Amateur-built 4 accident near Franksville, Wisconsin, October 15, 2023
On October 15, 2023 at about 2:00 pm local time, a 2017 amateur-built 4, registered N42VZ, was substantially damaged in an accident during enroute (climb to cruise) near Franksville, Wisconsin (Cindy Guntly Memorial Airport). It was a personal flight under general aviation rules (Part 91). 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 improper installation of the supplemental ignition system, which resulted in a total loss of engine power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 15, 2023 · about 2:00 pm local time
- Place
- Franksville, Wisconsin · Cindy Guntly Memorial Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built 4, built 2017
- Registration
- N42VZ · registry record · serial 1080
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot of the experimental, amateur-built airplane stated that the airplane sustained a total loss of engine power during the departure climb. The pilot then performed a forced landing on a field near the departure end of the runway. During the landing, the airplane’s landing gear dug into soft terrain resulting in a nose over of the airplane. The airplane sustained substantial damage to both wings. Postaccident examination revealed the airplane was equipped with a supplemental ignition system. Two units of the supplemental system were installed with fuses that were not called for in the system installation instructions. One of the fuses was blown, which disabled one of the two units and did not allow for the airplane’s magneto system to continue providing engine ignition, resulting in a total loss of engine power.
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
- Nose over/nose down during landing (landing roll)
- Aircraft maintenance event during prior to flight
- Powerplant sys/comp malf/fail during enroute (climb to cruise) defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Ignition system › Ignition power supply › Incorrect service/maintenance
- Aircraft › Aircraft power plant › Ignition system › Ignition power supply › Failure
- Personnel issues › Task performance › Maintenance › Installation › Other
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 312 hours in all; 60 in this make and model; 69 in the last 90 days; 29 in the last 30 days; 278 as pilot in command
- Last flight review: September 1, 2022
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 63.6 hours
- Last inspection: condition inspection, February 22, 2023
- Maximum gross weight: 2,400 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming IO-360-C1E6 (piston); 0 hours total
The flight
- Destination: VOK Camp Douglas WI
- Flight plan: none
- Runway 1, 2,381 ft by 70 ft
Weather at the time
- Light: daylight
- Wind: from 350° at 15 knots, gusting 24
- Visibility: 10 statute miles
- Sky: a few clouds at 5,000 ft
- Temperature: 52°F (11°C), dew point 39°F (4°C)
- Altimeter: 30.08 inHg
- Observation at 9:52 am from MKE, 12 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
8 documents, released by the NTSB on May 10, 2024. 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, 11 pages | View Download |
| 2 | FAA Inspector's Statement | PDF, 2 pages | View Download |
| 3 | Record of Correspondence - Pilot December 4 2023 | PDF, 1 page | View Download |
| 4 | Record of Correspondence - Pilot February 27 2024 | PDF, 1 page | View Download |
| 5 | G3I Installation Instructions | PDF, 41 pages | View Download |
| 6 | Memorandum of Record - Flight Manual Supplement Availability | PDF, 1 page | View Download |
| 7 | Aircraft Maintenance Record | PDF, 1 page | View Download |
| 8 | Photos | PDF, 5 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.