Bell B-3 N21424
18 June 1993 · Annette Bay, Alaska, United States · No injuries
Summary
On 18 June 1993 at about 02:00 local time, a Bell B-3 registered N21424, operated by Rocky Mountain Helicopters Inc, was involved in an accident near Annette Bay, Alaska, United States. 4 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.
The record
- Date
- at 02:00
- Classification
- Accident
- Location
- Annette Bay, Alaska, United States
- Coordinates
- 55.6107, -131.5804
- Aircraft
- Bell B-3
- Registration
- N21424
- Category
- Helicopter
- Engines
- 1
- Operator
- Rocky Mountain Helicopters Inc
- Operating rule
- Part 91: General Aviation
- Purpose of flight
- Business
- Phase of flight
- Not recorded
- Aircraft damage
- Substantial
- Weather
- VMC
- Light
- Day
- NTSB number
- ANC93LA095
People
Nobody was injured.
| On board | Died | Serious | Minor | Uninjured |
|---|---|---|---|---|
| 4 | 0 | 0 | 0 | 4 |
Probable cause
THE FAILURE OF THE TAIL ROTOR DRIVE SHAFT COUPLING AND THE INADEQUATE INSPECTION OF THE TAIL ROTOR DRIVE SYSTEM BY COMPANY MAINTENANCE PERSONNEL AFTER THE FIRST TAIL ROTOR STRIKE.
Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.
Read the full NTSB narrative
THE HELICOPTER HAD BEEN INVOLVED IN A PREVIOUS TAIL ROTOR STRIKE AND THE DRIVESHAFT WAS INSPECTED. THE ADAPTER ON TAIL ROTOR DRIVE SHAFT NUMBER 4 DEBONDED AND ROTATED ON THE SHAFT. METALLURGICAL EXAMINATION SHOWED DEBONDING BUT THE MODE COULD NOT BE DETERMINED DUE TO ROTATIONAL DAMAGE. OTHER SHAFT ADAPTERS SHOWED DEBONDING AND WERE CAUSED BY PLASTIC BLASTING. THE INSPECTION PROCEDURE CALLS FOR INSPECTIONS ON THE SHAFT USING MAGNETIC PARTICLE OR FLUORESCENT PENETRANT METHODS AND DOES NOT CALL FOR PLASTIC MEDIUM BLASTING.
Quoted verbatim from the NTSB record.
Other accidents in this area
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 21 Jul 1993 | Cessna A185F | Denali Nat'l Pk, Alaska, United States | James Okonek | Serious injuries | - |
| 4 Aug 1993 | Piper PA-32R-300 | Atigun Pass, Alaska, United States | Yutana Airlines | Fatal | 1 |
| 19 Aug 1993 | De Havilland DHC-3 | Nikabuna Lake, Alaska, United States | Ketchum Air Service Inc. | Minor injuries | - |
| 31 Aug 1993 | De Havilland DHC-2 | Iliamna, Alaska, United States | Rainbow King, Inc | Fatal | 3 |
| 2 Sep 1993 | Piper PA-18A-150 | Sanona Creek, Alaska, United States | Garfield, Wade E. | Fatal | 2 |
| 8 Sep 1993 | Interstate S-1B2 ARCTIC TERN | Talkeetna River, Alaska, United States | Franklin, Gary L. | Serious injuries | - |