Originally Posted by
turbidus
From my experience, I have been banged at least once a year if not more....so once a year is very conservative, and I think it is more often. Boeing claiming WORST CASE STRIKE (WTF does that mean??) is once every 10 to 15 years??? That has NOT been my experience.
The once/year average for a commercial aircraft is a standard industry assumption. Obviously it depends where you fly and when, and how hard you try to avoid that type of weather. Lightning is a somewhat random event, and just like snowflakes, every lightning strike is different. Some are big, some are small (as defined by peak voltage, amperage, and time factor of the strike), and a small number are massive. Attachment points, while predictable, are also somewhat random which makes a difference in how they affect the aircraft. Most lightning strikes are pretty much non-events - no adverse effects or aircraft damage - but not all.
Although not talked about much, it's simply not possible to
completely protect from adverse lightning effects. For example, there have been documented cases where the pressure/temperature shock from a direct attachment to the inlet caused the engine to surge and flameout (CFM56-3/737-3/4/500). There was also a case back in the late 1990s where a 757 took a massive strike to the nose - the induced electromagnetic effects were so strong around the flight deck that it incapacitated one pilot and affected the other pilot - although not enough to incapacitate - so they landed safely and the pilots both recovered fully from the affects. Hence the importance of avoidance whenever practical.