ASN Aircraft accident Cessna 208B Grand Caravan N97HA Fairbanks, AK
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Status:Accident investigation report completed and information captured
Date:Monday 16 August 2021
Type:Silhouette image of generic C208 model; specific model in this crash may look slightly different
Cessna 208B Grand Caravan
Operator:Wright Air Service
Registration: N97HA
MSN: 208B0610
First flight: 1997
Total airframe hrs:15382
Engines: 1 Pratt & Whitney Canada PT6A-140
Crew:Fatalities: 0 / Occupants: 1
Passengers:Fatalities: 0 / Occupants: 8
Total:Fatalities: 0 / Occupants: 9
Aircraft damage: Substantial
Aircraft fate: Repaired
Location:near Fairbanks, AK (   United States of America)
Phase: En route (ENR)
Nature:Domestic Scheduled Passenger
Departure airport:Fairbanks International Airport, AK (FAI/PAFA), United States of America
Destination airport:Huslia Airport, AK (HSL/PAHL), United States of America
Wright Air Service flight 440, a Cessna 208B, was substantially damaged when it was involved in an inflight upset near Fairbanks, Alaska. The pilot and eight passengers were not injured.

According to the accident pilot, flight 440 departed about 14:24 from the Fairbanks International Airport (FAI), destined for Huslia, Alaska (HLA), located about 220 miles east-northeast of FAI. After departure, she climbed the airplane to her assigned altitude of 10,000 ft mean sea level (MSL), where she encountered what she described as “light rime” icing conditions. In an effort to exit the icing conditions, she asked and was assigned a block altitude from 10,000 - 12,000 ft msl, and subsequently climbed the airplane to 10,500 ft msl. Unable to exit the icing conditions, she elected to begin a gradual descent back to 10,000 ft msl. She added that instrument meteorological conditions prevailed, and that the autopilot was engaged. The pilot also noted that while en route, the airplane’s deicing boots, and heated propeller were operating normally by removing ice accumulations.

She said that while in a gradual descent from 10,500 ft. msl to 10,000 ft. msl, the autopilot suddenly disengaged, without warning, and the airplane entered an abrupt uncommand right bank followed by a steep nose down, spiraling descent. The pilot said that it felt as if the aileron controls were jammed as she tried to regain control of the airplane. After regaining control of the airplane, she declared an inflight emergency and subsequently made an emergency landing at FAI.

A review of preliminary flight track data revealed that after departing FAI, the flight proceeded to the west, northwest for about 47 nm, cruising at about 10,000 ft msl. Prior to the upset, a climb was initiated and the flight reached an altitude of about 10,700 ft msl before descending to about 10,300 ft msl followed by abrupt changes to altitude and ground speed.

A postflight inspection of the airplane revealed substantial damage to the right aileron. Flight control continuity was established continuously from each control surface to the corresponding cockpit controls.

Although the airplane was equipped for flight into known icing conditions, the pilot’s operating handbook (POH) contained information that flight in freezing rain, freezing drizzle, mixed conditions, or conditions defined as severe were prohibited. In addition, the minimum speed for flight in icing conditions with the flaps up was 130 knots indicated airspeed with a maximum
weight of 8,550 lbs. The POH further required that the autopilot be disconnected once every 10 minutes in icing conditions to check for any out-of-trim conditions caused by ice buildup.
Data obtained from the autopilot revealed that it was not disconnected every 10 minutes through the course of the flight as required. The indicated air speed was consistently below 130 knots, and it was below 100 knots in the seconds preceding the upset. Furthermore, the low airspeed alert activated at 107 kts about 16 minutes, 5 minutes and 2 1/2 minutes before the upset, respectively. Additionally, the estimated gross weight of the airplane at the time of the accident was about 293.5 lbs over its maximum approved gross weight and 805.5 lbs over its approved maximum gross weight for flight in known icing conditions.

Probable Cause:

Probable cause: The pilot’s unexpected encounter with supercooled liquid droplets (SLD), which resulted in a loss of control due to ice accumulation. Contributing to the accident were: (1) the pilot’s failure to maintain the minimum airspeed for flight in icing conditions, (2) the pilot’s failure to disconnect the autopilot every 10 minutes to check for ice buildup, (3) the overweight airplane, (4) the lack of an SLD forecast product for the state of Alaska, and (5) the Federal Aviation Administration's failure to require weight and balance documentation for each flight in Title 14 Code of Federal Regulations Part 135 single-engine operations.

Accident investigation:

Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year and 9 months
Accident number: ANC21LA073
Download report: Summary report

Loss of control

» NTSB AIR-22-07


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This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Fairbanks International Airport, AK to Huslia Airport, AK as the crow flies is 404 km (252 miles).
Accident location: Exact; as reported in the official accident report.

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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