3 fatalities

1988-02-03: Cessna 421A Golden Eagle I (N517S) — Minuteman Aviation — Helena, United States of America

Helena, United States of AmericaLanding (descent or approach)

On February 3, 1988, a Cessna 421A Golden Eagle I (registration N517S) operated by Minuteman Aviation was involved in an aviation accident near Helena, United States of America during landing or approach. 3 people were killed. Investigators recorded the probable cause as: Occurrence #1: in flight collision with terrain/water Phase of operation: approach - iaf to faf/outer marker (ifr) Findings 1. Terrain condition - mountainous/hilly 2. (f) light condition - dark night 3. (c) ifr procedure - improper - pilot in command 4. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 3 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781215496Data APIEditorial standards

During a night ILS approach in IMC, an aircraft collided with a mountain 12 nm east-southeast of the airport. The investigation revealed improper use of navigation receivers and that the pilot in command was seated in the right front seat.

Accident Overview

An aircraft conducting an instrument landing system (ILS) approach to runway 27 at night in instrument meteorological conditions (IMC) collided with a mountain 12 nautical miles east-southeast of the airport. The accident occurred while the aircraft was turning inbound to intercept the localizer course. All three occupants were killed.

Navigation Equipment Configuration

Investigation into the navigation equipment revealed that one VOR receiver was set to the destination ILS frequency, the second VOR receiver was set to an en route VOR located 51 nautical miles west of the destination airport, and the separate DME transceiver was set to the destination DME transmitter. The frequencies of the en route VOR and the destination VOR were 117.1 MHz and 117.7 MHz, respectively. The outbound course for the ILS approach procedure was 088°, and the accident site was located on the 088 radial of the en route VOR.

Cockpit Seating and Instrument Layout

The pilot in command (PIC) was occupying the right front seat, while an experienced pilot who was not current in this aircraft was occupying the left seat. The control head for the second VOR receiver was located in the lower right portion of the instrument panel, in a position where the selected frequency was difficult to read.

Probable Cause

According to the official findings, the probable cause of the accident was an in-flight collision with terrain/water during the approach phase (from IAF to FAF/outer marker). Contributing factors included: (1) mountainous/hilly terrain, (2) dark night lighting conditions, (3) improper IFR procedure by the pilot in command, and (4) improper use of the navigation receiver by the pilot in command.