NTSB Identification: DEN88FA063.
The docket is stored on NTSB microfiche number 36680.
Nonscheduled 14 CFR
Accident occurred Wednesday, February 03, 1988 in HELENA, MT
Probable Cause Approval Date: 01/16/1990
Aircraft: CESSNA 421A, registration: N517S
Injuries: 3 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

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.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

IFR PROCEDURE..IMPROPER..PILOT IN COMMAND

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

NAVIGATION RECEIVER..IMPROPER USE OF..PILOT IN COMMAND



Contributing Factors

LIGHT CONDITION..DARK NIGHT

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