曝光台 注意防骗
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Figure H-1 shows the Class A Mishap Rate per 100,000 hours versus cumulative flight hours for the Global Hawk, Predator, Hunter, and Pioneer fleet for the period 1986 through 2003. Class A mishaps are those aircraft accidents resulting in loss of the aircraft (in Naval parlance, “strike”), human life, or causing over $1,000,000 in damage2. These data show a mishap rate (i.e., Class A accidents per 100,000 hours of flight) of 20 for Predator, 47 for Hunter (24 since the major reliability improvements in 1996), 88 for Global Hawk, 281 for Pioneer, and 191 for Shadow. For comparison to two manned military aviation mishap rates, the U-2 and F-16 have cumulative Class A mishap rates of 6.8 and 4.1 per 100,000 hours, respectively. Comparing to non-military aircraft, general aviation suffers about 1 Class A mishap per 100,000 hours, regional/commuter airliners about a tenth of that rate, and larger airliners about a hundredth of that rate.
With the exception of Pioneer and to a lesser extent Shadow, these statistics make it apparent that the reliability of UA is tracking that of early manned military aircraft, and maturing to approach an equivalent level of reliability to their manned military counterparts. Specifically, the early Pioneers (as discussed later in this appendix) had an analog air data system, problems with ship-board EMI, and generally suffered from poor design practices. (A planned conversion to a more reliable engine for the Pioneer never took place.) Compared to this low benchmark, the Hunter program has seen continuous reliability enhancements from efforts initiated in the mid-1990’s to improve hardware and maintenance. Not surprisingly for the higher-end systems, the Predator has enjoyed relatively high and stable reliability
2 Per OPNAV Instruction 3750.6R, “Loss of a UAV is not a Class A unless the cost is $1,000,000 or greater.” All Pioneer mishaps discussed are therefore Class B Mishaps.
APPENDIX H – RELIABILITY
Page H-2
UAS ROADMAP 2005
throughout its ACTD to operational phases, and the Global Hawk appears to be tracking the reliability of its manned counterpart, the U-2.
The reliability trends calculated during these flight hours are detailed in Tables H-1 and H-2. Following these data is a discussion about the individual UA systems and how their fielding and operation contribute to the reliability data.
100 1,000 10,000 100,000
Cumulative Flight Hours
FIGURE H-1. U.S. MILITARY AIRCRAFT AND UA CLASS A MISHAP RATES (LIFETIME), 1986 – 2004. TABLE H-1. SUMMARY OF UA RELIABILITY FINDINGS.
MTBF (hrs) Availability Reliability Mishap Rate per 100,000 hrs (Series) Mishap Rate per 100,000 hrs (Model)
RQ-1A/ Predator Requirement n/a n/a n/a n/a 20
Actual 32.0 40% 74% 43
MQ-1B/ Predator Requirement 40 80% 70% n/a
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