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A320 / B789 / A343, San Francisco CA USA, 2017

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On 7 July 2017 the crew of an Airbus A320, cleared for an approach and landing on runway 28R at San Francisco in night VMC, lined up for the visual approach for which it had been cleared on the occupied parallel taxiway instead of the runway extended centreline and only commenced a go-around at the very last minute, having descended to about 60 feet agl whilst flying over two of the four aircraft on the taxiway. The Investigation determined that the sole direct cause of the event was the poor performance of the A320 flight crew.
Event Details
When July 2017
Actual or Potential
Event Type
Human Factors, Loss of Separation, Runway Incursion
Day/Night Night
Flight Conditions VMC
Flight Details
Aircraft AIRBUS A-320
Operator Air Canada
Domicile Canada
Type of Flight Public Transport (Passenger)
Origin Toronto/Lester B. Pearson International Airport
Intended Destination San Francisco International Airport
Take off Commenced Yes
Flight Airborne Yes
Flight Completed Yes
Flight Phase Missed Approach
Flight Details
Aircraft BOEING 787-9 Dreamliner
Operator United Airlines
Domicile United States
Type of Flight Public Transport (Passenger)
Origin San Francisco International Airport
Intended Destination Singapore Changi Airport
Take off Commenced No
Flight Phase Taxi
Flight Details
Aircraft AIRBUS A-340-300
Operator Philippine Airlines
Domicile Philippines
Type of Flight Public Transport (Passenger)
Origin San Francisco International Airport
Intended Destination Manila/Ninoy Aquino International Airport
Take off Commenced No
Flight Phase Taxi
Location - Airport
Airport San Francisco International Airport
Tag(s) Aircraft-aircraft near miss,
CVR overwritten,
Visual Approach
Tag(s) Fatigue,
Inappropriate crew response - skills deficiency,
Ineffective Monitoring,
Plan Continuation Bias,
Ineffective Monitoring - PIC as PF
Tag(s) Required Separation not maintained,
Lateral Navigation Error,
Near Miss,
VFR Aircraft Involved
Tag(s) Accepted ATC Clearance not followed,
Visual Response to Conflict
Damage or injury No
Causal Factor Group(s)
Group(s) Aircraft Operation
Safety Recommendation(s)
Group(s) Aircraft Operation,
Aircraft Airworthiness,
Airport Management
Investigation Type
Type Independent


On 7 July 2017, an Airbus A320 (C-FKCK) being operated by Air Canada on a scheduled international passenger flight from Toronto to San Francisco as AC759 was cleared to make an approach and land on runway 28R at destination in night VMC but instead lined up with its parallel taxiway on which four aircraft were waiting to depart and descended to about 60 feet agl and overflew two of those aircraft before climbing away. The subsequent positioning to a landing occurred without further event.


An Investigation was carried out by the NTSB. Relevant flight data was available but relevant data on the CVR was not because it had been overwritten. It was noted that the absence of CVR data precluded a meaningful examination of human factors issues which were prominent in the event, especially instances where there had been a clear lack of effective CRM. These had included, for example, “both pilots’ failure to assimilate the runway 28L closure information included in the ATIS information, the First Officer’s failure to manually tune the ILS frequency and the Captain’s failure to verify the tuning of the ILS frequency (and) there was no way of telling whether distraction, workload and/or other factors contributed to these failures”.

It was established that the Captain had been PF for the investigated approach. Four aircraft were waiting in line on taxiway ‘C’ to depart from runway 28R which was being used for both arrivals and departures because runway 28L was closed. The first aircraft on the taxiway, a Boeing 787-9, was overflown at 100 agl but as a subsequent go around was at last initiated, the second aircraft on the taxiway, an Airbus A340-300, was also overflown as the A320 reached a minimum height of about 60 feet agl before beginning to climb away. Two further aircraft, another Boeing 787 and a Boeing 737 were also further back in the taxiway ‘C’ departure line.

It was established that both A320 pilots had recent experience flying into San Francisco at night although probably when both runways were in operation. However, on the night involved, closure of runway 28L had been the subject of a NOTAM which was available to the crew at pre-flight briefing. The First Officer subsequently stated that he “could not recall” seeing this NOTAM and the Captain subsequently stated that, although he had seen it at that time, the fact that he aligned the aircraft with taxiway ‘C’ instead of runway 28R had “demonstrated that he did not recall that information when it was needed”. This was despite the crew receiving ATIS ‘Q’ which included the same information about the runway 28L closure via ACARS. Both pilots "recalled reviewing ATIS information Quebec” but there had not then been any discussion about the implications of its content in respect of the approach they could expect.

In preparation for the approach to runway 28R, the First Officer was supposed to set up the corresponding ILS as back up for the expected visual approach procedure but had not done so and the omission was not detected by the Captain. The Captain stated that, as the aircraft approached the airport, “he thought that he saw runway lights for runway 28L and thus believed that runway 28R was runway 28L and that taxiway C was runway 28R”. At this time, the First Officer was still programming the missed approach and setting the runway heading and did not monitor the approach. The Captain asked the First Officer to contact ATC and “confirm that the runway was clear” at which time the First Officer reported having looked up and “presumed” that the aircraft was aligned with runway 28R. There was some delay in asking for this ATC clarification because of congestion on the TWR frequency. However, after ATC confirmed that runway 28R was clear, the pilots “were unable to reconcile their confusion” about lights that they assumed were on the landing runway with this assurance and neither then recognised that the aircraft was not aligned with the landing runway until it was over the taxiway.

The Investigation noted that “multiple cues were available to the flight crew to distinguish runway 28R from taxiway C (such as the green centreline lights and flashing yellow guard lights on the taxiway)” and that “the cues available to the flight crew to indicate that the airplane was aligned with a taxiway did not overcome the crew’s belief, as a result of expectation bias, that the taxiway was the intended landing runway”.

Given the difficulty of visually distinguishing the approach track alignment being flown by the aircraft from the correct one on the runway extended centreline, it was considered that “the controller responded appropriately once he became aware of the potential conflict”.

It was considered on the basis of the timing of the flight under investigation - at a time when the flight crew would normally have been asleep - and the fact that at the time of the incident, the Captain had been awake for more than 19 hours and the First Officer for more than 12 hours, both the pilots involved could be considered fatigued.

The formal statement of the Findings of the Investigation covered all the matters mentioned above and re-emphasised the significance of the lack of CVR data given that the investigated event was entirely a product of human factors issues relating to the performance of the A320 flight crew involved. The absence of this data had obliged the Investigation to speculate on the reasons for significant elements of this performance, notably their “preparation for the approach, flight deck coordination, perception of the airport environment and decision-making.

Six ‘Safety Issues’ were identified as a result of the Investigation which, in summary, were as follows:

  • The need for consistent FMS auto-tuning capability within any air carrier fleet. The ‘FMS Bridge’ visual approach to runway 28R was the only approach in Air Canada’s Airbus A320 database for which the relevant navigation aid(s) had to be manual set up. It was considered that because manual tuning of the ILS frequency was therefore an unusual procedure for the crew, the development of an auto-tune solution would help preclude such a situation from recurring. It was also noted that although an explicit instruction to manually tune the ILS frequency was on the chart, it was “not conspicuous”.
  • The need for more effective presentation of flight operations information to optimize pilot review and retention of relevant information. Although the NOTAM about the runway 28L closure was readily available at pre-flight briefing and in the ACARS message that the flight crew received, it was considered that the way it was presented had not conveyed the importance of the runway closure information in way that would be conducive to retention.
  • The need for aircraft landing at primary airports within class B/C airspace to be equipped with a system that will alert their pilots the aircraft is not aligned with a runway. A system which provided an alert if it appeared that a landing on a surface other than a runway would provide pilots with additional positional awareness information. It was considered that if such a system had been installed on the incident aircraft it “could have helped the flight crew identify its surface misalignment error earlier” and resulted in the go-around being performed before the aircraft was “dangerously close” to the aircraft on the taxiway.
  • The need for ASDE and airport surface surveillance capability (ASSC) systems to be able to detect potential taxiway landings and provide alerts to ATC. The San Francisco TWR had an ASSC system but it was not designed to predict an imminent collision involving an arriving airplane lined up with a taxiway. It was considered that an automated ASDE alert of such a situation could assist controllers and noted that an FAA demonstration in February 2018 had shown the potential effectiveness of such a system.
  • The need for a more effective way of visually alerting pilots to a runway temporary closure when at least one parallel runway remains in use. It was noted that although a runway closure marker with a lighted flashing white “X” was placed at the approach and departure ends of closed runway 28L, this marker was “not designed to capture the attention of a flight crew on approach to a different runway” and did not do so in the case of the investigated approach. It was considered that increased conspicuity of such markers, especially those used in parallel runway configurations, could help prevent runway misidentification.
  • The need for revisions to Canadian regulations to address the potential for fatigue when pilots on daytime standby duty are then called to operate evening flights that would extend an FDP into their window of circadian low. Although the flight crew roster for the flight duty period involved was in accordance with the applicable Canadian regulations, it would not have been allowable under the equivalent US regulations. It was noted that the Canadian regulations have not been updated since 1996 but that potential revisions which were issued in 2014 and revised and reissued in 2017. No changes to the 1996 regulations has yet occurred but it was noted that “according to Transport Canada, the proposed regulations would better address the challenge of fatigue mitigation for pilots on standby duty who are called to operate evening flights extending into their window of circadian low”.

The Investigation determined that the Probable Cause of the accident was “the flight crew’s misidentification of taxiway ‘C’ as the intended landing runway, which resulted from the crewmembers’ lack of awareness of the parallel runway closure due to their ineffective review of NOTAM information before the flight and during the approach briefing”.

Two Contributory Factors were also identified as follows:

  1. the flight crew’s failure to tune the ILS frequency for backup lateral guidance, expectation bias, fatigue due to circadian disruption and length of continued wakefulness, and breakdowns in CRM and
  2. Air Canada’s ineffective presentation of approach procedure and NOTAM information.

A total of 7 Safety Recommendations were made as a result of the Investigation:

  • that the Federal Aviation Administration work with air carriers conducting operations under Title 14 Code of Federal Regulations Part 121 to:
    • assess all charted visual approaches with a required backup frequency to determine the flight management system auto-tuning capability within an air carrier’s fleet,
    • identify those approaches that require an unusual or abnormal manual frequency input, and
    • either develop an auto-tune solution or ensure that the manual tune entry has sufficient salience on approach charts.
  • that the Federal Aviation Administration establish a group of human factors experts to review existing methods for presenting flight operations information to pilots, including flight releases and general aviation flight planning services (pre-flight) and aircraft communication addressing and reporting system messages and other in-flight information; create and publish guidance on best practices to organise, prioritise, and present this information in a manner that optimises pilot review and retention of relevant information; and work with air carriers and service providers to implement solutions that are aligned with the guidance.
  • that the Federal Aviation Administration establish a requirement for airplanes landing at primary airports within class B and class C airspace to be equipped with a system that alerts pilots when an airplane is not aligned with a runway surface.
  • that the Federal Aviation Administration collaborate with aircraft and avionics manufacturers and software developers to develop the technology for a cockpit system that provides an alert to pilots when an airplane is not aligned with the intended runway surface and, once such technology is available, establish a requirement for the technology to be installed on airplanes landing at primary airports within class B and class C airspace.
  • that the Federal Aviation Administration modify airport surface detection equipment (ASDE) systems (ASDE-3, ASDE-X, and airport surface surveillance capability) at those locations where the system could detect potential taxiway landings and provide alerts to air traffic controllers about potential collision risks.
  • that the Federal Aviation Administration conduct human factors research to determine how to make a closed runway more conspicuous to pilots when at least one parallel runway remains in use, and implement a method to more effectively signal a runway closure to pilots during ground and flight operations at night.
  • that Transport Canada revise current regulations to address the potential for fatigue for pilots on reserve (standby) duty who are called to operate evening flights that would extend into the pilots’ window of circadian low.

The draft Final Report was considered by the NTSB on 25 September 2018. An Abstract of its content on which this summary is based, and which “is subject to further review and editing to reflect changes adopted during the Board meeting”, was issued the same day. Pending the release of the Final Report, some pertinent background information not included in the Abstract is contained in the Investigative Update which was issued by the NTSB on 2 August 2017 after its preliminary assessment of the event.

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