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Back order? 延期交货

I worked in the aerospace industry for about 8 years after graduation but then transferred to the nuclear power industry. Aircraft striking nuclear power plants was a concern then — and still is as far as I know — and I worked on standards and statistical methods to calculate whether an airplane crash would compromise a nuclear power station. The estimated odds had to be less than one in 10 million per year.

Most aircraft accidents occur within 2 miles of an airport, generally aligned with the direction of the runway. Once the aircraft is airborne — and this is where the two accidents in Africa occurred — airline travel is incredibly safe. Boeing’s web page says 49% of airline crashes for commercial jets occur at a 15-second interval during landing.

For perspective, airline flying is about a thousand times safer than flying a small airplane piloted by yourself or a friend, on a per mile basis.

Yet 95% of the time a passenger survives an airline carrier crash during this landing period, also from the Boeing web page. This is consistent with my experience in impacting structures; the odds of survival and the impact on facilities is best case since airspeeds are the lowest, e.g. just above stall speeds.

On the other hand, infrequent “en route” crashes at altitude after takeoff and before landing often result in loss of all passengers — a total of 346 deaths in the two African air crashes. The proper design should have prevented this from happening.