Gann was a commercial pilot himself for a number of years and drew on his experiences when writing his novels. The High And The Mighty was rooted in an incident which occurred when he was piloting a flight from Honolulu to California. The stewardess noticed that a vibration of some sort was causing the cutlery on her tray to rattle. Gann inspected the tail area but could find nothing wrong; the problem was eventually traced to a missing bolt which almost caused them to lose control of the plane. The parallels are obvious. Incidentally, Gann also wrote a memoir about his years as a pilot called Fate Is The Hunter, which was also made into a movie and is considered to be one of the best books ever written on aviation.
One reason I really enjoy this book is Gann's knowledgeable writing; he very obviously knows the aviation industry of that time period, inside and out, and imparts that knowledge in a way which is illuminating without being overly technical. The reader is made to understand how dire the situation is without being swamped with too much information. Gann also has a gift for depicting tension and fear, and how these things manifest themselves both physically and mentally in different people. It causes the reader to contemplate how one would react and behave, faced with a similar situation. The novel also skillfully navigates through the three main locations in which the story plays out: the cockpit, the passenger cabin, and the airport in San Francisco. Gann divvies up the time spent in these places wisely, each scene furthering the story but never at the expense of other elements. All the scenes complement each other.
On board the plane, you also get a kind of us/ them feel as the situation plays out. The flight crew knows what is wrong and how low their chances of survival are. They have to tell the passengers something approaching the truth, but must decide just how honest to be with them. On one hand, they have a right to know what they're facing, but the crew has to weigh that consideration against the possibility of dealing with hysterical passengers when they need to have their attention focused elsewhere. They choose to underplay the danger, though a number of the passengers see this for what it is.
I think that this is ultimately makes The High And The Mighty so compelling. On one level, it's a very suspenseful tale of pilots trying to land their crippled airplane without killing everyone on board and also people on the ground. It is, however, also the story of a number of complete strangers who are brought together in a small, enclosed space which they can't get out of, and then are faced with what appears to be imminent death. It's fascinating to observe how each reacts to the situation: some as you would expect considering their dispositions, but others who either surprisingly rise to the occasion or crumple unexpectedly. Again, this impels the reader to consider how one would personally react to being suddenly thrust into such a situation. If you knew that you probably only had a couple of hours left to live, what would you think about?
Time also plays a large part in the narrative. Obviously, the tension is ratcheted up as the flight crew attempts to race against the clock, playing the odds about how long they can keep the plane in the air. Because the crisis doesn't happen right away, however- they have a number of hours before they must attempt to either ditch in the ocean or make for the coast- time becomes a factor in another way. For some these hours just provide more time for them to slowly lose their nerve and panic. For quite a few others though, this time spent knowing that they may die soon makes them examine their lives and the problems, pains and resentments which seemed previously to loom so large. The situation they're in has the effect of putting things in perspective and making them realize just what is important and what isn't.
The High And The Mighty works as a work of suspense, but what makes it memorable is its very human characters, faced with what for many is their greatest fear. It makes for compelling reading from start to finish.