NTSB Issues Investigative Update on San Francisco Airport Near Miss
Summary of new / confirmed details:
- The National Transportation Safety Board (NTSB) was notified of the incident on Sunday, July 9 [two days after the incident]
- The NTSB investigator-in-charge has formed the following groups: Air Traffic Control (ATC), Operational Factors, Human Performance, Airports, and Flight Data Recorders (FDR)
- The incident airplane’s cockpit voice recorder had been overwritten, so NTSB investigators did not have that data.
- The captain was the pilot flying ACA759, and the first officer was the pilot monitoring. Both pilots held Canadian airline transport pilot certificates.
- The captain had over 20,000 total flight hours, of which about 4,797 hours were as captain in Airbus A320‑series airplanes. The first officer had about 10,000 total flight hours, of which over 2,300 hours were in Airbus A320-series airplanes.
- At 2349 PDT (7 minutes before the incident), all positions in the ATC tower (controller-in-charge local control, local control assist, ground control, flight data, and clearance delivery) were combined at the local control position.
- As ACA759 approached SFO, at 2355:52 PDT, the airplane flew too far right of course to be observed by the local controller’s ASDE-X/ASSC and was not visible on the ASDE-X/ASSC display for about 12 seconds.
- At 2355:56 PDT, when ACA759 was about 0.3 mile from the landing threshold, the local controller confirmed and recleared ACA759 to land on runway 28R.
- The flight crew of the first airplane in queue on taxiway C (UAL1) transmitted statements regarding ACA759, one of which mentioned the alignment of ACA759 with the taxiway while ACA759 was on short final (see figures 2 and 3). The flight crew of the second airplane in queue on taxiway C switched on their airplane’s landing lights as the incident airplane approached.
- The incident pilots advanced the thrust levers when the airplane was about 85 ft agl. FDR data indicate that the airplane was over the taxiway at this time, approaching the vicinity of taxiway W.
- At 2356:04 PDT, ACA759 reappeared on the local controller’s ASDE-X/ASSC display as it passed over the first airplane positioned on taxiway C.
- About 2.5 seconds after advancing the thrust levers, the minimum altitude recorded on the FDR was 59 ft agl.
- At 2356:10 PDT, the local controller directed ACA759 to go around. The airplane had already begun to climb at this point
- In postincident interviews, both incident pilots stated that, during their first approach, they believed the lighted runway on their left was 28L and that they were lined up for 28R. They also stated that they did not recall seeing aircraft on taxiway C but that something did not look right to them.
NTSB narrative:
Figure 3 shows UAL1’s transmission at 2356:04 and ACA759’s position as it overflies the first airplane waiting on the taxiway; note that the second airplane has turned on its landing lights.
Links:
https://www.ntsb.gov/news/press-rele...r20170802.aspx
https://ntsb.gov/investigations/Pages/DCA17IA148.aspx
NTSB finds 'blind spot' in SFO radar after Air Canada event