Accident Overview
On November 25, 2020, at 0009 eastern standard time, a Cessna 172 (registration N8125U) and an Aero Commander 500 (registration N777CM) collided during landing at Dekalb-Peachtree Airport (PDK) in Atlanta, Georgia. The Cessna was being operated as a Title 14 Code of Federal Regulations Part 91 personal flight, while the Aero Commander was operating under Part 135. No injuries occurred.
Cessna Pilot Account
According to the Cessna pilot, en route to PDK—his home base—he deviated around fog, delaying his arrival until after the control tower had closed. Upon arrival, he listened to the automatic terminal information service, wrote down radio channels, and proceeded, noting his dislike of operating without air traffic control. He activated pilot-controlled lighting and saw green lights at the approach end of what he believed to be runway 21R, which he interpreted as indicating the active runway. In fact, these lights marked the displaced threshold of runway 21L. He switched radio channels and made routine calls, hearing no other traffic. He reported that his landing and navigation lights were on during approach.
While landing on runway 21L, about 200 ft past the runway numbers at 10–15 ft altitude and 65 knots, he saw a small white light approaching rapidly. About three seconds later, he heard a bang and the airplane pitched hard right. He maneuvered back to the centerline, landed, and exited at taxiway F without further radio calls. An airport security guard informed him of the collision.
Aero Commander Pilot Account
The Aero Commander pilot stated he opted to land on runway 3R because other aircraft were landing there. He followed an EMS helicopter onto a right downwind pattern, making appropriate CTAF calls on frequency 120.9. He turned to a right base and entered a ½-mile final for runway 3R, announcing each leg. He typically did not adjust runway light intensity and noticed the intensity increase during approach. After landing, he saw lights and initially was unsure, then realized an oncoming aircraft was landing on runway 21L. Both airplanes swerved, and the right wingtip of the Cessna contacted the right outboard wing section of the Aero Commander.
Radio Communications and Tracking Data
A review of FAA recordings on CTAF frequency 120.9 revealed that at 0005, the Aero Commander pilot initially announced a left downwind for runway 21L. About two minutes later, the EMS pilot reported a modified base leg for runway 3R. The Aero Commander pilot then announced final for runway 21L. The EMS pilot acknowledged and offered to approach runway 3L. The Aero Commander pilot agreed, stating he would go around and enter a right downwind for runway 3R. He subsequently transmitted his position on downwind and final. Just after his turn to final, the EMS pilot announced clear of the runway. The Aero Commander pilot acknowledged.
FAA ADS-B data showed that at the time the Aero Commander pilot had the helicopter in sight, the Cessna was on final about ½ mile from the displaced threshold of runway 21L. The recording contained no radio calls from the Cessna pilot.
Aircraft Damage
Examination revealed that the Cessna sustained substantial damage to the right wingtip, including the outermost wing rib and bending of the right aileron. The right wingtip navigation light separated from the wing. Postaccident testing of all other lights and the communication radio showed no anomalies. The Aero Commander had minor scrapes and paint transfer to the underside of the right wing near the outboard flap edge and minor damage to the right-wing flap.
The CTAF frequency at PDK is published as 120.9, which is the same frequency used by the control tower when operating. When the tower is closed, high-intensity runway lights for runway 3R/21L are preset to medium intensity. The pilot-controlled lighting system uses a separate frequency, 120.0, and can adjust runway edge light intensity, activate the approach lights for runway 21L (including green threshold lights), and activate taxiway lights. The green threshold lights denote the displaced threshold location and are not an indication of the active runway.