San Francisco, CA, USA
N986SW
BOMBARDIER INC CL 600 2B19
UNK
BOEING 737
The runway incursion occurred when a CRJ inadvertently turned onto a highspeed exit taxiway and entered a runway after a Boeing 737 was cleared for takeoff on the same runway. Air traffic control ground controller issued the pilots of the CRJ taxi instructions to runway 28L from their ramp exit point. The instructions included clearance to cross runway 1 left and runway 1 right. Subsequently, the ground controller issued revised taxi instructions requiring the pilots to taxi on the taxiway closest to but parallel to runway 28L, then make a slight right turn to another taxiway to taxi to the approach end of runway 28L. During the taxi, the captain made a left turn onto a runway 28L highspeed exit and began to cross the runway hold short line, instead of making the slight right turn required to follow their taxi clearance. The captain reported that "something did not feel right" and stopped the airplane as the ground controller commanded the CRJ to stop. Although the captain of the CRJ had taxied at San Francisco International Airport (SFO) "many times" and was familiar with a hotspot in the area he made the mistaken turn, he had no explanation as to why he turned left at that point in the taxi. Recorded data indicated that the B737 passed in front of the CRJ within 188 feet laterally. The pilots of the B737 did not observe the CRJ during the takeoff roll. A review of air traffic control procedures and equipment showed that appropriate procedures were followed and there were no irregularities noted with the equipment. Federal Aviation Administration guidance on taxiway design indicated that complex intersections increase the possibility of pilot error. It offered the "three-node concept" which means that a pilot is presented with no more than three choices at an intersection. The intersection where the incursion began contained five choices: a left turn, a slight left turn, straight, slight right turn, and a right turn. After this incident, SFO placed temporary barricades at this intersection preventing its use before permanently closing the taxiway. Following this event, SkyWest Airlines developed and disseminated, on January 19, 2017, a "Flight Operations Message" to all pilots titled "Surface Movement Safety – Preventing Incursions" discussing the events surrounding this event and what crews should do to be vigilant. Although the area in which this incident occurred may have contributed to the captain’s mistaken turn, it was designated as a hot spot location that required enhanced crew vigilance during wayfinding through this area. Further, there were multiple cues at the intersection before the turn was made that could be used by the pilots to support the wayfinding task. Finally, the taxiway in which the captain mistakenly turned had signs, marking, and lighting to indicate both the identification of the taxiway and the identification of and presence of a runway and the fact it was active. These cues were not heeded by either pilot before the airplane entered the runway.
On December 14, 2016, about 1743 Pacific standard time, a runway incursion occurred at San Francisco International Airport (SFO), San Francisco, California, when SkyWest Airlines flight 5086, a CL-600-2B19, crossed the runway hold short line to runway 28L at the taxiway Juliet (J) intersection while another air carrier flight, a B737, was on takeoff roll. There were no injuries reported to the crew or passengers of either flight. The SkyWest flight was operating under the provisions of Title 14 Code of Federal Regulations Part 121 from SFO to Ontario International Airport (ONT), Ontario, California. Night visual meteorological conditions (VMC) prevailed at the time of the incident. According to the pilots, the incident flight was an Initial Operating Experience (IOE) flight for the first officer. Prior to pushback, the captain, who was going to be the pilot flying (PF) for the incident flight, provided the first officer (FO) with a briefing which included using the SkyWest acronym WANT. The briefing consisted of the takeoff briefing, the potential taxi route, discussion of hot spots located on the airport, weather, and NOTAMs. After pushback the ground controller provided the crew with taxi instructions to taxi via "Alpha, Foxtrot, cross 1 left, 1 right to 28 left." During the taxi, while on "Alpha" the controller modified their instructions and issued the crew instructions to taxi via "Alpha, Delta, Bravo, Foxtrot to 28L." The crew briefed the modified clearance to each other and proceeded to taxi via the new instructions. While the flight was taxiing on "Bravo" the first officer announced to the captain that they were approaching taxiway "Foxtrot." The captain, who had taxied via the modified route "many times" had briefed that the taxi would be a "slight right turn" to taxi on "Foxtrot;" however, he erroneously made a slight left turn onto taxiway "Juliet." The captain estimated that he went about 5 feet over the runway hold short line and stopped the airplane, because "something did not feel right." He then observed a white light off of the right side of the airplane. Subsequently he heard the controller over the ground frequency saying "stop." After the departing airplane was airborne, the ground controller subsequently gave the crew modified taxi instructions to taxi to runway 28L, which they followed and subsequently departed for their destination airport. According to a statement from a representative of the operator for the departing aircraft. Neither flight crewmember observed the airplane crossing the runway hold short line while they were on the departure roll. FLIGHT CREW INFORMATION The incident flight crew consisted of a line check airman captain and a first officer. The captain was 47 years old and held an Airline Transport Pilot (ATP) certificate with a rating for airplane multiengine land and a type rating on the CL-65. Additionally, he held a commercial pilot certificate for airplane single-engine land. He also held an FAA first-class medical certificate dated November 10, 2016, with a restriction of "must wear corrective lenses for near and distant vision." The captain reported he was wearing his glasses at the time of the incident. At the time of the incident he was based at Los Angeles International Airport (LAX), Los Angeles, California, an assistant chief pilot at the LAX base, and a line check airman. According to the captain's interview summary, he had been employed at SkyWest Airlines for about 17 years, based out of LAX for the preceding 9 years, an assistant chief pilot for the previous 5 years, and had been a check airman for 3 years and 4 months. He stated that he had operated many flights into and out of SFO, while based at LAX. He also estimated, approximately 10 percent of his line check airman operated flights were into and out of SFO. The FO was 27 years old and held an ATP certificate with a type rating on the CL-65. He also had commercial pilot privileges for airplane single-engine land. He held an FAA first-class medical certificate dated May 16, 2016, with a limitation of "must wear corrective lenses," which he reported he was wearing at the time of the incident. At the time of the incident he was based at Fresno Yosemite International Airport (FAT), Fresno, California. METEROLOGICAL INFORMATION The aviation routine weather report (METAR) for SFO originated from an Automated Surface Observing System (ASOS). The METAR issued prior to the incident stated: Special Weather Report for San Francisco International Airport on the 15th at 0130Z; wind was from 170 degrees at 9 knots; visibility 10 statute miles; few clouds at 2,100 feet agl, ceiling broken at 2,700 feet agl, overcast at 4,600 feet agl; temperature 14°C; dew point 12°C; altimeter 29.99 inches of mercury; Remarks: automated station with precipitation discriminator, rain ended at 6 minutes past the hour; hourly precipitation amount of 0.0 inches, temperature 14.4°C, dew point 12.2°C, visibility at secondary location not available. According to the United States Naval Observatory, Astronomical Applications Department website, official sunset was at 1652 and the end of civil twilight was at 1721 official moonrise was at 1809. The moon was a waning gibbous with 99% of the moon's visible disk illuminated. AIR TRAFFIC CONTROL INFORMATION For detailed information about ATC transmissions with the incident flight, ATC equipment available, and ATC procedures, reference the ATC Specialist Report in the docket for this event. Radar data recorded that the B737 passed approximately 188 feet laterally in front of the CRJ. ADDITIONAL INFORMATION Runway Incursion Hot Spot According to the FAA's website, a runway safety hot spot was defined as "a location on an airport movement area with a history of potential risks of collision or runway incursion, and where heightened attention by pilots and drivers is necessary. By identifying hot spots, it is easier for users of an airport to plan the safest possible path of movement in and around that airport. Planning is a crucial safety activity for airport users — both pilots and air traffic controllers alike. By making sure that aircraft surface movements are planned and properly coordinated with air traffic control, pilots add another layer of safety to their flight preparations. Proper planning helps avoid confusion by eliminating last-minute questions and building familiarity with known problem areas." The FAA's website also provided links to hot spot description based on 9 different geographical areas. The link for the "Southwest U.S." brought up pages 493-500 of the FAA Chart Supplement. The introductory paragraphs contained the following definition: An "Airport surface hot spot" is a location on an aerodrome movement area with a history or potential risk of collision or runway incursion, and where heightened attention by pilots/drivers is necessary. A "hot spot" is a runway safety related problem area on an airport that presents increased risk during surface operations. Typically it is a complex or confusing taxiway/taxiway or taxiway/runway intersection. The area of increased risk has either a history of or potential for runway incursions or surface incidents, due to a variety of causes, such as but not limited to: airport layout, traffic flow, airport marking, signage and lighting, situational awareness, and training. Hot spots are depicted on airport diagrams as open circles or polygons designated as "HS 1", "HS 2", etc. and tabulated in the list below with a brief description of each hot spot. Hot spots will remain charted on airport diagrams until such time the increased risk has been reduced or eliminated. SFO had three charted hot spots on the airport diagram and were designated "HS 1," "HS 2," and "HS 3." The airport diagram page included an inset diagram of HS 1 that was enlarged to see detail. The three charted hot spots on the SFO airport diagram page also included textual description. HS 1 included the area where the incursion occurred. The textual description stated: Pilots instructed to follow Twy B south sometimes continue onto Twy J or Twy F by mistake. Figure 1: HS 1 Inset on Jeppesen 10-9 Airport Diagram. SkyWest Airlines Procedures Departure WANT Briefing The SkyWest Airlines CRJ SOPM contained the following guidance in regard to the departure briefing: Weather – • ATIS/ASOS, etc. • Takeoff minimums/alternate requirements • Low visibility taxi/takeoff procedures • Windshear/gusty wind considerations and limitations • Cold weather operations (deice/anti-ice) Airport/Area Departure – • Runway of departure (e.g., runway length, surface condition, special considerations, etc.) • Expected taxi route • SID/ODP/RNAV DPs • Terrain considerations • Navigation radio management • Automation (level of automation to be used during departure and climb) *Rejected takeoff plan. This must include reasons for rejecting the takeoff and crew duties. The captain calls and accomplishes the rejected takeoff for any warning message or engine failure prior to V1. • Engine failure after V1 procedures (standard/simple/complex) NOTAMs – • ATIS Advisories • Flight release messages and remarks Threats – • Discuss highest threat (e.g., complex taxi procedures, MEL/CDL limitation, terrain) Runway Status Lights According to the SkyWest Airlines Managing Director of Safety, Runway Status Lights (RWSL) training was conducted in AQP Continuing Qualification (CQ) Bulletin Training. It was covered in 2005 and 2011. At the time of the incident, SkyWest, expected pilots "to understand RWSL as a part of their basic airmen prerequisite knowledge." The captain received this SkyWest training. RELEVANT SYSTEMS RWSL The FAA website stated the following, in part: "Runway Status Lights is an essential FAA system which uses Airport Surface Surveillance data to determine vehicle and aircraft locations. Runway Status Lights processes this data using complex software algorithms with adjustable parameters to control airfield lights in accordance with Air Traffic operations, including anticipated separation. Red airfield lights (Runway Entrance Lights and Takeoff Hold Lights) illuminate and extinguish as vehicles and aircraft traverse the airfield. System • Runway Status Lights integrates airport lighting equipment with approach and surface surveillance systems to provide a visual signal to pilots and vehicle operators indicating that is unsafe to enter/cross or begin takeoff on runway. The system is fully automated based on inputs from surface and terminal surveillance systems. Airport surveillance sensor inputs are processed through light control logic that commands in-pavement lights to illuminate red when there is traffic on or approaching the runway. • Runway Entrance Lights (RELs) provide signal to aircraft crossing entering runway from intersecting taxiway • Takeoff Hold Lights (THLs) provide signal to aircraft in position for takeoff" RELs The FAA website stated the following, in part: Runway Entrance Lights are a string of lights located around the center of taxiways/runway crossings and illuminate red when there is high-speed traffic on or approaching the runway to signal that it is unsafe to enter the runway. Taxiway J was not equipped nor was it required to be equipped with RELs since it was a high-speed taxiway and was designed for use to exit the runway only. However, taxiway J did have a “Do Not Enter” sign located to the right of the taxiway facing away from the runway as intended, in addition to painted red boxed markings with white numbers at the runway hold short line indicating the runway that the taxiway was intersecting. FAA Guidance Advisory Circular 150/5300-13A Defined a high-speed exit taxiway as "An acute-angled exit taxiway forming a 30 degree angle with the runway centerline, deigned to allow an aircraft to exit a runway without having to Decelerate to typical taxi speed." In addition, Chapter 4 "Taxiway and Taxilane Design" of the advisory circular provided, in part, the following about "Design Method:" Three-Node Concept. Good airport design practices keep taxiway intersections simple by reducing the number of taxiways intersecting at a single location and allows for proper placement of airfield markings, signage and lighting. Complex intersections increase the possibility of pilot error. The "three-node concept" means that a pilot is presented with no more than three choices at an intersection – ideally, left, right and straight ahead. The advisory circular further provided a graphical figure of "taxiway designs that are not recommended." This figure depicted four illustrations of various taxiways such as "high-speed exit and wide throated runway entrances, extra-wide throated taxiway leading from the apron directly to parallel taxiway and runways, taxiway intersection exceeds '3-node' concept, and taxiway intersecting multiple runways." Figure 2: Taxiway Intersections Not Recommended (Source: AC 150/5300-13A) High Speed Exit Taxiways FAA provided media video on "High Speed Exit Taxiways" which was published August 13, 2015. The video was 7:41 in length and provided graphical discussions of high speed taxiways. During the video presentation the narrator stated in part "High speed exit taxiways are for one way traffic. They are not runway entrances or crossings. All high speed exit taxiways form an angle of 30 degrees with the runway centerline, and the radius of the turn off the runway is always 1500 feet."
The captain’s inadvertent turn onto the incorrect taxiway and subsequent entry onto an active runway without a clearance, which resulted in the runway incursion.
Source: NTSB Aviation Accident Database
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