Average flight

Failure rate (basic event), P = pT, where T = average flight time... 

The probability per flight can then be calculated for the top-level event. To convert back to a failure rate, this number can simply be divided through by the average flight time to get back to an average probabiUty per flight hour. 

Dormant failures relate to nonactive failures, where the failure is not detectable. In this case, the probability for a flight cycle is the probability per flight hour multiplied by the check interval rather than the average flight time. The accepted equation actually uses half of the check interval, on the basis that the furthest you can be from knowing the state of the item is either half the check interval from the last checked state, or half the check interval from the future checked state. 

The results of calculations of both simulations are showed on the Figure 1. The length of a average flight was designated as ty= 42 min. 

Step 2 calculation of the probability of a failure condition fora certain average flight ... 

If the failure is relevant only during certain flight phases, the calculation should be based on the probability of failure during the relevant at risk time for the average flight . 

If the failure rate of one element varies during different flight phases, the calculation should consider the failure rate and related time increments in such a maimer as to establish the probability of the failure condition occurring on an average flight . 

It is assumed that the average flight can be divided into n phases (phase 1,..., phase n), so ... 

This process may be very complicated and, with reference to Fig. 5.1, unnecessarily accurate. A rough estimate of average flight time (e.g. 10 hours for long haul 747 aircraft, or 3 hours for military C-130 aircraft) may prove of be sufficiently accurate. 

Another simplified model is the freely jointed or random flight chain model. It assumes all bond and conformation angles can have any value with no energy penalty, and gives a simplified statistical description of elasticity and average end-to-end distance. 

A US Airways flight leaves Philadelphia in the early evening and arrives in Frankfurt 8.05 hours later. The airline distance from Philadelphia to Frankfurt is about 6.6 X 103 km, depending to some extent on the flight path followed. What is the average speed of the plane, in kilometers per hour ... 

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