ATC Mistakes Sent 777 Towards California Mountain, NTSB Finds
May 14, 2019 Sean Broderick | Aviation Daily
WASHINGTON—An air traffic controller’s errant instruction to turn left instead of right towards an assigned heading during a rare departure pattern out of Los Angeles International Airport (LAX) led an EVA Air Boeing 777 to within hundreds of feet of a mountain peak topped with large antennas, an NTSB investigation found.
The incident took place Dec. 16, 2016. Weather at the time was overcast with steady rain and visibility of about 1,000 ft. The weather and winds had the airport operating in a rare “east flow” departure configuration starting at about midnight Dec. 15, NTSB said. Prevailing winds usually have LAX operating a west flow, with departures heading directly out over the Pacific Ocean.
The crew of the 777-300ER, Flight 015 (EVA015) headed for Taipei, requested Runway 07 Right for departure, and was granted the request.
After receiving their takeoff clearance at 0117:49 a.m. local time, the pilots lifted off, flying the Ventura Seven Departure standard instrument procedure, and were transferred to Southern California Terminal Radar Approach Control (SCT). Soon after departure, the controller working SCT’s Manhattan sector told EVA015 to climb and maintain 7,000 ft. and fly heading 090 deg. The pilot confirmed the instruction and proceeded.
About one minute later, the controller instructed EVA015 to “turn left heading of 180 [deg.], climb and maintain 7,000 [ft.],” the report said. A pilot confirmed the heading and altitude and requested a high-speed climb, which the controller approved.
The aircraft began a slow turn and was soon headed northwest towards the San Gabriel Mountains north of Los Angeles. About 41 sec. after the turn began, the controller ordered EVA015 to “turn right, right turn heading 180 [deg.].” The pilot read back the instructions and confirmed them.
“Radar data indicated the aircraft stopped the left turn to 180 deg, and slowly began to turn right,” the report said.
At 0122:10, the controller asked EVA015 to “expedite its right turn.” The controller also ordered an Air Canada Boeing 787-8 that was 5.5 nm west of EVA015 and heading towards the 777 to expedite a climb and turn left, and asked EVA015 to “stop your climb.” One of the EVA015 pilots confirmed the instruction and said it would hold at 5,000 ft.
At 0122:50, the controller instructed EVA015 to “turn left, left turn to a heading of ah, two nine ah, correction two seven zero,” the report said. The pilot of EVA015 acknowledged the left turn to 270 deg. and began a slow turn. Seconds later, the controller asked EVA015, “What are you doing? Turn southbound, southbound now. Stop your climb.” The crew responded with a partially unintelligible message that included “maintain 5,000.”
About a minute after ordering the left turn, the SCT controller cleared EVA015 to 6,000 ft., and asked if the aircraft was going south. “I see you going northbound,” the controller said.
EVA015 replied that was “turning south” and would maintain 5,000 ft.
The SCT controller then contacted Los Angeles arrivals sector controllers and asked them to stop departures out of LAX.
At 0124:17, the SCT controlled ordered EVA015 to “climb and maintain 7,000 ft.” The pilot of EVA015 acknowledged the climb. At 0124:22 the Low Altitude Alert (LA) began to flash on the SCT controllers’ radar display and continued until 0125:37.
At 0124:25, the SCT controller told EVA015, “I see you’re going southbound, turn south, correction I see you going northbound now, turn south now, climb and maintain 7,000,” The pilots did not respond.
The controller repeated the instruction to climb and maintain 7,000 ft. and “turn south now.” EVA015 confirmed, and began a right turn to 180 deg.
As the aircraft turned, it was climbing through an altitude of 6,200 ft. above ground level, and passed about 1,600 ft. south of Mt. Wilson, investigators determined. The minimum vectoring altitude for the segment was 7,800 ft., NTSB said. Mt. Wilson’s peak is 5,700 ft., and its summit hosts a number of telecommunications antennas—the tallest of which is 970 ft.
At 0126:25, EVA015 contacted the controller and reported it was heading 180 deg. at an altitude of 7,000 ft. There were no other transmissions relevant to the incident.
NTSB, working through the Taiwanese Aviation Safety Council, obtained enhanced ground proximity warning system data from the aircraft. The data revealed that the system generated two sets of caution warnings to the pilots, and then a seven-second “pull up” alert that began at 0124:49, as the aircraft was turning just south of Mt. Wilson.
NTSB determined that the SCT controller’s erroneous instruction to turn left to the assigned heading instead of right began the incident. The issue was exacerbated when EV015 was given permission to conduct a high-speed climb while making the left turn. This “resulted in the aircraft accelerating beyond the 250 kt LAX class B speed restriction and required additional airspace in order to complete an assigned turn,” NTSB found.
Once the controller realized the problem, the 777 was vectored back around to the right, which created a separation issue with the Air Canada 787 that had departed LAX, leading to a command to EV015 to stop its climb and turn left.
“The incident was caused by the air traffic controller assigning the pilots a left turn instead of the required right turn after departure which placed the aircraft in an unsafe proximity with terrain and obstruction,” NTSB found. “Contributing to the incident was the air traffic controller’s inadequate recovery technique during the development of the incident.”
Activity for the time period was considered normal, NTSB said, although there were a few go-arounds linked to the shifting winds that led to the change to east flow. The STC controller believed that the initial command given to EVA015 included a right turn. “By the time [the controller noticed EVA015 turning left, [the controller] realized the conflict with the Air Canada flight and just needed somebody stop their climb.
In a post-incident interview, the EVA015 crew reported significant confusion over receiving three different, conflicting turn instructions within such a short period of time, NTSB said. A fourth instruction to turn south with no heading provided compounded their confusion.
The board did not determine why the controller made the initial error, but details in the investigation’s docket suggest the east-flow configuration’s rarity likely played a role. When operating west, terrain is not an issue. But the east flow means that MVAs must be factored in.
“SCT operated ‘west traffic’ or ‘over water’ 99% of the time, and when LAX switched to east traffic no one considered the minimum vectoring altitudes,” an NTSB summary of one controller’s interview said. This controller “felt that facility training was not good for east traffic operations, and that there was a reluctance to switch to east traffic, usually waiting until the last minute to do so,” the summary added.
NTSB’s report does not include any recommendations or reported safety actions.