Enstrom Helicopter CORP 480B accident near Marinette, Wisconsin, June 24, 2008
On June 24, 2008 at about 1:45 pm local time, a Enstrom Helicopter CORP 480B, registered N480PD, was substantially damaged in an accident during maneuvering near Marinette, Wisconsin. It was a flight test 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 pilot inadvertently operating the helicopter at a gross weight greater than its maximum allowable operating weight, and flying the helicopter at an airspeed greater than the never-to-exceed speed for the helicopter’s gross weight condition, resulting in structural damage to the tailcone.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 24, 2008 · about 1:45 pm local time · cases in 2008
- Place
- Marinette, Wisconsin · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Enstrom Helicopter CORP 480B · all 480Bs on the register
- Registration
- N480PD · no longer on the register · serial 5080
- Damage
- Substantial damage
- Flight
- Flight test · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The purpose of the test flight was to determine performance characteristics of the manufacturing company's helicopter at maximum gross weight and maximum aft center of gravity (CG). The helicopter was in a climb at 95 knots indicated airspeed and the pilot had just applied power when he and his passenger noticed a moderate to severe vibration which lasted a few seconds. The pilot reduced power and it went away. The pilot then reduced power to around 55 psi torque at about 90 knots indicated airspeed and trimmed forward to do a reverse trim check while trying to maintain torque and altitude with slightly heavy collective. Then there was a shudder, followed almost instantly by a loud bang and crunching sound, before the nose pitched down and the helicopter turned 120 to 150 degrees to the left. The pilot regained control, selected a field, and proceeded to make an emergency landing. As he began his landing, he noted he no longer had pedal control. The pilot added throttle, managed to bring the nose around, and landed the helicopter straight ahead. Postaccident inspection of the helicopter revealed that the tailcone was buckled in front of the horizontal stabilizer, displacing the stabilizer trailing edge downward and causing slack in the tail rotor control cables. No other preimpact anomalies were found with the helicopter or its systems. Further examination determined that before the flight they had put more fuel in the helicopter than was indicated on the fuel gauges. This resulted in the helicopter being operated at a higher-than-maximum gross weight, at its aft most CG, and reduced the helicopter's never-to-exceed airspeed (Vne) to 87 knots indicated airspeed. When the pilot exceeded Vne during the climb, structural damage occurred.
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
- Abrupt maneuver during maneuvering
- Sys/Comp malf/fail (non-power) during maneuvering defining event
The NTSB's findings
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Airspeed › Capability exceeded
- Aircraft › Aircraft structures › Empennage structure › (general) › Capability exceeded other cases naming the airframe structure
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instrument: helicopter; rotorcraft: helicopter
- Flight time: 7,409 hours in all; 673 in this make and model; 109 in the last 90 days; 29 in the last 30 days; 6,730 as pilot in command
- Last flight review: March 20, 2007
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 707 hours
- Last inspection: 100-hour inspection, March 28, 2008
- Maximum gross weight: 3,000 lb
- Seats: 3
- Landing gear: fixed
- Engine: Rolls-Royc 250-C20W (turboshaft); 0 hours total
- Operator: Enstrom Helicopter Corporation
The flight
- Departed from: MNM Menominee MI at 5:00 am
Weather at the time
- Light: daylight
- Wind: from 200° at 4 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 63°F (17°C), dew point 0°F (-18°C)
- Altimeter: 30.15 inHg
- Observation at 12:55 pm from KMNM, 5 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
4 documents, released by the NTSB on May 2, 2011. 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 | Pilot Statement | PDF, 1 page | View Download |
| 3 | Crew Statement | PDF, 1 page | View Download |
| 4 | Charts from Enstrom 480B Operator's Manual | PDF, 2 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Connections how this case links to the rest of the register
- N480PD: not on the register today · the record of its deregistration
- Enstrom Helicopter Corp 480 73 registered today · the model family and its accident history
- Engine: Rolls-Royc 250-C20W 51 aircraft carry this series today · as the NTSB recorded it
- Menominee Regional · departed from
- Accidents and incidents in Wisconsin 1,622 since 1982 · 225 in the last ten years
- Wisconsin 6,161 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/CHI08FA172.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.