Accident de Havilland Canada DHC-3T Vazar Turbine Otter N270PA,

ASN Wikibase Occurrence # 320275

Date:	Thursday 25 June 2015
Time:	12:16
Type:	de Havilland Canada DHC-3T Vazar Turbine Otter
Owner/operator:	Promech Air
Registration:	N270PA
MSN:	270
Year of manufacture:	1958
Engine model:	Pratt & Whitney Canada PT6A-135A
Fatalities:	Fatalities: 9 / Occupants: 9
Aircraft damage:	Destroyed, written off
Category:	Accident
Location:	near Ella Lake, Misty Fjords National Monument, AK - United States of America
Phase:	En route
Nature:	Passenger - Non-Scheduled/charter/Air Taxi
Departure airport:	Rudyerd Bay, AK
Destination airport:	Ketchikan Harbor Seaplane Base, AK (WFB)
Investigating agency:	NTSB
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
The float equipped DHC-3T Turbine Otter aircraft, operated by Promech Air, was destroyed when it impacted steep, mountainous tree-covered terrain about 25 miles northeast of Ketchikan above Ella Lake in the Misty Fjords area of Alaska. The pilot and eight passengers were killed.
The accident airplane was the third of four Promech-operated float-equipped airplanes that departed at approximate 5-minute intervals from a floating dock in Rudyerd Bay. The accident flight and the two Promech flights that departed before it were carrying cruise-ship passengers who had a 12:30 "all aboard" time for their cruise ship that was scheduled to depart at 13:00. The sightseeing tour flight, which the cruise ship passengers had purchased from the cruise line as a shore excursion, overflew remote inland fjords; coastal waterways; and mountainous, tree-covered terrain in the Misty Fjords National Monument Wilderness.
Promech pilots could choose between two standard tour routes between Rudyerd Bay and Ketchikan, referred to as the "short route" (which is about 52 nautical miles, takes about 25 minutes to complete, and is primarily over land) and the "long route" (which is about 63 nm, takes about 30 minutes to complete, and is primarily over seawater channels). Although the long route was less scenic, it was generally preferred in poor weather conditions because it was primarily over water, which enabled the pilots to fly at lower altitudes beneath cloud layers. Route choice was at each pilot's discretion based on the pilot's assessment of the weather. The accident pilot and two other Promech pilots (one of whom was repositioning an empty airplane) chose the short route for the return leg, while the pilot of the second Promech flight to depart chose the long route.
The accident flight encountered deteriorating weather conditions with terrain becoming obscured by overcast clouds with visibility restricted in rain and mist.
Although the accident pilot had climbed the airplane to an altitude that would have provided safe terrain clearance had he followed the typical short route (which required the flight to pass two nearly identical mountains before turning west), the pilot instead deviated from that route and turned the airplane west early (after it passed only the first of the two mountains). The pilot's route deviation placed the airplane on a collision course with a 1,900-ft mountain, which it struck at an elevation of about 1,600 ft mean sea level. In the final 2 seconds of the flight, the airplane pitched up rapidly before colliding with terrain. The timing of this aggressive pitch-up maneuver strongly supports the scenario that the pilot continued the flight into near-zero visibility conditions, and, as soon as he realized that the flight was on a collision course with the terrain, he pulled aggressively on the elevator flight controls in an ineffective attempt to avoid the terrain.

The National Transportation Safety Board determines that the probable cause of this accident was
(1) the pilots decision to continue visual flight into an area of instrument meteorological conditions, which resulted in his geographic disorientation and controlled flight into terrain; and
(2) Promechs company culture, which tacitly endorsed flying in hazardous weather and failed to manage the risks associated with the competitive pressures affecting Ketchikan-area air tour operators; its lack of a formal safety program; and its inadequate operational control of flight releases.

Accident investigation: