Eurocopter AS 350 accident near San Juan, Puerto Rico, February 21, 2017
On February 21, 2017 at about 2:15 pm local time, a 1999 Eurocopter AS 350 (helicopter), registered N413LP, was substantially damaged in an accident near San Juan, Puerto Rico (Fernando Luis Ribas Dominicci airport). It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The flight instructor's incorrect manipulations of the twist grip throttle control during a practice autorotation, which resulted in an engine overspeed and subsequent fire.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 21, 2017 · about 2:15 pm local time
- Place
- San Juan, Puerto Rico · Fernando Luis Ribas Dominicci · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Eurocopter AS 350 B3, built 1999 · all AS 350s on the register
- Registration
- N413LP · registry record · serial 3228
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot/owner of the turbine helicopter was practicing autorotations with a flight instructor. After completing several autorotations uneventfully, the instructor asked if he could perform one, and the pilot agreed. Near the flare at the end of the maneuver, the pilot heard the engine overrev, followed by an Nr (rotor speed) aural warning, followed by a fire warning light illumination on the instrument panel. After landing, the pilot exited the helicopter with a fire extinguisher and attempted to extinguish an engine fire. Review of data downloaded from a vehicle-engine multifunction display and digital engine control unit revealed that the first failure recorded during the flight indicated that the gas generator rotation speed (N1) reached an out-of-limit value. At that time, the fuel regulation was in mixed mode, as the collective twist grip throttle control was out of the "flight" detent and the pilot was manually controlling the throttle. A second failure was recorded 2 seconds later, which indicated that the free turbine rotation speed (N2) reached an out-of-limit value. The failure was triggered by the maximum recorded value of 545 rpm, which equated to a turbine speed (Nr) of 140%. The engine's freewheeling turbine was designed to separate turbine blades at 150% Nr in order to prevent the turbine disc separating at 170% Nr. It is likely that the flight instructor excessively opened the fuel metering unit via the twist grip throttle manual control, which resulted in an engine overspeed, turbine blade separation, and subsequent engine fire.
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
- Autorotation Miscellaneous/other
- Autorotation Fire/smoke (non-impact) defining event
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine fuel and control › Fuel controlling system › Incorrect use/operation
- cause Personnel issues › Action/decision › Action › Incorrect action performance › Instructor/check pilot
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instructor: instrument helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 6,250 hours in all; 950 in this make and model; 280 in the last 90 days; 40 in the last 30 days; 5,500 as pilot in command; 2,250 on instruments
- Last flight review: September 20, 2016
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: left
- Injury: no injuries
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; rotorcraft: helicopter
- Flight time: 8,467 hours in all; 5,200 in this make and model; 31 in the last 90 days; 12 in the last 30 days; 8,467 as pilot in command
- Last flight review: January 1, 2016
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 1,846 hours
- Last inspection: 100-hour inspection, June 9, 2016; 59 hours since
- Maximum gross weight: 4,961 lb
- Seats: 6
- Landing gear: fixed
- Engine: Turbomeca Arriel 2B (turboshaft); 1,846 hours total
The flight
- Departed from: TJIG San Juan PR at 1:00 pm
- Destination: TJIG San Juan PR
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 330° at 6 knots, gusting 12
- Visibility: 8 statute miles
- Sky: broken clouds at 5,500 ft; scat at 3,000 ft
- Temperature: 73°F (23°C), dew point 66°F (19°C)
- Altimeter: 29.95 inHg
- Observation at 2:01 pm from TJIG
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
10 documents, released by the NTSB on October 30, 2017. 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 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 12 pages | View Download |
| 2 | Airport Security Video Excerpt (45 Seconds in MP4 Format, 14MB) | PDF, 1 page | View Download |
| 3 | Interview Summary | PDF, 1 page | View Download |
| 4 | Helicopter Manufacturer Report of Vemd Data Download | PDF, 20 pages | View Download |
| 5 | Engine Manufacturer Report of Decu Data Download | PDF, 43 pages | View Download |
| 6 | Engine Manufacturer Report of Hmu and Assembly Valve Tests | PDF, 36 pages | View Download |
| 7 | BEA Report of Vemd and Decu Data Download | PDF, 5 pages | View Download |
| 8 | BEA Report of Hum and Assembly Valve Tests | PDF, 3 pages | View Download |
| 9 | Photo Array | PDF, 3 pages | View Download |
| 10 | Evidence Control Form | PDF, 1 page | 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 N413LP 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.