Bell UH-1B N4028F

Summary

On 22 April 1992 at about 11:10 local time, a Bell UH-1B registered N4028F, operated by Colony Services, Inc., was involved in an accident near La Belle, Florida, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

22 April 1992 at 11:10

Classification

Accident

Location

La Belle, Florida, United States

Coordinates

26.6408, -81.3409

Aircraft

Bell UH-1B

Registration

N4028F

Category

Helicopter

Engines

1

Operator

Colony Services, Inc.

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

MIA92LA111

1 person was seriously injured.

IMPROPER PREFLIGHT BY THE PILOT-IN-COMMAND, IN HIS FAILURE TO IDENTIFY A CRACK IN A BRAZED AREA SURROUNDING AN ATTACH POINT ON THE AIR DIFFUSER. CONTRIBUTING TO THE ACCIDENT FOLLOWING THE LOSS OF ENGINE POWER WAS OBSTACLES THAT WERE AHEAD OF THE FLIGHT PATH.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

THE PLT STATED THAT THE FLT PATH OF THE HELICOPTER WAS PERPENDICULAR TO POWER LINES THAT WERE AHEAD. THE FLIGHT CONTINUED AND HE FURTHER STATED THAT HE HEARD A LOUD EXPLOSION & THE ENG QUIT. HE PULLED THE COLLECTIVE CONTROL & CLEARED THE POWER LINES THEN LOWERED IT, & PRIOR TO IMPACT WITH THE GROUND, PULLED THE COLLECTIVE CONTROL TO CUSHION THE IMPACT. THE HELICOPTER LANDED HARD, BOUNCED, TOUCHED DOWN, ROLLED OVER ON THE LT SIDE, THEN NOSED OVER & CAME TO REST INVERTED. A SMALL FIRE WAS EXTINGUISHED BY SEVERAL INDIVIDUALS WHO RESPONDED TO THE ACCIDENT SITE. THE ENG WAS REMOVED & SENT TO THE MANUFACTURER'S FACILITY FOR EXAMINATION. EXAM OF THE ENG REVEALED THAT A MOUNTING BOSS ON THE AIR DIFFUSER FAILED DUE TO FATIGUE. THE LINE ATTACHED TO THE BOSS WAS THE INTERSTAGE BLEED AIR LINE. ALSO, A POWER TURBINE BLADE FAILED DUE TO FATIGUE. REVIEW OF THE ENG LOGBOOKS REVEALED THAT THIS ENG WAS REMOVED FROM ANOTHER HELICOPTER & INSTALLED IN THIS HELICOPTER 6 DAYS PRIOR TO THE ACCIDENT. THE ENG HAD ACCUMULATED ABOUT 10 HRS SINCE THEN & 703 HRS SINCE MAJOR OVERHAUL. ACCORDING TO THE ENG DAILY INSPECTION CHECKLIST, THE AIR DIFFUSER EXTERNAL VANE BRAZEMENTS SHOULD BE CHECKED FOR CRACKS.

Quoted verbatim from the NTSB record.