Above is a chart of altitude data for the recent near-miss of two aircraft at Austin-Bergstrom International Airport in Texas, involving a Southwest 737 and FedEx 767, which the NTSB is investigating. Data for the chart is from Flightradar24 (at 25 foot resolution, and not totally accurate because it is calculated from air pressure). See that link also for the story, or this tweet and this other tweet.
In the chart, the emergency go-around by the FedEx aircraft is obvious (it began about 5 seconds before minimum separation, when horizontal separation was about 650 feet). The temporary rise of Southwest to 25 feet appears to be an artifact. I estimate minimum separation as 187 feet. FedEx was about 0.58 nautical miles (1.08 km) away, on course to land, when Southwest started rolling.
The landing approach was CAT III ILS due to heavy fog. It seems to me that the clear-thinking FedEx pilots saved lives that day. A recording of the radio communication is here. Transcript is as follows (accurate to-the-second timestamps are not available):
- FDX1432: Austin tower, FedEx 1432 heavy passing 5.4 for that CAT III ILS 18L.
- Tower: FedEx 1432 heavy, Austin Tower, 18L RVR [Runway Visual Range] touchdown 1400, midpoint 600, rollout 1800, 18L cleared to land.
- FDX1432: Cleared to land 18L, FedEx 1432 heavy.
- SWA708: Tower, Southwest 708, we’re short of 18L and we’re ready.
- Tower: Southwest 708, Austin Tower, runway 18L RVR 1200, midpoint 600, rollout 1600, fly heading 170, runway 18L, cleared for takeoff, traffic 3 mile final is a heavy 767.
- SWA708: Okay, 170 cleared for takeoff, 18L, copy the traffic, Southwest 708.
- FDX1432: Tower, confirm FedEx 1432 heavy is cleared to land on 18L [hearing the message to SWA708 and seeing a potential problem].
- Tower: FedEx 1432 heavy that is affirmative, 18L you are cleared to land, traffic departing prior to your arrival is a 737.
- FDX1432: Roger.
- Tower: Southwest 708 confirm on the roll.
- SWA708: Rolling now.
- FDX1432: Southwest abort [seeing SWA708 on the runway in front of him at the limit of visibility in the fog].
- FDX1432: FedEx is on the go [go-around].
- Tower: Southwest 708, roger [apparently believing “abort” came from SWA708], you can turn right when able.
- SWA708: Negative.
- Tower: FedEx 1432, climb and maintain 3000 [feet], when able you can turn left heading 080.
- FDX1432: Left turn to 080, 3000, FedEx 1432 heavy.
- Tower: Southwest 708, you can turn left heading 170.