Hughes 369HS N5410W
6 July 1985 · Keystone, South Dakota, United States · Fatal
Summary
On 6 July 1985 at about 17:09 local time, a Hughes 369HS registered N5410W, operated by Rushmore Helicopters, Inc., was involved in an accident near Keystone, South Dakota, United States. 5 people were on board and 4 died, one was seriously injured. The aircraft was destroyed. No probable cause statement is available for this record.
The record
- Date
- at 17:09
- Classification
- Accident
- Location
- Keystone, South Dakota, United States
- Coordinates
- 43.8890, -103.4206
- Aircraft
- Hughes 369HS
- Registration
- N5410W
- Category
- Helicopter
- Engines
- 1
- Operator
- Rushmore Helicopters, Inc.
- Operating rule
- Part 91: General Aviation
- Purpose of flight
- Unknown
- Phase of flight
- Not recorded
- Aircraft damage
- Destroyed
- Weather
- VMC
- Light
- Day
- NTSB number
- DEN85FA180
People
4 people died.
| On board | Died | Serious | Minor | Uninjured |
|---|---|---|---|---|
| 5 | 4 | 1 | 0 | 0 |
Probable cause
The NTSB has not published a probable cause for this record. No probable cause statement is present in the source data.
Nothing about the cause is stated here that is not in the source record.
Read the full NTSB narrative
MAIN ROTOR HUB WAS OVERHAULED BY A REPAIR STATION THAT WAS NOT AUTHROIZED BY HUGHES HELICOPTERS FOR HUB OVERHAULS. THE MAIN ROTOR HUB AND BLADES SEPARATED IN-FLT 279 HRS AFTER OVERHAUL. THE ACFT CRASHED IN A DENSILY WOODED AREA. POST ACCIDENT EXAM OF THE MAIN ROTOR SYSTEM REVEALED THE TORSION-TENSION STRAP PACK FAILED DUE TO FATIGUE CRACKING IN THE STAINLESS STEEL LAMINANTS. METALLURGICAL EXAM REVEALED EVIDENCE OF CORROSION PITTING IN THE LAMINANTS. THE CORROSION PITS WERE THE ORIGIN OF FATIGUE CRACKS. THE MAXIMUM ALLOWABLE NUMBER OF LAMINANT FAILURES IN ANY ONE STRAP IS 3. THE FAILED STRAP PACK CONTAINED 9 FATIGUE FAILED LAMINANTS.
Quoted verbatim from the NTSB record.
Other Hughes 369 accidents
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 6 Feb 1985 | Hughes 369D | Hilo, Hawaii, United States | - | Fatal | 1 |
| 19 Nov 1985 | Hughes 369D | Kunia, Oahu, Hawaii, United States | - | No injuries | - |
| 7 Jun 1985 | Hughes 369HS | Aiken, South Carolina, United States | - | No injuries | - |
| 15 Mar 1985 | Hughes 369HS | Princeton, Missouri, United States | Kcmo Radio | No injuries | - |
| 8 May 1985 | Hughes 369HS | Malvern, Arkansas, United States | Three Rivers Helicopters | Minor injuries | - |
| 15 Feb 1985 | Hughes 369D | Hilo, Hawaii, United States | Sunair Copters, Inc. | No injuries | - |
Other accidents in this area
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 10 Nov 1985 | Piper PA-18-150 | Buffalo, South Dakota, United States | - | Serious injuries | - |
| 1 Feb 1985 | Cessna 180A | Sioux, South Dakota, United States | - | No injuries | - |
| 27 Nov 1985 | Piper PA-18-150 | Hayes, South Dakota, United States | - | No injuries | - |
| 16 Feb 1985 | Piper PA-28-140 | Hot Springs, South Dakota, United States | - | No injuries | - |
| 19 Mar 1985 | Cessna 172 | Wesbter, South Dakota, United States | - | No injuries | - |
| 19 May 1985 | Cessna 182 | Plankinton, South Dakota, United States | - | No injuries | - |