Реклама Google — средство выживания форумов :)
Необходимо отметить, что даже при таких условиях установление НРИ в США и странах Европы
государственные органы гражданской авицации ( FAA, JAA ), как правило, вводят ограничения на
эксплуатацию самолетов, имеющих наработку боле 30 000 лч, что стимулирует эксплуатантов
этих стран к постоянному обновлению парка самолетов и сбыту "стареющих" экземпляров самолетов
в другие страны, не имеющие ограничения на эксплуатацию таких самолетов.
Corrosion and structural fatigue have been factors in at least 36 accidents since 1983.
...
In April 1988, the crash of an Aloha Airlines Boeing 737 highlighted the problem of aging aircraft and triggered an immediate response in the aviation community.
...
The economic design life of a typical aircraft is 20 years or 60,000 cycles. 47 This figure is based primarily on economic considerations, which assume regular replacement of certain critical parts. Because of economic trends in the industry, the number of planes operating beyond their design life will increase dramatically in the next ten years, as will their proportion to the total fleet. While aircraft over 20 years old comprised 28% of the world fleet in 1988, it is projected that over 40% of the fleet will fall within this category by the year 2000. Unless airlines begin to retire their older planes, this aging trend will continue, resulting in operation of aircraft well beyond their economic design life goals. As the fleet ages, safety concerns will become more and more pressing.
In the past, the FAA utilized a "damage tolerance" approach to aircraft maintenance, which concentrated on identifying parts of aircraft that were likely to crack and estimating when such cracks were likely to develop. Based on these predictions, maintenance inspections were scheduled early enough to detect any cracks. When a crack was found, the FAA monitored its growth, but it
delayed repair until the crack reached a certain size.
Problems existed with this approach, including the tediousness of the inspection process, which usually entailed a visual inspection of hundreds of individual rivets and had little built-in redundancy as an extra safety measure. The procedure failed to recognize fully the danger that
even small cracks in the fuselage skin present.
The new program utilizes a system of "supplemental inspection" based on an analysis that assumes the existence of crack damage at each critical point on the plane, determines its rate of growth, and estimates the point in time at which it will become unsafe. The new approach mandates repair or modification at specified intervals, regardless of what inspections reveal. Additionally, the FAA plans to exercise more "hands-on" involvement during heavy maintenance checks and to develop new techniques in the areas of structural testing and repair. A program of mandatory modification for planes that have exceeded their economic design life is also intended to reduce the possibility of structural failure. In effect, the FAA has established life limits on aircraft component parts, rather than on the aircraft as a whole. The life limits vary among the structural elements, and the span assigned to each part depends on a combination of several factors, including the number of flight cycles, chronological age, or actual hours of operation.
In addition to repair directives like the one described above, the FAA finalized directives of a slightly different nature, again primarily as a result of the Aloha incident. These directives imposed an altitude restriction on 737s that have completed more than 40,000 flights. Since altitude is a factor that affects stress levels, these aircraft are not allowed to fly above 26,000 feet until they have passed a rigorous inspection."
Потребный запас топлива состоит из топлива, расходуемого на земле (на запуск двигателей 350 кг и на руление - из расчета расхода 70 кг в мин), основного запаса топлива (ОЗТ) и аэронавигационного запаса топлива (АНЗ).
Основной запас топлива (рейсовое топливо) включает топливо, расходуемое на взлет и разгон до скорости набора высоты (750 кг), топливо, расходуемое в полете по маршруту, и топливо для захода на посадку и посадку (1000 кг).