相关题目
The decision to provide a stopway and/or a clearwayas an alternative to an increased length of runway will depend on the physical characteristics of the area beyond the runway end, and on the operating performance requirements of the prospective aeroplanes. The runway, stopway and clearway lengths to be provided are determined by the aeroplane takeoff performance, but a check should also be made of the landing distance required by the aeroplanes using the runway to ensure that adequate runway length is provided for landing. The length of a clearway, however, cannot exceed half the length of take-off run available. The aeroplane performance operating limitations require a length which is enough to ensure that the aeroplane can, after starting a take-off, either be brought safely to a stop or complete the take-off safely. Let’s suppose the runway, stopway and clearway lengths provided at the aerodrome are only just adequate for the aeroplane requiring the longest take-off and accelerate-stop distances, taking into account its take-off mass, runway characteristics and ambient atmospheric conditions. Under these circumstances there is, for each take-off, a speed, called the decision speed; below this speed, the take-off must be abandoned if an engine fails, while above it the take-off must be completed. A very long take-off run and take-off distance would be required to complete a take-off when an engine fails before the decision speed is reached, because of the insufficient speed and the reduced power available. There would be no difficulty in stopping in the remaining accelerate-stop distance available if action is taken immediately. In these circumstances, the correct course of action would be to abandon the take-off. On the other hand, if an engine fails after the decision speed is reached, the aeroplane will have sufficient speed and power available to complete the take-off safely in the remaining take-off distance available. However, because of the high speed, there would be difficulty in stopping the aeroplane in the remaining accelerate-stop distance available. The decision speed is not a fixed speed for any aeroplane, but can be selected by the pilot within limits to suit the accelerate-stop and take-off distance available, aeroplane take-off mass, runway characteristics, and ambient atmospheric conditions at the aerodrome. Normally, a higher decision speed is selected as the accelerate-stop distance available increases. A variety of combinations of accelerate-stop distances required and take-off distances required can be obtained to accommodate a particular aeroplane, taking into account the aeroplane take-off mass, runway characteristics, and ambient atmospheric conditions. Each combination requires its particular length of take-off run.4. What can we learn from Para. 4?
The decision to provide a stopway and/or a clearwayas an alternative to an increased length of runway will depend on the physical characteristics of the area beyond the runway end, and on the operating performance requirements of the prospective aeroplanes. The runway, stopway and clearway lengths to be provided are determined by the aeroplane takeoff performance, but a check should also be made of the landing distance required by the aeroplanes using the runway to ensure that adequate runway length is provided for landing. The length of a clearway, however, cannot exceed half the length of take-off run available. The aeroplane performance operating limitations require a length which is enough to ensure that the aeroplane can, after starting a take-off, either be brought safely to a stop or complete the take-off safely. Let’s suppose the runway, stopway and clearway lengths provided at the aerodrome are only just adequate for the aeroplane requiring the longest take-off and accelerate-stop distances, taking into account its take-off mass, runway characteristics and ambient atmospheric conditions. Under these circumstances there is, for each take-off, a speed, called the decision speed; below this speed, the take-off must be abandoned if an engine fails, while above it the take-off must be completed. A very long take-off run and take-off distance would be required to complete a take-off when an engine fails before the decision speed is reached, because of the insufficient speed and the reduced power available. There would be no difficulty in stopping in the remaining accelerate-stop distance available if action is taken immediately. In these circumstances, the correct course of action would be to abandon the take-off. On the other hand, if an engine fails after the decision speed is reached, the aeroplane will have sufficient speed and power available to complete the take-off safely in the remaining take-off distance available. However, because of the high speed, there would be difficulty in stopping the aeroplane in the remaining accelerate-stop distance available. The decision speed is not a fixed speed for any aeroplane, but can be selected by the pilot within limits to suit the accelerate-stop and take-off distance available, aeroplane take-off mass, runway characteristics, and ambient atmospheric conditions at the aerodrome. Normally, a higher decision speed is selected as the accelerate-stop distance available increases. A variety of combinations of accelerate-stop distances required and take-off distances required can be obtained to accommodate a particular aeroplane, taking into account the aeroplane take-off mass, runway characteristics, and ambient atmospheric conditions. Each combination requires its particular length of take-off run.3. If an engine fails after the is reached, the aeroplane will have sufficient speed and power available to complete the take-off safely in the remaining take-off distance available.
The decision to provide a stopway and/or a clearwayas an alternative to an increased length of runway will depend on the physical characteristics of the area beyond the runway end, and on the operating performance requirements of the prospective aeroplanes. The runway, stopway and clearway lengths to be provided are determined by the aeroplane takeoff performance, but a check should also be made of the landing distance required by the aeroplanes using the runway to ensure that adequate runway length is provided for landing. The length of a clearway, however, cannot exceed half the length of take-off run available. The aeroplane performance operating limitations require a length which is enough to ensure that the aeroplane can, after starting a take-off, either be brought safely to a stop or complete the take-off safely. Let’s suppose the runway, stopway and clearway lengths provided at the aerodrome are only just adequate for the aeroplane requiring the longest take-off and accelerate-stop distances, taking into account its take-off mass, runway characteristics and ambient atmospheric conditions. Under these circumstances there is, for each take-off, a speed, called the decision speed; below this speed, the take-off must be abandoned if an engine fails, while above it the take-off must be completed. A very long take-off run and take-off distance would be required to complete a take-off when an engine fails before the decision speed is reached, because of the insufficient speed and the reduced power available. There would be no difficulty in stopping in the remaining accelerate-stop distance available if action is taken immediately. In these circumstances, the correct course of action would be to abandon the take-off. On the other hand, if an engine fails after the decision speed is reached, the aeroplane will have sufficient speed and power available to complete the take-off safely in the remaining take-off distance available. However, because of the high speed, there would be difficulty in stopping the aeroplane in the remaining accelerate-stop distance available. The decision speed is not a fixed speed for any aeroplane, but can be selected by the pilot within limits to suit the accelerate-stop and take-off distance available, aeroplane take-off mass, runway characteristics, and ambient atmospheric conditions at the aerodrome. Normally, a higher decision speed is selected as the accelerate-stop distance available increases. A variety of combinations of accelerate-stop distances required and take-off distances required can be obtained to accommodate a particular aeroplane, taking into account the aeroplane take-off mass, runway characteristics, and ambient atmospheric conditions. Each combination requires its particular length of take-off run.2. Which of the following statements is true?
The decision to provide a stopway and/or a clearwayas an alternative to an increased length of runway will depend on the physical characteristics of the area beyond the runway end, and on the operating performance requirements of the prospective aeroplanes. The runway, stopway and clearway lengths to be provided are determined by the aeroplane takeoff performance, but a check should also be made of the landing distance required by the aeroplanes using the runway to ensure that adequate runway length is provided for landing. The length of a clearway, however, cannot exceed half the length of take-off run available. The aeroplane performance operating limitations require a length which is enough to ensure that the aeroplane can, after starting a take-off, either be brought safely to a stop or complete the take-off safely. Let’s suppose the runway, stopway and clearway lengths provided at the aerodrome are only just adequate for the aeroplane requiring the longest take-off and accelerate-stop distances, taking into account its take-off mass, runway characteristics and ambient atmospheric conditions. Under these circumstances there is, for each take-off, a speed, called the decision speed; below this speed, the take-off must be abandoned if an engine fails, while above it the take-off must be completed. A very long take-off run and take-off distance would be required to complete a take-off when an engine fails before the decision speed is reached, because of the insufficient speed and the reduced power available. There would be no difficulty in stopping in the remaining accelerate-stop distance available if action is taken immediately. In these circumstances, the correct course of action would be to abandon the take-off. On the other hand, if an engine fails after the decision speed is reached, the aeroplane will have sufficient speed and power available to complete the take-off safely in the remaining take-off distance available. However, because of the high speed, there would be difficulty in stopping the aeroplane in the remaining accelerate-stop distance available. The decision speed is not a fixed speed for any aeroplane, but can be selected by the pilot within limits to suit the accelerate-stop and take-off distance available, aeroplane take-off mass, runway characteristics, and ambient atmospheric conditions at the aerodrome. Normally, a higher decision speed is selected as the accelerate-stop distance available increases. A variety of combinations of accelerate-stop distances required and take-off distances required can be obtained to accommodate a particular aeroplane, taking into account the aeroplane take-off mass, runway characteristics, and ambient atmospheric conditions. Each combination requires its particular length of take-off run.1. The aeroplane takeoff performance determines .
Most bird strikes on aerodromes involve a small range of species: primarily gulls (especially black-headed and common gulls), waders (mostly lap wing, but also golden plover and oystercatcher), pigeons, corvids, starling, skylark, swift, swallow and martins. There is a clear relation between bird mass and risk that the aircraft will be damaged: small birds (less than 100g) cause damage on less than 3% of occasions when they are struck; medium-sized birds (101g-1000g) -12%; and large birds (over 1000g) - nearly 23%. There is also a strong relation between bird numbers and the chances that the aircraft will be damaged: single birds cause damage on 8% of occasions; small flocks (2-10) - 14%; and larger flocks (11-100 birds) - 40%. Thus, species which are larger than 100g or occur on aerodromes in flocks are most likely to cause damage to aircraft. Gulls, waders, pigeons, corvids and starling all occur commonly on aerodromes, are responsible for the majority of bird strikes and are most likely to cause damage. However, they also respond well to habitat management and active dispersal techniques and are, therefore, controllable. These birds can be classed as the Priority Group for control. Many other species, most of which are less susceptible to available control measures, are involved in aerodrome bird strikes. Total numbers of bird strikes are not very useful in assessing an aerodrome＇s bird hazard or performance in controlling it. However, a more detailed breakdown can provide useful insights, as follows: ? Priority group species. If a high proportion of an aerodrome＇s bird strikes involve priority group species, then the hazard level is probably high and control standard low. ? Multiple strikes. If there are multiple strikes with priority group species, it is an indication that flocks are permitted to build up and remain on or close to runways. Bird strikes, especially multiple strikes, with these species commonly cause damage and, even if the reporting standard is low, these incidents cannot be suppressed. Thus, the hazard is obviously high and there are problems with controlling it. ? Small birds. All aerodromes have many small birds which are inevitably involved in strikes: Skylarks all year but especially in autumn; finches in winter; and swifts, swallows and martins in summer. If the common small birds are absent from an aerodrome＇s strike statistics, it can be assumed that the true situation is not reflected: the reporting standard must be suspect. ? Less common medium-sized and large species. The significance of the occurrence of these species in an aerodrome＇s strike records can only be properly interpreted with a detailed knowledge of local conditions. By adopting priorities of minimizing strikes with: (1) the greatest potential for serious accidents (multiple strikes with large birds); (2) priority group species; and (3) controllable species, and by using the prevalence of strikes with small birds as a check of reporting standard, the data can provide indicators of hazard level and performance which are independent of comparison with other aerodromes.5. Which of the following statements is true?
Most bird strikes on aerodromes involve a small range of species: primarily gulls (especially black-headed and common gulls), waders (mostly lap wing, but also golden plover and oystercatcher), pigeons, corvids, starling, skylark, swift, swallow and martins. There is a clear relation between bird mass and risk that the aircraft will be damaged: small birds (less than 100g) cause damage on less than 3% of occasions when they are struck; medium-sized birds (101g-1000g) -12%; and large birds (over 1000g) - nearly 23%. There is also a strong relation between bird numbers and the chances that the aircraft will be damaged: single birds cause damage on 8% of occasions; small flocks (2-10) - 14%; and larger flocks (11-100 birds) - 40%. Thus, species which are larger than 100g or occur on aerodromes in flocks are most likely to cause damage to aircraft. Gulls, waders, pigeons, corvids and starling all occur commonly on aerodromes, are responsible for the majority of bird strikes and are most likely to cause damage. However, they also respond well to habitat management and active dispersal techniques and are, therefore, controllable. These birds can be classed as the Priority Group for control. Many other species, most of which are less susceptible to available control measures, are involved in aerodrome bird strikes. Total numbers of bird strikes are not very useful in assessing an aerodrome＇s bird hazard or performance in controlling it. However, a more detailed breakdown can provide useful insights, as follows: ? Priority group species. If a high proportion of an aerodrome＇s bird strikes involve priority group species, then the hazard level is probably high and control standard low. ? Multiple strikes. If there are multiple strikes with priority group species, it is an indication that flocks are permitted to build up and remain on or close to runways. Bird strikes, especially multiple strikes, with these species commonly cause damage and, even if the reporting standard is low, these incidents cannot be suppressed. Thus, the hazard is obviously high and there are problems with controlling it. ? Small birds. All aerodromes have many small birds which are inevitably involved in strikes: Skylarks all year but especially in autumn; finches in winter; and swifts, swallows and martins in summer. If the common small birds are absent from an aerodrome＇s strike statistics, it can be assumed that the true situation is not reflected: the reporting standard must be suspect. ? Less common medium-sized and large species. The significance of the occurrence of these species in an aerodrome＇s strike records can only be properly interpreted with a detailed knowledge of local conditions. By adopting priorities of minimizing strikes with: (1) the greatest potential for serious accidents (multiple strikes with large birds); (2) priority group species; and (3) controllable species, and by using the prevalence of strikes with small birds as a check of reporting standard, the data can provide indicators of hazard level and performance which are independent of comparison with other aerodromes.4. Which of the following is the best title for the text?
Most bird strikes on aerodromes involve a small range of species: primarily gulls (especially black-headed and common gulls), waders (mostly lap wing, but also golden plover and oystercatcher), pigeons, corvids, starling, skylark, swift, swallow and martins. There is a clear relation between bird mass and risk that the aircraft will be damaged: small birds (less than 100g) cause damage on less than 3% of occasions when they are struck; medium-sized birds (101g-1000g) -12%; and large birds (over 1000g) - nearly 23%. There is also a strong relation between bird numbers and the chances that the aircraft will be damaged: single birds cause damage on 8% of occasions; small flocks (2-10) - 14%; and larger flocks (11-100 birds) - 40%. Thus, species which are larger than 100g or occur on aerodromes in flocks are most likely to cause damage to aircraft. Gulls, waders, pigeons, corvids and starling all occur commonly on aerodromes, are responsible for the majority of bird strikes and are most likely to cause damage. However, they also respond well to habitat management and active dispersal techniques and are, therefore, controllable. These birds can be classed as the Priority Group for control. Many other species, most of which are less susceptible to available control measures, are involved in aerodrome bird strikes. Total numbers of bird strikes are not very useful in assessing an aerodrome＇s bird hazard or performance in controlling it. However, a more detailed breakdown can provide useful insights, as follows: ? Priority group species. If a high proportion of an aerodrome＇s bird strikes involve priority group species, then the hazard level is probably high and control standard low. ? Multiple strikes. If there are multiple strikes with priority group species, it is an indication that flocks are permitted to build up and remain on or close to runways. Bird strikes, especially multiple strikes, with these species commonly cause damage and, even if the reporting standard is low, these incidents cannot be suppressed. Thus, the hazard is obviously high and there are problems with controlling it. ? Small birds. All aerodromes have many small birds which are inevitably involved in strikes: Skylarks all year but especially in autumn; finches in winter; and swifts, swallows and martins in summer. If the common small birds are absent from an aerodrome＇s strike statistics, it can be assumed that the true situation is not reflected: the reporting standard must be suspect. ? Less common medium-sized and large species. The significance of the occurrence of these species in an aerodrome＇s strike records can only be properly interpreted with a detailed knowledge of local conditions. By adopting priorities of minimizing strikes with: (1) the greatest potential for serious accidents (multiple strikes with large birds); (2) priority group species; and (3) controllable species, and by using the prevalence of strikes with small birds as a check of reporting standard, the data can provide indicators of hazard level and performance which are independent of comparison with other aerodromes.3. It can be inferred from the passage that （ ）.
Most bird strikes on aerodromes involve a small range of species: primarily gulls (especially black-headed and common gulls), waders (mostly lap wing, but also golden plover and oystercatcher), pigeons, corvids, starling, skylark, swift, swallow and martins. There is a clear relation between bird mass and risk that the aircraft will be damaged: small birds (less than 100g) cause damage on less than 3% of occasions when they are struck; medium-sized birds (101g-1000g) -12%; and large birds (over 1000g) - nearly 23%. There is also a strong relation between bird numbers and the chances that the aircraft will be damaged: single birds cause damage on 8% of occasions; small flocks (2-10) - 14%; and larger flocks (11-100 birds) - 40%. Thus, species which are larger than 100g or occur on aerodromes in flocks are most likely to cause damage to aircraft. Gulls, waders, pigeons, corvids and starling all occur commonly on aerodromes, are responsible for the majority of bird strikes and are most likely to cause damage. However, they also respond well to habitat management and active dispersal techniques and are, therefore, controllable. These birds can be classed as the Priority Group for control. Many other species, most of which are less susceptible to available control measures, are involved in aerodrome bird strikes. Total numbers of bird strikes are not very useful in assessing an aerodrome＇s bird hazard or performance in controlling it. However, a more detailed breakdown can provide useful insights, as follows: ? Priority group species. If a high proportion of an aerodrome＇s bird strikes involve priority group species, then the hazard level is probably high and control standard low. ? Multiple strikes. If there are multiple strikes with priority group species, it is an indication that flocks are permitted to build up and remain on or close to runways. Bird strikes, especially multiple strikes, with these species commonly cause damage and, even if the reporting standard is low, these incidents cannot be suppressed. Thus, the hazard is obviously high and there are problems with controlling it. ? Small birds. All aerodromes have many small birds which are inevitably involved in strikes: Skylarks all year but especially in autumn; finches in winter; and swifts, swallows and martins in summer. If the common small birds are absent from an aerodrome＇s strike statistics, it can be assumed that the true situation is not reflected: the reporting standard must be suspect. ? Less common medium-sized and large species. The significance of the occurrence of these species in an aerodrome＇s strike records can only be properly interpreted with a detailed knowledge of local conditions. By adopting priorities of minimizing strikes with: (1) the greatest potential for serious accidents (multiple strikes with large birds); (2) priority group species; and (3) controllable species, and by using the prevalence of strikes with small birds as a check of reporting standard, the data can provide indicators of hazard level and performance which are independent of comparison with other aerodromes.2. What can we learn from Para. 1?
Most bird strikes on aerodromes involve a small range of species: primarily gulls (especially black-headed and common gulls), waders (mostly lap wing, but also golden plover and oystercatcher), pigeons, corvids, starling, skylark, swift, swallow and martins. There is a clear relation between bird mass and risk that the aircraft will be damaged: small birds (less than 100g) cause damage on less than 3% of occasions when they are struck; medium-sized birds (101g-1000g) -12%; and large birds (over 1000g) - nearly 23%. There is also a strong relation between bird numbers and the chances that the aircraft will be damaged: single birds cause damage on 8% of occasions; small flocks (2-10) - 14%; and larger flocks (11-100 birds) - 40%. Thus, species which are larger than 100g or occur on aerodromes in flocks are most likely to cause damage to aircraft. Gulls, waders, pigeons, corvids and starling all occur commonly on aerodromes, are responsible for the majority of bird strikes and are most likely to cause damage. However, they also respond well to habitat management and active dispersal techniques and are, therefore, controllable. These birds can be classed as the Priority Group for control. Many other species, most of which are less susceptible to available control measures, are involved in aerodrome bird strikes. Total numbers of bird strikes are not very useful in assessing an aerodrome＇s bird hazard or performance in controlling it. However, a more detailed breakdown can provide useful insights, as follows: ? Priority group species. If a high proportion of an aerodrome＇s bird strikes involve priority group species, then the hazard level is probably high and control standard low. ? Multiple strikes. If there are multiple strikes with priority group species, it is an indication that flocks are permitted to build up and remain on or close to runways. Bird strikes, especially multiple strikes, with these species commonly cause damage and, even if the reporting standard is low, these incidents cannot be suppressed. Thus, the hazard is obviously high and there are problems with controlling it. ? Small birds. All aerodromes have many small birds which are inevitably involved in strikes: Skylarks all year but especially in autumn; finches in winter; and swifts, swallows and martins in summer. If the common small birds are absent from an aerodrome＇s strike statistics, it can be assumed that the true situation is not reflected: the reporting standard must be suspect. ? Less common medium-sized and large species. The significance of the occurrence of these species in an aerodrome＇s strike records can only be properly interpreted with a detailed knowledge of local conditions. By adopting priorities of minimizing strikes with: (1) the greatest potential for serious accidents (multiple strikes with large birds); (2) priority group species; and (3) controllable species, and by using the prevalence of strikes with small birds as a check of reporting standard, the data can provide indicators of hazard level and performance which are independent of comparison with other aerodromes.1. Medium-sized birds (101g-1000g) cause damage on less than of occasions when they are struck
Normally, air must become saturated for condensation or sublimation to occur. Saturation may result from cooling temperature, increasing dew point, or both. Cooling is far more predominant. In aviation community the clouds are classified as 14 sorts. They are cumulus, cumulus congestus, cumulonimbus, fractocumulus, stratus, stratocumulus, nimbostratus, fractostratus, fractonimbus, altocumulus, altostratus, cirrus, cirrocumulus and cirrostratus. Clouds are the weather signposts in the sky to the pilots. They give them an indication of air motion, stability, and moisture. Clouds help to visualize weather conditions and potential weather hazards pilots might encounter in flight. Let’s examine these signposts and how to identify them. For identification purposes, you need be concerned only with the more basic cloud types, which are divided into four families. The families are: high clouds, middle clouds, low clouds. The first three families are further classified according to the way they are formed. Clouds formed by vertical currents in unstable air are cumulus meaning accumulation or heap; they are characterized by their lumpy, billowy appearance. Clouds formed by the cooling of a stable layer are stratus meaning stratified or layered; they are characterized by their uniform, sheet-like appearance. In addition to the above, the prefix nimbo or the suffix nimbus means raincloud. Thus, stratified clouds from which rain is falling are nimbostratus. A heavy, swelling cumulus type cloud which produces precipitation is cumulonimbus. Clouds broken into fragments are often identified by adding the prefix fractus; for example, fragmentary cumulus is fractocumulus. The high cloud family is cirriform and includes cirrus, cirrocumulus, and cirrostratus. They are composed almost entirely of ice crystals. The height of the bases of these clouds ranges from above 20,000 feet in middle latitudes. In the middle cloud family are altostratus and altocumulus. These clouds are primarily water, much of which may be supercooled. The height of the bases of these clouds ranges from about 6,500 to 20,000 feet in middle latitudes. In the low cloud family are the cumulus, cumulus congestus, cumulonimbus, fractocumulus, stratus, stratocumulus, nimbostratus, fractostratus，fractonimbus. Low clouds are almost entirely water, but at times the water may be supercooled. Low clouds at subfreezing temperatures can also contain snow and ice particles. The bases of these clouds range from near the surface to about 6,500 feet in middle latitudes. The vertically developed cloud includes cumulus congestus and cumulonimbus. These clouds usually contain supercooled water above the freezing level. But when a cumulus grows to great heights, water in the upper part of the cloud freezes into ice crystals forming a cumulonimbus. The heights of cumuliform cloud bases range from 1,000 feet or less to above 10,000 feet.5. Vertically developed clouds usually contain （ ）.
