Two passenger jets departing San Francisco International Airport in near-lockstep on a busy spring evening have become the focus of a federal safety investigation, reigniting debate over how tightly U.S. air traffic controllers can sequence takeoffs on closely spaced parallel runways. A United Airlines Airbus A320 and a SkyWest Airlines CRJ-200, operating as a United Express flight, departed almost simultaneously from adjacent runways, then converged in the climb after a timing and heading error that brought them uncomfortably close above the waters of San Francisco Bay.
A Routine Parallel Departure That Suddenly Was Not
The incident unfolded around 5:10 p.m. on May 13, 2025, as San Francisco International Airport, one of United’s largest hubs, was deep into the late-afternoon rush. According to recordings and radar data reviewed by investigators, United Flight 1152, an Airbus A320 bound for Dallas Fort Worth, was cleared to depart from Runway 1 Right with instructions to turn right after takeoff. Moments later, SkyWest Flight 5272 to Fresno, operating as a United Express service, rolled down the parallel Runway 1 Left with a clearance to turn left on climb-out.
In visual conditions, this kind of choreography is standard at San Francisco, where the intersecting grid of runways is used aggressively to keep traffic flowing. With aircraft launching from the parallel 1L and 1R in quick succession and other jets lined up to land on the cross runways, the airport relies on precise timing, clear phraseology, and strict adherence to departure procedures.
This time, however, the sequence broke down. Instead of banking right toward its assigned departure path, the United jet initiated a sharp left turn at low altitude, swinging directly toward the SkyWest aircraft’s intended track. Within seconds, two departures that should have diverged horizontally were converging, compressing vertical and lateral separation as they climbed through just a few hundred feet.
What Investigators Say Went Wrong
The Federal Aviation Administration has opened a formal investigation into the event, gathering tower audio, radar telemetry, flight-management data and crew statements. Early accounts from aviation outlets and local media indicate that the United flight crew initially followed the guidance displayed in the aircraft’s flight-management system rather than the verbal clearance from the tower, which had directed a right turn instead of a left.
By the time the United captain recognized the discrepancy and attempted to correct the heading, the aircraft had already encroached on the other departure’s path. Onboard collision-avoidance systems triggered a traffic alert, prompting SkyWest’s pilots to execute an evasive maneuver. At their closest point, the two jets were separated by a little over a mile horizontally and roughly 280 to 300 feet vertically, figures that fall uncomfortably near the limit of safe margins during a dynamic phase of flight.
Complicating matters further, recordings from the control tower suggest that the controller may have added to the confusion by using the phrase “fly runway heading” in a context where “fly present heading” would have been clearer. Managing multiple aircraft in quick succession, including international arrivals on final approach, the controller was operating in a high-workload environment that leaves little room for ambiguity.
Parallel Operations at SFO and Across the U.S.
Parallel runway operations are a fixture at large U.S. airports, where keeping traffic moving depends on maximizing every available strip of pavement. At San Francisco, the north-south runways 1L and 1R sit side by side, allowing controllers to alternate between paired landings and paired departures in favorable weather. On clear days, visitors often capture dramatic images of jets launching or touching down almost wingtip to wingtip.
The system rests on a web of procedural safeguards. Simultaneous takeoffs on parallel runways must comply with minimum distances and strict heading assignments designed to ensure that aircraft diverge from one another quickly after liftoff. Pilots are expected to follow those headings precisely unless instructed otherwise, while collision-avoidance equipment stands by as an electronic backstop if human error pushes aircraft too close.
Yet as traffic has rebounded and airlines such as United expand their schedules at key hubs, San Francisco’s tightly constrained airfield has come under renewed scrutiny. The airport’s parallel runways are relatively close to one another compared with some other major U.S. fields, which limits the kind of independent instrument approaches and departures controllers can authorize in low visibility. When fog or low clouds descend on the Bay, SFO often must fall back on single-runway operations, triggering delays and cancellations that ripple through the national network.
United’s Growing Presence Meets Heightened Safety Focus
United has positioned San Francisco as one of its premier international gateways and is in the midst of a multiyear expansion at the airport that includes new long-haul destinations in Asia and the Pacific and a multibillion-dollar terminal upgrade. The carrier plans to operate roughly 300 daily departures from SFO in peak seasons, a capacity increase of about 20 percent compared with recent years.
That growth has coincided with a cluster of headline-grabbing safety events involving United aircraft at SFO and elsewhere. In March 2024, a series of mechanical issues affecting the airline drew national attention, while 2025 has already brought several incidents at San Francisco alone, including a pair of United Boeing 777 jets clipping wings while one was pushing back from the gate and another runway close call in which a United aircraft was cleared to cross an active runway just as an Air Canada jet began its takeoff roll.
United has emphasized that it is cooperating fully with regulators in each case and has reiterated its commitment to safety as its top priority. Airline officials say internal reviews are underway to understand the specific chain of events in the May parallel departure incident and to determine whether any additional training or procedural changes are warranted for flight crews operating in complex airspace like San Francisco.
Air Traffic Control Under the Microscope
The near-convergence of the United and SkyWest flights is also sharpening focus on the air traffic control system that orchestrates the movements of thousands of aircraft in U.S. skies each day. In the San Francisco incident, the FAA has acknowledged that the United jet turned without authorization, but investigators are also parsing every word spoken in the tower to understand how instructions might have been misinterpreted at a critical moment.
Controllers at high-density airports are trained to sequence departures with rapid-fire precision, balancing maximizing throughput with preserving buffers between aircraft. Standard phraseology is meant to strip away ambiguity, but even small deviations or momentary lapses in attention can have consequences when two heavily laden jets are accelerating into the sky on adjacent strips of concrete.
The event at SFO comes amid broader concerns about controller staffing and fatigue across the national airspace system. Industry groups and pilot unions have repeatedly warned that chronic understaffing in some facilities increases workload and pressure on controllers. The FAA has responded with new hiring initiatives and schedule adjustments, but incidents such as the SFO near-miss are likely to fuel additional calls for investment in personnel, training, and technology that can reduce reliance on split-second human judgment.
How Close Is Too Close in the Climb?
To the average traveler watching two departures rise into the evening sky, a separation of a mile or so may appear reassuring. In aviation terms, however, the margins that briefly separated the United and SkyWest jets were razor thin, especially given their low altitude and the speed at which they were converging. Climb-out after takeoff is one of the most workload-intensive phases of any flight, with crews focused on gear and flap retraction, engine performance, navigation modes, and initial communications with departure control.
Standard separation requirements vary with airspace and conditions, but horizontal buffers of several miles and vertical separations of at least 1,000 feet are typical targets in controlled airspace. Collision-avoidance systems can function effectively at much closer ranges, issuing climb or descent commands designed to keep flight paths from intersecting. Even so, when aircraft in close proximity are rapidly changing altitude and heading, there is less time for either pilots or software to react.
Aviation safety specialists note that in this case, the system ultimately worked as designed: the alert on board the SkyWest aircraft activated, the crew executed the prescribed maneuver, and both flights continued on to their destinations without injury or damage. The fact that no one on board either jet may have fully appreciated how close the call was only underscores how quietly such systems operate in the background to protect travelers when humans and machines briefly fall out of sync.
Travelers’ Perception and the Reality of Risk
For passengers reading about a series of incidents concentrated at a single airport and involving a single major carrier, the psychological impact can be significant. The notion of jets crossing paths in the sky or clipping wings on the ground at a familiar departure point plays into a natural fear of flying, even as experts emphasize that modern commercial aviation remains extraordinarily safe by historical standards.
Analysts point out that high-profile events at large hubs such as San Francisco may reflect visibility rather than a deeper systemic problem unique to one airport or airline. As air travel volumes return to or exceed pre-pandemic levels, more flights mean more recorded anomalies, even as the rate of serious accidents continues to trend downward. Near misses and surface incidents that once might have passed with little notice now spread rapidly through social media feeds, amplifying public concern.
At the same time, transparency around close calls has increased, with federal authorities publishing more data and independent aviation analysts dissecting radar tracks and radio calls in near real time. That scrutiny can be uncomfortable for airlines and regulators, but safety advocates argue that it serves a valuable purpose, helping to identify weak points before they contribute to a catastrophic outcome.
What Comes Next for SFO and United
In the wake of the May parallel departure incident, both the FAA and United Airlines are under pressure to demonstrate that lessons will be learned and applied. For the agency, that may mean reviewing departure procedures at San Francisco and other airports with closely spaced parallel runways, clarifying phraseology, and reinforcing expectations around heading compliance in mixed traffic environments.
For United, the investigation arrives at a moment when the airline is staking much of its long-haul strategy on San Francisco’s role as a Pacific gateway. As it prepares to add more destinations and increase aircraft movements, the carrier must reassure both regulators and customers that the ramp-up in capacity is being matched by investments in training, safety management systems, and operational discipline.
Travelers passing through SFO in the coming months are unlikely to notice visible changes on the concourses or from their window seats as a direct result of the investigation. Parallel departures will continue when weather and traffic patterns allow, and the sight of two jets lifting off in near unison will remain part of the airport’s daily rhythm. Behind the scenes, however, the near-simultaneous takeoff that almost went wrong has already joined a growing list of close calls driving a deeper reassessment of how tightly U.S. airports can be run while still leaving room for human error.