Sikorsky S58 accident near Azusa, California, September 11, 2019
On September 11, 2019 at about 8:00 pm local time, a 1959 Sikorsky S58 (helicopter), registered N1168U, was substantially damaged in an accident during enroute near Azusa, California. It was a ferry flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 11, 2019 · about 8:00 pm local time
- Place
- Azusa, California · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Sikorsky S58 ET, built 1959 · all S58s on the register
- Registration
- N1168U · registry record · serial 58-1070
- Damage
- Substantial damage
- Flight
- Ferry flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Part(s) separation from AC during enroute defining event
- Off-field or emergency landing during enroute
The NTSB's findings
- Aircraft › Aircraft propeller/rotor › Tail rotor › Tail rotor blade › Fatigue/wear/corrosion
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; rotorcraft: helicopter
- Flight time: 9,819 hours in all; 1,022 in this make and model; 43 in the last 90 days; 22 in the last 30 days; 9,700 as pilot in command; 0 on instruments
- Last flight review: May 6, 2019
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 19,929 hours
- Last inspection: continuous airworthiness programme, August 1, 2019
- Maximum gross weight: 13,000 lb
- Seats: 2
- Landing gear: fixed
- Engine 1: Pratt & Whitney PT6T-6 (turboshaft); 25,561 hours total
- Engine 2: Pratt & Whitney PT6T-6 (turboshaft); 61,615 hours total
The flight
- Departed from: MIT Shafter CA at 6:38 pm
- Destination: AJO Corona CA
Weather at the time
- Light: daylight
- Wind: from 260° at 5 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 75°F (24°C), dew point 55°F (13°C)
- Altimeter: 30.00 inHg
- Observation at 7:47 pm from KPOC, 7 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
7 documents, released by the NTSB on May 25, 2022. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Materials Laboratory Factual Report | PDF, 10 pages | View Download |
| 2 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 3 | Pilot's Statement | PDF, 1 page | View Download |
| 4 | Memo for Record Damage Summary | PDF, 2 pages | View Download |
| 5 | Memo for Record (Email Summaries) | PDF, 1 page | View Download |
| 6 | Memo for Record (Maintenance Records) | PDF, 4 pages | View Download |
| 7 | Photos | PDF, 6 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Other NTSB records under N1168U the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.