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5 fatalities

Night Approach Ends in Mountainous Terrain Crash (N400N)

Ryderwood, WA, US

On December 1, 1990, an Aero Commander 690A (registration N400N) operated by Aero Air was involved in an aviation accident near Ryderwood, WA. 5 people were killed. Investigators recorded the probable cause as: THE PILOT'S IMPROPER INFLIGHT PLANNING AND FAILURE TO MAINTAIN PROPER ALTITUDE IN MOUNTAINOUS TERRAIN AT NIGHT. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-07-04Data APIEditorial standards

An aircraft crashed in mountainous terrain during a night approach after the pilot canceled the IFR flight plan and descended below radar coverage. The search began December 1, 1990, and the aircraft and a surviving passenger were found the next day. Five occupants were fatally injured.

Accident Overview

On a night approach to the destination airport, the pilot obtained vectors for a descent over mountainous terrain. During the approach, the pilot canceled the IFR flight plan and the aircraft descended below radar coverage. Subsequently, the aircraft crashed in a wooded area at an elevation of about 2700 feet, northwest of the destination airport.

Impact and Wreckage

The initial impact was with trees. The main portion of the fuselage traveled approximately 1000 feet before coming to rest. The emergency locator transmitter (ELT) did not activate during the accident.

Search and Rescue

A search was initiated on December 1, 1990. However, the aircraft and a surviving passenger were not found until the following day.

Injuries and Occupants

The pilot, a Canadian ATP, and the other four passengers sustained fatal injuries. One passenger survived.

Examination

No preimpact mechanical problems were found.

Controlled flight into terrain

Related events

Same operator

Frequently asked questions

What happened in the 1 Dec 1990 Aero Commander 690A accident near Ryderwood, WA?

An aircraft crashed in mountainous terrain during a night approach after the pilot canceled the IFR flight plan and descended below radar coverage. The search began December 1, 1990, and the aircraft and a surviving passenger were found the next day. Five occupants were fatally injured.

Were there any fatalities in the 1 Dec 1990 Aero Commander 690A accident?

The accident was fatal, resulting in 5 fatalities.

What aircraft was involved and where did it happen?

The accident on 1 Dec 1990 involved an Aero Commander 690A, registration N400N, operated by Aero Air, at Ryderwood, WA.

What was the probable cause of the accident?

THE PILOT'S IMPROPER INFLIGHT PLANNING AND FAILURE TO MAINTAIN PROPER ALTITUDE IN MOUNTAINOUS TERRAIN AT NIGHT.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X24698. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.