DEN07LA083 · Beech 35
Beech 35 · Accident: partial loss of engine power (mechanical failure) during initial climb
From Philip Billard Municipal Airport (TOP) to Charles B. Wheeler Downtown Airport (MKC)
Event
- NTSB case
- DEN07LA083
- 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
Beech 35
- Aircraft type
- Beechcraft 35
- 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
- N460B
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Philip Billard Municipal Airport (TOP), Topeka, KSTo Charles B. Wheeler Downtown Airport (MKC), Kansas City, MO
- 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
- Initial climb
- 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
- Partial loss of engine power (mechanical failure)
- 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
- Engine installation, mounting bolt › Failure, total
- Engine installation, mounting bolt › Improper
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
According to the pilot, shortly after departing runway 18 she heard what "sounded like a loud backfire, a single bang," and then the engine lost power. The pilot selected a nearby field and performed a forced landing. During the landing the nose gear collapsed resulting in substantial damage. An examination of the engine revealed that the crankshaft gear separated from the crankshaft and was loose inside the accessory case. The upper portions of five of the six screws used to secure the gear to the crankshaft were found in the accessory case. Metallurgical examination of the fracture surface revealed signatures consistent with fatigue fractures. One screw was sectioned and tested for hardness with the results of 29, 30, 30, and 31 Rockwell C Harness (HRC). According to TCM, the drawing specifies an H5 fastener with a hardness requirement of 32 through 37 HRC. In addition, the head of the screw had a diameter of .40 inches or less. The TCM drawing specifies a diameter of .44 inches. According to TCM, this could have resulted in inadequate torque for this installation. An examination of the airplane flight controls and engine controls revealed no anomalies.
Probable cause
The use of unapproved bolts to mount the crankshaft and gear together, causing fatigue and failure of those mounting bolts, resulting in the subsequent loss of engine power. Factors contributing to the accident were the separation of the crankshaft gear, and the lack of suitable terrain for a forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN07LA083
- Event ID
- 20070412X00403
- Case number
- DEN07LA083
- 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: 78e6a391ba8e48c3994cf2a013a32d49d15eafa4b6c4de45e5363f534e2402e9; retrieved 2026-09-21T18:33:04.918Z.