Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “pilot learning”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

An Approach to Identifying Aspects of Positive Pilot Behavior within the Aviation Safety Reporting System

The National Airspace System (NAS) is constantly evolving as air traffic continues to ramp up to pre-pandemic numbers and projected to grow to unprecedented levels in the coming years. As well as increasing demand to the current system, emerging operations such as Unmanned Autonomous Systems are also expected to add to complexity in the airspace. To address these issues, the industry and government agencies supporting the NAS will need to rely upon additional automation and new technologies to address future operational requirements, while continuing to be a world-leading safe transportation system. As these new technologies are implemented, the system continues to rely on human pilots and controllers in the loop to monitor the system and intervene in situations the automation cannot handle. The goal of proactively addressing safety is of foremost concern to ensure passenger confidence. The industry has implemented various Safety Monitoring Systems to identify safety risks and proactively address them before they result in a serious incident or accident. One such program is the Aviation Safety Reporting System (ASRS). ASRS is a long-established system where pilots and controllers voluntarily and anonymously report safety incidents they experienced and observed during line operations by providing rich text narratives describing the events, the environment, and conditions leading to the safety event of concern. These narratives provide insight and context around events of interest and can be used to identify emerging problems. They can trigger investigations within Flight Operational Quality Assurance or Flight Data Monitoring programs. However, this process typically focuses on the adverse events and the unsafe aspects of the operations surrounding the reported or detected events. This perspective of investigating factors that went wrong around an adverse event is commonly referred to as Safety I. Alternatively, characterizing successful actions that operators perform every day under varying conditions that keep the system within safe operating bounds is a concept referred to as Safety II. The benefit of the Safety II view is that the scope is much larger than that of Safety I since a vast majority of the operations result in successful flights. Many of the successful techniques used to manage operational threats are not documented in standard operating procedures or taught during training. They are typically acquired over time by working with experienced pilots during line operations or in many cases after experiencing a problem for the first time and reacting to it in situ, drawing from years of experience to manage the threat. In an attempt to quantify these positive actions, we are proposing an approach to extracting key behaviors within ASRS reports that can support the Safety II concept. Our analysis assumes that ASRS reports contain some descriptions of corrective actions that operators performed to prevent a situation from leading to an accident. Leveraging recent advances in Natural Language Process modeling, we have developed an approach to extract positive sentiment from reports, embed these positive statements in a vector space where they can be numerically analyzed, and clustering these statements into similar contextual categories. From these contextualized categories we can attempt to summarized and distilled aspects of the positive behavior. The goal is to identify categories of behavior that describe consistent operator techniques that supports the Safety II concept. With this information, airlines may enable learning from these positive actions, or address procedures that need to be changed to avoid having pilots implement a workaround. These insights can provide a lens into what is “going right” in the operations that may otherwise not be known widely within the community. It is envisioned that this approach can be extended to other narrative programs such as Line Operation Safety Audit or Learning Improvement Team reports where similar observed behavior can be analyzed to extract positive actions and inform the overall operations.

NLP↗
NASA NTRSDate not supplied

An Approach to Identifying Aspects of Positive Pilot Behavior within the Aviation Safety Reporting System

The National Airspace System (NAS) is constantly evolving as air traffic continues to ramp up to pre-pandemic numbers and projected to grow to unprecedented levels in the coming years. As well as increasing demand to the current system, emerging operations such as Unmanned Autonomous Systems are also expected to add to complexity in the airspace. To address these issues, the industry and government agencies supporting the NAS will need to rely upon additional automation and new technologies to address future operational requirements, while continuing to be a world-leading safe transportation system. As these new technologies are implemented, the system continues to rely on human pilots and controllers in the loop to monitor the system and intervene in situations the automation cannot handle. The goal of proactively addressing safety is of foremost concern to ensure passenger confidence. The industry has implemented various Safety Monitoring Systems to identify safety risks and proactively address them before they result in a serious incident or accident. One such program is the Aviation Safety Reporting System (ASRS). ASRS is a long-established system where pilots and controllers voluntarily and anonymously report safety incidents they experienced and observed during line operations by providing rich text narratives describing the events, the environment, and conditions leading to the safety event of concern. These narratives provide insight and context around events of interest and can be used to identify emerging problems. They can trigger investigations within Flight Operational Quality Assurance or Flight Data Monitoring programs. However, this process typically focuses on the adverse events and the unsafe aspects of the operations surrounding the reported or detected events. This perspective of investigating factors that went wrong around an adverse event is commonly referred to as Safety I. Alternatively, characterizing successful actions that operators perform every day under varying conditions that keep the system within safe operating bounds is a concept referred to as Safety II. The benefit of the Safety II view is that the scope is much larger than that of Safety I since a vast majority of the operations result in successful flights. Many of the successful techniques used to manage operational threats are not documented in standard operating procedures or taught during training. They are typically acquired over time by working with experienced pilots during line operations or in many cases after experiencing a problem for the first time and reacting to it in situ, drawing from years of experience to manage the threat. In an attempt to quantify these positive actions, we are proposing an approach to extracting key behaviors within ASRS reports that can support the Safety II concept. Our analysis assumes that ASRS reports contain some descriptions of corrective actions that operators performed to prevent a situation from leading to an accident. Leveraging recent advances in Natural Language Process modeling, we have developed an approach to extract positive sentiment from reports, embed these positive statements in a vector space where they can be numerically analyzed, and clustering these statements into similar contextual categories. From these contextualized categories we can attempt to summarized and distilled aspects of the positive behavior. The goal is to identify categories of behavior that describe consistent operator techniques that supports the Safety II concept. With this information, airlines may enable learning from these positive actions, or address procedures that need to be changed to avoid having pilots implement a workaround. These insights can provide a lens into what is “going right” in the operations that may otherwise not be known widely within the community. It is envisioned that this approach can be extended to other narrative programs such as Line Operation Safety Audit or Learning Improvement Team reports where similar observed behavior can be analyzed to extract positive actions and inform the overall operations.

NLP↗
NASA NTRSDate not supplied

An Approach to Identifying Aspects of Positive Pilot Behavior within the Aviation Safety Reporting System

The National Airspace System (NAS) is constantly evolving as air traffic continues to ramp up to pre-pandemic numbers and projected to grow to unprecedented levels in the coming years. As well as increasing demand to the current system, emerging operations such as Unmanned Autonomous Systems are also expected to add to complexity in the airspace. To address these issues, the industry and government agencies supporting the NAS will need to rely upon additional automation and new technologies to address future operational requirements, while continuing to be a world-leading safe transportation system. As these new technologies are implemented, the system continues to rely on human pilots and controllers in the loop to monitor the system and intervene in situations the automation cannot handle. The goal of proactively addressing safety is of foremost concern to ensure passenger confidence. The industry has implemented various Safety Monitoring Systems to identify safety risks and proactively address them before they result in a serious incident or accident. One such program is the Aviation Safety Reporting System (ASRS). ASRS is a long-established system where pilots and controllers voluntarily and anonymously report safety incidents they experienced and observed during line operations by providing rich text narratives describing the events, the environment, and conditions leading to the safety event of concern. These narratives provide insight and context around events of interest and can be used to identify emerging problems. They can trigger investigations within Flight Operational Quality Assurance or Flight Data Monitoring programs. However, this process typically focuses on the adverse events and the unsafe aspects of the operations surrounding the reported or detected events. This perspective of investigating factors that went wrong around an adverse event is commonly referred to as Safety I. Alternatively, characterizing successful actions that operators perform every day under varying conditions that keep the system within safe operating bounds is a concept referred to as Safety II. The benefit of the Safety II view is that the scope is much larger than that of Safety I since a vast majority of the operations result in successful flights. Many of the successful techniques used to manage operational threats are not documented in standard operating procedures or taught during training. They are typically acquired over time by working with experienced pilots during line operations or in many cases after experiencing a problem for the first time and reacting to it in situ, drawing from years of experience to manage the threat. In an attempt to quantify these positive actions, we are proposing an approach to extracting key behaviors within ASRS reports that can support the Safety II concept. Our analysis assumes that ASRS reports contain some descriptions of corrective actions that operators performed to prevent a situation from leading to an accident. Leveraging recent advances in Natural Language Process modeling, we have developed an approach to extract positive sentiment from reports, embed these positive statements in a vector space where they can be numerically analyzed, and clustering these statements into similar contextual categories. From these contextualized categories we can attempt to summarized and distilled aspects of the positive behavior. The goal is to identify categories of behavior that describe consistent operator techniques that supports the Safety II concept. With this information, airlines may enable learning from these positive actions, or address procedures that need to be changed to avoid having pilots implement a workaround. These insights can provide a lens into what is “going right” in the operations that may otherwise not be known widely within the community. It is envisioned that this approach can be extended to other narrative programs such as Line Operation Safety Audit or Learning Improvement Team reports where similar observed behavior can be analyzed to extract positive actions and inform the overall operations.

NLP↗
NASA NTRS2001

Rotary Wing Flight Test Methods Used for the Evaluation of Night Vision Devices

A number of rotary wing flight tests have been conducted by the Army Aeroflightdynamics Directorate in cooperation with NASA which involved the use of night vision devices and simulated devices. The test set up and data analysis have been taken from two perspectives. Some of the flight tests were structured to look at aircraft handling qualities when the pilot's image quality was reduced from normal daylight levels. In this case, aircraft flight path information was given to the pilot as one input into the Handling Qualities Ratings. Other flight tests were structured to look at pilot and workload directly. In this second case, aircraft position was accurately measured and used as pilot performance data. This paper provides an overview of the test methods used, lessons learned, and recommendations for future tam of night vision devices.

Haworth, Loran↗
NASA NTRS2016

Enhancing Systems Engineering Education Through Case Study Writing

Developing and refining methods for teaching systems engineering is part of Systems Engineering grand challenges and agenda for research in the SE research community. Retention of systems engineering knowledge is a growing concern in the United States as the baby boom generation continues to retire and the faster pace of technology development does not allow for younger generations to gain experiential knowledge through years of practice. Government agencies, including the National Aeronautics and Space Administration (NASA), develop their own curricula and SE leadership development programs to "grow their own" systems engineers. Marshall Space Flight Center (MSFC) conducts its own Center-focused Marshall Systems Engineering Leadership Development Program (MSELDP), a competitive program consisting of coursework, a guest lecture series, and a rotational assignment into an unfamiliar organization engaged in systems engineering. Independently, MSFC developed two courses to address knowledge retention and sharing concerns: Real World Marshall Mission Success course and its Case Study Writers Workshop and Writers Experience. Teaching case study writing and leading students through a hands-on experience at writing a case study on an SE topic can enhance SE training and has the potential to accelerate the transfer of experiential knowledge. This paper is an overview of the pilot experiences with teaching case study writing, its application in case study-based learning, and identifies potential areas of research and application for case study writing in systems engineering education.

Stevens, Jennifer Stenger↗
NASA NTRSDate not supplied

GL4U: Bioinformatics training for students and educators using space omics data

NASA’s GeneLab project provides researchers open access to space-relevant experiment multi-omics data that can be mined to understand the effects of spaceflight on biological systems. To maximize the number of scientists who understand and utilize GeneLab data and data processing pipelines, GeneLab has created GeneLab for Colleges and Universities (GL4U). GL4U provides space biology-relevant training in bioinformatics to the next generation of scientists through direct and indirect approaches. The GeneLab team plans to host two annual data processing bootcamps, one for college-level students (direct) and one for college educators (indirect – training of trainers), in which participants learn to analyze GeneLab’s space-relevant omics data. The GL4U direct training pilot program was conducted in June 2021. During the pilot, students participated in a week-long bootcamp consisting of space biology-specific lectures and hands-on instruction using Jupyter Notebooks to analyze RNA sequence data. This pilot demonstrated the capacity of GL4U for training young scientists and encouraging data re-use. During the educator pilot, scheduled for June 2022, educators will receive materials and training to enable them to run the bootcamp at their home institutions or alternatively to adapt the content to implement within existing courses, thereby extending the reach of this initiative.

Amanda Marie Saravia-butler↗
NASA NTRSDate not supplied

GL4U: Bioinformatics Training for Students and Educators Using Space Omics Data

NASA’s GeneLab project provides researchers open access to space-relevant experiment multi-omics data that can be mined to understand the effects of spaceflight on biological systems. To maximize the number of scientists who understand and utilize GeneLab data and data processing pipelines, GeneLab has created GeneLab for Colleges and Universities (GL4U). GL4U provides space biology-relevant training in bioinformatics to the next generation of scientists through direct and indirect approaches. The GeneLab team plans to host two annual data processing bootcamps, one for college-level students (direct) and one for college educators (indirect – training of trainers), in which participants learn to analyze GeneLab’s space-relevant omics data. The GL4U direct training pilot program was conducted in June 2021. During the pilot, students participated in a week-long bootcamp consisting of space biology-specific lectures and hands-on instruction using Jupyter Notebooks to analyze RNA sequence data. This pilot demonstrated the capacity of GL4U for training young scientists and encouraging data re-use. During the educator pilot, scheduled for June 2022, educators will receive materials and training to enable them to run the bootcamp at their home institutions or alternatively to adapt the content to implement within existing courses, thereby extending the reach of this initiative.

Amanda Marie Saravia-butler↗
NASA NTRS1978

Effects of visual and motion simulation cueing systems on pilot performance during takeoffs with engine failures

Data are presented that show the effects of visual and motion during cueing on pilot performance during takeoffs with engine failures. Four groups of USAF pilots flew a simulated KC-135 using four different cueing systems. The most basic of these systems was of the instrument-only type. Visual scene simulation and/or motion simulation was added to produce the other systems. Learning curves, mean performance, and subjective data are examined. The results show that the addition of visual cueing results in significant improvement in pilot performance, but the combined use of visual and motion cueing results in far better performance.

Parris, B. L.↗
NASA NTRS2019

The Comprehensive LOFT

The training of pilots at major US air carriers has changed little over the years. These courses often begin in learning each and every sub-system of the particular airplane to be flown. The training course culminates in a series of training sessions in a full-motion, full-mission flight simulator. Most US airlines now incorporate one final simulator training session known as LOFT, Line Oriented Flight Training, where rather than going through a series of disconnected, isolated, flight maneuvers, the session is conducted as a flight from a departure airport to a destination airport. Flying for an Air Line, one is a Line Pilot, flying the "line." And so the LOFT session in the simulator is supposed to represent the reality of line operations and thus prepare the trainee to fly the line. But if the ultimate goal of the training is to produce a pilot who is ready to safely and efficiently fly the line, shouldn't all training be "line oriented"? This paper describes an approach to structuring airline flight training such that all training is "line oriented." This approach represents an opportunity to translate many of the training principles offered by Healy and her colleagues into training specifications.

Training Principles↗
NASA NTRS2001

The Urban Heat Island Pilot Project (UHIPP)

Urban heat islands increase the demand for cooling energy and accelerate the formation of smog. They are created when natural vegetation is replaced by heat-absorbing surfaces such as building roofs and walls, parking lots, and streets. Through the implementation of measures designed to mitigate the urban heat island, communities can decrease their demand for energy and effectively "cool" the metropolitan landscape. Measures to reverse the urban heat island include afforestation and the widespread use of highly reflective surfaces. To demonstrate the potential benefits of implementing these measures, EPA has teamed up with NASA and LBNL to initiate a pilot project with three U.S. cities. As part of the pilot, NASA is using remotely-sensed data to quantify surface temperature, albedo, the thermal response number and NDVI vegetation of each city. To pursue these efforts, more information is needed about specific characteristics of several different cities. NASA used the Advanced Thermal and Land Applications Sensor (ATLAS) to obtain high spatial resolution (10 m pixel resolution) over each of the three pilot cities (Baton Rouge, Sacramento, and Salt Lake City). The goal of the UHIPP is to use the results from the NASA/LBNL analysis, combined with knowledge gained through working with various organizations within each pilot city to identify the most effective means of implementing strategies designed to mitigate the urban heat island, These "lessons learned" will be made available and used by cities across the U.S. to assist policy makers and others within various communities to analyze their own urban heat islands and determine which, if any, measures can be taken to help save energy and money, and to prevent pollution. The object of this session is for representatives from each of the pilot cities to present their results of the study and share the experience of working with these data in managing their urban landscape.

Luvall, Jeff↗
NASA NTRS1994

Application of an Integrated Methodology for Propulsion and Airframe Control Design to a STOVL Aircraft

An advanced methodology for integrated flight propulsion control (IFPC) design for future aircraft, which will use propulsion system generated forces and moments for enhanced maneuver capabilities, is briefly described. This methodology has the potential to address in a systematic manner the coupling between the airframe and the propulsion subsystems typical of such enhanced maneuverability aircraft. Application of the methodology to a short take-off vertical landing (STOVL) aircraft in the landing approach to hover transition flight phase is presented with brief description of the various steps in the IFPC design methodology. The details of the individual steps have been described in previous publications and the objective of this paper is to focus on how the components of the control system designed at each step integrate into the overall IFPC system. The full nonlinear IFPC system was evaluated extensively in nonreal-time simulations as well as piloted simulations. Results from the nonreal-time evaluations are presented in this paper. Lessons learned from this application study are summarized in terms of areas of potential improvements in the STOVL IFPC design as well as identification of technology development areas to enhance the applicability of the proposed design methodology.

Garg, Sanjay↗
NASA NTRS2008

Instrument Display Visual Angles for Conventional Aircraft and the MQ-9 Ground Control Station

Aircraft instrument panels should be designed such that primary displays are in optimal viewing location to minimize pilot perception and response time. Human Factors engineers define three zones (i.e. cones ) of visual location: 1) "Easy Eye Movement" (foveal vision); 2) "Maximum Eye Movement" (peripheral vision with saccades), and 3) "Head Movement (head movement required). Instrument display visual angles were measured to determine how well conventional aircraft (T-34, T-38, F- 15B, F-16XL, F/A-18A, U-2D, ER-2, King Air, G-III, B-52H, DC-10, B747-SCA) and the MQ-9 ground control station (GCS) complied with these standards, and how they compared with each other. Selected instrument parameters included: attitude, pitch, bank, power, airspeed, altitude, vertical speed, heading, turn rate, slip/skid, AOA, flight path, latitude, longitude, course, bearing, range and time. Vertical and horizontal visual angles for each component were measured from the pilot s eye position in each system. The vertical visual angles of displays in conventional aircraft lay within the cone of "Easy Eye Movement" for all but three of the parameters measured, and almost all of the horizontal visual angles fell within this range. All conventional vertical and horizontal visual angles lay within the cone of Maximum Eye Movement. However, most instrument vertical visual angles of the MQ-9 GCS lay outside the cone of Easy Eye Movement, though all were within the cone of Maximum Eye Movement. All the horizontal visual angles for the MQ-9 GCS were within the cone of "Easy Eye Movement". Most instrument displays in conventional aircraft lay within the cone of Easy Eye Movement, though mission-critical instruments sometimes displaced less important instruments outside this area. Many of the MQ-9 GCS systems lay outside this area. Specific training for MQ-9 pilots may be needed to avoid increased response time and potential error during flight. The learning objectives include: 1) Know three physiologic cones of eye/head movement; 2) Understand how instrument displays comply with these design principles in conventional aircraft and an uninhabited aerial vehicle system. Which of the following is NOT a recognized physiologic principle of instrument display design? Cone of Easy Eye Movement 2) Cone of Binocular Eye Movement 3) Cone of Maximum Eye Movement 4) Cone of Head Movement 5) None of the above. Answer: # 2) Cone of Binocular Eye Movement

Kamine, Tovy Haber↗
NASA NTRS2018

Aeronautics Autonomy Testbed Capability (AATC) Team Developed Concepts

In 2015, the National Aeronautics and Space Administration (NASA) formed a multi-center, interdisciplinary team of engineers from three different aeronautics research centers who were tasked with improving NASA autonomy research capabilities. This group was subsequently named the Aeronautics Autonomy Testbed Capability (AATC) team. To aid in confronting the autonomy research directive, NASA contracted IDEO, a design firm, to provide consultants and guides to educate NASA engineers through the practice of design thinking, which is an unconventional method for aerospace design processes. The team then began learning about autonomy research challenges by conducting interviews with a diverse group of researchers and pilots, military personnel and civilians, experts and amateurs. Part of this design thinking process involved developing ideas for products or programs known as concepts that could enable real world fulfillment of the most important latent needs identified through analysis of the interviews. The concepts are intended to be sacrificial, intermediate steps in the design thinking process and are presented in this report to record the efforts of the AATC group. Descriptions are provided in present tense to allow for further ideation and imagining the concept as reality as was attempted during the teams discussions and interviews. This does not indicate that the concepts are actually in practice within NASA though there may be similar existing programs independent of AATC. These concepts were primarily created at two distinct stages during the design thinking process. After the initial interviews, there was a workshop for concept development and the resulting ideas are shown in this work as from the First Round. As part of succeeding interviews, the team members presented the First Round concepts to refine the understanding of existing research needs. This knowledge was then used to generate an additional set of concepts denoted as the Second Round. Some concepts were created by a single person in a few minutes while others were refined by the entire team over several weeks. Thus, certain ideas are more detailed than others but those from the second round are not necessarily more comprehensive than the first round concepts. Primarily, as reported here in the Second Round section, the designs serve to encompass more of the high level end user research needs which were not necessarily known to the team during the prior workshop. In the figures provided throughout this report, illustrations are often provided to represent a concept. Nearly all of the images are informal sketches or renderings and this casualness should, hopefully, not be held to negate the potential insights available within the concepts.

Smith, Phillip J.↗
NASA NTRS1982

Lessons learned - Americans in space

Milestones in the learning process during development of spaceflight capability for different NASA missions are traced from the initial launch of the Mercury escape rocket to the advent of the Shuttle. A detached heat shield on the first manned Mercury orbital flight led to a decision for reentry with retrorockets attached, a situation which demonstrated a need for on-line communications with the spacecraft construction engineers. The Gemini program served to develop EVA techniques and docking procedures essential for the Apollo missions. Apollo 8 circled the moon after only one manned test flight of the equipment due to the success of the first flight. Lunar landing simulation training exposed the astronauts to situations beyond the human ability to respond. The training was justified when computer overload required the pilot to retake manual control of some spacecraft functions during the successful first lunar landing. All lessons previously learned were used to safely return the damaged Apollo 13 to earth. The Skylab missions provided an opportunity to maintain rotating teams of flight controllers on a 24-hr/day basis for periods of months. Finally, the six-year hiatus of U.S. manned space activities between the end of the Skylab missions and the first Shuttle flight provided time for incorporating previous lessons into new procedures, training strategies, and data resources.

Kranz, E.↗
NASA NTRS2006

Spacecraft Design Considerations for Piloted Reentry and Landing

With the end of the Space Shuttle era anticipated in this decade and the requirements for the Crew Exploration Vehicle (CEV) now being defined, an opportune window exists for incorporating 'lessons learned' from relevant aircraft and space flight experience into the early stages of designing the next generation of human spacecraft. This includes addressing not only the technological and overall mission challenges, but also taking into account the comprehensive effects that space flight has on the pilot, all of which must be balanced to ensure the safety of the crew. This manuscript presents a unique and timely overview of a multitude of competing, often unrelated, requirements and constraints governing spacecraft design that must be collectively considered in order to ensure the success of future space exploration missions.

Stroud, Kenneth J.↗
NASA NTRS1982

Helicopter simulation technology: An Ames Research Center perspective

The total experience for evidence regarding the levels of motion and visual cueing fidelity required for handling-qualities research in ground-based simulators is reviewed. Positive contributions of cockpit motion were identified, but much remains to be learned regarding the sensitivities of individual control modes to cueing attenuation. A firmer understanding of the pilot's utilization of visual and motion cues is the key to more efficient use of simulation in helicopter control-systems research.

Bray, R. S.↗
NASA NTRS2007

X-31 Mishap: Lessons Learned

The experimental X-31 High Angle of Attack Research Aircraft crashed during a 1995 test mission flight conducted by NASA at Edwards Air Force Base, California. The pilot lost control of the airplane and was forced to eject, sustaining a permanent back injury that ended his flying career. Prior to this incident the airplane had a perfect record of several hundred non-eventful flights supported by an experienced team. During the subsequent investigation by a mishap committee it was discovered that a series of cascading events contributed to this accident. Some of the identified contributing factors that resulted in this mishap are common to aircraft design and to flight-test in general. The mistakes and the solutions are presented here so that the flight-test community may consider and learn from them. The primary cause of the crash was icing and, ultimately, a complete blockage of the pitot-static nose probe. The icing was caused by a freak weather phenomenon that was neither expected nor known to exist on the day of the mishap. The normal probe had been replaced with a special Kiel probe to allow total pressure measurements of up to 70 degrees angle of attack for flight-test purposes. The Kiel probe did not include a heater, because it was assumed that the airplane would not be flown in the clouds or in conditions conducive to icing. This assumption was later proven to be incorrect. The iced Kiel probe caused incorrect gain scheduling in the flight control system, resulting in an unstable aircraft. This failure was essentially undetected because of a faulty design in the flight control system architecture. There were, however, also a number of other issues that lead up to this situation that never should have happened. This presentation discusses what the issues were that contributed to the incident. After the incident was investigated, some of these issues were addressed and some changes were made. The second X-31 aircraft flew the remainder of the flight tests, and the program was successfully completed without incident. This presentation also shows a video of the mishap including lessons learned, and the changes that were made to resume the flight-test program are presented.

Larson, Richard R.↗