Casualties unknown

1991-10-26: DE Havilland DHC-6 (N724CA) — Markair Express Inc. — Chevak, AK

Chevak, AK, US

On October 26, 1991, a DE Havilland DHC-6 (registration N724CA) operated by Markair Express Inc. was involved in an aviation accident near Chevak, AK. Investigators recorded the probable cause as: THE HIGH CROSSWIND CONDITION, THE PILOT IN COMMANDS INABILITY TO COMPENSATE FOR THE WIND CONDITIONS, AND HIS FAILURE TO FOLLOW COMPANY PROCEDURES AND THE PROCEDURES RECOMMENDED IN THE AIRCRAFT FLIGHT MANUAL. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 3 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

During a crosswind takeoff at Chevak, the captain used 20 degrees of flaps contrary to manual's recommendation, leading to weather vaning and right drift. The right wing struck the ground.

Incident Overview

A takeoff on Runway 14 at Chevak resulted in a right wing striking the ground after the airplane experienced weather vaning and drifted right. The captain elected to use 20 degrees of flaps for the takeoff, whereas the flight manual recommends only 10 degrees of flaps for crosswind takeoffs. The flight manual states that the demonstrated crosswind component for the airplane was 20 knots but notes that this is not a limiting factor.

Wind Conditions

Wind information from various sources differed. According to the first officer, station manager, and director of flight operations, the wind was blowing from 090 to 100 degrees at 35 to 40 knots. The captain reported the wind from 060 to 090 degrees at 22 to 25 knots, gusting to 35 knots.

Takeoff Sequence

The captain performed the takeoff. Upon lift-off, the airplane weather vaned and began to drift to the right. Simultaneously, the left wing rose into the air and the right wing dragged along the ground.

Related Operational Decisions

According to the director of flight operations, other company flights in the area had canceled their flights earlier due to high winds.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X18228. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.