FlarePath

What happened

NTSB summary, verbatim

Alaska Airlines cargo flight 9623 from Ted Stevens Anchorage International Airport (ANC), Anchorage, Alaska to Kodiak Airport (ADQ), Kodiak, Alaska collided with two stationary baggage carts while taxiing on the contaminated (slush, ice and water) ramp at ADQ. The airplane sustained substantial damage to the aft right cargo door and frame. There were no injuries. According to the flight crew, the airplane landed uneventfully on runway 26, then taxied to the ramp via taxiway F. They reported the braking action on the runway as good to medium, and that the brakes were effective while on taxiway F. Figure 1. Airport Diagram. (Source: Federal Aviation Administration) After turning left from taxiway F to the ramp, the captain noticed that “eventually the braking action went to nil” and when he attempted to stop, the airplane weather vaned (nose to the left) and struck the ground equipment at the airplane’s right rear side. Figure 2. Damage to cargo door. (Source: Alaska Airlines) The reported accident time was 1253 Alaska Standard Time. The weather reported at ADQ at the time of the accident included moderate rain and mist, temperature 39° F, and wind from 120° at 15 knots with gusts to 25 knots. Field condition reports (FICONs), provided in Notices To Airmen for ADQ, described the condition of different surfaces around the airport. The flight crew had these FICONs, however the most recently available reports were issued several hours prior to the accident, including: At 0531, all of the apron/ramp area was described as having 2 inches of wet snow; At 0715, taxiway F contained ice; At 0825, runway 26 was described as 100 percent of the surface being wet. The flight crew reported that at the time of the accident, the ramp surface initially appeared as though it had “a lot of slush.” After the airplane came to a stop, they noticed standing water over ice on the ramp. The flight crew had a difficult time walking on the ramp and requested sand be spread in the area between the airplane and the terminal.

Photographs

5the aircraft, and what the investigators found

The aircraft before the accident

Wreckage and site documentation · 4 photographs from the docket

Photographs are NTSB docket attachments — works of the US government, in the public domain. Captions are the Board’s own.

Probable cause

the Board's determination

The reduced surface friction of the contaminated ramp which led to a loss of directional control during taxi.

Occurrence sequence

1 stepsNTSB coding · CICTT taxonomy

1 · Taxi
Loss of control on ground
defining event

Findings

2 causal · 0 contributing

CAUSE
Environmental issues › Physical environment › Runway/land/takeoff/taxi surface › Snow/slush/ice covered surface — Effect on operation
CAUSE
Personnel issues › Task performance › Use of equip/info › Aircraft control — Pilot

NTSB analysis

from the final report

Alaska Airlines cargo flight 9623 from Ted Stevens Anchorage International Airport (ANC), Anchorage, Alaska to Kodiak Airport (ADQ), Kodiak, Alaska collided with two stationary baggage carts while taxiing on the contaminated (slush, ice and water) ramp at ADQ. The airplane sustained substantial damage to the aft right cargo door and frame. There were no injuries. According to the flight crew, the airplane landed uneventfully on runway 26, then taxied to the ramp via taxiway F. They reported the braking action on the runway as good to medium, and that the brakes were effective while on taxiway F. Figure 1. Airport Diagram. (Source: Federal Aviation Administration) After turning left from taxiway F to the ramp, the captain noticed that “eventually the braking action went to nil” and when he attempted to stop, the airplane weather vaned (nose to the left) and struck the ground equipment at the airplane’s right rear side. Figure 2. Damage to cargo door. (Source: Alaska Airlines) The reported accident time was 1253 Alaska Standard Time. The weather reported at ADQ at the time of the accident included moderate rain and mist, temperature 39° F, and wind from 120° at 15 knots with gusts to 25 knots. Field condition reports (FICONs), provided in Notices To Airmen for ADQ, described the condition of different surfaces around the airport. The flight crew had these FICONs, however the most recently available reports were issued several hours prior to the accident, including: At 0531, all of the apron/ramp area was described as having 2 inches of wet snow; At 0715, taxiway F contained ice; At 0825, runway 26 was described as 100 percent of the surface being wet. The flight crew reported that at the time of the accident, the ramp surface initially appeared as though it had “a lot of slush.” After the airplane came to a stop, they noticed standing water over ice on the ramp. The flight crew had a difficult time walking on the ramp and requested sand be spread in the area between the airplane and the terminal.