CHI07LA159 · Cessna 340A
Cessna 340A · Accident: main gear collapsed during landing
From Dane County Regional Truax Field (MSN) to Middleton Municipal Morey Field (C29)
Event
- NTSB case
- CHI07LA159
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Cessna 340A
- Aircraft type
- Cessna 340
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N17MH
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Dane County Regional Truax Field (MSN), Madison, WITo Middleton Municipal Morey Field (C29), Middleton, WI
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Landing · landing roll
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Main gear collapsed
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Landing gear, main gear › Collapsed
- Landing gear, normal retraction/extension assembly › Failure
- Other maintenance personnel › Maintenance, adjustment, improper
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot stated that multiple approaches and landings had been conducted during the dual proficiency flight. Prior to the accident landing, he observed three green lights indicating that the landing gear was properly extended. The landing touchdown was "light." A "few seconds" after touchdown the aircraft began to "shudder" and the gear horn started to sound. The airplane began to drift right and the right wing began to settle. As the right main gear collapsed, the aircraft departed the runway pavement, striking two runway lights in the process. The aircraft came to rest in a grass area adjacent to the runway. The nose and left main landing gear remained extended during the accident. A post accident examination of the aircraft revealed that the forward bellcrank attachment flange on the landing gear strut failed. In addition, the lower flange on the bellcrank had also failed. According to the airplane manufacturer, the location of the failures was consistent with the cumulative effect of improper adjustment of the downlock mechanism over time. However, any improper adjustment procedure could not be attributed to any specific maintenance action or to a particular mechanic. Additionally, the maintenance log entry related to the adjustments made during the most recent annual inspection indicated that the airplane maintenance manual instructions regarding landing gear adjustments were complied with properly.
Probable cause
Failure of the right main landing gear extension and retraction linkage, which allowed the gear assembly to collapse during landing rollout. An additional cause was the improper adjustment procedure(s) by undetermined mechanic(s). The runway lights struck during the accident sequence were contributing factors.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI07LA159
- Event ID
- 20070703X00857
- Case number
- CHI07LA159
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 8f0ed82b3e0ef057969484a1ea2a525c00cd9195c8ae7e7a9eca9965d73a41e4; retrieved 2026-09-22T03:47:44.848Z.