Bell Helicopter Textron Canada 407 accident near Renton, Washington, December 28, 2012
On December 28, 2012 at about 6:15 pm local time, a Bell Helicopter Textron Canada 407, registered N407KS, was substantially damaged in an accident during standing (engine(s) operating) near Renton, Washington (Renton Municipal Airport). It was a public-use flight (local) under public-use (government) rules. 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 pilot's failure to maintain helicopter control during takeoff from an unstable landing platform. Contributing to the accident was the operator's inadequate chocking procedures for the wheeled landing platform, which included chocking only two of the platforms four rear wheels and led to the platform's instability.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 28, 2012 · about 6:15 pm local time
- Place
- Renton, Washington · Renton Municipal Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell Helicopter Textron Canada 407 · all 407s on the register
- Registration
- N407KS · registry record · serial 53812
- Damage
- Substantial damage
- Flight
- Public-use flight (local) · public-use (government) rules
The NTSB's narrative final · quoted from the NTSB record
The commercial pilot was conducting a public aircraft flight in the helicopter. The pilot reported that the helicopter was located on an 18-inch-high portable landing platform with eight sets of casters, including four fixed rear casters. The pilot reported that, while he was preparing for departure, he increased the throttle, and the helicopter and platform started to rotate. A witness reported that the helicopter lifted up about 1 foot, shifted forward, and then came down hard on the front of the platform, which caused the platform to rotate. Although the pilot attempted to stop the rotation, he was unsuccessful, and the helicopter began to spin. As the helicopter spun, it tipped rearward, and the tail rotor struck the ground. The helicopter's right landing skid came off the platform. The helicopter and cart stopped rotating, and the pilot shut down the engine. The operator reported that it had only been chocking two of the four fixed rear casters on the platform, which, they determined postaccident, resulted in the platform being unstable. The pilot likely prematurely lifted off, touched back down on the forward edge of the unstable platform, and subsequently lost helicopter control when the platform began to rotate.
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
- Loss of control on ground during standing (engine(s) operating) defining event
The NTSB's findings
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › (general) › Not attained/maintained
- factor Organizational issues › Management › Policy/procedure › Adequacy of policy/proc › Operator
- factor Environmental issues › Physical environment › Runway/land/takeoff/taxi surface › (general) › Effect on operation
Pilot
- Certificate: commercial pilot
- Ratings: rotorcraft: helicopter
- Flight time: 431 hours in all; 184 in this make and model; 45 in the last 90 days; 20 in the last 30 days; 384 as pilot in command
- Last flight review: December 10, 2010
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Last inspection: inspection type not recorded
- Maximum gross weight: 5,250 lb
- Seats: 8
- Landing gear: fixed
- Engine: Rolls-Royc 250-C47B (turboshaft); 0 hours total
- Operator: King County Sheriffs Office
The flight
- Departed from: RNT Renton WA
- Destination: RNT Renton WA
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 104°F (40°C), dew point 100°F (38°C)
- Altimeter: 30.13 inHg
- Observation at 5:53 pm from RNT
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
2 documents, released by the NTSB on January 13, 2016. 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, 9 pages | View Download |
| 2 | Factual Narrative Revision | 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.
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.