At 0957 The Airplane Reached Its Highest Altitude Of 14,950 Ft, Then It Began A Left Turn And Rapid Descent.

Location: Cape Yakataga, AK Accident Number: ANC23LA065
Date & Time: August 27, 2023, 10:00 Local Registration: N6709Q
Aircraft: Beech B36TC Injuries: 2 Fatal
Flight Conducted Under: Part 91: General aviation - Personal

On August 27, 2023, about 1000 Alaska daylight time, a Beech B36TC airplane, N6709Q, was destroyed when it was involved in an accident near Cape Yakataga, Alaska. The pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight.

The airplane departed Snowshoe Lake Airport (5AK4), Glennallen, Alaska, at 0850, destined for Ketchikan, Alaska. A review of preliminary air traffic control (ATC) communications from the Federal Aviation Administration (FAA), and automatic dependent surveillance – broadcast (ADS-B) data, revealed that radar contact and radio communications were intermittent along the route of flight due to high terrain.

About 0915 the pilot stated he was currently in visual flight rules (VFR) conditions, at an altitude of 12,500 ft mean sea level (msl). The Anchorage Air Route Traffic Control Center (ARTCC) controller asked the pilot if he could climb higher, and the pilot acknowledged that he would climb to 13,500 ft msl.

About 0920, the controller confirmed radar contact with N6709Q. The controller asked what the pilot’s requested final altitude was, the pilot replied 13,000 ft, and that he knew he had some weather ahead of him. The controller responded that he had weather and higher terrain, and that he would need to climb higher. The pilot responded that they had oxygen onboard and that the airplane was turbocharged, and that a climb to a higher altitude would not be a problem.

At 0922, the controller instructed the pilot to climb to 14,000 ft, and the pilot subsequently confirmed that he would start a climb to an assigned altitude of 14,000 ft.

At 0926, the controller told the pilot he would lose him on frequency and issued multiple backup frequencies to maintain radio communication.

At 0928, the pilot established radio communications on the new frequency. The controller told him he would lose him on all frequencies for about 10 minutes, issued the altimeter setting, and frequency to monitor.

At 0938, the controller instructed the pilot to turn 20° to the right to avoid higher terrain along the route of flight, but there was no response from the pilot. 

At 0945, the controller asked another airplane to relay instructions to the pilot of N6709Q, stating, in part, to make a 20° right turn, vectors for a higher terrain.

At 0945, the pilot of the other airplane relayed a message to the controller that N6709Q had acknowledged the updated instructions.

At 0953, after reestablishing radio contact with the controller, the pilot of N6709Q requested a climb to 15,000 ft and the controller approved the request.

At 0958, the controller states “N6709Q, Anchorage center”, then again, “N6709Q, Anchorage center”, with no response from the pilot. The controller asks another airplane to broadcast on frequency and ask N6709Q what their intentions are. 

At 0958, the controller states, “All other aircraft standby real quick, N6709Q, Anchorage center, you up? N6709Q, I see you rapidly descending at 11,000.”

There were no further communications from the pilot of N6709Q. According to archived FAA ADS-B data, at 0957 the airplane reached its highest altitude of 14,950 ft, then it began a left turn and rapid descent. At 0959, the final radar target was near the accident site at 8,875 ft, and 138 knots groundspeed.

On August 28, the crew of a U.S. Coast Guard HC-130 airplane located the wreckage site near Mt. Leeper located in the Wrangell-St. Elias National Park and Preserve, at an elevation of about 4,787 ft, but terrain and continued poor weather conditions precluded reaching the site.

On September 5, weather conditions improved briefly, and a National Park Service (NPS) ranger was able to fly over and photograph the accident site. The fragmented airplane wreckage came to rest in a highly crevassed area on the Yahtse Glacier that continually accumulates snow (see figure 2). A sizable portion of the airplane wreckage was found in a large snow crater on the snow and ice-covered glacial terrain, with smaller portions of airplane wreckage observed adjacent to the crater.
On September 13, the Wrangell-St. Elias National Park and Preserve mountaineering team determined that due to the location, crevasse danger, and poor weather conditions, recovery of the airplane’s two occupants or wreckage is not possible. 

FMI: www.ntsb.gov