Overview
On an unspecified date, two aircraft collided in mid-air over the northwest end of Mercer Island, Washington. The collision occurred at an altitude of approximately 1500 feet MSL, at coordinates 47°35'N, 122°15'W. The location is about 5 miles northeast of Boeing Field and about 10 miles north of Seattle-Tacoma International Airport (Sea-Tac). The airspace above the site is part of a Terminal Control Area (TCA) with a floor of 3000 feet, meaning the collision took place below controlled airspace.
Aircraft Involved
One aircraft was a Cessna 172, registration N2428E. It had departed from Sea-Tac Airport on a visual flight rules (VFR) flight to Snohomish, Washington, approximately 27 miles on the 355-degree radial from the Sea-Tac VORTAC. The aircraft proceeded north-northwest over the west shore of Mercer Island.
The other aircraft was a Cessna 152 (designated C-A152 in the source), registration N761EL. It was southwest-bound, preparing for entry into the Boeing Field Airport traffic area. The pilot's last radio contact had been a position report to Boeing Field Tower.
Collision Details
The two aircraft collided over the northwest end of Mercer Island. The point of collision is about 5 miles northeast of Boeing Field. No further details on the sequence of events or post-collision circumstances are provided in the source.