Pullman, WA, USA
N412QX
BOMBARDIER INC DHC 8 402
This incident occurred when Horizon flight 2184 landed on a parallel taxiway to runway 6 at Pullman/Moscow Regional Airport (PUW), Pullman, Washington. Pullman/Moscow Airport was not served by an air traffic control tower (i.e. an uncontrolled airport). The runway lighting at KPUW was not operating at the time of the incident and there was no NOTAM regarding the inoperative lights. However, at the time of landing, the taxiway lights on the parallel taxiway were operational. The lighting system had been tested about two hours prior to the incident landing but airport personnel did not notice the runway lights were not functioning until informed by the flight crew. Following the incident landing, airport personnel found that the runway lighting wiring vaults were flooded, likely from recent heavy rains and snow from the previous day, and issued a NOTAM that the runway lights were inoperative. As the flight proceeded inbound, the captain could not determine whether the lights were on bright or dim and indicated that he keyed the radio to increase the lighting, but was uncertain if the intensity had changed. The captain disengaged the autopilot soon after calling runway in sight when the airplane was about 4.5 miles from the runway 6 threshold after he thought he saw the actual runway. The captain stated he then looked down to check that the gear was down and, as he looked back out, saw nothing but black in front of the airplane before identifying pavement that was lit up. He stated he then smoothly slid the airplane over a little to line up with the illuminated pavement. He stated that he thought he had aligned with the runway. The flight crew noticed they were on a taxiway as they were in the flare and touching down on the pavement. During the taxi to the terminal, the flight crew again attempted to illuminate the runway lights via the CTAF with no success, only the taxiway lights changed illumination intensity. Although some cues, such as the taxiway light color and alignment of the PAPI relative to the intended landing surface, were available to the flight crew to distinguish the taxiway from the from nonilluminated runway, sufficient cues also existed, such as a single lighted paved surface similar in width to the runway, to confirm the crew's expectation that the airplane was aligned with the intended landing runway. As a result, once the airplane was aligned with what the flight crew thought was the correct landing surface, they were likely not strongly considering contradictory information. Once the flight had exited the clouds, the flight crew had expected to see an illuminated runway. The taxiway and runway were about 200 feet apart, and only a small correction while in flight would be required to align the aircraft with the taxiway. The captain indicated that after the runway was in sight, he focused on the runway surface, and not the lighting until the airplane had landed on the taxiway. The NTSB concludes that the cues available to the flight crew to indicate that the airplane was aligned with a taxiway were not sufficient to overcome their belief, as a result of expectation bias, that the illuminated taxiway was the intended landing runway.
HISTORY OF FLIGHT On December 29, 2017, about 1840 pacific standard time, Horizon Air flight 2184, a Bombardier DHC-8-402, N412QX, landed on a taxiway parallel to runway 6 at Pullman/Moscow Regional Airport (KPUW), Pullman, Washington. Weather at the time of landing was reported as wind from the southeast, light rain, overcast ceiling with 5 miles visibility. There were no injuries to the 42 passengers and crew onboard and the airplane was not damaged. After the airplane landed, the flight crew observed that the runway lights were inoperative. The passenger flight was operating under 14 Code of Federal Regulation (CFR) Part 121 on an instrument flight rules flight plan from Seattle/Tacoma International Airport (KSEA), Seattle, Washington, to KPUW. An instrument flight rules (IFR) flight plan had been filed. Night instrument meteorological conditions (IMC) prevailed at the time of the incident. The incident flight occurred on the second flight of the day for the flight crew. Both pilots began their duty day at 1513 local time on December 29, 2017, in Missoula International Airport (KMSO), Missoula, Montana. The captain and first officer flew a 2 hour and 10-minute flight from KMSO to KSEA, arriving in SEA at 1630. According to the flight release for Horizon Air flight 2184, there were no Notice to Airmen (NOTAM) for the runway lights being out of service at KPUW. Horizon Air flight 2184 departed KSEA at 1748 with 2 flight crewmembers, 2 flight attendants and 38 passengers for a planned 1 hour flight to Moscow Pullman Airport. According to the flight crew, the takeoff, climb, cruise and descent were uneventful. Flight 2184 was then cleared by air traffic control (ATC) for the RNAV (RNP) M instrument approach to runway 06 at PUW. The captain was the pilot flying and the first officer (FO) was the pilot monitoring for the incident flight. Conditions at the KPUW airport were wind from the southeast, light rain, overcast ceiling with 5 miles visibility, and the captain used the Head-up Guidance System (HGS) installed on the captain's side of the cockpit during the approach. During post accident interviews, the captain stated he attempted to illuminate the KPUW airport lighting via the common traffic advisory frequency (CTAF) prior to the initial approach fix and prior to exiting the clouds. The captain stated that shortly after crossing the initial approach fix, the airplane exited the clouds and that he observed what he believed was runway 06 and runway lights, though according to his interview he questioned whether the runway lights were on bright or dim. The captain stated he attempted to turn the lights up brighter via the CTAF several times, and it was unclear if they had changed. The captain stated he clearly felt he had the runway in sight and the runway lights were on, and it was just a question of the lights not going up to bright, not to an "on" setting. The captain stated he checked that the gear was down, and as he looked back out to see the runway and saw nothing but black out in front of the airplane, and he saw identifiable pavement that was lit up. He stated he slid the airplane over a little to line up with the illuminated pavement, but there was no abrupt maneuver. The captain stated he lined up with the pavement and did not notice the taxiway lights and stated that what he saw and aligned with looked like runway pavement. As the airplane was approaching the ground and while in the flare, the FO stated that he was looking for visual cues and noticed the blue taxi lights. Right before touchdown the FO stated he saw that they were on the taxiway. The airplane subsequently landed uneventfully to the left of runway 06 and on the parallel taxiway at PUW at 1840. The captain stated that there was nothing in front of the airplane on the taxiway that was of any danger and that he did not see taxiway lights, but saw the pavement and concentrated on stopping the airplane As they slowed down, they taxied on the full length of the taxiway, back-taxied on the runway, then continued to the gate. According to both pilots, they attempted to change the illumination of the taxiway and runway lights via the CTAF during their 6-minute taxi to parking and observed the blue taxiway lights change illumination, but the runway lights did not illuminate. PERSONNEL INFORMATION The captain was 49 years old and was based in Medford, Oregon as A Q-400 captain. According to company records and information provided by the captain, he had accumulated 13,528 hours total flight experience, including about 5,997 hours in the Q-400. A review of the FAA Accident/Incident Data System, Enforcement Information System and Program Tracking and Reporting Subsystem (PTRS) database showed no records or reports of any previous aviation incidents or accidents involving the captain. The captain began flying a 3-day trip on December 25, 2017. The captain flew from Rogue Valley International-Medford Airport (MFR) to Reno/Tahoe International Airport (RNO) with a stop in SEA. His duty day began at 0445 and ended at 1200. On December 26, 2017, he had a 0515 show at RNO and flew 5 legs followed by a deadhead to Mahlon Sweet Field Airport (KEUG), Eugene, Oregon, for an overnight. His duty day ended at 1611. He did not recall anything of significance about the trip and did not recall what time he went to sleep, but knew he was trying to get to sleep early. On December 27, 2017, he thought he woke up about 0400-0415. His duty day began at 0455. He flew 4 legs (KEUG-KSEA-KMSO-KSEA-KMFR) with an overnight in Medford. His duty day ended at 1355. He was based in Medford, so he stayed at a hotel at his expense. He did routine activities during the day and was in bed between 2100-2300. On December 28, 2017, he woke up between 0700-0900, asked for a late checkout of 1130 and had a 1207 show time. He flew 3 legs (KMFR-KSEA-KRDM-KSEA) and was then paired with the incident FO for a flight from KSEA to KMSO. His duty day ended at 0012 MST on December 29. He thought he went to bed about 0100-0130. On December 29, 2017, he and the incident FO had a show time of 1513 MST, with an hour prior van ride. He was up "way" before then but did not recall the specific time he woke up. He did not have any problems falling asleep the previous night and felt rested. He did routine activities during the day which included walking around outside and did not take a nap. The incident crew flew KMSO to KSEA, and then flew the incident flight from KSEA to KPUW. The incident occurred about 1830. He had no changes in his health, personal or financial status in the previous 12 months; he rated his health as an 8.5-9 out of 10. He did not take any prescription or non-prescription medication in the 72 hours prior to the event that might have affected his performance. He had never been diagnosed with a sleep disorder. The FO was 38 years old and was based in Medford, Oregon, as a Q-400 FO. The FO's date of hire with Horizon Air was July 10, 2017, and according to company records, he had accumulated 1,582 hours total flying time, including 95.5 total hours in the Q-400. A review of the FAA Accident/Incident Data System, Enforcement Information System and PTRS database showed no records or reports of any previous aviation incidents or accidents involving the FO. The FO did not recall when he woke up on Tuesday, December 26, 2017. He thought he had commuted to work that day since he was scheduled to be on reserve for the 27th but did not recall specifics. He stayed at a hotel in Portland, Oregon, that night and thought he went to bed about 2200. On Wednesday, December 27, 2017, the FO thought he woke up about 0430 but possibly a little bit later because he thought he was on hotel reserve. He was on home reserve from 1030 until 1230 and airport reserve from 1230 until 2030. He did not get called to fly that day. He did not recall much of his activities but recalled he exercised. He did not take a nap. He thought he went to bed by 2100. On Thursday, December 28, 2017, the FO thought he woke up about 0430 and was on airport reserve from 1030 until 1429. He sat in the crew room at the airport, walked laps around the airport, and did some people-watching. He did not get called to fly that day. He then deadheaded to KSEA and flew from KSEA to KMSO with the incident captain. He went straight to the hotel and to bed about an hour after getting into the hotel. His duty day ended at 0012 MST on December 29. He was not sure the exact time he went to bed. On Friday, December 29, 2017, the FO slept in and woke about 0900 or 1000. His activities that day included going to the gym, watching TV and preparing for the day's flights since he was still new to the company. He and the incident captain utilized the hotel van services for transportation, and those schedules were pre-arranged by the company. His duty day began at 1513 MST and the incident occurred about 1830. He indicated felt fine that day. He had no problems falling asleep at night, and he had never been diagnosed with a sleep disorder. He characterized his health as "pretty healthy," and he exercised "a lot". He had no major changes to his health, financial situation or personal life in the 12 months prior to the incident. He did not take any prescription or non-prescription medications in the 72 hours prior to the incident that could have affected his performance. The captain and FO had previously flown together on two flight legs preceding the incident flight. Both pilots were drug tested the day following the incident with negative results. According to Horizon Air, the pilots were not able to get on-site drug testing within a 1-hour window following the incident. Attempts to get a qualified tester to Pullman were made immediately after incident notification to duty officer, without success. The pilots were flown to KPDX the next day, all other testing requirements met the timeline. No alcohol testing was conducted. AIRCRAFT INFORMATION Photo 1: Photo of incident airplane N412QX. The incident airplane was a Bombardier DHC-8-402, registration number N412QX, serial number 4059. It was a fixed wing multiengine aircraft with two Pratt and Whitney PW150A turbo-prop engines. The airplane was manufactured in 2002, and was registered to BCC Equipment Leasing Corporation in Seattle, Washington. Per OpSpecs A001, Horizon Air was authorized to conduct operations under the provisions of 14 CFR 119.21(a)(1)-(3) for domestic, flag and supplemental operations. The incident airplane was listed on OpSpecs D085, issued to Horizon Air Certificate number QXEA002A, and authorized to conduct operations under 14 CFR Part 121. There were no deferred maintenance items related to the avionics, navigation or head-up display on the incident flight. METEOROLOGICAL INFORMATION The incident occurred about 0240 UTC. Meteorology Aerodrome Reports (METARs) for KPUW valid at the time of the incident were as follows. SPEC KPUW 300217Z AUTO 14009KT 5SM RA BR FEW018 BKN025 OVC032 03/02 A2988 RMK AO2 P0004 T00330017= METAR KPUW 300253Z AUTO 15010KT 5SM -RA BR FEW024 BKN030 OVC035 04/02 A2986 RMK AO2 SLP128 60027 T00440022 58019= The Terminal Aerodrome Forecast (TAF) for KPUW in effect at time of departure was calling for IFR at time of landing, and recorded as follows: TAF KPUW 292322Z 3000/3024 07003KT 3SM RA BR BKN006 OVC012 FM300900 24020G30KT P6SM BKN010 FM301800 25016G25KT P6SM BKN030 BKN150 AIRPORT INFORMATION Pullman/Moscow Regional Airport (KPUW) was located three miles northeast of the central business district of Pullman, Washington, at an elevation of 2,554.9 feet and a latitude/longitude of 46-44-37.9000N / 117-06-34.5000W. The airport had two runways (06/24) and was not served by an ATC control tower (uncontrolled). Runway 06 had a length of 6,730 feet and was 100 feet wide with a 0.4% gradient. The taxiway at KPUW was approximately 57 feet wide. The wingspan of the Q400 is 93 feet 3 inches and the main wheelbase is 28 feet 10 inches. The distance between the runway centerline, and the taxiway centerline is 200 feet. Based on this distance, KPUW has an operational note stating, "Aircraft must delay taxiing and remain behind the intermediate holding position line when large aircraft operations are in progress." According to the Executive Director of the Pullman-Moscow Regional Airport, after the incident KPUW operations personnel found flooded electrical wiring vaults associated with the runway lighting system from heavy rains and snow that had occurred on the previous day. NOTAMs were published 43 minutes after the incident reporting the lighting out of service. The lighting system was previously tested at about 1600 local time the day of the incident, and all lights were found to be operational. Figure 1: PUW Jeppesen 10-9 Airport Chart. INSTRUMENT APPROACH PROCEDURE The instrument approach used by the incident crew was the PUW RNAV (RNP) M approach to runway 06. According to the captain, he was not sure if he had flown that actual approach before, but pretty sure he had flown that at least once before. When asked how often he had landed at KPUW, he said it "comes and goes," but maybe about 5 or 6 times each year depending on his monthly schedule. He did not remember the last time he had landed at KPUW. The approach chart was published by Jeppesen specifically for Horizon Air and Alaska Airlines utilizing proprietary required navigation performance (RNP) data from Alaska Airlines. The PUW RNAV (RNP) M approach to runway 06 was a Special Instrument Approach authorized to be flown by Horizon Air using DHC- 8-402 aircraft per Horizon Air OpSpecs C081. The UNS-1Ew Flight Management System (FMS) onboard the DHC-8-402 was approved for RNAV (RNP) approaches to an RNP level of: • With Flight Director, 0.30 nm for approach, • With Autopilot, 0.10 nm for approach, and • Less than 1.0 for missed approach. The minimums for the PUW RNAV (RNP) M approach to runway 06 utilizing an RNP value of was 2,858 feet, or 320 feet above the threshold of the runway, and the chart indicated that the RNAV glidepath would continue to bring the airplane to a threshold crossing height (TCH) of 57 feet above the threshold. OFXEF was the initial approach fix (IAF) with a minimum crossing altitude of 5,400 feet msl (mean sea level), and located 11.8 miles from the end of the runway. FITEL was the final approach fix (FAF) with a minimum crossing altitude of 4,100 feet msl and located 4.7 miles from the end of the runway. The chart indicated that the runway had REIL lighting and a precision approach path indicator (PAPI) on the left side of runway 06, and pilot-controlled lighting, activated on the KPUW Unicom frequency. The Horizon Air Q-400 Flight Standards Manual, page 3.1.11 stated the following in part: Approaches Approaches with Vertical Guidance • Except as provided below, only approaches with vertical guidance shall be used inside the FAF. Vertical guidance is provided by any ILS and by FMS VNAV on all approaches with a runway designated in the approach title (e.g., RNAV (GPS) Rwy 14, VOR 14). • Approach selection should satisfy the minimums required for weather conditions, provide an optimal descent profile, and reduce track miles. Because of their efficiency, predictability, and stability, RNAV approaches are the preferred approaches. With these considerations, if practical, the following approach priority should be followed: 1. RNAV (RNP) (RNP approaches provide the most stable approaches and are often the most efficient). 2. RNAV (GPS). 3. ILS. 4. If an RNAV or ILS approach is not available to the intended runway, a LOC or VOR based approach may be flown via the FMS. HIGH INTENSITY RUNWAY LIGHTS (HIRL) Runway 06 at KPUW was equipped with runway edge lights used to outline the edges of the runways during periods of darkness or reduced visibilities. The KPUW runway light system was an HIRL system, with colored white edge lights. The lights marking the ends of the runway emitted red light toward the runway to indicate the end of t
the flight crew's misidentification of the taxiway as the landing runway due to the failure of the runway lighting that caused only the taxiway lights to be illuminated.
Source: NTSB Aviation Accident Database
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