Amateur-built LANCAIR IV-P accident near Shawano, Wisconsin, November 15, 2015
On November 15, 2015 at about 3:04 pm local time, a 2002 amateur-built LANCAIR IV-P, registered N10UU, was substantially damaged in an accident during maneuvering near Shawano, Wisconsin. It was an instructional flight under general aviation rules (Part 91). 2 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A total loss of engine power due to a dual magneto failure, as a result of an exceedance of the engine’s operating limitations while maneuvering.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 15, 2015 · about 3:04 pm local time
- Place
- Shawano, Wisconsin · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built LANCAIR IV-P, built 2002
- Registration
- N10UU · no longer on the register · serial LIV-417
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While practicing an emergency descent during a dual training flight, the pilot receiving instruction entered the airplane into a steep dive, which resulted in a 0.5-G load factor for about 5 seconds and a transient drop in engine oil pressure of about 15 psi. As the descent continued, engine speed steadily increased beyond the maximum operating limit of 2,700 rpm. While still in the dive, the pilot initiated a left turn with a 3-G load factor, during which the engine oversped to 3,390 rpm. The engine immediately began to run rough, and subsequently experienced a total loss of power. The pilot executed a forced landing to a field with the landing gear and flaps retracted, during which the airplane struck a rock wall and tumbled. Postaccident examination revealed that 8 teeth on the left magneto distributor drive gear and 16 teeth on the right gear had fractured. No evidence of progressive damage or material anomaly was observed with the distributor drive gear teeth. The nylon gear teeth were most likely damaged by the abnormal shock loads on the gear train during the engine overspeed. The damage to the gear teeth resulted in a dual magneto failure and subsequent loss of engine power. The flight profile of a low-G pushover to a steep dive, which was accompanied by a drop in engine oil pressure, may have led to the propeller governor not supplying adequate oil pressure to the propeller, which subsequently contributed to the engine overspeed and the failure of the magnetos.
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 engine power (total) during maneuvering defining event
- Collision with terrain or object (not controlled flight into terrain) during after landing
The NTSB's findings
- cause Aircraft › Aircraft power plant › Ignition system › Magneto/distributor › Capability exceeded
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › (general) › Incorrect use/operation
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane
- Flight time: 23,000 hours in all; 5 in this make and model; 17 in the last 90 days; 11 in the last 30 days; 23,000 as pilot in command; 3,000 on instruments
- Last flight review: September 1, 2015
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: minor injuries
Flight instructor
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 1,416 hours in all; 32 in this make and model; 124 in the last 90 days; 35 in the last 30 days; 1,302 as pilot in command; 307 on instruments
- Last flight review: October 12, 2014
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: rgt
- Injury: minor injuries
The aircraft
- Airframe total time: 910 hours
- Last inspection: condition inspection, October 1, 2015
- Maximum gross weight: 3,550 lb
- Seats: 4
- Landing gear: retractable
- Engine: Cont Motor TSIO-550 SER (piston); 282 hours total
The flight
- Departed from: EZS Shawano WI at 2:41 pm
- Destination: EZS Shawano WI
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 41°F (5°C), dew point 36°F (2°C)
- Altimeter: 30.11 inHg
- Observation at 2:55 pm from KCLI, 10 miles away
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 January 23, 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, 9 pages | View Download |
| 2 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 - Flight Instructor | PDF, 3 pages | View Download |
| 3 | Photo of Airplane at Accident Site | PDF, 1 page | View Download |
| 4 | Chelton EFIS Data - All Parameters | spreadsheet | Download |
| 5 | Chelton EFIS Data - NTSB Iic Selected Parameters | spreadsheet | Download |
| 6 | Materials Laboratory Factual Report 16-077 | PDF, 10 pages | View Download |
| 7 | Propeller Governor Examination | PDF, 11 pages | View Download |
| 8 | Australian Airworthiness Bulletin on Magnetos | PDF, 25 pages | View Download |
| 9 | Engine Type Certificate Data Sheet | PDF, 10 pages | View Download |
| 10 | Statement of Party Representatives to NTSB Investigation | 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.
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.