Runway excursion Accident ATR 72-212A (ATR 72-500) YJ-AV71,

ASN Wikibase Occurrence # 319601

Date:	Saturday 28 July 2018
Time:	10:37
Type:	ATR 72-212A (ATR 72-500)
Owner/operator:	Air Vanuatu
Registration:	YJ-AV71
MSN:	720
Year of manufacture:	2005
Total airframe hrs:	19887 hours
Engine model:	Pratt & Whitney Canada PW127M
Fatalities:	Fatalities: 0 / Occupants: 43
Aircraft damage:	Substantial, written off
Category:	Accident
Location:	Port Vila-Bauerfield Airport (VLI) - Vanuatu
Phase:	Landing
Nature:	Passenger - Scheduled
Departure airport:	Tanna-White Grass Airport (TAH/NVVW)
Destination airport:	Port Vila-Bauerfield Airport (VLI/NVVV)
Investigating agency:	PNG AIC
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
An ATR 72-500 operated by Air Vanuatu as flight 239 veered off the runway during the initial landing roll at Port Vila-Bauerfield Airport, Vanuatu, hitting two parked aircraft.
The aircraft was operating a scheduled passenger service from Tanna-Whitegrass Airport to Bauerfield Airport with 39 passengers and a crew of four.
As the airplane overflew the island of Erromango, the pilots reported hearing a 'bang' sound and the cockpit engine instruments indicted a loss of oil pressure on the no.2 (right) engine and smoke. They shut down the no.2 engine and commenced the checklists for engine shut down and smoke.
The pilots reported that they encountered flight control abnormalities during the approach to the Bauerfield Airport runway, with the aircraft making uncommanded roll actions.
During the initial touchdown, the aircraft veered left and tracked about 450 metres from the runway towards the hangar. It impacted a parked BN-2 Islander aircraft of Unity Airlines (YJ-OO9) and severing the vertical stabilizer of another parked BN-2 Islander (YJ-AL2 of Air Taxi).
The pilot in command stated that they had no nose-wheel steering or brakes and they were powerless to stop the aircraft. It came to an abrupt stop after the collision with the Islanders. The passengers and crew safely egressed the aircraft without injury.

Causes [Contributing factors]
The engine malfunction, although not directly causal to the accident, caused the generation of smoke, which prompted the declaration of a Mayday and an immediate descent.
The smoke detection by the electrical smoke detector caused the ambiguous ELEC SMK warning to activate in the cockpit causing the PICs confirmation bias and subsequent diversion of the attention away from the engine issue.
The confirmation bias created by the ambiguous ELEC SMK warning led to the selection and action of the Electrical Smoke checklist The copilots lack of aircraft systems knowledge and introverted behaviour increased the workload on the PIC and contributed to the steep cockpit authority gradient. This significantly contributed to the degraded CRM.
The oversight of the Note in the QRH SMOKE checklist and the absence of similar information in the QRH ELECTRICAL SMOKE checklist encouraged the crew to continue the checklist without other consideration.
The ACW generators were switched off and the DC BTC was isolated through compliance with the QRH ELECTRICAL SMOKE checklist by the flight crew resulting in the loss of hydraulic system pump power and the illumination of several fault lights.
The crew were referred by the QRH ELECTRICAL SMOKE checklist action of the QRH ACW GEN 1+2 LOSS checklist and completed the before landing section in place of the normal QRH Before Landing checklist. This caused the crew not to check the TLU setting.
With the DC BTC isolated, the shutdown of the No. 2 engine caused all DC bus 2 supplied systems to lose power. This resulted in a number of system faults, failures and cautions.
The activation of numerous fault and failure messages as a result of the QRH ELECTRICAL SMOKE checklist and the shutdown of the No. 2 engine, significantly contributed to crew cognitive saturation and reduced situational awareness and crew vigilance.
The lack of situational awareness caused the crew to select reverse thrust with ground control and braking systems unavailable.
The selection of reverse thrust caused the aircraft to turn to the left and exit the runway.
The absence of hydraulic control, brakes, and aerodynamic control prevented the crew from correcting the undesired course change, runway excursion, and subsequent collision with the parked aircraft.

Accident investigation: