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

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On 7 July 2017, an Air Canada Airbus A320 crew unintentionally made and almost completed a night visual final approach to the taxiway parallel to the runway on which they had been cleared to land at San Francisco. Despite seeing lights ahead on what they presumed was the runway, they continued the approach descending over the taxiway and overhead two aircraft on it which were awaiting full length departures before commencing a go around at approximately 85 feet agl and reaching a minimum height of 59 feet agl before beginning to climb away. The NTSB is conducting an Investigation.
Event Details
When July 2017
Actual or Potential
Event Type
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 Standing
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 Standing
Location - Airport
Airport San Francisco International Airport
Tag(s) CVR overwritten,
Visual Approach
Tag(s) Inappropriate crew response - skills deficiency,
Ineffective Monitoring,
Ineffective Monitoring - PIC as PF
Tag(s) Accepted ATC Clearance not followed,
Visual Response to Conflict
Damage or injury No
Causal Factor Group(s)
Group(s) Aircraft Operation
Investigation Type
Type Independent


On 7 July 2017, the crew of an Airbus A320 (C-FKUK) being operated by Air Canada on a scheduled international passenger flight from Toronto to San Francisco as ACA 759 with 140 persons on board made the night VMC final approach to their assigned landing runway at San Francisco aligned with the parallel taxiway. Several other aircraft including a Boeing 787-9 and an Airbus A340-300 were waiting on this taxiway for departure from the same runway that the A320 was supposed to be landing on. The approach was only discontinued at a very late stage after the aircraft had made a close overflight of the first two aircraft on the taxiway. The subsequent approach to the same runway was correctly flown to an uneventful landing.


An Investigation into the accident has been opened by the NTSB. The CVR was overwritten and therefore not of use but the Canadian TSB obtained the FDR data from the aircraft and provided it to the NTSB. Copies of recorded ATC radar and voice data and relevant Airport Authority Security Camera recordings have also been obtained. A preliminary review of all the recorded data has been completed and the crew members and controllers involved have all been interviewed.

It was found that the Air Canada Captain, who had been PF for the flight involved, had accumulated in excess of 20,000 total flying hours of which "about" 4,797 hours were on type. The First Officer had accumulated about 10,000 total flying hours of which in excess of 2,300 hours were on type. No evidence was found of any relevant ATC equipment discrepancies and it has been confirmed that as per normal controller staffing for the shift, two controllers were on duty in Local (Runway) Control of whom one was in position in the TWR cabin at the time of the event and covering all TWR cabin positions including GND and Clearance Delivery.

It was noted that at the time of the occurrence, "runway 28L was closed to accommodate construction; its approach and runway lights were turned off, and a 20.5-ft-wide lighted flashing X (runway closure marker) was placed at the threshold". This work was part of a project that started several months earlier and had been the subject of a NOTAM. The ATIS message also included the fact that runway 28L was closed and that its approach lighting system not in service. The runway and approach lighting for 28R was working normally at default settings and included centreline lighting. Taxiway 'C' lighting was also working normally at default settings and included green centreline lighting along its full length and on the links between the taxiway and runway 28R. Four aircraft were waiting in turn well spaced out on Taxiway 'C' for runway 28R departures. First was a United Airlines 787 which was being followed by a Philippine Airlines A340, another United Airlines 787 and a United Airlines 737.

It was established that the Northern California TRACON controller had cleared the ACA759 for the FMS Bridge Visual approach to runway 28R and the TWR controller subsequently gave landing clearance for that runway. FDR data indicated that for the final 3 nm of this approach, the aircraft was aligned with the taxiway rather than the runway. When it was passing about 300 feet agl and about 0.7 mile from the runway 28R threshold, the crew called TWR and stated that they had "seen lights on the runway" and requested confirmation of their landing clearance which was given. During this exchange, the aircraft deviated sufficiently far to the right of the runway 28R extended centreline to cause it to disappear from the TWR controllers ASDE-X/ASSC display for about 12 seconds before reappearing on it as it passed over the first aircraft on the taxiway.

A few seconds after the landing clearance had been reconfirmed, the crew of the first aircraft in the departure queue on taxiway 'C', the United Airlines Boeing 787-9 operating as UAL1 to Singapore who had become concerned at the apparent flight path of the approaching aircraft, transmitted "where's this guy going" followed by "he's on the taxiway" and the crew of the second aircraft in the queue, a Philippine Airlines Airbus A340-300 operating as PAL 115 to Manila, switched on their landing lights.

FDR data showed that having continued to descend over the taxiway itself maintaining its centreline, ACA 759 was approaching taxiway 'W', the first link taxiway between taxiway 'C' and the runway and was at about 85 feet agl when the crew advanced the thrust levers to begin a go around and about 2½ seconds later reached its minimum recorded altitude of 59 feet agl. With the aircraft already climbing away, the TWR controller instructed it to go around.

The following four composite illustrations have been released by the Investigation and show the sequence of events described:

The positions of the aircraft on Taxiway 'C' - the top diagram is based on radar track data and the bottom picture is taken from the San Francisco airport security video. [Reproduced from the 2 August 2017 NTSB Investigative Update]
UAL1’s initial transmission about ACA759 as it approaches the taxiway. [Reproduced from the 2 August 2017 NTSB Investigative Update]
ACA759 overflying UAL 1 - note that the second aircraft has turned on its landing lights. [Reproduced from the 2 August 2017 NTSB Investigative Update]
The position of ACA759 as it climbs away after its close over-flight of both the 787 and the A340 on the taxiway and ATC belatedly instruct it to "go around". [Reproduced from the 2 August 2017 NTSB Investigative Update]

It was noted that during interviews, "both incident pilots stated that […] they believed the lighted runway on their left was 28L and that they were lined up for 28R [and] they also stated that they did not recall seeing aircraft on taxiway 'C. but that something did not look right to them".

The NTSB 'Investigative Update' on which this summary is based was issued on 2 August 2017.

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