On Sun, 20 Jan 2008 19:39:44 -0800, C J Campbell
wrote in
2008012019394416807-christophercampbell@hotmailcom:

That fact that it is extremely rare ...

A MAC occurred at Corona Municipal Airport less than ten years ago:
3/19/1998

http://www.ntsb.gov/ntsb/brief.asp?e...11X09700&key=1
NTSB Identification: LAX98FA118A
14 CFR Part 91: General Aviation
Accident occurred Thursday, March 19, 1998 in CORONA, CA
Probable Cause Approval Date: 10/13/2000
Aircraft: Cessna 310H, registration: N310RR
Injuries: 3 Fatal.
A Cessna 310 and a Cessna 152 collided in-flight about 2 miles
south of the Corona airport at 2,600 feet mean sea level (about
2,000 above ground level). The Cessna 310, with two pilots aboard,
was descending toward another nearby area airport, and the Cessna
152, flown by a certified flight instructor (the sole occupant)
from the right seat, was orbiting south of the airport awaiting
the reopening of the runway following construction. Radar data
showed that in the 1 minute 18 seconds prior to the collision, the
Cessna 310 descended from 4,000 feet to the collision point on a
southeast bound ground track at a rate of about 1,200 feet per
minute. Nine seconds prior to the collision, the Cessna 152, which
had been on a westbound track, began a right turn toward a
northwest bound ground track. Over the 1 minute 18 second period,
the horizontal separation decreased from 6.01 nautical miles to
zero as the vertical separation decreased 1,400 feet.
Reconstruction of the two airplanes revealed that at the point of
collision, the Cessna 310's lateral axis was about 80 degrees to
the Cessna 152's vertical axis as the 310's outer right wing and
tip tank contacted the 152's left main gear strut, lift strut, and
inboard left wing. In the one minute prior to the collision, the
relative horizontal bearing from the Cessna 310 ground track to
the Cessna 152 was between 8 and 10 degrees left of the track.
During this same period, the relative horizontal bearing from the
Cessna 152 ground track to the Cessna 310 varied between 25
degrees and 40 degrees right of the Cessna 152 ground track as it
maneuvered prior to the right turn. Trigonometric calculation of
altitude difference between the targets yielded a 2 degree 10
minute relative vertical angle between the target positions.

The National Transportation Safety Board determines the probable
cause(s) of this accident as follows:

The failure of both pilots to maintain an adequate visual lookout
and to see and avoid the other airplane.

Full narrative available