On Wed, 12 Sep 2007 00:38:13 +1200, Dave Doe wrote in
:

I've read a few replies, and most seem to say it was ok. However,
they could be wrong, ...


Apparently it's the controller's call:

http://www.faa.gov/regulations_polic...a/7110.65R.pdf
FAA Order 7110.65R Air Traffic Control

3-9-5. ANTICIPATING SEPARATION
Takeoff clearance needs not be withheld until
prescribed separation exists if there is a reasonable
assurance it will exist when the aircraft starts takeoff
roll.

3-9-6. SAME RUNWAY SEPARATION
Separate a departing aircraft from a preceding
departing or arriving aircraft using the same runway
by ensuring that it does not begin takeoff roll until:
a. The other aircraft has departed and crossed the
runway end or turned to avert any conflict. (See
FIG 3-9-1.) If you can determine distances by
reference to suitable landmarks, the other aircraft
needs only be airborne if the following minimum
distance exists between aircraft: (See FIG 3-9-2.)
1. When only Category I aircraft are involved-
3,000 feet.
2. When a Category I aircraft is preceded by a
Category II aircraft- 3,000 feet.
3. When either the succeeding or both are
Category II aircraft- 4,500 feet.
4. When either is a Category III aircraft-
6,000 feet.
5. When the succeeding aircraft is a helicopter,
visual separation may be applied in lieu of using
distance minima.