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At least 55 records · Page 3
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NASA NTRS1976

Accident investigation: Analysis of aircraft motions from ATC radar recordings

A technique was developed for deriving time histories of an aircraft's motion from air traffic control (ATC) radar records. This technique uses the radar range and azimuth data, along with the downlinked altitude data (from an onboard Mode-C transponder), to derive an expanded set of data which includes airspeed, lift, thrust-drag, attitude angles (pitch, roll, and heading), etc. This method of analyzing aircraft motions was evaluated through flight experiments which used the CV-990 research aircraft and recordings from both the enroute and terminal ATC radar systems. The results indicate that the values derived from the ATC radar records are for the most part in good agreement with the corresponding values obtained from airborne measurements. In an actual accident, this analysis of ATC radar records can complement the flight-data recorders, now onboard airliners, and provide a source of recorded information for other types of aircraft that are equipped with Mode-C transponders but not with onboard recorders.

Wingrove, R. C.↗
NASA NTRS2003

Columbia Accident Investigation Board

The CAIB requested these data be included in this Appendix. This Appendix is a summary of present and past efforts that were initiated to characterize the moisture absorption capability of sprayed-on-foam-insulation (SOFI) and specifically, BX-250.

White, Donald J.↗
NASA NTRS2004

Material Modeling of Space Shuttle Leading Edge and External Tank Materials For Use in the Columbia Accident Investigation

Upon the commencement of the analytical effort to characterize the impact dynamics and damage of the Space Shuttle Columbia leading edge due to External Tank insulating foam, the necessity of creating analytical descriptions of these materials became evident. To that end, material models were developed of the leading edge thermal protection system, Reinforced Carbon Carbon (RCC), and a low density polyurethane foam, BX-250. Challenges in modeling the RCC include its extreme brittleness, the differing behavior in compression and tension, and the anisotropic fabric layup. These effects were successfully included in LS-DYNA Material Model 58, *MAT_LAMINATED_ COMPOSITE_ FABRIC. The differing compression and tension behavior was modeled using the available damage parameters. Each fabric layer was given an integration point in the shell element, and was allowed to fail independently. Comparisons were made to static test data and coupon ballistic impact tests before being utilized in the full scale analysis. The foam's properties were typical of elastic automotive foams; and LS-DYNA Material Model 83, *MAT_FU_CHANG_FOAM, was successfully used to model its behavior. Material parameters defined included strain rate dependent stress-strain curves for both loading and un-loading, and for both compression and tension. This model was formulated with static test data and strain rate dependent test data, and was compared to ballistic impact tests on load-cell instrumented aluminum plates. These models were subsequently utilized in analysis of the Shuttle leading edge full scale ballistic impact tests, and are currently being used in the Return to Flight Space Shuttle re-certification effort.

Carney, Kelly↗
NASA NTRS2004

Ontology Development and Evolution in the Accident Investigation Domain

InvestiigationOrganizer (IO) is a collaborative semantic web system designed to support the conduct of mishap investigations. IO provides a common repository for a wide range of mishap related information, allowing investigators to integrate evidence, causal models, and investigation results. IO has been used to support investigations ranging from a small property damage case to the loss of the Space Shuttle Columbia. Through IO'S use in these investigations, we have learned significant lessons? about the application of ontologies and semantic systems to solving real-world problems. This paper will describe the development of the ontology within IO, from the initial development, its growth in response to user requests during use in investigations, and the recent work that was done to control the results of that growth. This paper will also describe the lessons learned from this experience and how they may apply to the implementaton of future ontologies and semantic systems.

Carvalho, Robert↗
NASA NTRS2004

Implementing Recommendations of the Columbia Accident Investigation Board

As many are aware, a piece of insulating foam liberated itself from the external tank and impacted the leading edge of Columbia during ascent on STS-107. It is believed that this impact left a hole in the thermal protection system (TPS), which protects the shuttle from hot plasma generated during re-entry. Unfortunately, the orbiter did not have the margin to withstand this compromise, and it is believed that the result of these events caused the loss of crew and orbiter.

Ottens, B.↗
NASA NTRS2005

Implementing Recommendations of the Columbia Accident Investigation Board - Development of on-Orbit RCC Thermography

One of NASA s Space Shuttle Return-to-Flight (RTF) efforts has been to develop thermography for the on-orbit inspection of the Reinforced Carbon Carbon (RCC) portion of the Orbiter Wing Leading Edge (WLE). This paper addresses the capability of thermography to detect cracks in RCC by using in-plane thermal gradients that naturally occur on-orbit. Crack damage, which can result from launch debris impact, is a detection challenge for other on-orbit sensors under consideration for RTF, such as the Intensified Television Camera and Laser Dynamic Range Imager. We studied various cracks in RCC, both natural and simulated, along with material characteristics, such as emissivity uniformity, in steady-state thermography. Severity of crack, such as those likely and unlikely to cause burn through were tested, both in-air and in-vacuum, and the goal of this procedure was to assure crew and vehicle safety during re-entry by identification and quantification of a damage condition while on-orbit. Expected thermal conditions are presented in typical shuttle orbits, and the expected damage signatures for each scenario are presented. Finally, through statistical signal detection, our results show that even at very low in-plane thermal gradients, we are able to detect damage at or below the threshold for fatality in the most critical sections of the WLE, with a confidence exceeding 1 in 10,000 probability of false negative.

Ottens, Brian↗
NASA NTRS2005

Implementing Recommendations of the Columbia Accident Investigation Board: Development of On-Orbit IR Thermography

One of NASA's Space Shuttle Return-to-Flight (RTF) efforts has been to develop thermography for the on-orbit inspection of the Reinforced Carbon Carbon (RCC) portion of the Orbiter Wing Leading Edge (WLE). This paper addresses the capability of thermography to detect cracks in RCC by using in-plane thermal gradients that naturally occur on-orbit. Crack damage, which can result from launch debris impact, is a detection challenge for other on-orbit sensors under consideration for RTF, such as the Intensified Television Camera and Laser Dynamic Range Imager. We studied various cracks in RCC, both natural and simulated, along with material characteristics, such as emissivity uniformity, in steady-state thermography. Severity of crack, such as those likely and unlikely to cause burn through were tested, both in-air and in-vacuum, and the goal of this procedure was to assure crew and vehicle safety during reentry by identification and quantification of a damage condition while on-orbit. Expected thermal conditions are presented in typical shuttle orbits, and the expected damage signatures for each scenario are presented. Finally, through statistical signal detection, our results show that even at very low in-plane thermal gradients, we are able to detect damage at or below the threshold for fatality in the most critical sections of the WLE, with a confidence exceeding 1 in 10,000 probability of false negative.

Ottens, Brian P.↗
NASA NTRS2004

High Temperature Chemistry in the Columbia Accident Investigation

Initial estimates on the temperature and conditions of the breach in Columbia's wing focused on analyses of the slag deposits. These deposits are complex mixtures of the reinforced carbon/carbon (RCC) constituents, insulation material, and wing structural materials. However it was possible to clearly discern melted/solidified Cerachrome(R) insulation, indicating the temperatures had exceeded 1760 C. Current research focuses on the carbon/carbon in the path from the breach. Carbon morphology indicates heavy oxidation and erosion. Raman spectroscopy yielded further temperature estimates. A technique developed at Sandia National Laboratories is based on crystallite size in carbon chars. Lower temperatures yield nanocrystalline graphite; whereas higher temperatures yield larger graphite crystals. By comparison to standards the temperatures on the recovered RCC fragments were estimated to have been greater than 2700 C.

Jacobson, Nathan↗
NASA NTRS2005

The Application of Electron Microscopy Techniques to the Space Shuttle Columbia Accident Investigation

The Space Shuttle Columbia was returning from a 16-day research mission, STS- 107, with nominal system performance prior to the beginning of the entry interface into earth's upper atmosphere. Approximately one minute and twenty four seconds into the peak heating region of the entry interface, an off-nominal temperature rise was observed in the left main landing gear brake line. Nearly seven minutes later, all contact was lost with Columbia. Debris was observed periodically exiting the Shuttle's flight path throughout the reentry profile over California, Nevada, and New Mexico, until its final breakup over Texas. During the subsequent investigation, electron microscopy techniques were crucial in revealing the location of the fatal damage that resulted in the loss of Columbia and her crew.

Shah, Sandeep↗
NASA NTRS2004

DSMC Simulations in Support of the Columbia Shuttle Orbiter Accident Investigation

Three-dimensional Direct Simulation Monte Carlo simulations of Columbia Shuttle Orbiter flight STS-107 are presented. The aim of this work is to determine the aerodynamic and heating behavior of the Orbiter during aerobraking maneuvers and to provide piecewise integration of key scenario events to assess the plausibility of the candidate failure scenarios. The flight of the Orbiter is examined at two altitudes: 350-kft and 300-kft. The flowfield around the Orbiter and the heat transfer to it are calculated for the undamaged configuration. The flow inside the wing for an assumed damage to the leading edge in the form of a 10- inch hole is studied.

Boyles, Katie↗
NASA NTRS2003

Direct Simulation Monte Carlo Calculations in Support of the Columbia Shuttle Orbiter Accident Investigation

The Direct Simulation Monte Carlo method was used to provide 3-D simulations of the early entry phase of the Shuttle Orbiter. Undamaged and damaged scenarios were modeled to provide calibration points for engineering "bridging function" type of analysis. Currently the simulation technology (software and hardware) are mature enough to allow realistic simulations of three dimensional vehicles.

Gallis, Michael A.↗
NASA NTRS2010

Medical Response, Search and Recovery during the Space Shuttle Columbia Accident Investigation

On February 1, 2003, the Space Shuttle Columbia broke apart during atmospheric re-entry on mission STS-107. After an event such as this, with high visibility and international interest, the operational challenge of recovering the crewmembers could not be underestimated. The Space Shuttle Program is organized to respond to a vehicle mishap using the resources of the Mishap Investigation Team (MIT). On the afternoon of Feb. 1, 2003, the MIT deployed to Barksdale Air Force Base (AFB), Louisiana. This location became the investigative center and interim storage location for crewmembers received from the Lufkin, Texas Disaster Field Office (DFO). The Lufkin DFO served as the primary area for all operations, including staging assets and deploying field teams for search, recovery and security of crewmember remains. More than 2,000 people from numerous organizations were involved with the recovery of the crew. All seven crewmembers of STS-107 were recovered and ceremonial last rights were administered. Astronaut and military personnel escorted the crew with honor to the MIT at Barksdale AFB, Louisiana. At Barksdale AFB a temporary morgue was established in an aircraft hangar and operated for approximately two weeks during which time coordination with the DFO field recovery teams, Armed Forces Institute of Pathology (AFIP) medical personnel, and the crew surgeons was on going. Families of crewmembers and NASA management were notified daily of the current findings. Working under the leadership of the MIT Lead, the medical team developed and executed a short-term plan to identify and relocate the crew with a military honor guard and protocol to the medical examiner at the Armed Forces Port Mortuary, Dover AFB, Delaware. After operations at Barksdale AFB were concluded the medical team transitioned back to Houston and a long-term plan was developed and implemented which involved the Air Force Mortuary Affairs at Randolph AFB, Texas. This plan was coordinated with search teams in the field, Barksdale AFB Mortuary Affairs, KSC security, AFIP, and the crew surgeons at JSC.

Stepaniak, Philip C.↗
NASA NTRS2008

Nondestructive Testing As a Tool in the Space Shuttle Columbia Accident Investigation

Nondestructive testing (NDT) played a crucial role in determining the Columbia tragedy's cause. Over 84,000 pieces of debris were recovered; hundreds were subsequently subjected to NDT and materials analysis. Visual NDT of the debris revealed localized areas of damage such as erosion, excessive heating, knife edging and mechanical damage. Three-dimensional reconstructions were made of the left wing leading edge, utilizing a tripod-mounted laser scanning head and focused laser beam, and an advanced topometric optical scanner (ATOS) with digital white light to scan complex-shaped debris, producing monochrome 3-D models. Texture mapping provided a means to capture true colors of the debris and superimpose them on the scanned images. Uniform deposits were found over large portions of debris, obscuring underlying materials. To determine what was beneath, inverse radiography was enlisted. The radiographs guided investigators to where samples should be taken. To ascertain compositions, these samples were subjected to analytical testing, including energy dispersive X-ray spectroscopy and electron microprobe analysis. This combination of visual evidence, radiography, virtual reconstruction, and materials analysis allowed the forensic scientists to verify that a breach occurred in the leading edge of the left wing, the path the plasma followed, and the sequence of events that led to the loss.

McDanels, Steve↗
NASA NTRS2000

The ''Rock'': The Role of the Press in Bringing about Change in Aircraft Accident Policy

From 1926 to 1938, the Aeronautics Branch, forerunner of the Federal Aviation Administration (FAA), had been charged with aircraft accident investigation. While the Branch had been investigating accidents since its inception, it had, early in its tenure, put into place a policy making its findings secret. Media and political pressure began to mount in late 1928 over its policy of nondisclosure and the debate brought pressure to bear on the young Aeronautics Branch to reverse its policy and make its findings public. The focusing event for the Branch's policy reversal was the death of Knute Rockne, the famous Notre Dame football coach, in a Transcontinental and Western Airways (TWA) airliner on March 31, 193 1. This paper will examine the role of print media in bringing about a significant, and lasting, change in aircraft accident public-disclosure policy.

Johnson, Randy↗