NTSB: Crossed brake wires, pilot error, FAA error factored into fatal 2019 Unalaska crash
Zaz Hollander, Anchorage Daily News, Alaska
5 min read
Nov. 3—The 2019 Unalaska crash of a commercial flight that killed a passenger was caused by crossed wiring that prompted anti-skid brakes to malfunction coupled with the inexperienced pilots' decision to land in gusty tailwinds, according to the federal board that oversees aviation safety.
The Federal Aviation Administration's erroneous decision to approve the Saab 2000 for landing at the demanding Unalaska airport without a long enough runway safety zone also played a role, the five-member National Transportation Safety Board during a probable cause hearing on Tuesday.
The board unanimously approved 10 safety recommendations, the majority addressing the FAA as well as checking for possible wiring issues on the Saab and addressing the potential for human error.
The turboprop operated by Ravn Air Group left Anchorage with 42 passengers and crew and overran the runway at Unalaska in October 2019, killing one passenger and injuring nine others. The short Aleutian runway is notoriously challenging, flanked on both sides by water at the base of a mountain.
The death of 38-year-old Washington state resident David Allan Oltman — killed when parts of the plane's propeller pierced the plane's cabin — was the first crash-related fatality for a U.S. commercial passenger airline in a decade.
A propeller separating and entering a cabin is very rare, leading to just two serious injuries in the past 38 years over millions of flights, chief crash investigator Sathya Silva said during the hearing.
PenAir Flight 3296, a Saab SA-2000, was making a second attempt to land in windy conditions when the accident occurred. Reports contained in a massive docket released last year identified the flight crew as first officer Justin Lunn, 39, and captain Paul Wells, 56.
The pilots missed the first landing and, going around for another approach, Wells suggested landing into a headwind from the other direction, investigators found.
A minute or so before touching down, the pilots checked the wind and a local observer reported a 24-knot tailwind — far higher than the 15 knots both men knew the Saab was rated for, investigators said. But they decided to stick with the original plan, landing with a tailwind later estimated at 15 knots.
Wells knew the other approach was preferable based on the wind but didn't push for it, investigators found.
Both men had barely 100 hours flight time into Unalaska, far less than the 300 hours that PenAir, the prior carrier on the Unalaska route, had required of its pilots.
An NTSB aviation safety division chief, Marvin Frantz, told the board that the Ravn Air Group subsidiary operating the flight "misapplied" a waiver provision so Wells could fly the route.
That led to "a captain operating at one of the most demanding airports in (the) system with limited experience in the airplane and at the airport," Frantz said.
The plane came down hard, passengers reported at the time. At some point, a left tire blew. A surveillance camera video played during Tuesday's hearing showed the plane careening into view, smoke or dust rising from its left side, before it veered sharply left.
The aircraft crashed through a perimeter fence, crossed a road and came to rest on shoreline rocks at the harbor's edge.
But with normal braking, investigators found, the plane still should have been able to stop safely.
That's where the wiring problems came in.
A mechanic inadvertently crossed wires on the plane's anti-skid braking components when the plane's landing gear was overhauled in 2017, investigators said. The mistake was hard to discern and wouldn't be easily spotted during maintenance or visible to pilots checking equipment.
The plane didn't go into service until June 2019 — about four months before the crash, investigators said Tuesday. There were few red flags about bad wiring except for an unspecified warning four days before the crash and a tire that needed replacement.
The wiring problem caused one tire to blow out on landing and left the plane with just one of four tires with working brakes, an NTSB brake expert testified Tuesday.
The NTSB also found that the FAA certified the Saab to fly into Unalaska despite a 300-foot safety area at the end of the runway. That's far less than the 1,000 feet required by a plane with the landing speed of that aircraft, investigators said Tuesday.
Investigators, in a draft report, recommended the board approve a probable cause that reflected the crossed wiring and the FAA decision to approve the plane despite the short safety area.
But the board on Tuesday disagreed. An amendment from board member Thomas Chapman raised the pilots' decision to land in such strong tailwinds to the level of a contributing factor.
"I believe we must place greater emphasis on the role of the crew in this accident," Chapman said.
The NTSB's deputy director of aviation safety, David Helson, disagreed. The landing decision was wrong, Helson said, but the plane could have stopped on the runway "if not for the loss of more than 50%" of its braking power.
The board voted unanimously for a probable cause report that included the crew's landing decision.
The flight was sold by Alaska Airlines and marketed under the PenAir name, short for longtime Alaska carrier Peninsula Airways, which previously flew the Saab 2000s into Unalaska.
On Tuesday, board members and investigators referred exclusively to "PenAir" when discussing the company involved in the crash.
The flight was actually operated by Ravn Air Group subsidiary Peninsula Aviation Services Inc., which bought PenAir's name and assets including the planes in 2018 after PenAir declared bankruptcy. Before that, the company was scaling back routes due to shortages of mechanics and pilots, NTSB investigators said Tuesday.
Ravn Air Group declared its own bankruptcy in 2020, about five months after the Unalaska crash.
A new company, Ravn Alaska, emerged from bankruptcy proceedings in November.
Ravn Alaska flies into Unalaska but with a different kind of aircraft now. A representative of Ravn Alaska said the company had no comment on the safety board's finding Tuesday.
