First of all, thank you so much for your website. It has helped me a lot in dealing with my anxiousness regarding long-haul flights. As it appears, many seem to share my fear of turbulence, which is actually a comfort in itself, not to be alone with these fears. I acknowledge that most of my worries are down to a sad lack of knowledge and understanding.
I apologize if I missed a response that has dealt with my questions before, but it seems to me that only the problem of "severe" turbulences has been discussed in abundance.
1. However, just coming back from Houston last week and having experienced the delay of my flight due to the fact that the plane hit conditions that were later labeled "severe" on its way to Houston ( by Lufthansa ), I wonder what actually constitutes "extreme" conditions?
2. And under what circumstances can severe or extreme turbulences become a fatality for the plane (be it Airbus 340 or the Boeing 777)? This is actually the most important question to me.
3. Also, Lufthansa reported that these turbulence might have caused structural damage to the plane. Considering the fact that Airlines usually claim their planes can withstand all weather conditions, I find this troubling. What kind of structural damage can turbulence cause?
Thanks again for the information you provide on your site. May you travel safely always!
1. I am unable to extract the official definition of what is severe or extreme turbulence at the moment. All I can say unofficially is that, severe turbulence would entails some very rough ride, almost like riding on a roller coaster. Some light injuries may arise if passengers or crew are not securely fastened. Extreme turbulence would be something where, in addition to some injuries or death, some structural damage would be seen on the body surfaces.
2. Again, I cannot officially say when extreme turbulence would lead to fatality in any of the airplanes (Airbus A340 or Boeing 777) you mentioned. So far, I have not come across an incident where a modern commercial airliner has crashed due to extreme turbulence in the cruise. Yes, crashes have occurred due to wind shear, which is another weather phenomenon that give rise to turbulence near the ground level. Please read my topic on Wind shear.
3. Structural damage that can arise would be, slight buckling of body surfaces and some rivets coming loose on the panels. If you are thinking of the wings falling apart or the engines dropping off, then that would not happen. Remember, the airplanes are designed to withstand the worst of the turbulence. They are made to fly in any conditions that the planes are likely to encounter and they are very, very strong machines. During flights, the fuselage bends a little and wings do essentially "flap". During the development tests, some wings are flexed as much as 150 degrees from normal position. In a Boeing 777, that is 24 feet!
So, remember, the airframe can take far more punishment than the pilots can, and pilots can take far more punishment than the passengers. Pilots have more experience flying in turbulence than passengers and understand what it is to be inside this rough condition. So their concern is more for the passengers and would make every effort to avoid them by climbing or descending to another smoother altitude. This again, does not mean that the plane is endangered, but rather the Captain is simply trying to give his passenger a more comfortable flight. Nor is he struggling to fly or that the airplane is out of control - a popular misperception of turbulence. In fact, many flights are navigated in rough skies on autopilot. In the Boeing 777, there is even a gust suppressor to lessen the impact of turbulences and the computers in the autopilot are better equipped to anticipate the shifts in temperature and air pressures. Although the airplane might be bouncing around all over the sky, the aircraft is safe.
Hope my explanation would lesson the fear in your next flight!
Thank you VERY much for your response. Yes you have helped another passenger troubled by irrational fears. I am not meaning to talk ill about Lufthansa, but their information policy is often designed not to make it better, but to increase my restlessness. So I am always grateful for some words of encouragement and will try to keep them in mind at all cost should the necessity to fly occur again. :-)