization. Several issues must be considered including:

• Policy on the appropriateness for referring to existing independent authority
• The necessary monitoring and follow up requirements on referred items
• Potential for large resource commitment working phantom issues
  

Recommendation(s):

The recommendations are twofold: (1) the FRR Process and (2) a strategy for addressing dissenting opinions.

1. Benchmark Dryden Flight Center's FRR process (Dryden Handbook DHB-X-001) which provides for a robust, independent review of a project's readiness for flight and should be adopted across the Agency. The X-43A Flight Readiness Review (FRR) process defined in Dryden Handbook DHB-X-001, Airworthiness and Flight Safety Review, Independent Review, Mission Success Review, Technical Brief and Mini-Tech Brief Guidelines, appears to be an excellent FRR process that

• Provides an alternative approach to the more traditional single meeting method
• Avoids the potential for the large data dump and “rubber stamp” type review
• Allows for FRR initiated actions, necessary response time and appropriate follow up on the identified technical issues.
• Provides a mechanism for dissenting opinions via Request For Action (RFA)
• Is independently established from outside the program
• Can draw on the necessary expertise and skills from across the agency as required
• Reports independently to the Airworthiness and Flight Safety Review Board (AFSRB) on a programs flight readiness
  

2. Benchmark the NESC's approach to addressing dissenting opinions it receives with the intent of developing an agency-level strategy for addressing dissenting opinions. It takes courage and conviction to openly present and defend a dissenting opinion to a program or organization; thus, it is in NASA's best interest to create an environment that encourages dissenting opinions within its programs. Other organizations within NASA need to develop strategies for handling dissenting opinions.

To accomplish this, several issues must be considered including:

• A policy to address when it is appropriate to communicate a dissenting opinion to an existing independent authority.
• The necessary monitoring and follow up requirements on referred items.
• Potential for large resource commitment working phantom issues
  

Evidence of Recurrence Control Effectiveness:

TBD Implementation of the DFRC FRR process across the agency.

Documents Related to Lesson:

Dryden Flight Center's FRR process (Dryden Handbook DHB-X-001); generic Flight Readiness Review documents

Mission Directorate(s):

• Exploration Systems
• Science
• Space Operations
• Aeronautics Research

Additional Key Phrase(s):

• Administration/Organization
• Configuration Management
• Flight Equipment
• Flight Operations
• Ground Equipment
• Ground Operations
• Hardware
• Independent Verification and Validation
• Launch Process
• Policy & Planning
• Program and Project Management
• Risk Management/Assessment
• Safety & Mission Assurance
• Spacecraft

Additional Info:

Approval Info:

• Approval Date: 2004-05-20
• Approval Name: Ronald Montague
• Approval Organization: JSC
• Approval Phone Number: 281-483-8576