Sikorsky S-76A N110AL

Summary

On 15 June 1993 at about 19:02 local time, a Sikorsky S-76A registered N110AL, operated by Southern Company Services, Inc, was involved in an incident near Cullman, Alabama, United States. 5 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

15 June 1993 at 19:02

Classification

Incident

Location

Cullman, Alabama, United States

Coordinates

34.1697, -86.8296

Aircraft

Sikorsky S-76A

Registration

N110AL

Category

Helicopter

Engines

2

Operator

Southern Company Services, Inc

Operating rule

Part 91: General Aviation

Purpose of flight

Executive/Corporate

Phase of flight

Not recorded

Route

Unknown → Birmingham

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

ATL93IA111

Nobody was injured.

THE FAILURE OF COMPANY MAINTENANCE PERSONNEL TO PROPERLY INSPECT THE TAIL ROTOR CONTROL CABLE AT THE LAST 750 HOUR INSPECTION, AND THE SUBSEQUENT TOTAL FAILURE OF THE CABLE DUE TO WEAR.

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

Read the full NTSB narrative

THE PILOT REPORTED THAT DURING CRUISE FLIGHT, AT ABOUT 200 FEET AGL, HE HEARD A 'SNAP' SOUND, AND THE HELICOPTER YAWED ABOUT 30 DEGREES TO THE RIGHT. HE OBSERVED THE LEFT ANTITORQUE PEDAL TO BE INOPERATIVE. DIRECTIONAL CONTROL WAS MAINTAINED WITH ENGINE POWER ADJUSTMENTS. A RUN ON LANDING WAS PERFORMED AT THE BIRMINGHAM AIRPORT. THE HELICOPTER WAS THEN TOWED FROM THE RUNWAY. AN INSPECTION OF HELICOPTER REVEALED THAT THE LEFT TAIL ROTOR CABLE ASSEMBLY HAD FAILED IN THE VICINITY OF A PULLEY. METALLURGICAL EXAMINATION INDICATED THAT THE CABLE FAILED FROM SEVERE WEAR OF THE INDIVIDUAL WIRES OF THE CABLE STRANDS. THE CABLE WAS INSPECTED 521 HOURS PRIOR TO THE INCIDENT; MAINTENANCE MANUAL DICTATES CABLE INSPECTION AT EVERY 750 HOUR INSPECTION. CABLE WAS ORIGINAL EQUIPMENT ON THIS HELICOPTER (4110 HRS TOTAL TIME).

Quoted verbatim from the NTSB record.