On the evening of July 7, 2017, at the conclusion of the regularly scheduled international passenger flight from Toronto to San Francisco, Air Canada Flight 759 nearly landed on a taxiway which already had four fully loaded and fueled airplanes holding short for takeoff. A retired pilot stated the runway confusion that almost happened "probably came close to the greatest aviation disaster in history" as five airplanes and over 1,000 passengers were at imminent risk. A major FAA/NTSB investigation has been launched in the wake of the incident.
Video Air Canada Flight 759
Incident
At 11:46 p.m. local time, Air Canada Flight 759, carrying 135 passengers and 5 crew members, was cleared to land at SFO at Runway 28R. The adjacent Runway 28L had been closed at 10 p.m. local time and its lights were off, except for a 20.5-foot (6.2 m)-wide lighted flashing "X" at the eastern runway threshold. The captain was flying AC759 and the first officer was monitoring. Initial speculation was the AC759 pilot assumed 28R was 28L and therefore lined up for landing on the parallel taxiway C, which was confirmed in post-event interviews with the captain and first officer. However, runways and taxiways are lit with different colors and intensities, and it was not clear whether radio alignment signals were operating at the time. Preliminary post-event investigation results noted that Runway 28R and Taxiway C were lit on default settings (in different colors), and the automatic terminal information service broadcast information was current and advised that 28L was closed and unlit. According to preliminary Transportation Board investigation results, as the weather was clear, the pilot of AC759 was not required to activate the instrument landing system and relied instead on a visual approach, as typical for the prevailing conditions.
Taxiway C already contained four airplanes, three from United Airlines and one from Philippine Airlines, queueing for takeoff. At 11:55:46 p.m. local time, upon spotting aircraft lights approximately 0.7 miles (1.1 km) from the runway, the AC759 pilot asked the tower if he was clear to land on 28R, to which the air traffic controller responded at 11:55:56 p.m., "There's no one on 28R but you," when AC759 was approximately 0.3 miles (0.48 km) from the runway threshold. The AC759 pilots "did not recall seeing aircraft on Taxiway C, but something did not look right to them" according to a post-incident interview summary. The crew of Philippine Airlines Flight 115 turned on their landing lights to alert AC759 they were lined up on the taxiway. The pilot of United Airlines Flight 1 (UA001), first in line for takeoff, interrupted the radio traffic at 11:56:01 p.m. and asked "Where is this guy going? He's on the taxiway." The air traffic controller then ordered AC759 to abort the landing at 11:56:10 p.m. After AC759 acknowledged the go-around, the air traffic controller stated, "It looks like you were lined up for Charlie [Taxiway C] there." AC759 had already started to climb before the go-around order.
Afterwards, the pilot of UA001 radioed the tower saying "Air Canada flew directly over us" and the air traffic controller responded "Yeah, I saw that guys." During the first approach, AC759 flew for 1/4 mile (0.40 km) over Taxiway C, descended to an altitude as low as 81 feet (25 m) and approached as close as 29 feet (8.8 m) laterally to the four planes waiting on Taxiway C before being ordered to abort the landing. According to the flight data recorder, the pilots advanced the thrust levers when AC759 was 85 feet (26 m) above the ground and the minimum altitude was 59 feet (18 m), approximately 2.5 seconds after the thrust levers had been advanced. Following a reconstruction of events, one pilot not involved in the incident noted that had AC759 waited five more seconds before pulling up, it would have collided with the third plane (UAL 863) on the taxiway.
SFO was the first airport in the United States to install an Airport Surface Surveillance Capability (ASSC) system, which should have alerted the tower of a potential conflict between runway and taxiway movements. AC759 disappeared from the local controller's ASSC display for twelve seconds, between 11:55:52 and 11:56:04 p.m. local time (from shortly after the AC759 pilot asked for confirmation that 28R was clear, to the time the UA001 pilot noted that AC759 was lined up for Taxiway C), as AC759 was too far off-course from 28R.
AC759 completed its go-around and landed without incident after the second approach. A single air traffic controller was monitoring ground and tower frequencies, which would typically be handled by two controllers.
Maps Air Canada Flight 759
Aircraft
The aircraft flying AC759 that night was C-FKCK, an Airbus A320-200. The aircraft was 24.5 years old on the day of the incident, first flying in December 1992.
Investigation
The incident was not considered reportable under current federal regulations, but former NTSB chairman Jim Hall called it "the most significant near-miss we've had in this decade" and urged the NTSB to re-evaluate those reporting requirements. The United States National Transportation Safety Board (NTSB) was informed of the incident on July 9, and took the lead on the investigation, with assistance from the Federal Aviation Administration (FAA). The Transportation Safety Board of Canada (TSB) served as a facilitator to convey information between Air Canada and the NTSB. TSB released preliminary information from Occurrence No. A17F0159 on July 11, 2017. NTSB assigned identification number DCA17IA148 to the incident.
A retired pilot stated that SFO requires "precision flying" as the two runways (28R and 28L) are laterally separated by 750 feet (230 m), and Taxiway C is separated from 28R by less than 500 feet (150 m). Other pilots pointed out that some airlines require all aircraft to use the instrument landing system (ILS) regardless of weather or visibility, which could have alerted the cockpit that the aircraft was lined up with the taxiway. Dave Jones, California Insurance Commissioner and a passenger on AC759, wrote a letter to Air Canada a week after the incident requesting their cooperation with the investigation.
Final investigation results are still pending. Preliminary NTSB investigation results from flight data recorder telemetry, released on August 2, 2017, indicate that AC759 reached a minimum altitude of 59 feet (18 m) above ground level, comparable to the 55 ft 10 in (17.02 m) tail height of a Boeing 787-9, two of which were on Taxiway C. The cockpit voice recorder had been overwritten before the investigation was launched, as C-FKCK flew three more flights on July 8 before the NTSB was informed of the near-miss on July 9.
Final stages
In a 25 September 2018 board meeting, the NTSB cited as probable cause the pilots misunderstanding the taxiway for runway 28R as they overlooked the 28L closure buried in the NOTAM, and as contributing factors: not taking advantage of the ILS, which was not tuned, in the FMS visual approach; and pilot fatigue. The crew's body clock was at the Toronto 03:00 Eastern Time: the first officer had no significant rest for 12h, and the captain for 19h - he could not fly under US pilot fatigue rules. Transport Canada plans to bring its pilot rest rules in line with international standards later in 2018.
The FAA received six recommendations: identifying approaches requiring an unusual manual frequency input; displaying it noticeably on charts; reviewing NOTAMs to prioritise and present relevant information; requiring airspace class B/C aircraft to alerts pilots when not aligned with a runway; modifying airports to alert on collision risks; clearly showing closed runways, as construction lighting on 28L looked like ramp lighting.
Air Canada is simplifying its SFO approach charts and includes SFO-specific training in aircraft simulators, trains its staff to reduce expectation bias, and will retrofit new aircraft like the Airbus A220 and Boeing 737 Max with dual heads-up displays to enhance situational awareness in low-visibility, high-risk approaches.
Aftermath
Following the incident, in early August the Federal Aviation Administration modified nighttime landing procedures at SFO, forbidding visual approaches at night "when an adjacent parallel runway is closed" and replacing them with instrument approaches, either ILS or satellite-based, and requiring two air traffic controllers in the control tower "until the late-night arrival rush is over".
See also
- Continental Airlines Flight 1883 - a similar incident that involved an aircraft landing on a taxiway
- China Eastern Airlines Flight 5106 near collision upon takeoff after ignoring control tower.
- LAX runway collision: USAir Flight 1493 & SkyWest Flight 5569
- Accidents and incidents involving the Airbus A320 family
References
External links
- "SFO ATC audio recording". Live ATC. July 7, 2017. Archived from the original on July 18, 2017. Retrieved July 18, 2017.
- "Near Midair Collision on approach to San Francisco International Airport". Accident Investigations, DCA17IA148. National Transportation Safety Board. July 2017. Retrieved July 20, 2017.
- Aviation Herald Report
- "May 2, 2018: San Francisco International Airport Terminal 2 security camera video of the July 7, 2017, Air Canada taxiway overflight", NTSB, YouTube, May 2, 2018
Source of article : Wikipedia
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