Aviation Accident Summaries

Aviation Accident Summary ANC19LA045

Buckland, AK, USA

Aircraft #1

N451CE

DOUGLAS C 118A

Analysis

The flight crew was landing the transport-category airplane at a remote, gravel-covered runway. According to the captain, the terrain on the approach to the runway sloped down toward the approach end, which positioned the airplane close to terrain during the final stages of the approach. A video recorded by a bystander showed that while the airplane was on short final approach, it flew low on the glidepath and dragged its landing gear through vegetation near the approach end of the runway. The video showed that, just before the main landing gear wheels reached the runway threshold, the right main landing wheel impacted a dirt and rock berm. The captain said that to keep the airplane from veering to the right, he placed the No. 1 and No. 2 engine propellers in reverse pitch. The flight engineer applied asymmetric reverse thrust to help correct for the right turning tendency, and the airplane tracked straight for about 2,000 ft. The video then showed that the right main landing gear assembly separated, and the airplane continued straight down the runway before veering to the right, exiting the runway, and spinning about 180°, resulting in substantial damage to the fuselage.  On-site examination of the runway revealed several 4-ft piles of rocks and dirt at the runway threshold, which is likely what the right main landing wheel impacted. Given that the airplane landing gear struck vegetation and rocks on the approach to the runway, it is likely that they were below the proper glidepath for the approach. The crew stated there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation.

Factual Information

On August 1, 2019, about 1400 Alaska daylight time, a Douglas C-118A (DC-6A) airplane, N451CE, sustained substantial damage while landing at Candle 2 Airport (AK75), Candle, Alaska. The captain and first officer, both certificated airline transport pilots and the certificated flight engineer were uninjured. The airplane was registered to Tatonduk Outfitters Limited and operated by Everts Air Cargo as a Title 14 Code of Federal Regulations Part 121 supplemental air-cargo flight. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed. The flight departed Fairbanks, Alaska about 1140. According to the captain, after overflying AK75, they entered the traffic pattern for landing on Runway 20, a remote, 3,880 ft. long, by 90 ft. wide gravel-covered runway. He added that down sloping terrain at the approach end of Runway 20 positioned the airplane closer to the terrain during the final stages of the approach. He stated that during touchdown near the runway threshold, he felt a bump, and the first officer exclaimed "we caught the right main gear." He said that in an effort to keep the airplane from veering to the right, he placed number 1, and number 2 engines in reverse pitch. In addition, the flight engineer applied asymmetric reverse to correct for the right turning tendency, and the airplane tracked straight for about 2,000 ft. It then veered sharply to the right and spun 180° resulting in substantial damage to the fuselage. The crew stated there were no preaccident mechanical malfunctions or anomalies that would have precluded normal operation. A postaccident inspection of the runway revealed several 4 ft tall piles of rocks and dirt at the threshold of runway 20. A video, recorded by a bystander, captured the accident sequence and revealed that the airplane, while on short final approach, was low on the glide path and dragging its landing gear through vegetation located near the approach end of the runway. The video shows that, just before the main landing gear wheels reached the runway threshold, the right main landing wheel impacted a dirt and rock berm. The right main landing gear assembly separated, and the airplane continued straight down the runway before veering to the right, exiting the runway, and spinning about 180°. A copy of the video is included in the public docket for this accident. Following the accident, the operator implemented several changes that included, but were not limited to, the following: Develop a written short field procedure for the DC-6/C-46 aircraft and include the procedure in the Operations Manual. Develop a short field flight and ground training segment to be included in the Flight Operations Training Manual. Adjust airport risk assessment to account for high-risk/short-field airports, elevating the management alert criteria. Develop a strict policy regarding conduct associated with visual means of glide path calculation/factors. Develop a list of aircrews, to be maintained by flight control, that have had the appropriate training and may be used for high-risk/short-field airports. The closest weather reporting facility was Buckland Airport (PABL), Buckland, Alaska. At 1356, PABL was reporting, in part: wind 250° at 11 knots, gusting 15 knots; visibility 10 statute miles; few clouds 4,100 ft; temperature 57°F; dew point 39°F; altimeter 30.01 inches mercury.

Probable Cause and Findings

The pilot's failure to maintain an adequate glidepath during the approach, which resulted in the airplane impacting rocks and dirt at the runway threshold, a separation of the right main landing gear, and a loss of directional control.

 

Source: NTSB Aviation Accident Database

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