Aircraft strike vehicle on runway threshold in Alaska

No fatalities • Unalaska-Tom Madsen (Dutch Harbor), United States of America • Landing (descent or approach)

A commuter aircraft struck a truck and trailer during its final approach to Runway 30 after the aircraft's belly made contact with the vehicle's top.

What happened

During the final approach for a scheduled commuter flight under visual flight rules, an aircraft was attempting to land on Runway 30. As the pilot approached the landing threshold, they activated the threshold warning lights via radio microphone clicks to alert ground traffic of the incoming flight. However, the physical gates designed to block vehicles from entering the runway area were non-functional.

The pilot, who was already aware that the gates were inoperative, observed a large truck and trailer positioned near the runway threshold. As the aircraft continued its descent, the pilot noticed the truck moving into the threshold area. An attempt to execute a go-around was made, but the underside of the aircraft type/model (not specified in source) struck the top of the 13-foot-tall trailer. This impact caused the aircraft to lose control and descend onto the runway, resulting in structural damage to the plane.

The driver of the truck stated that although the red warning lights were flashing, the gates remained open. After waiting approximately 45 seconds and seeing no approaching aircraft, the driver proceeded onto the roadway. The impact occurred as the vehicle was crossing the threshold.

Findings

Investigation into the incident revealed that the gate system had been inoperative for over a year due to budget limitations. Furthermore, no Notice to Airmen (NOTAM) had been issued to alert pilots to the malfunctioning gates or the hazard of vehicle incursions. While the airport is managed by the State of Alaska, records indicated that the airport's maintenance and inspection processes failed to identify the broken gate system; no discrepancies regarding the gates were noted in FAA compliance inspections until 16 days after the accident occurred.

Probable cause

The failure to maintain functional runway gates and the lack of a NOTAM regarding the inoperative safety system allowed a vehicle to enter the runway threshold during an approach.

Frequently asked questions

What happened in the 2008-04-09 Grumman G-21A Goose accident near Unalaska-Tom Madsen (Dutch Harbor), United States of America?

A commuter aircraft struck a truck and trailer during its final approach to Runway 30 after the aircraft's belly made contact with the vehicle's top.

Were there any fatalities in the 2008-04-09 Grumman G-21A Goose accident?

No fatalities were recorded in this accident.

What aircraft was involved and where did it happen?

The accident on 2008-04-09 involved a Grumman G-21A Goose, registration N741, operated by PenAir - Peninsula Airways - Alaska Airlines Commuter, at Unalaska-Tom Madsen (Dutch Harbor), United States of America.

What was the probable cause of the accident?

The failure to maintain functional runway gates and the lack of a NOTAM regarding the inoperative safety system allowed a vehicle to enter the runway threshold during an approach.

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