Preliminary Report: Cheyanne and 172 in Midair

 - January 28, 2008, 8:26 AM

PIPER PA-31T AND CESSNA 172P, DENVER, COLO., JAN. 24, 2003–Piper N360LL–registered to and operated by Lee Larson Aircraft Sales of Northglenn, Colo.–collided with a Cessna N52241 (registered to and operated by EDB Air of Englewood, Colo.) over Denver at approximately 5:22 p.m. MST.

The private pilot and both passengers aboard the Cessna and the two commercial pilots aboard the Piper were killed. Denver police reported six people on the ground, including a 15-year-old boy and a two-year-old girl, received minor injuries from falling debris. Conditions in the area of the accident were VFR, and neither airplane was on a flight plan.

The Cessna flight originated at Denver Centennial Airport (APA) and was en route to Cheyenne, Wyo. The Piper originated at Jeffco Airport (BJC), Broomfield, Colo., and was en route to APA.

Preliminary information indicated both airplanes were operating outside Denver’s Class B airspace and within Class E airspace. At 5:10 p.m. the Piper pilot departed BJC toward the southeast, and seven minutes later told Denver Tracon that he was inbound for APA. The controller assigned the pilot a transponder code and radar identified the airplane about four miles south of the airport. The controller advised the pilot he was not receiving a mode-C transponder altitude signal and asked if he was squawking altitude. The pilot responded, “yes sir, we are.” The controller then requested that the pilot verify his altitude and the pilot advised that he was at 7,800 feet. N360LL’s groundspeed was 230 knots at this time.

At 5:10 the pilot of the Cessna departed APA northbound and contacted Denver Tracon eight minutes later advising that he was VFR en route to Cheyenne at 7,300 feet and requesting clearance to climb to 8,500 feet. The controller assigned a transponder code and radar identified the airplane 15 miles southeast of Jeffco Airport. The controller cleared the pilot to enter Class B airspace on course at 8,500 feet. N52241’s groundspeed was 110 knots at this time.

The controller then asked the pilot of the Piper to say altitude. The pilot said he was at 7,600 feet, and the controller issued him a traffic advisory for Cessna traffic at the Piper’s 12 o’clock position, one mile at 7,600 feet. There was no acknowledgement from the pilot. The collision occurred 2.5 minutes after the pilot contacted Denver Tracon.

Witnesses said they saw the two airplanes collide head-on. One witness said the Piper made an evasive maneuver, a sharp left bank, at the last second. After the collision, the Piper entered an inverted flat spin and fell into the backyard of a residence. The Cessna descended nose down and struck an unoccupied house, rupturing a natural-gas line and causing an explosion that blew out the walls of the house and collapsed a portion of the roof.

The majority of the Cessna’s wreckage was in the house, and sections of the Piper were scattered over approximately 24 square blocks. An investigation is still under way.