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NTSB cites technology, training in deadly Togiak crash [复制链接]

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发表于 2018-4-11 10:01:27 |显示全部楼层

A plane crash that killed three people near Togiak more than a year ago was a symptom of larger problems spanning from the handling of excessive terrain alerts in cockpits to inadequate equipment at Alaska's airports, the National Transportation Safety Board concluded Tuesday.

The Hageland Aviation Cessna 208B Caravan which crashed on Oct. 2, 2016 was operating as Ravn Connect’s Flight 3153 when it slammed into mountainous terrain at an altitude of 2,300 feet. Pilots Timothy Cline, 43, and Drew Welty, 29, were killed along with passenger Louie John; the men were from Homer, Anchorage and Manokotak respectively.

[backcolor=inherit !important]The Oct. 2, 2016 crash near Togiak of Ravn Connect's Flight 3153, operated by Hageland Aviation, killed all three people on board. (From NTSB) [backcolor=inherit !important]

The NTSB hosted a live stream of Tuesday’s hearing, and has posted its reports to date regarding the crash on its website.

In August, the NTSB convened a rare and heavily attended remote investigative hearing at the Hotel Captain Cook in Anchorage to speak with various stakeholders in Alaska regarding the crash.

Hageland has been participating in the non-profit Medallion Foundation’s Shield Program for aviation safety. The carrier had achieved “shield” status with the foundation, which was formed in 2001 by the Alaska Air Carriers Association.

The board unanimously determined that the crash’s primary cause was “the flight crew’s decision to continue flying under visual flight rules into deteriorating visibility, and their failure to conduct an immediate escape maneuver which resulted in controlled flight into terrain,” or CFIT.

At Tuesday’s hearing, the three board members currently serving in the NTSB’s five seats – chair Robert Sumwalt, Bella Dinh-Zarr and Earl Weener – questioned a panel of experts headed by Shaun Williams, the Alaska-based investigator who led examination of the Togiak crash.

Sumwalt summed up much of the ensuing hearing, which focused on the Caravan’s terrain avoidance warning system or TAWS, in his initial statements.

“The accident airplane was equipped with TAWS, but this technological solution met an operational reality which rendered it useless in this situation,” Sumwalt said.

NTSB staff gave a brief report of the crash to the board, saying Cline and Welty’s itinerary on the morning of the crash took them from Bethel to Togiak, then on a round trip from Togiak to Quinhagak. After landing in Togiak at about 10:30 a.m. and in Quinhagak at about 11:30 a.m., the Cessna crashed roughly 20 minutes later as it was returning to Togiak.

[backcolor=inherit !important]NTSB investigator in charge Shaun Williams discusses a 2016 Togiak crash that killed three people during a board hearing in Washington, D.C. on Tuesday, April 10, 2018. (From NTSB) [backcolor=inherit !important]

Williams said the plane had been flying roughly 500 to 700 feet above ground level during both of its flight legs to Togiak, including the one on which it crashed.

“In the final four minutes of the flight, the plane climbed to about 2300 feet [above mean sea level] before colliding with mountainous terrain,” Williams said.

Rain had been reported between Bethel and Togiak that morning, and the Cessna wasn’t found until Alaska State Troopers spotted it at about 4:30 p.m. Williams said Hageland didn’t specify its planes’ routes, and another crew on the same trip a few minutes after the fatal flight diverted south around the mountainous area where the crash ultimately occurred.

Board members quickly dismissed any concerns in the crash regarding the aircraft’s mechanical performance, the flight crew’s health or managerial pressure from Hageland, zeroing in on the usage of the TAWS.

NTSB staff told the board that Hageland often flew at altitudes as low as 500 feet, in accordance with Federal Aviation Administration regulations, but its planes’ TAWS displays sounded terrain warnings at altitudes below 700 feet. That discrepancy led to a 200-foot belt in which pilots typically received “nuisance alarms,” causing many Hageland pilots to hit an “inhibit” switch to disable them.

Investigators suspected the TAWS had been disabled for most or all of the deadly flight, a factor the Anchorage Daily News said was also discovered in a 2015 Promech Air crash near Ketchikan and a fatal Wings of Alaska crash later that year.

“Why does the pilot do it? They really have to, if they’re going to fly at an altitude below the clouds which is below the TAWS altitude,” Sumwalt said after staffers reported on the system’s usage during the Togiak crash. “If you’re going to sit there at that altitude, you’re going to have to put up with that thing going off which is going to drive you crazy.”

The board also touched on Hageland’s training to avoid CFIT incidents, which was conducted with input from the non-profit Medallion Foundation. The group, formed in 2001 by the Alaska Air Carriers Association, issues participating carriers “shields” and “stars” for meeting voluntary safety standards above and beyond those required by the FAA.

According to the NTSB, however, Hageland’s flight-simulator training didn’t properly demonstrate flat light conditions, in which the sky and ground become hard to separate. The carrier’s simulator also didn’t include a TAWS console or switch, with pilots instead told verbally that they were receiving a terrain warning during simulated flights.

[backcolor=inherit !important]NTSB Robert Sumwalt gives an overview of safety issues in the fatal 2016 Togiak crash of Ravn Connect Flight 3153 during a board hearing in Washington, D.C. on Tuesday, April 10, 2018. (From NTSB) [backcolor=inherit !important]

Sumwalt also addressed a matter not directly mentioned by the report: Alaska’s relatively sparse infrastructure supporting pilots' use of instrument flight rules.

“Well, the first thing I would do would be to mandate that the state of Alaska be equipped with the same IFR equipment as the rest of the Lower 48; in case you haven't gotten it, the infrastructure in Alaska must change,” Sumwalt said. “If people could fly IFR and get up into the system, it would be a whole different ball game – and I intend to change that with our recommendations.”

The board identified a number of contributing factors in the crash, including Hageland’s policies regarding use of the TAWS inhibit switch. It also cited inadequacies in Hageland’s CFIT training and FAA oversight of that training, as well as the training not being tailored to Hageland’s operations and current anti-CFIT technologies.

In addition to adopting the report along with its probable and supporting causes for the crash, the board also adopted two dozen findings, ranging from emphasizing Alaska’s need for more IFR equipment to stating that Medallion-certified carriers’ safety records show “no meaningful difference” versus non-Medallion carriers due to a lack of assessment.

The board also issued eight new safety recommendations and reiterated eight existing NTSB recommendations. They included calls for expanding CFIT-avoidance training required for helicopter pilots to those at so-called Part 135 carriers like Hageland, preventing TAWS inhibit switches from indefinitely disengaging the system, fitting Part 135 carriers’ planes with crash-resistant data recorders and ensuring that those recorders be capable of flight data monitoring capable of tracking how pilots use TAWS. In addition, the NTSB urged pilots and airlines' village agents to more freely share "pilot reports" or PIREPs on local weather.

One finding and two recommendations Tuesday – that improving Alaska's IFR infrastructure "can reduce the risk of CFIT accidents and better support the state’s air-traffic needs," that IFR gear be added first in areas served by Part 135 carriers and that the same locations receive improved weather reporting capabilities – were added in unanimous votes by the board at Sumwalt's request.

“I do believe this report, if these recommendations can be implemented – and we will push these recommendations – will make a big difference in improving safety in the state of Alaska,” Sumwalt said. “Recommendations are about doing the right thing: preventing the loss of life and injuries. The right thing should not change from state to state, or from fixed-wing (aircraft) to helicopters.”

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