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Over the past 5 years, various efforts addressed the problems associated with Foreign Object Damage (FOD) to aircraft operating in a debris strewn environment following an airbase attack. These efforts include engine object ingestion probability, engine (FOD) damage, aircraft damage from tire lofted foreign objects, external stores FOD, tire cutting FOD, and the operability of tires subjected to FOD. This report was written to provide a summary and preliminary assessment to the tire cutting FOD portion of the overall post-attack FOD program. The report summarizes the approach and results of tests on over 126 aircraft tires which were tested in a simulated post-attack environment under full scale test conditions. Tests tires included F-16 main and nose, and an F-4 nose tire setup. Test variables included speed, load, size, pressure, tire type, turning, water effects, debris type, debris size, debris distribution, braking, and combined variable effects. Analysis consideration involved cut types, cut depths, number of cuts, cut/hit probabilities, tire failures, and aircraft operational impacts.

Ground operations over rough surfaces and/or debris strewn taxiways and runways may result in cut damage to the tires. Cut progression during continued flight operations has not been seriously studied. This report will follow a group of Type VII Extra High Pressure tires which were damaged by running them over a debris strewn test bed, then run though alternating taxi-takeoff and landing-taxi tests on the 3.05 meter (120 inch) dynamometer in the Landing Gear Development Facility at Wright-Patterson Air Force Base. Only 1.3 - 23% of the debris struck by these tires resulted in cuts. While testing on the dynamometer, the cut depth grew rapidly until it reached the outer carcass ply, then slowed. The test group included new and recapped bias ply, and prototype radial main landing gear tires. This paper will summarize the tire tests and offer recommendations for future evaluation of the tires and materials., Also available as rept. no. SAE-912155.

The Bird Strike Committee Europe consists of civil and military participants from Europe with a common interest in the bird strike problem. Attendance is open to participants from other parts of the world. Annual Meeting Proceedings include Chairman's Report, Working Group Reports and Papers Presented.

Some airport operators, airlines, and fixed base operators have extensive formal training programs for employees whose duties involve operating a ground vehicle on the air operations area. However, many rely solely on informal on-the-job training. In an effort to improve the safety of ground vehicle operations on airports, the FAA developed this guide to ground vehicle operations. The guide provides airport orientation and operational information and would be used as a resource document by the airport operators and other members of the aviation community responsible for training ground vehicle operators. In addition to orientation and operational information, the guide touches on some other areas that a ground vehicle operator may encounter such as Foreign Object Damage, security, and reporting emergencies. (emk)

This research describes an investigation of the use of polymer- modified aggregate (PMA) as a bomb damage repair material. PMA, an open-graded aggregate partially bonded with polymer at the particle interfaces, could be an economical repair material and provide a strong subgrade for repaired airfield surfaces. A PMA repair material would consist of a 6 to 18 in. layer of partially bonded, porous aggregates over push-back debris or over a layer of ballast stone base material. The select fill, an open-graded aggregate, would provide the primary load bearing strength. Adding polymer would provide tensile strength to the aggregate matrix, which, in its unbonded state, would not exhibit any tensile strength. A PMA repair material would also provide FOD protection.

In-flight wire strikes poses a serious threat to low-level helicopter operations. Under the sponsorship of Headquarters, US Army Aviation Research and Development Command (AVARADCOM) tests were conducted by ATL to determine the suitability for UH-1H helicopter application of a Wire Strike Protection System (WSPS) manufactured by Bristol Aerospace Limited (BAL). The WSPS initially tested consisted of fuselage-mounted upper and lower cutters and a windshield centerpost deflector with a sawtooth cutter. Using the NASA-Langley Research Center's Impact Dynamics Research Facility, a UH-1H helicopter fitted with the WSPS was subjected to pendulum swing tests in which the helicopter struck strung wires at approximately 40 knots airspeed. The WSPS demonstrated its capability to sever an 11,500-pound tensile strength steel, seven-strand 3/8 guy wire. Also, a significant wire-cutting limitation peculiar to the UH-1H was identified. At wire impact 30 degrees from the normal to the flight path, it was demonstrated that the wire could be snagged by the windshield wiper shaft, preventing the wire from being deflected into the upper cutter. As a result, BAL and ATL analyzed the situation and both concluded that a simple windshield wiper shaft deflector could alleviate the problem. Windshield wiper shaft deflectors fabricated by BAL were installed on the test aircraft and additional swing tests were conducted. Successful deflection and wire cutting were demonstrated. Installation of the WSSPS,. as modified by this effort, on the Army's UH-1H helicopter fleet is recommended.

An investigation of historical data was conducted in an attempt to assign a specific cause to each foreign object damage incident reported during an eighteen month period. Interviews were conducted with engineers and fleet maintenance personnel in support of the above research. The impact of current FOD reporting procedures, the foreign objects, the ingestion process and the operating environment are discussed. Conclusions and recommendations are included. (Author)

This pamphlet was prepared to notify personnel of the damage that has been caused by foreign objects, to assist commanders, supervisors, and other individuals in preventing foreign object damage (FOD), and to provide suggested solutions to prevent FOD and subsequent aircraft mishaps. The term "mishap" will be all inclusive in reference to all occurrences as classified in paragraphs 2.9b(1) through 2-9b(11), AR 385-40. Mishaps due to wire, tree, and stump strikes during nap-of-the-earth flights and bird strikes have not been included. Wood strikes, other than NOE, have been included when there was damage to the aircraft due to crew error or error on the part of ground guides.

The Bird Strike Committee Europe consists of civil and military participants from Europe with a common interest in the bird strike problem. Attendance is open to participants from other parts of the world. Annual Meeting Proceedings include Chairman's Report, Working Group Reports and Papers Presented: (1) Report on Overseas National DC-10 Accident at Kennedy Airport; (2) Bird Strikes to Engines; (3) Height Distribution of Bird Movements in Southern Sweden Measured by Radar; (4) Presentation of Bird Intensity on an 8 Point Scale Display Unit; (5) Soaring of Birds by use of Lights and Lasers; (6) Growth Prohibiting Substances and Effects on Grassland; (7) Allocation of Finance to Strengthen Aircraft Structure; (8) Attempts to Get Rid of Wood Pigeons from Orly Airport; (9) Bird Strikes during 1974 to European Registered Civil Aircraft; (10) Bird Strikes at projected Munich 2 Airport; (11) Trials of Bird Repellant Substances at Ben Gurion Airport; (12) Radar Study of Waders; (13) Migrating Birds and Their Danger to Aeroplanes; and (14) The Problems of Planting Trees and Shrubs Near Airfields.

The Bird Strike Committee Europe consists of civil and military participants from Europe with a common interest in the bird strike problem. Attendance is open to participants from other parts of the wond. Annual Meeting Proceedings include Chairman's Report, Working Group Reports and Papers Presented: TABLE OF CONTENTS: Birdstnke Risk Forecast. Dr. J. Hild (Germany) Bird Strikes during 1975 to European Registered Civil Aircraft. J. Thorpe (UK) Establishment of Bird Control Units at 6 Dutch Air Bases. L.S. Buurma (Netherlands) Birds Killed by Aircraft in the United Kingdom 1966-76. J.B.A. Rochard and N. Horton (UK) Some Statistic Data on Birds Strike to Aircraft and Helicopters over the TerrItory of the Soviet Union. A.l. Rogachev and O.K. Trunov (USSR) Bird Strikes in German Air Force 1968-1976. Dr. J. Hild (Germany) Attempts to Control the Breeding Population of the HerrIng Gull (Larus argentatus) near Copenhagen Airport. H.Lind (Denmark) Development of the Theoretical Constmct of Synergised Aluminum Ammonium Sulphate for the Control of Birds at Airports. R.J. Stone Treatment for Repelling Birds at Ben Gurion (LOD) Intemational Airport. (Israel) The Influence of Weather Vanables on the Density of Noctumal Migration in Spring. S.A. Gauthreaux (USA) Weather-dependence of height, Density and Direction of Migration in Switzerland. B. Bruderer (Switzerland) Autumn Radar Study of the Coastal Migration in Western Holland. L.S. Buurman (Netherlands) Surveys of Bird Concentration Areas as a Tool in Aviation Safety Work with an Example from Sweden. J. Karisson (Sweden) Bird Strike problems at Ben-Gurlon International Airport (LOD). S. Suaretz (Israel) Plane as a Deterrent an Attractant. V.E. Jacoby (USSR)

The Bird Strike Committee Europe consists of civil and military participants from Europe with a common interest in the bird strike problem. Attendance is open to participants from other parts of the world. Annual Meeting Proceedings include Chairman's Report, Working Group Reports and Papers Presented.

The Bird Strike Committee Europe consists of civil and military participants from Europe with a common interest in the bird strike problem.

The Bird Strike Committee Europe consists of civil and military participants from Europe with a common interest in the bird strike problem. Attendance is open to participants from other parts of the world.

This report presents the results of a program to determine the impact resistance of composite fan blades subjected to foreign object damage (FOD) while operating under conditions simulating a short takeoff and landing (STOL) engine at takeoff. The full-scale TF39 first-stage fan blade was chosen as the base design for the demonstration component since its configuration and operating tip speeds are similar to a typical STOL fan blade and several composite configurations had already been designed and evaluated under previous programs. The first portion of the program was devoted toward fabricating and testing high impact resistant, aerodynamically acceptable composite blades which utilized only a single material system in any given blade. The material systems utilized were a graphite/epoxy system (AU/PR 288) and a boron/epoxy system (4.0 mil/5505). It was determined that the blades of each material system were both capable of sustaining impact equivalent to a half bite of a 624 gram (22ounce) bird without total failure. Beyond this point, both blades broke off at the root at impact. In order to increase the blade impact capability beyond this point, several mixed material (hybrid) designs were investigated using S-glass and Kevlar as well as boron and graphite fibers. These hybrid composite blades showed a marked improvement in resistance to bird impact over those blades made of a single composite material.

The top portion of a composite (boron filament/aluminum matrix) blade which is useable in a fluid flow machine is made more resistant to impact energy by forming a cavity in the boron filament layer of the tip portion of each laminate (or ply) of the blade, then filling each cavity with a resin, and then bonding together the laminates with the resin-filled cavities therein. (Author), Supersedes PAT-APPL-227 319-81, AD-D008 450.

This report presents the results of a program conducted between July, 1974 and Nov. 1975 under NASA-Lewis Contract NAS3-17837. The objective of this program was to demonstrate the improved foreign object damage resistance of Hamilton Standard's metal matrix advanced composite fan blade which was developed beginning in 1973. The contract program included the fabrication, whirl impact test and subsequent evaluation of nine advanced composite fan blades of the "QCSEE' type design. The blades were designed to operate at a tip speed of 282 m/sec. (925 fps). The blade design was the spar/shell type, consisting of a titanium spar and boron/aluminum composite airfoils. The blade retention was designed to rock on impact with large birds, thereby reducing the blade bending stresses. The program demonstrated the ability of the blades to sustain Impacts with up to 681 g (24 oz) slices of birds at 0.38 rad with little damage (only 1.4% max weight loss) and 788 g (27.8 oz) slices of birds at 0.56 rad with only 3.2% max weight loss. Unbonding did not exceed 1.1% of the post-test blade area during any of the tests. Cne test using a fixed retention to preclude rocking confirmed improved FOD performance of the rocking retention. Correlation of the Hamilton Standard FOD analysis with the empirical results (strain gauge data in some tests) was very satisfactory, particularly in the prediction of gross loads. All blades in the post-test condition were judged capable of operation in accordance with the FAA guidelines for medium and large bird impacts. (MM)

This report describes the results of a 20-month program, beginning in June 1974, designed to investigate parameters which effect the foreign object damage resulting from ingestion of birds into fan blades of a QOSEE-type engine. Work performed on this program included the design, fabrication, and impact testing of QOSEE fan blades to demonstrate improvement in FOD resistance relative to existing blades and also the design and demonstration of a pin root attachment concept. In the first phase of the program, it was found that, in general, for the small objects used, the strains in the blade are proportional to the mass of the impacting object and the square of the relative velocity component normal to the blade chord at the impact location. These parameters can be further combined into an average or nominal force normal to the blade at the impact location. A finite element computer program gave results that compare well with the test data. In the second phase of the program four improved blades exhibited substantial improvement in FOD resistance relative to former designs.

Natural icing tests were conducted in Nov-Dec 1986 as a continuation of the icing evaluation to establish a moderate icing envelope for the AH-64A apache. The AH-64A ice protection and detection/rate measuring systems were found to be satisfactory and the aircraft demonstrated that it will have the capability to operate safely in icing conditions through the moderate level of intensity following correction of the one deficiency noted during testing. The deficiency was the high potential for engine foreign object damage due to shed ice from the mismatch at the joint between the fore and aft nose gearbox/cross shaft fairings. Eleven shortcomings identified included: the susceptibility of the helicopter engines to damage due to ice shed from the external airframe components; unpredictable failure of the blade deice system due to the design/ operation of the K-3 contactor relay; the potential failure of the deice controller caused by penetration of oil and water into the unit; the inadvertent unplugging of the helmet communication cord; adn the poor location of the ice protection system advisory lights/anti-ice control panel. No degradation of aircraft handling qualities was noted as a result of aircraft ice accretion. Activation of the engine anti-ice system results in approximately 10% loss in power available and 8% decrease in maximum effective range. Keywords: Attack helicopters.

This report describes a loading model for computation of the pressure distribution exerted on surfaces during bird and ice impacts. Bird and ice impacts are considered as fluid dynamic in nature and are modeled as fluid jets impinging on arbitrarily shaped three dimensional deformable surfaces. A quasi-steady, potential flow analysis is applied to the jet impact problem thereby reducing the impact problem to the problem of solving Laplace's equation. The surface singularity technique is used to solve Laplace's equation. A computer program for computing pressure distributions on both rotating and non-rotating turbine engine components is both rotating and non-rotating turbine engine components is described. A model for treating slicing of birds and ice by rotating blades is incorporated into this computer program. The loading model computer program is specifically developed to be interfaced with finite-element structural analysis computer programs. Given the instantaneous impacted surface shape and displacement velocity the loading model computer program computes the pressure distribution existing on the impacted surface. The shape of the impact surface is fed to the loading model in the loading model in the form of finite element surface nodal computer program constructs a system of quadrilateral elements covering the impacted surface. The shape of the impact surface is fed to the loading model in the form of finite element surface nodal point coordinates. From this information, the loading model computer program constructs a system of quadrilateral elements covering the impacted surface., Prepared in cooperation with Dayton Univ., Research Inst., OH.

Impact damage on titanium leading edge configurations was investigated by performing leading edge soft-body impacts on flat-edge and tapered-edge specimens. The objectives were to determine the laboratory specimen size, boundary condition, and test methods necessary to adequately simulate the leading edge local damage of actual blades from soft-body impacts (such as birds). The effects of leading edge geometry, specimen mounting, impact velocity, impactor type, impactor size, and impact angle were investigated. The damage modes excited in ti-tanium were identified. Damage measurement techniques were devised and the damage quantified. Comparisons of the damage were drawn regarding the effects of specimen size and mounting.

Resistance of advanced fiber reinforced epoxy matrix composite materials to ballistic impact was investigated as a function of impacting projectile characteristics, and composite material properties. Ballistic impact damage due to normal impacts, was classified as transverse (stress wave delamination and splitting), penetrative, or structural (gross failure). Steel projectiles were found to be >gelatin >ice projectiles in causing penetrative damage leading to reduced tensile strength. Gelatin and ice projectiles caused either transverse or structural damage, depending upon projectile mass and velocity. Improved composite transverse tensile strength, use of dispersed ply lay-ups, and inclusion of PRD-49-1 or S Glass fibers correlated with improved resistance of composite materials to transverse damage. In non-normal impacts against simulated blade shapes, the normal velocity component of the impact was used to correlate damage results with normal impact results. Stiffening the leading edge of simulated blade specimens led to reduced ballistic damage, while addition of a metallic leading edge provided nearly complete protection against 0.64cm diameter steel, and 1.27 cm diameter ice and gelatin projectiles, and partial protection against 2.54 cm diameter projectiles of ice and gelatin.

The resistance of current-design Pratt & Whitney Aircraft low aspect ratio advanced fiber reinforced epoxy matrix composite fan blades to foreign object damage (FOD) at STOL operating conditions was investigated. Five graphite/epoxy and five boron/epoxy wide chord fan blades with nickel plated stainless steel leading edge sheath protection were fabricated and impact tested. The fan blades were individually tested in a vacuum whirlpit under FOD environments. The FOD environments were typical of those encountered in service operations. The impact objects were ice balls, gravel, starlings and gelatin simulated birds. Results of the damage sustained from each FOD impact are presented for both the graphite and boron reinforced blades. Tests showed that the present design composite fan blades, with wrap around leading edge protection have inadequate FOD impact resistance at 244 m/sec (800 ft/sec) tip speed, a possible STOL operating condition.

Five composite spar-shell fan blades for a l.83 meter (6 feet) diameter fan stage were fabricated and tested in a whirling arm facility to evaluate foreign object damage (FOD) resistance. The blades were made by adhesively bonding boron-epoxy shells on titanium spars and then adhesively bonding an Inconel 625 sheath on the leading edge. The rotating blades were individually tested at a tip speed of 800 feet per second. Impacting media used were gravel, rivets, bolt, nut, ice balls, simulated birds, and a real bird. Incidence angles were typical of those which might be experienced by STOL aircraft. The tests showed that blades of the design tested in this program have satisfactory impact resistance to small objects such as gravel, rivets, nuts, bolts, and two inch diameter ice balls. The blades suffered nominal damage when impacted with one-pound birds (9 to 10 ounce slice size). However, the shell was removed from the spar for a larger slice size.

Boron/epoxy and graphite/epoxy composite blades were impacted in a rotating whirligig facility with conditions closely simulating those which might be experienced by a STOL engine impacted with various foreign objects. The tip speed of the rotating blades was 800 feet per second. The blades were impacted with simulated birds, real birds, ice balls, and gravel. Strain gages, accelerometers, high speed movies, TTUCS (Through Transmission Ultrasonic C-Scan) measurements and sonic velocity measurements provided data on the extent and mode of impact damage. The results of composite blade impact tests were compared with a titanium blade tested under similar conditions. Delamination of the composite airfoil occurred when impacted with a 6 ounce bite from a 12 ounce bird. Both composite blades broke off at the root when impacted with a 12 ounce bite from a 28 ounce bird. Neither composite material indicated a clear superiority over the other. Blades made from both composite materials showed more damage than the titanium blades. These data are the result of an eleven month testing effort extending from July 1972 to June 1973. (AN)