On Saturday morning, Delta Air Lines flight 1070 from Detroit and United Airlines flight 1724 from San Francisco came perilously close to colliding above Phoenix Sky Harbor International Airport. Despite bad air traffic control instructions, the aircrafts’ onboard Traffic Collision Avoidance Systems (TCAS) alerted the pilots in time, preventing what could have been a catastrophic accident.
- Delta 1070 was a 17-year old Airbus A330-300 (registration N820NW) with 245 onboard
- United 1724 was a 9-year old Boeing 737-900ER (registration N68891),with 123 onboard
The flights were both on final approach around 11:00 a.m. United 1724 was established on a straight-in approach to Runway 7R, Delta 1070 was being vectored for a base leg to Runway 8.
The approach controller was handling multiple aircraft converging on the parallel runways. Delta 1070 was instructed to fly a base leg at an altitude that inadvertently placed the aircraft close to the glide path for the parallel runway – as United 1724 continued inbound on its straight-in approach.
The controller was engaged in lengthy communication with a UPS freighter, and that delayed giving instructions for Delta 1070’s left turn onto final. By the time the turn instructions were hastily issued, the two aircraft were converging.
Both planes received Traffic Collision Avoidance System proximity warnings. They may have come as close as 400 feet to each other vertically, and about 1,200 feet horizontally, well below allowable minimums for separation. After taking evasive maneuvers, the two planes were re-vectored for new approaches and landed without further incident.
Enilria comments “it seems that the planes were vectored directly into each other.” And One Mile at a Time offers,
You’ve gotta give credit to TCAS for being awesome. It’s always impressive how many checks are in place to ensure that aviation is safe, and ultimately us humans just can’t compete with automation when it comes to catching every possible catastrophe.
I agree with this. The Boeing 737 MAX MCAS issues were a problem because the plane was meant to basically fly itself, even with Lion Air pilots, and didn’t live up to that standard. U.S. airline pilots likely wouldn’t have had the same runaway MCAS issues, and U.S. airlines wouldn’t have had the same issues with lack of angle of attack disagree indicators, or hopefully with undocumented maintenence issues either. Our standards in aviation have gotten incredibly high.
The challenge is that these high standards seem not to apply at the FAA’s Air Traffic Organization which is very broken and a silent safety risk. Controllers aren’t the tools they need. Technology modernization has been poorly managed and in crisis there for decades. And we’re also not moving quickly enough to take advantage of AI in the cockpit either.
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