Welcome to my blog

I can foresee a time when my thoughts and words will be a benefit to someone.

Lighthearted, in love and always learning - my favourite place to be.  Airplanes, one of my favourite things to think about.

Something interesting about aircraft:  When a plane is taking off, it's performance limits (how far it can go, how many passengers it can carry) is calculated based on the requirement to continue to safely climb and land, even if one of the engines fails at the most critical point in the takeoff.  The most critical point in the takeoff is right as the aircraft is passing the point at which there is no longer enough runway remaining to stop the aircraft safely.  At this point, the aircraft is committed to taking off.  If one engine failed completely at that point, the aircraft would continue to takeoff safely and would declare an emergency and be permitted to go around the airport and land immediately.

The likelihood of an engine failing at any time during a flight is approximately 1 in 100,000 flights.  The probability, therefore, of 2 engines failing during the same flight (for reasons that are related to the engine and not to other problems like running out of fuel) is therefore 100,000 x 100,000 as the 2 engines are completely independent of each other.  That is 1 in 10 Billion, or essentially never.  Although the probablity of an engine failure is 1 in 100,000, the timing of the failure is also statistical.  The failure is more likely at takeoff than at other times of the flight because at takeoff the engines are producing the most thrust possible.  Assume, for example that the probability of failure of an engine during takeoff is 1/10 of the probability of failure at any time during the flight.  That is biased high, as the takeoff is normally a very small fraction of the total time of the flight (approximately 1 minute vs 2 hours for an average flight, or 1/120).   This means that the probability of an engine failure on takeoff is approximately 1 in 1,000,000.  The period of the takeoff that is critical right as the aircraft passes the point on the runway at which it must takeoff is only a few seconds.  If it is assumed to be 5 seconds, then the probability of an engine failure during that period is approximately 1/10 of the probability of an engine failure during takeoff, or 1 in 10,000,000.  Even if this failure did occur, the aircraft is still fully capable of a safe takeoff and landing with a full load of passengers and fuel.

Conclusion - aircraft are designed very conservatively to be safe - enjoy your flight!!!!

Dad