NASA · Aviation Safety Reporting System
D01 Controller reported aircraft acknowledged traffic in sight then returned on frequency to report a NMAC.
What is ASRS?
The Aviation Safety Reporting System is NASA's voluntary, confidential, non- punitive incident-reporting system, established 1976. Pilots, controllers, dispatchers, and maintenance technicians file reports describing safety- relevant events. NASA de-identifies every report before adding it to the public database. Reports are not investigated by NASA, the FAA, or the NTSB — they represent the reporter's perspective.
Pilot narrative
Verbatim from the de-identified NASA record. First-person account by the
reporter. NASA strips identifying details (names, company, specific time);
anonymization placeholders are ZZZ,
X, Y.
I had Aircraft X, VFR, on the practice approach for 12L at BJC at 7,100. As the aircraft was passing BDU pattern, I called traffic on two aircraft at 1 O'clock and 3 miles indicating 8,000. They appeared to be a glider and a tow aircraft, which I included in the traffic call. Aircraft X reported the traffic in sight, and I switched him to BJC Tower. A couple miles later, Aircraft X turned to the east and checked back on with me reporting a near mid-air. I asked who it was with, and they said it was an aircraft doing a rapid spiral descent and they had to turn to avoid. There were no other aircraft in Aircraft X's path, so I believe this was the glider tow aircraft descending back into BDU's pattern. Aircraft X stated they would leave the area and return to ZZZ. This VFR corridor is very congested, and we have multiple approaches that fly through it. Including many jet aircraft. I recommend we either work on adjusting the BJC approach to be farther away from BDU, or do pilot outreach, especially to BDU glider ops, to show them what to watch for, or help work out where it is best for them to do their climbs/descents. Maybe similar to how we work with Parachute Ops at LMO. There was nothing I could have done different in this situation. Traffic was issued, they were indicating 1000 ft. apart, and the pilot had them in sight. The BDU pattern traffic did something dramatic and unexpected. We either start doing pilot outreach, or we start denying practice approaches due to unsafe VFR volume in the area. It is scary to run traffic in this area, and we HAVE TO run all aircraft through this area when we are landing 12L.I will start denying approaches to 12L if I have to from now on. This is getting dangerous.
NASA classification — Anomalies
- Conflict
- No Specific Anomaly Occurred
NASA classification — Assessments
- Contributing Factors / Situations
- Airport · Procedure
- Primary Problem
- Airport
ASRS reports are voluntarily submitted, de-identified by NASA, and represent the reporter's perspective. The presence of reports on a topic cannot be used to infer prevalence in the National Airspace System. The authoritative source is the NASA ASRS Database Online at asrs.arc.nasa.gov ↗.