Flight Data Analysis Research Articles

Induced activity in scintillation detectors in space

An experimental system was flown on the Space Shuttle Columbia from August 8 to 13, 1989 as part of the Shuttle Activation Monitor (SAM) program [P.S. Haskins et al., IEEE Trans. Nucl. Sci. NS-37 (6) (1990) 1256]. Gamma-ray spectra were collected both during flight and after landing from two 3 in. × 3 in. scintillation detectors, Nal and BGO. The shuttle was in a high inclination (57 °) orbit, at an altitude of 300 km which provided exposure to the trapped charged particles in the South Atlantic Anomaly (SAA) as well as the electrons in the Polar regions. The induced radiation observed by the detectors resulted from both external and internal sources activated by the interaction with the energetic charged particles. The flight data analysis indicates variation of the induced external radiation as a function of geomagnetic coordinates and amount of shielding, whereas the post-landing data exhibits induced internal radiation from the two different types of detector materials.

Wind measurements from four airliners in 1988 Denver microburst

Flight and radar position records are analyzed to determine the winds encountered by four airliners that penetrated a microburst on approach to Denver's Stapleton International Airport on July 11, 1988. The four encounters provide information about the time-varying changes in the strength, size, and location of the microburst phenomenon. The results show significant expansion in the size of the microburst and indicate the presence of fluctuations in the internal wind velocity associated with multiple microburst cells. At its peak strength, as experienced by the second aircraft, the microburst produced a headwind-to-tailwind velocity change of 115 ft/s. It is shown that the developing wind patterns derived from the flight-data analysis are in general agreement with results derived from ground-based Doppler weather radar and from a numerical microburst simulation. The data from the four aircraft complement these other findings by providing a more detailed analysis of the microburst's internal wind environment.

Parameter estimation for flight vehicles

The aircraft parameter estimation problem is used to illustrate the utility of parameter estimation, which applies to many engineering and scientific fields. Maximum-likelihood estimation has been used to extract stability and control derivatives from flight data for many years. This paper presents some of the basic concepts of aircraft parameter estimation and briefly surveys the literature in the field. The maximum-likelihood estimator is discussed, and the basic concepts of minimization and estimation are examined for a simple simulated aircraft example. The cost functions that are to be minimized during estimation are defined and discussed. Graphic representations of the cost functions are given to illustrate the minimization process. Finally, the basic concepts are generalized, and estimation from flight data is discussed. Some of the major conclusions for the simulated example are also developed for the analysis of flight data from the F-14 and Space Shuttle vehicles.

The spacelab 2 XRT xenon-filled position-sensitive proportional counters

The dual coded-mask X-ray telescope flown on the Spacelab 2 mission utilised two position-sensitive proportional counters, the largest yet used in space for X-ray astronomy. Each had a geometric area of over 1000 cm 2 and a depth of 5.3 cm atmospheres of xenon-methane, providing useful sensitivity up to 30 keV. A novel position readout technique used a combination of delay line timing and measuring ratios of cathode signal amplitudes. Analysis of flight data indicates the performance was close to that obtained during ground calibration tests. The possibilities for developments for higher energies and larger areas are discussed.

Effect of sunlight on stratospheric emission at 10–12 microns

Analysis of stratospheric balloon flight data is interpreted as showing that metastable water vapour species are important in the 10 μm spectral region.

Use of piezoelectric foil for measurement of pressure fluctuations and local shear stress in flight

The measurement of pressure fluctuations in air flows poses several serious problems to the experimentalist. Generally a very limited frequency response is available, as the cavity above ordinary pressure transducers plays a crucial role for the sensor response. This type of transducer requires extensive work for incorporation into a surface. Recently, piezoelectric foil has become available for various applications. It offers ease of application and distributed measurements without strict frequency response limits. However, although the data acquisition is straightforward, it appears that particular caution is required for interpretation of the data as pressure fluctuations. In the present paper, emphasis is put on frequency response, true root‐mean‐square determination, as well as interpretation into skin friction data. Through analysis of flight data and laboratory calibrations, it is shown that the piezoelectric foil in general will respond to pressure fluctuations, and it is also shown that the piezofoil constitutes a repeatable and rugged source of information.

FDAD: A Lab/Field Test Tool

Flight Data Analysis and Display, FDAD, is a hardware and software tool that permits the monitoring of the hardware and software of a multi-processor Electronic Countermeasure, ECM, system in a non-interfering mode. FDAD monitors user-defined memory addresses and hardware lines and displays in real-time the changes to these locations. Data is also stored for subsequent analysis and display. This tool allows developers to identify the operating characteristics of an extremely complex and fast system with the assurance that the instrumentation does not alter the true performance of that system.

Robot Efficiency for British Airways' Flight Data Analysis

A Robotic cell, designed and manufactured by 600 Fanuc Robotics Ltd., of Colchester, (Essex), and installed into British Airways at its maintenance base, London Airport, (Heathrow), for the loading/unloading of flight recorder cassettes into, and out of, tape readers, has so radically increased the overall effficiency of the operation that only four readers are now needed to carry out work that previously required 16.

On aircraft flight performance in a perturbed atmosphere

SummaryWe consider the effect of atmospheric disturbances, such as wind, shears, turbulence, wakes and downflows, on aircraft performance (section 1), recalling the minimum of aerodynamics (section 2) necessary for the calculation of the effects on flight mechanics. For example, it is shown (section 3) that the relative lift change, due to wind, shear or both, coincides with the disturbance intensity G, defined as the instantaneous vertical acceleration, measured in g's, that an aircraft will experience as a consequence of atmospheric disturbances, assuming constant velocity and attitude. The disturbance intensity is a measure of the total force that the atmospheric disturbance can exert on the aircraft; this force may cause changes in normal acceleration, flight velocity and angle-of-attack, either isolated (section 5) or combined (section 6), in straight and level flight; in the case of a horizontal turn (section 7), the disturbance intensity specifies the changes in instantaneous turn rate, velocity, radius (section 8), acceleration and bank angle (section 9) due to atmospheric perturbations, and their cumulative effect over time in (section 10) deforming and displacing trajectories. These effects (section 11) are quantified by formulas and illustrated in graphics, and we indicate throughout the flight mechanical consequences of disturbances with the critical intensities G1 = — 0·17 and G2 = — 0·42; these are the disturbance intensities which, if uncompensated, would be just enough to cause an aircraft to stall (section 4) respectively at unstick on take-off and on approach to land. We conclude (section 12) with a discussion of the use of the disturbance intensity as a parameter in the reduction and analysis of flight data.

Aerodynamic parameters estimated from flight and wind tunnel data

A procedure for determination of aerodynamic model structure and estimation of aerodynamic parameters is applied to data from a modern fighter operating within an angle of attack range of 5-60 deg. The paper briefly describes the airplane, available flight and wind tunnel data, postulated models for airplane aerodynamic coefficients, and flight data analysis. The results presented contain only a small number of selected longitudinal and lateral parameters. These parameters were obtained from various maneuvers and subsets of joined data from several flights. The estimated parameters are in good agreement with the wind tunnel measurements. The resulting aerodynamic model equations seem to be satisfactory for the prediction of airplane motion.

Applications of state estimation in aircraft flight-data analysis

This paper traces the evolution of the use of state estimation in the analysis of aircraft flight data and discusses some recent applications associated with airline turbulence upsets and high-angle-of-attack flight tests. A unifying mathematical framework for state estimation is reviewed, and several examples are shown that illustrate a general approach for estimating variables that are difficult to measure. It is hoped that the diversity of the applications discussed and the examples presented will make the flight-data analyst mindful of the potential advantages of using state estimation methods.

Flight Flutter Test and Data Analysis Techniques Applied to a Drone Aircraft

Modal identification results are presented that were obtained from recent flight flutter tests of a drone vehicle with a research wing called the DAST ARW-1 (for drones for aerodynamic and structural testing, aeroelastic research wing-1). This vehicle is equipped with an active flutter suppression system (FSS). Frequency and damping of several modes are determined by a time-domain modal analysis of the impulse response function obtained by Fourier transformations of data from fast-swept sine wave excitation by the FSS control surfaces on the wing. Flutter points are determined for two different altitudes with the FSS off. Data are given for near the flutter boundary with the FSS on.

Integral Rocket/Ramjet Propulsion- Flight Data Correlation and Analysis Techniques

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.

Absolute concentrations of O(³P) in the lower thermosphere at night

A rocket borne instrument module for detecting atomic oxygen concentrations by the resonance fluorescence technique is reported. The module contained a source lamp emitting OI 1304Å photons and a detector for the scattered photons. The module was constructed so that it could be coupled to a fast flow reactor for calibration purposes. During the flight the module was radially deployed from the payload on an oscillating boom with a maximum extension of 90 cm from the skin. Analysis of the initial flight data indicates that the shock formed by the motion of the rocket had a substantial effect on the data and the maximum concentration of the layer at 93 km was about 1.1 × 1011cm−3.

Approximate Prediction of Airframe Noise

Theme IRFRAME noise from aerodynamically clean airframes A is assumed to be trailing-edge noise caused by convection of the wing turbulent boundary layer past the wing trailing edge. Resulting maximum flyover noise is predicted from an existing solution for trailing-edge noise plus estimates of turbulent boundary-layer integral scale length and turbulence intensity. Typical airplanes with retracted or well-faired landing gear but with wing-mounted engine nacelles and extensive trailing-edge flap-track shields generate about 8 dB more than this minimum trailing-edge noise. Resulting predicted acoustic intensity varies with airspeed t o the fifth power, in agreement with a linear regression analysis of flight data. ' Trailing-edge noise has been previously inferred' to be the mechanism for airframe noise because of the observed fifthpower velocity dependence. In contrast, other analyses 3.4 have assumed a lift dipole directivity associated with fluctuating-drag noise mechanisms and have predicted a sixthpower velocity dependence.

Flight performance of a high-impulse monopropellant thruster

A discussion of flight experience obtained on a 250 lbf thrust monopropellant hydrazine thruster is presented. Consistent and highly predictable performance was achieved over the full range of operating conditions, and the catalyst bed resistance parameter was employed successfully in performance prediction. An unexpected decline in catalyst bed resistance, not observed in previous ground testing, caused initial concern over possible engine washout, although eventual stabilization occurred. Analysis of ground and flight data indicates incomplete simulation in ground testing, and suggests caution in the extrapolation of flight thruster life expectancy from ground test results.

A bremsstrahlung-identification technique for cosmic-ray electrons and positrons

We introduce a new technique to separate energetic e + and e − from a background of other particles. The technique utilizes a selective trigger, radiation of bremsstrahlung photons by incident e ±, magnetic deflection of the e ± after photon emission, and the separate detection of both the e ± and the photons in a shower detector. Descriptions are given of a balloon-borne apparatus using this technique for cosmic-ray e ± spectral measurements in the energy range from 5 to 50 GeV. Calibrations of the apparatus at particle accelerators and the method of flight data analysis are also described. Our balloon-borne apparatus provides an efficiency of about 50% for the detection of e ± and a proton rejection of about 10 −5.

A Satellite-Borne High Resolution Ge(Li) Gamia-Ray Spectrometer System Part 2: Description of the Electronic, Data Handling and Auxiliary Sensor Systems

The first high-resolution gamma-ray spectrometer system employing Ge(Li) detectors has been designed and successfully flown on an earth-orbiting satellite. The complete scientific payload consists of two large-volume Ge(Li) spectrometers for the measurements of photons in the 40 keV - 2.8 MeV energy range with 4096-channel energy resolution and six auxiliary sensors for measuring the location, intensity and energy spectra of charged-particle backgrounds in earth orbit. To achieve and maintain an overall systems resolution of 3.5-4 keV in photon energy, a low-noise bias power supply and charge sensitive preamplifier-amplifier combination were designed for the germanium detectors. Amplified signals are analyzed in a 4096-channel analyzer of the linear-ramp type, with an integral and differential linearity of ± 0.2 percent and ± 1.0 percent, respectively. Individual pulse-height addresses are sampled at a rate of 1625 addresses/sec and time tagged together with absolute count-rate data by the experiment digital-data-handling system and then stored on magnetic tape recorders. A detailed description of the gamma-ray spectrometer electronic system including the method of collecting and analysis of flight data is given.

Flat Plate Solar Thermoelectric Generator Orbital Experiment

A preliminary analysis of orbital flight data, ground-test data, and correlation of orbital and ground-test results from a flat plate solar thermoelectric generator orbital experiment are presented. The small thermnoelectric panels used were fabricated and ground tested by General Atomic and placed into orbit from Vandenberg AFB by Space Systems Division, USAF. The entire program was conducted for and under the cognizance of Aeronautical Systems Division, USAF.