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Fisher, Bruce D.

Publications and source records attributed to Fisher, Bruce D..

13 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

Pilot Weather Advisor System

The Pilot Weather Advisor (PWA) system is an automated satellite radio-broadcasting system that provides nearly real-time weather data to pilots of aircraft in flight anywhere in the continental United States. The system was designed to enhance safety in two distinct ways: First, the automated receipt of information would relieve the pilot of the time-consuming and distracting task of obtaining weather information via voice communication with ground stations. Second, the presentation of the information would be centered around a map format, thereby making the spatial and temporal relationships in the surrounding weather situation much easier to understand

Lindamood, Glenn↗
NASA NTRS1992

Joint NASA/USAF Airborne Field Mill Program - Operation and safety considerations during flights of a Lear 28 airplane in adverse weather

A NASA Langley Research Center Learjet 28 research airplane was flown in various adverse weather conditions in the vicinity of the NASA Kennedy Space Center from 1990-1992 to measure airborne electric fields during the Joint NASA/USAF Airborne Field Mill Program. The objective of this program was to characterize the electrical activity in various weather phenomena common to the NASA-Kennedy area in order to refine Launch Commit Criteria for natural and triggered lightning. The purpose of the program was to safely relax the existing launch commit criteria, thereby increasing launch availability and reducing the chance for weather holds and delays. This paper discusses the operational conduct of the flight test, including environmental/safety considerations, aircraft instrumentation and modification, test limitations, flight procedures, and the procedures and responsibilities of the personnel in the ground station. Airborne field mill data were collected for all the Launch Commit Criteria during two summer and two winter deployments. These data are now being analyzed.

Fisher, Bruce D.↗
NASA NTRS1990

Multistroke cloud-to-ground strike to the NASA F-106B airplane

An analysis of electromagnetic waveform records and video images of a multistroke cloud-to-ground (CG) strike to the NASA F-106B instrumented airplane is presented. The CG flash started as a lightning strike triggered by the airplane and later produced multiple return strokes to the ground (the ground strike network registered six return strokes). Although there are some uncertainties in data interpretation resulting from lack of independent measurements with other than the airborne instruments, recoil streamers and eight sequences of dart leaders followed by return strokes (two more than were indicated by the ground network) were identified in the airborne data. At least three of the subsequent return strokes were attached to the airplane. The analysis provides evidence that formation of recoil streamers and dart leaders is accompanied by a surge in continuous current. This feature is similar to that observed in the bidirectional leader development during lightning initiation on the airplane.

Mazur, Vladislav↗
NASA NTRS1989

Effects of lightning on operations of aerospace vehicles

Traditionally, aircraft lightning strikes were a major aviation safety issue. However, the increasing use of composite materials and the use of digital avionics for flight critical systems will require that more specific lightning protection measures be incorporated in the design of such aircraft in order to maintain the excellent lightning safety record presently enjoyed by transport aircraft. In addition, several recent lightning mishaps, most notably the loss of the Atlas/Centaur-67 vehicle at Cape Canaveral Air Force Station, Florida in March 1987, have shown the susceptibility of aircraft and launch vehicles to the phenomenon of vehicle-triggered lightning. The recent findings of the NASA Storm Hazards Program were reviewed as they pertain to the atmospheric conditions conducive to aircraft lightning strikes. These data are then compared to recent summaries of lightning strikes to operational aircraft fleets. Finally, the new launch commit criteria for triggered lightning being used by NASA and the U.S. Defense Department are summarized. The NASA Research data show that the greatest probability of a direct strike in a thunderstorm occurs at ambient temperatures of about -40 C. Relative precipitation and turbulence levels were characterized as negligible to light for these conditions. However, operational fleet data have shown that most aircraft lightning strikes in routine operations occur at temperatures near the freezing level in non-cumulonimbus clouds. The non-thunderstorm environment was not the subject of dedicated airborne lightning research.

Fisher, Bruce D.↗
NASA NTRS1989

Cockpit display of ground-based weather data during thunderstorm research flights

This paper describes an integrated system for providing ground-based cockpit display, transmitting to an aircraft, upon request via VHF radio, important ground-based thunderstorm data such as radar precipitation reflectivity contours, aircraft ground track, and cloud-to-ground lightning locations. Examples of the airborne X-band weather radar display and the ground-based display are presented for two different missions during the NASA Storm Hazards Program. In spite of some limitation, the system was found to be helpful in the selection of the route of flight, the general ground track to be used, and, occasionally, in clarifying the location of a specific cell of interest.

Fisher, Bruce D.↗
NASA NTRS1988

Aircraft jolts from lightning bolts

The trend toward the use of composite materials and digital electronics has renewed the need to quantify the effects of lightning strikes to airplanes, since composite structures do not provide shielding equivalent to that of metal aircraft, and digital systems are potentially more susceptible to upset by electrical transients than are analog electronic systems. A research program, called the Storm Hazards Program, has been run by the National Aeronautics and Space Administration (NASA) for the past eight years and has provided the first statistically significant measurements of the electromagnetic interaction between lightning and aircraft. A NASA-owned F-106B airplane has been flown through thunderstorms about 1500 times at altitudes between 5,000 and 40,000 feet (1,500 to 12,000 meters). The airplane, lightning-hardened and outfitted with special instruments, was hit by lightning 714 times. The types of measurements made and the results are described.

Pitts, Felix L.↗
NASA NTRS1988

Implications of a recent lightning strike to a NASA jet trainer

On February 24, 1987, a NASA T-38A airplane experienced a lightning strike while approaching the Los Alamitos Army Aviation Facility in California. The airplane was landed safely at Los Alamitos with no injury to the crew members. However, the airplane suffered extensive fire damage in the center of the fuselage section. The NASA investigation board concluded that the airplane was struck by lightning, which resulted in an inflight explosion with subsequent fire. The implications of this mishap to aircraft lightning protection and the avoidance of those conditions conducive to lightning strikes to aircarft are discussed.

Fisher, Bruce D.↗
NASA NTRS1988

Cloud-to-ground strikes to the NASA F-106 airplane

Cloud-to-ground (CG) lightning strike data on the NASA F-106B research aircraft obtained during the 1984-86 storm seasons in the vicinity of Wallops Island, Virginia, are analyzed. The results suggest that CG strikes may represent a significant portion of the total number of lightning strikes encountered by the aircraft at altitudes below 6 km. It is unlikely that an aircraft encounters the first return stroke of the CG flash. The current values of the CG strikes are not different from currents in other types of strikes.

Mazur, Vladislav↗
NASA NTRS1988

Implications of a recent lightning strike to a NASA jet trainer

On February 24, 1987, a NASA T-38A airplane experienced a lightning strike while approaching the Los Alamitos Army Aviation Facility in California. The airplane was landed safely at Los Alamitos with no injury to the crew members. However, the airplane suffered extensive fire damage in the center fuselage section. The NASA investigation board concluded that the airplane was struck by lightning, which resulted in an inflight explosion with subsequent fire. This paper describes the most probable cause of the incident, and the implications of this mishap to aircraft lightning protection and to the avoidance of those conditions conducive to lightning strikes to aircraft.

Fisher, Bruce D.↗
NASA NTRS1988

Final results of the NASA storm hazards program

Lightning swept-flash attachment patterns and the associated flight conditions were recorded from 1980-1986 during 1496 thunderstorm penetrations and 714 direct strikes with a NASA F-1068 research airplane. These data were studied with an emphasis on lightning avoidance by aircraft and on aircraft protection design. The individual lightning attachment spots, along with crew comments and on-board photographic data were used to identify lightning swept-flash attachment patterns and the orientations of the lightning channels with respect to the airplane. The full-scale in-flight data were compared to results from scale-model arc-attachment tests. The airborne and scale-model data showed that any exterior surface of this airplane may be susceptible to direct lightning attachment. In addition, the altitudes, ambient temperatures, and the relative turbulence and precipitation levels at which the strikes occurred in thunderstorms are summarized and discussed. It was found that the peak strike rate occurred at pressure altitudes betwen 38,000 ft and 40,000 ft, corresponding to ambient temperatures colder than -40 C.

Fisher, Bruce D.↗
NASA NTRS1987

In-flight environmental effects on airplane composite vertical fin caps

The NASA-Langley Storm Hazards Program has given attention to the effects of severe in-flight weather environments on composite structures, using an instrumented F-106B in storm penetration experiments. The vertical fin cap was chosen for the study of lightning strike attachments on composite structures of four different types: (1) glass/epoxy with flame-sprayed aluminum; (2) Kevlar/epoxy with aluminized glass cloth; (3) graphite-epoxy without lightning protection; and (4) unprotected graphite-epoxy with electrical isolation from the rest of the aircraft structure. Flight test results are evaluated.

Howell, William E.↗