"George Patterson" wrote in message
news:79uQe.2271$LK.187@trndny09...
Steven P. McNicoll wrote:
A Near Midair Collision (NMAC) is "an incident involving one or more
aircraft in which a hazard or a perceived potential hazard to safety is
involved."

In that case, we have a NMAC here because the MD-80 pilot perceived a
potential hazard to safety.

George Patterson

Actually, what we have is a a report of a NMAC. During the subsequent
investigation, the MD80 pilot's perception of the potential hazard to
safety, based apparently on his TCAS interpretation of the event, will
probably not correlate with the voice and radar tapes, nor with the witness
reports from ATC and the Learjet crew. The AAL was heading 150 at 6000.
The Learjet was launching out of BOS on a 070 heading climbing to 5000.
Visual contact was aquired between the Lear and the MD80. The controller
used correct phraseology to provide for visual separation. The MD80 driver
starts an on-air ****ing contest with the Lear driver. "That's bogus. You
were 300 feet below us." How does he know the Lear was 300 feet below him?
TCAS. And why does it matter? The Learjet was the maneuvering aircraft,
and climbing visually through the MD80. The vertical distance between
aircraft is irrelevent to flight safety in this event. A risk of collision
did not actually exist.

In my view, this situation will not be elevated into an NMAC incident
because it does not meet the definition of anything other than a "No
Hazzard" event. The MD80 did not have to maneuver to avoid the Learjet.
Even if he had maneuvered, he couldn't have hit the Learjet with a
sidewinder. The Learjet was maneuvering on a visual separation climb
clearance under positive ATC control. The weather was VFR. The Bankair was
turned behind the AAL before the visual sep clearance was issued. Doesn't
sound hazardous except maybe to the TCAS on the MD80. A risk of collision
did not actually exist.

More than likely, this event at BOS will not be classified as an NMAC
incident, but rather as a non-hazardous event.

Chip, ZTL