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Aviation safety reports, made easier to study

NTSB Reports is an independent research and search tool for public aviation accident and incident records. It brings NTSB aviation reports, structured fields, docket files, extracted figures, photos, videos, and update history into one searchable interface.

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February 4, 1988 · Cessna 421A · N517S

Helena, MT

Overview

Report Status
Preliminary report
Event Type
Accident
Date
February 4, 1988
Injury Outcomes
3 injuries (3 fatalities)
Location
Helena, MT
Aircraft
Cessna 421A
Tail Number
N517S
Operator
Minuteman Aviation
Injuries
Fatal
Aircraft Damage
Destroyed
NTSB Number
DEN88FA063

This accident occurred during a night, ILS approach to runway 27 in IMC. The aircraft collided with a mountain 12 nm ESE of the airport while turning inbound to intercept the localizer course. Investigation revealed that one VOR receiver was set on the destination ILS frequency, the second VOR was set on an en route VOR 51 nm west of the destination airport, and the DME radio, a separate transceiver, was set on the destination DME transmitter. The frequencies of the en route VOR and the destination VOR were 117.1 and 117.7, respectively. The outbound course for the ILS approach procedure was 088 degrees and the accident site was located on the 088 radial of the en route VOR. Investigation also revealed that the PIC was occupying the right front seat and an experienced pilot who was not current in this aircraft was occupying the left seat. The second VOR receiver control head was located in the lower right portion of the instrument panel, in a location where the selected frequency was difficult to read.

Full Narrative

THIS ACCIDENT OCCURRED DURING A NIGHT, ILS APP TO RWY 27 IN IMC. THE ACFT COLLIDED WITH A MOUNTAIN 12 NM ESE OF THE ARPT WHILE TURNING INBOUND TO INTERCEPT THE LOC COURSE. INVESTIGATION REVEALED THAT ONE VOR RECEIVER WAS SET ON THE DESTINATON ILS FREQ, THE SECOND VOR WAS SET ON AN EN ROUTE VOR 51 NM WEST OF THE DESTINATION ARPT, AND THE DME RADIO, A SEPARATE TRANSCEIVER, WAS SET ON THE DESTINATION DME TRANSMITTER. THE FREQS OF THE EN ROUTE VOR AND THE DESTINATION VOR WERE 117.1 AND 117.7, RESPECTIVELY. THE OUTBOUND COURSE FOR THE ILS APP PROCEDURE WAS 088 DEG AND THE ACDT SITE WAS LOCATED ON THE 088 RADIAL OF THE EN ROUTE VOR. INVESTIGATION ALSO REVEALED THAT THE PIC WAS OCCUPYING THE RT FRONT SEAT AND AN EXPERIENCED PLT WHO WAS NOT CURRENT IN THIS AIRCRAFT WAS OCCUPYING THE LEFT SEAT. THE SECOND VOR RECEIVER CONTROL HEAD WAS LOCATED IN THE LOWER RIGHT PORTION OF THE INST PANEL, IN A LOCATION WHERE THE SELECTED FREQ WAS DIFFICULT TO READ.

Flight

Event TypeAccident
Event Time20:00 MST
Nearest AirportHelena Regional (0nm N)
Runway27
Runway Length9000 ft
Runway Width150 ft
Flight Plan FiledIFR
Aircraft FireGrd
Aircraft ExplosionNo

Aircraft

AircraftCessna 421A
Tail NumberN517S
Aircraft CategoryAir
DamageDestroyed
OperatorMinuteman Aviation
Operating RulePart 135
Engines2
Engine TypeReciprocating
Engine DetailsContinental · GTSIO-520-D · Reciprocating · 375
Seats3

People & Injuries

Injury Summary3 injuries (3 fatalities)
Fatal3
Serious0
Minor0
Uninjured0
Total3
Crew 1Age 54 · Second Class

Conditions

ConditionsIMC
LightDark Night
WindCalm
CeilingNone
Temperature / Dew Point27 C / 19 C
Altimeter30.00 inHg
Observation Time02:53
Weather SourceWFAC

Appendix: Source Data