Sikorsky S58 N1168U

Summary

On 11 September 2019 at about 20:00 local time, a Sikorsky S58 registered N1168U was involved in an accident near Azusa, California, United States. One person was 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.

Date

11 September 2019 at 20:00

Classification

Accident

Location

Azusa, California, United States

Coordinates

34.1239, -117.8986

Aircraft

Sikorsky S58

Registration

N1168U

Category

Helicopter

Year built

1959

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Ferry

Phase of flight

Not recorded

Route

Shafter → Corona

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR19LA255

Nobody was injured.

The in-flight separation of a section of the tail rotor blade due to a fatigue crack, which resulted in the pilot’s forced autorotation into a field.

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

Read the full NTSB narrative

The pilot was conducting a ferry flight. During cruise flight while at an altitude of about 1,000 ft above ground level and at an airspeed of about 110 knots, one of the helicopter’s tail rotor blades separated, which resulted in a partial separation of the remaining tail rotor assembly and a forced autorotation. The remaining tail rotor assembly subsequently impacted the vertical stabilizer. The mechanic who performed the daily inspection of the helicopter before the accident flight did not observe any evidence of a crack on the tail rotor blades. The separated section of the tail rotor blade was not recovered. Postaccident fractographic examination of the tail rotor blade piece containing the root end revealed that most of the blade had cracked due to fatigue. No nicks, gouges, damage, or contamination were observed. Further examination revealed that the blade met the design specifications of the engineer drawings. Maintenance records revealed that the rotor blade was most recently repaired in April 2007, but details of the repair work were not available.

Quoted verbatim from the NTSB record.