Harry, that one was actually caused by voticies generated by another large passendger jet, which caused the Airbus to shed it's stabilizer. Once that happened, there was no saving it.
Actually, it wasn't the vortices from the 747, it was the pilot rapidly reversing the rudder from stop to stop in response to the vortex, thereby swinging the tail out far enough that when the rudder was reversed the final time, the aerodynamic load exceeded the ultimate load of the tail and the tail came off. The plane then continued to yaw and came apart in midair.
Aviation Week did a quite in-depth study of that crash (American Airlines flight 587, I think), and a simple calculation of the force on the tail at that airspeed, yaw angle, and rudder deflection significantly exceeded the calculated failure load of the tail.
Back to the original point of the thread--even if a plane is ON THE RUNWAY and coming STRAIGHT TOWARD YOU, it is almost impossible to hit a pilot or an engine due to bullet time-of-flight issues. An anti on Common Ground Common Sense and I were debating this (he said it would be easy to take out the pilot and copilot), so I ran some calculations and posted the following reply:
"Let's explore that scenario a bit. You pretty much have to have a straight frontal shot so you don't have to lead the plane by 100 feet, so that means your hypothetical sniper will be set up at the departure end of the runway. Using his ultra-sniper camoflage skills, we'll assume he's only, say, 200 yards from the departure end. But to hit a pilot, he'd have to hit the plane before it starts to rotate, because once the nose lifts putting a round into the cockpit would be extremely difficult due to obstruction (both visual and ballistic) by the nose angle. So your hypothetical terrorist sniper would probably be looking at an 1800-yard shot, given runway distances and such.
That's right at the maximum effective range of the .50 as given by the U.S. military. Let's run some numbers on a hypothetical 1800-yard frontal shot on an airliner on its takeoff roll, to see if it's a realistic scenario.
The trajectory table below is from from
http://www.eskimo.com/~jbm/ballistics/traj/traj.html. These are from a calculation I had previously run on a target five feet off the ground, but the numbers would be very close for a target 15 feet off the ground. So:
.50 BMG
Bullet: 750-grain Barnes, ballistic coefficient 1.07
Muzzle Velocity: 2800 feet/sec
Downrange Wind: 0
Crosswind: 3 mph
Temperature: 59.6 °F
Barometric Pressure: 29.92 in Hg
Relative Humidity: 0.0%
Altitude: Sea Level
Zero: 1800 yards
Target Height: 5 feet off ground
Elevation: 62.952 moa
Range.....Velocity.....Energy.......Drop
(yards)...(ft/sec)....(ft-lbs)....(inches)
...0.......2803.0.....13083.2.......-3.0
.200.......2629.0.....11509.6......119.6
.400.......2462.1.....10094.3......222.0
.600.......2301.9......8824.1......301.4
.800.......2147.8......7682.0......354.6
1000.......1999.1......6655.3......377.5
1200.......1857.0......5742.6......365.6
1400.......1722.1......4938.4......313.3
1600.......1594.7......4234.8......214.1
1700.......1534.2......3919.5......144.4
1750.......1504.8......3770.8......104.1
1800.......1476.0......3627.9.......60.0
1850.......1447.8......3490.7.......11.9
1900.......1420.3......3359.4......-40.4
1950.......1393.6......3233.9......-97.0
2000.......1367.5......3114.2.....-158.0
Target is moving toward the shooter at a speed of, let's say, 150 mph, or 220 feet per second. That's 73 yards per second. The target is roughly 4 feet high seated. The bullet at that distance is dropping roughly 4 feet per 50 yards. So the shooter would have to estimate the range to the airplane within 50 yards, when the airplane is moving at 73 yards per second, to even have a chance of hitting one pilot. That is an impossible shot even for a highly trained military sniper.
To hit the second pilot--we'll allow the hypothetical shooter two seconds to settle in from recoil and acquire a second sight picture. The still-accelerating airplane has moved another 150 yards toward the shooter, changing the bullet point of impact by 12.5 feet, but there's no time to readjust the scope so the shooter needs 12.5 feet of holdover, and still has to guesstimate the range to within 50 yards or so on a target moving 73 yards per second. A shot even more impossible than the first.
SO, I think we can say that long-distance shots on small, fast-moving targets are essentially IMPOSSIBLE with a .50 BMG rifle, even from straight ahead. If you had a .50 machine gun on a pedestal mount, and tracer ammunition so you could just walk the stream into the target (like the old .50 AA guns on WW2 battleships), maybe you'd get a hit. But not with a sniper rifle.
There's a reason why even the special forces use the .50 for disabling parked airplanes. Shoulder-fired missiles are a credible threat to airliners in the vicinity of an airport, but .50 BMG target rifles just aren't."