Analysis from a JHU CS Prof

Owen DeLong owen at delong.sj.ca.us
Wed Sep 12 04:31:35 UTC 2001


David Howe wrote:
> 
> >Also, it's worth remembering that airplanes aren't all that easy to
> > fly. This means that the perpetrators needed to find five adequate
> > pilots,
> Hmm. not actually sure about this - not having ever flown anything at
> all, but how much skill exactly does it take to keep something already
> pointed in more or less the right direction on target for two-three
> minutes until impact? ok, you couldn't expect a clean landing or even a
> halfway-smooth flight path from someone who has played a MS-Windows
> flight sim for a few months, but - if he was going from switching off
> autopilot to keeping the plane pointed at something the size of the
> WTC....... I would imagine it would all be on the yoke too, no throttles
> or concerns about airspeed given you are not really going to care that
> much what speed or acceleration you have on impact...

Sorry... I have to respond to this one.  I have actually flown a number
of
single engine airplanes, and I have some time in the cockpit of an
Airbus
A-319 (jumpseat, but still a good education).

All they really had to do was put a waypoint into the FMS (maybe they
had
the flight crew do this for them before they killed them), but if they
didn't,
that's not too hard, and I bet half the people on this mailng list could
figure it out.  It's more like configuring a router than flying an
airplane :-)  Once the waypoint was in, the only other thing they
needed to do was dial down the altitude preselect on the autopilot.
Then, sit back and enjoy the ride. If they were slightly more
sophisticated,
they could have switched the autopilot to heading mode and used the
heading
select knob to fine tune the direction of flight.  From what I saw of
the
footage for the second airplane into the tower, it flew a very straight
level course directly into the side of the tower.  It is not at all
unlikely that this was done by programming the autopilot.

> > which in turn means that they needed to know *in advance* which kinds
> > of planes they would be hijacking. While a lot of the pilot training
> > could be done using Flight  Simulator, you still need to know what to
> > train for.
> ... or train for the two/three more common types, then pick a flight *on
> the day* that actually is flying that type of plane. book seats at the
> last minute (not a problem for domestic flights) or pre-book three or
> four different seats per attacker, and each picks a flight with the
> right sort of plane from the "pool" of available flights.

Sorry... I've never flown any of the types involved, but I bet if you
put me in a realistic simulator and positioned me over the continental
US with adequate fuel, I could carry out the attack successfuly unless
I was shot down.  There wasn't really a type specific need, you just
needed a semi-modern (post 1965) set of cockpit avionics.  Guess what...
There's probably not a single domestic US airliner that doesn't fit that
bill.

Remeber, these guys didn't have to worry about any of the difficult
parts of flying a plane.  Here's a list (in no particular order) of
the factors I think could be a challenge for a non-pilot.

	1.	Judgement -- None required, they planned to die.
	2.	Weather -- Clear blue skies with virtually infinite vis.
	3.	Landing -- Nope... Didn't have to do that.
	4.	Airspace -- Who cares!
	5.	Radios -- Nope... Probably didn't bother with those.
	6.	Navigation -- OK... but pretty basic, and probably
		got flight crew assistance getting close.  Let's face
		it, you can aim for the world trade center from a very
		long ways away at an altitude of 2000 feet or more.
	7.	Takeoff -- Conveniently handled by the flight crew.
	8.	Clearances -- Who cares!
	9.	In flight emergencies -- Again, if something goes wrong,
		the plane just crashes.  Heck, that may explain the one in
		PA.

Adequate training for #6 can be gleaned from a copy of any of the
following
packages:
	Flight Unlimited (1 or 2)
	Fly (or Fly2K or Fly-2)
	Any of the SubLogic Flight Simulators
	Any PC based Flight Training Device
	Micro$oft Flight Simulator (any version)
	many others.

Also, you could learn enough to do this from about 10 hours of flight
instruction at your local FBO.  Total cost: ~$1,500.

Just my opinion about the matter, but at least I know a little about the
cockpits involved. (757 and 767 are so similar that they share a common
FAA type rating, so any pilot rated for one can fly either, and they
both
have "glass" advanced cockpits with very capable and easy to program
autopilot and FMS systems.)

Owen DeLong
KB6MER
Private Pilot, Airplane Single Engine Land, Instrument Airplane

-- 
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