Document
OAS-43A (12/12)
Interagency Aviation
Accident Prevention Bulletin
No. IA APB 25-01 December 12, 2024 Page 1 of 2 Subject: Non-Towered Airport Operations Area of Concern: Flight Safety Distribution: All Aviation Operations Discussion: Recently, a pilot reported a near miss in the traffic pattern at the Birchwood Airport (PABV) in the Anchorage Municipality. The ADS-B visual traffic alert was displaying traffic 100 feet directly above the pilot, but there was no audible traffic alert. Had the pilot not noticed the traffic alert and taken action, there’s a good possibility a midair collision would have occurred ( SAFECOM 24-1213 ). Here’s the story: A pilot was conducting a maintenance test flight. Inbound to the airport, he made his first radio call about 8 miles to the northwest. About 5 miles from the airport, he made a second call stating that he was inbound for left traffic for runway 2L. There were two other aircraft in the pattern at the time using runway 2L. The pilot spotted one Cessna on upwind and the other on left downwind.
A short time later, the pilot entered a mid-field left downwind for runway 2L behind the first Cessna. He saw the second Cessna on crosswind as they entered the pattern and made a radio call stating that he was entering mid-field left downwind for runway 2L behind the Cessna on downwind.
On downwind, the pilot followed the first Cessna ahead of him and noted that it was about two hundred feet below pattern altitude. The pilot descended to match the other aircraft’s altitude so that he could maintain better sight. As the pilot slowed to increase spacing, he watched the first Cessna turn base and then turn final.
The pilot was waiting for the first Cessna to pass abeam while on their final approach when he glanced in the cockpit and noticed a (visual) traffic alert on the ADS-B. His first thoughts were that it must be a ghost signal as it was displaying traffic 100’ directly above without any audible warning. The pilot looked up through the skylight but couldn’t see an aircraft. He didn’t think the second Cessna could be overtaking him since they should have heard him enter the pattern. In a split second, the pilot decided to start a steep descending turn to base.
As the pilot announced his turn to base, the second Cessna announced they were performing a right 360 for spacing before they turned base leg for runway 2L.
No. IA APB 25-01 December 12, 2024 Page 2 of 2 Had the pilot failed to notice the traffic alert display on the ADS-B, there’s a good chance the second Cessna would have descended into his aircraft.
Fortunately, the pilot resisted the temptation to ignore the visual alert indicating traffic directly above him.
Many pilots may have experienced ghost targets appearing in the display and then disappearing just as quickly. In this case, it wasn’t a “ghost”.
Operations Without an Operating Control Tower It’s essential that pilots be alert and practice sound lookout doctrine in addition to exchanging traffic information when approaching or departing non-towered airports. This is of particular importance in areas where other aircraft may not possess two-way radio communication capability at airports that do not require the use of two-way radios.
On June 6, 2023, the FAA released Advisory Circular (AC) 90-66C that deals with operations at non- towered airports. This AC has been updated to reflect current procedures and best practices at airports without an operating control tower or an airport with a control tower that operates only part time.
One final note - the FAA does not recommend that the pilot execute a straight-in approach for landing when there are other aircraft in the traffic pattern. The straight-in approach may cause a conflict with aircraft in the traffic pattern especially those turning from base to final as it increases the risk of a midair collision.
Make yourself heard, seen, and safe!
/s/ Keith C. Raley /s/ Lori Clark Keith C. Raley Lori Clark Chief, Aviation Safety, Training, Program Branch Chief - Aviation Safety Management Evaluation, and Quality Management Systems DOI, Office of Aviation Services USDA, Forest Service