Sikorsky S-76A N763AL

Summary

On 1 May 1984 at about 19:00 local time, a Sikorsky S-76A registered N763AL was involved in an accident near High Isl BLK595. 2 people were on board and nobody was injured. The aircraft was substantially damaged. No probable cause statement is available for this record.

Date

1 May 1984 at 19:00

Classification

Accident

Location

High Isl BLK595

Coordinates

Not recorded

Aircraft

Sikorsky S-76A

Registration

N763AL

Category

Helicopter

Engines

2

Operator

Not recorded

Operating rule

Part 135: Air Taxi & Commuter

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Hi Isl Blk 595 → Freeport

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

FTW84FA216

Nobody was injured.

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

DURING CRUISE FLIGHT AT 500 FT OVER GULF WATERS, THE LEFT ENGINE SUSTAINED A MASSIVE, UNCONTAINED, EXPLOSIVE FAILURE. SHARPNEL PENETRATED THE RIGHT ENGINE, WHICH FAILED FROM DAMAGE. SHARPNEL ALSO PENETRATED THE AC AND DC JUNCTION BOXES, CAUSING COMPLETE ELECTRICAL FAILURE (NO MAYDAY CALL POSSIBLE). SHARPNEL FURTHER SEVERED THE TAIL ROTOR DRIVE SHAFT AND PENETRATED THE ACFT FUEL SYSTEM; FIRE BROKE OUT IN THE TRANSMISSION AREA AND THE COCKPIT FILLED WITH SMOKE. USING THE CO-PLT'S SIDE WINDOW FOR VISUAL ACQUISITION OF THE WATER SURFACE, A SUCCESSFUL AUTOROTATION WAS PERFORMED. HOWEVER, THE ACFT ROLLED OVER AND SANK SINCE THE EMERGENCY FLOATATION GEAR IS ELECTRICALLY OPERATED AND FAILED TO DEPLOY. AFTER SUCCESSFUL EVACUATION BY ALL OCCUPANTS, PLT RETURNED TO THE INVERTED ACFT AND DEPLOYED LIFE RAFTS. INVESTIGATION REVEALED LEFT ENGINE COMPRESSOR-TO-TURBINE COUPLING HAD FAILED IN FATIGUE. TURBINE WENT OVERSPEED AND BURST UNDER CENTRIFUGAL LOADS.

Quoted verbatim from the NTSB record.