Agusta A109 accident near Los Angeles, California, November 6, 2020
On November 6, 2020 at about 11:00 pm local time, a 2009 Agusta A109 (helicopter), registered N109EX, was substantially damaged in an accident during landing near Los Angeles, California (Usc University Hospital (Keck airport). It was flown under charter and air-taxi rules (Part 135). 2 people were seriously injured and 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The loss of tail rotor control due to the separation of the tail rotor duplex bearing ring nut from the thrust sleeve, which resulted in the loss of helicopter control.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 6, 2020 · about 11:00 pm local time
- Place
- Los Angeles, California · Usc University Hospital (Keck · map
- Type
- Accident
- Injuries
- 2 people were seriously injured and 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Agusta A109 S, built 2009 · all A109s on the register
- Registration
- N109EX · no longer on the register · serial 22145
- Damage
- Substantial damage
- Flight
- Flight · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The pilot established the helicopter in an approach to land on a rooftop helipad. During the approach, as the helicopter was about 40 ft above the helipad, the helicopter began to yaw to the right despite the pilot’s control inputs. As the pilot continued the approach, he experienced a loss of tail rotor control and attempted to land on the helipad as the helicopter’s right yaw increased. A witness videoed the accident sequence which showed the helicopter rotating clockwise about the vertical axis and rolling to the left before it impacted the helipad. Postaccident examination of the helicopter revealed that the ring nut for the tail rotor duplex bearing was backed out of the sleeve, which resulted in the loss of tail rotor control. During the investigation, the manufacturer provided historical records of four previous cases that involved ring nut failures. These cases resulted in the manufacturer developing changes to maintenance practices, issuance of European Union Aviation Safety Agency Emergency Airworthiness Directive 2012-0195E in September 2012, and the issuance of Federal Aviation Administration Airworthiness Directive (AD) 2014-02-08, in March 2014, which was superseded by AD 2015-11-08, in June 2015, as a result of a fourth occurrence. The AD added, in part, a daily pilot check to enhance detection of an impending failure of a tail rotor duplex bearing ring nut installation. The accident pilot and the previous pilot who was assigned to the helicopter reported visually inspecting the two locking wires and signing off on the inspection.
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
- Flight control sys malf/fail during landing defining event
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- Aircraft › Aircraft propeller/rotor › Rotorcraft flight control › Tail rotor control system › Failure
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 4,579 hours in all; 81 in this make and model; 20 in the last 90 days; 6 in the last 30 days; 4,530 as pilot in command; 2,850 on instruments
- Last flight review: April 17, 2020
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: rgt
- Injury: minor injuries
Passenger
- Seat: left
- Injury: minor injuries
Passenger
- Seat: rgt
- Injury: minor injuries
The aircraft
- Airframe total time: 1,446.7 hours
- Last inspection: inspection type not recorded, October 22, 2020; 1,439.5 hours since
- Maximum gross weight: 7,000 lb
- Seats: 7
- Landing gear: retractable
- Engine 1: Pratt & Whitney PW207C (turboshaft); 1,449 hours total
- Engine 2: Pratt & Whitney PW207C (turboshaft); 1,449 hours total
- Operator: Helinet Aviation Services
The flight
- Departed from: 03CA La Mesa CA at 10:33 pm
Weather at the time
- Light: daylight
- Wind: from 190° at 10 knots
- Visibility: 10 statute miles
- Sky: scat at 3,200 ft
- Temperature: 72°F (22°C), dew point 57°F (14°C)
- Altimeter: 29.65 inHg
- Observation at 2:45 pm from EMT, 10 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
21 documents, released by the NTSB on January 25, 2023. 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.
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.