The NTSB adopted seven recommendations today in the wake of the Air Canada Flight 759 incident, in which an A320 jet nearly landed on a taxiway occupied by four fully loaded passenger jets (figure 1). At their Board Meeting today, which was live streamed as a webcast, the board heard a presentation by NTSB staff that included nineteen findings from the incident, seven recommendations, and the final probable cause of the incident. All of the material here comes from my recording and transcription of the board meeting.
Figure 1. NTSB illustration view from of Air Canada 759
I agree. I was the first to do the math from the preliminary data, in which I concluded that the Air Canada jet was “about 11 seconds from impact” with the jets below. As more detailed radar data became available later, it became clear that the aircraft was even closer. In today’s meeting, NTSB staff estimate the planes came as close as “10 to 20 feet vertically.”
The NTSB determined the probable cause of this incident was “The Flight Crew’s misidentification of taxiway Charlie as the intended landing runway, which resulted from the crew members’ lack of awareness of the parallel runway closure, due to their ineffective review of Notice To Airmen, that is NOTAM, information before the flight and during the approach briefing.
Contributing to the incident were:
(1) The flight crew failure to tune the Instrument Landing System (ILS) frequency for backup lateral guidance, expectation bias, fatigue due to circadian disruption and length of continued wakefulness, and breakdowns in crew resource management, and
(2) Air Canada’s ineffective presentation of approach procedure and NOTAM information."
NTSB staff noted that the Air Canada crew did not recall reading in the ten pages of NOTAMs for their flight that runway 28L was closed as they arrived at San Francisco. Staff noted that “**NEW**” preceded the runway closure NOTAM. Yellow highlights were added by staff to the San Francisco runway closure NOTAM (figure 2), shown in their presentation. Since they were unaware of the runway 28L closure, the crew had an expectation bias that they were properly lined up for the correct runway.
Figure 2. Yellow highlighting of NOTAM added by NTSB.
NOTAMs were a frequent target of board members, who said that the “NOTAM system was really messed up,” and that NOTAMs were written in a way that “only a software programmer would understand.” One estimate was made that it would have taken the flight crew 20 minutes to thoroughly read and understand all of the NOTAMs issued for Flight 759.
Staff also noted that the crew flew the Quiet Bridge Visual approach, which includes near the end of its two-page description a requirement to tune an ILS frequency into their flight management system to provide backup guidance to the runway. The crew failed to tune in the ILS frequency, which would have showed them that they were not properly lined up for runway 28R. Staff did note that Air Canada Airbus A320 automatically autotunes frequencies for all other approach into San Francisco, but not for the Quiet Bridge approach.
Crew fatigue may have been a factor. The flight crew was a “reserve crew,“ which stands by so that it can be called on short notice to fly a plane that suddenly require a new crew. The captain had been awake for 19 hours at the time of the incident. The flight originated in Toronto, where it was 3 AM, when the incident occurred.
Surprisingly, the crew stated afterwards that they were unaware that they’d overflown four aircraft on the taxiway, and that they estimated they started their go around at 400 feet, while data shows that it was initiated at 89 feet above the ground. After the go around was initiated, the airplane descended to a minimum altitude of 60 feet before beginning to climb. Staff estimated that Flight 759 was approximately 10-20 feet above the tails of the aircraft on the taxiways.
Overall, the NTSB had 19 findings from the incident.
(1) None of the following were factors in this incident: (1) flight crew qualifications, which were in accordance with Canadian and US regulations; (2) flight crew medical conditions;(3) airplane mechanical conditions; and (4) airport lighting, which met US regulations.
(2) The first officer did not comply with Air Canada’s procedures to tune the instrument landing system (ILS) frequency for the visual approach, and the captain did not comply with company procedures to verify the ILS frequency and identifier for the approach, so the crew members could not take advantage of the ILS’ lateral guidance capability to help ensure proper surface alignment.
(3) The flight crew’s failure to manually tune the instrument landing system (ILS) frequency for the approach occurred because (1) the Flight Management System Bridge visual approach was the only approach in Air Canada’s Airbus A320 database that required manual tuning of a navigation frequency, so the manual tuning of the ILS frequency was not a usual procedure for the crew, and (2) the instruction on the approach chart to manually tune the ILS frequency was not conspicuous during the crew’s review of the chart.
(4) The first officer’s focus on tasks inside the cockpit after the airplane passed the final waypoint reduced his opportunity to effectively monitor the approach and recognize that the airplane was not aligned with the intended landing runway.
(5) The flight crew-initiated, low-altitude go-around over the taxiway prevented a collision between the Air Canada airplane and one or more airplanes on the taxiway.
(6) The controller responded appropriately once he became aware of the potential conflict.
(7) Errors that the flight crew members made, including their false assumption that runway 28L was open, inadequate preparations for the approach, and delayed recognition that the airplane was not lined up with runway 28R, reflected breakdowns in crew resource management and led to minimal safety margins as the airplane overflew taxiway Charlie.
(8) The flight crew members' lack of awareness about the runway 28L closure and the crew members' previous experience of seeing two parallel runways at San Francisco International Airport, led to their expectation to identify two runway surfaces during the approach and resulted in their incorrect identification of taxiway Charlie, instead of runway 28R as the intended landing runway.
(9) Although the Notice to Airmen about the runway 28L closure appeared in the flight release, and in the Aircraft Communication Addressing and Reporting System [ACARS] message that were provided to the flight crew, the presentation of the information did not effectively convey the importance of the runway closure information and promote flight crew review and retention.
(10) The cues available to the flight crew members to indicate that the airplane was aligned with the taxiway were not sufficient to overcome their belief as a result of expectation bias that the taxiway was the intended landing runway.
(11) Multiple salient cues of the surface misalignment were present as the airplane approached the airport seawall and one or more of these cues likely triggered the captain's initiation of a go around, which reportedly occurred simultaneously with the first officer's call for a go around.
(12) The captain and the first officer were fatigued during the incident flight due to the number of hours that they had been continuously awake, and circadian disruption, which likely contributed to crew members' misidentification of the intended landing surface, their ongoing expectation bias, and the delayed decision to go around.
(13) Current Canadian regulations do not in some circumstances allow for sufficient rest for reserve pilots, which can result in these pilots flying in a fatigued state during their window of circadian low.
(14) Flight safety would be enhanced if airplanes landing at primary airports within Class B and Class C airspace were equipped with a cockpit system that provided flight crews with positional awareness information that is independent of and dissimilar from the current instrument landing system backup capabilities for navigating to a runway.
(15) Although the investigation into this incident identified significant safety issues, cockpit voice recorder information, had it been available, could have provided direct evidence regarding the flight crew's approach preparation, cockpit coordination, perception of the airport environment, and decision-making.
(16) Once the flight crew members perceived lights on the runway, they decided to contact the controllers to ask about the lights. However, their query was delayed because of congestion on the tower frequency, which reduced the time available for the crew members to reconcile their confusion about the lights with the controller’s confirmation that the runway was clear.
(17) Although the use of line up and wait procedures during single person air traffic control operation was not a factor in this incident, the tower controllers should have delayed consolidating local and nonlocal control positions until line up and wait procedures were no longer needed.
(18) If an airplane were to align with a taxiway, an automated airport service detection alert would assist controllers in identifying and preventing a potential taxiway landing, as well as a potential collision with aircraft, vehicles, or objects that are positioned along taxiways.
(19) Increased conspicuity of runway closure markers, especially those used in parallel runway configurations, could help prevent runway misidentification by flight crews following an approach to an airport.
As a result of their investigation, the NTSB made seven new recommendations, six for the FAA, and one for Transport Canada.
(1) 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 autotuning capability within an air carrier's fleet. Two, Identify those approaches that require an unusual or abnormal manual frequency input, and, three either develop an autotune solution or ensure that the manual tune entry has sufficient salience on approach charts.
(2) Establish a group of human factors experts to review existing methods for presenting flight operation information to pilots, including flight releases and general aviation flight planning services, that is preflight, and aircraft communications addressing and reporting system messages and other in-flight information, create and publish guidance on best practices to organize, prioritize, and present this information in a manner that optimizes pilot review and retention of relevant information, and work with air carriers and service providers to implement solutions that are aligned with the guidance.
(3) Establish requirements for airplanes landing at primary airports with Class B and Class C airspace to be equipped with a system that alerts pilots when an airplane does not align with a runway surface.
(4) Collaborate with manufactures 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.
(5) Modify Airport Surface Detection Equipment, or ASDE systems, such as 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.
(6) 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.
One recommendation to Transport Canada.
(7) Revise current regulations to address the potential for fatigue for pilots on reserve duty who are called to operate evening flights that would extend into the pilot's window of circadian low.
As I often say, anytime something doesn’t look right, a pilot should initiate an immediate go around. In this case, fatigue and a failure to follow procedures may have delayed this crew from initiating a go around until it was almost too late.