*Originally posted by Airblairxxx *

Don’t we in the States have them? Wasn’t one of the imperatives of Eisenhower’s highway program to make one out of every five miles of interstate highway flat and straight, so as to be able to convert them into use as runways in case of national emergency?

Uh…no. A couple or three statements:

If this was the case, I’m sure I would have heard about it in flight training. In fact, even the pilots of small planes capable of using roads for landing are cautioned against using roads as emergency landing areas. Why? Well… aside from the problems of merging with traffic… (and don’t laugh - plane vs. road vehicle collisions kill a certain number of people each and every year)… an airplane is frequently considerably wider than it is long. A two-seat “rinky-dink” Cessna has a 30 foot wide wingspan. If you try landing that on a two lane road you’re likely to either knock down telephone poles running alongside or knock the wings off the plane or both.

Larger planes may have a shorter wingspan vs. fuselage length, but the absolute width of the wings is very large. The big jets land on pavement 150 feet wide and the wings still can overhang the pavement. Now, imagine landing on a two-lane interstate with lightpoles alongside, or trees, or cliffs (as is the case in many mountainous parts of the country)… this is not a good sceanario. Yes, you can probably find patches of interstate here and there that would accomodate such a jet, and you could probably find instances of successful landings of airliners in such places - and just as easily find unsuccessful attempts with no survivors.

Also, big jets usually prefer runways longer than just one mile. 300,000 lbs traveling at 100+ mph takes a while to stop, just basic physics. Which brings up the question of whether or not the pavement can hold up such a plane without collapsing. Runway weight-bearing capcity is of great importance to larger planes, and in fact such information is published about airports in several places to assist pilots in landing their plane as opposed to using it to dig trenches in concrete.