CEN16FA013 · Cessna 421B B
Aero One Cessna 421B B · Accident: loss of engine power (total) during initial climb
From Hammond Northshore Regional Airport (HDC) to Hartsfield Jackson Atlanta International Airport (ATL)
Event
- NTSB case
- CEN16FA013
- 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
- 2 · 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 421B B
- Aircraft type
- Cessna 421
- 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
- N33FA
- Operator
- Aero One
- Onboard fatalities
- Unknown
- Route
- From Hammond Northshore Regional Airport (HDC), Hammond, LATo Hartsfield Jackson Atlanta International Airport (ATL), Atlanta, GA
- Aircraft age
- About 42 years (built 1973)
- 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
- Defining eventThe 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
- Loss of engine power (total)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Aircraft › Aircraft handling/service
- Aircraft › Aircraft oper/perf/capability
- Aircraft › Aircraft power plant
- Personnel issues › Action/decision
- Personnel issues › Task performance
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The twin-engine airplane, flown by a commercial pilot, was departing on a business flight from runway 31 when the right engine lost power. According to a pilot-rated witness, the airplane was about halfway down the 6,500 ft runway at an altitude of about 100 ft above ground level when he heard a "loud pop" and then saw the airplane's right propeller slow. The witness reported that the airplane yawed to the right and then began a right turn toward runway 18 with the right engine's propeller windmilling. The witness further reported that the airplane cleared a tree line by about 150 ft, rolled right, descended straight down to ground impact, and burst into flames.
Postaccident examination of the airplane's right engine revealed that the crankshaft was fractured adjacent to the No. 2 main bearing, which had rotated. The crankcase halves adjacent to the No. 2 main bearing were fretted where the case through-studs were located. The fretting of the mating surfaces was consistent with insufficient clamping force due to insufficient torque of the through-stud nuts. Records indicated that all six cylinders on the right engine had been replaced at the airplane's most recent annual inspection 8 months before the accident. In order to replace the cylinders, the through-stud nuts had to be removed as they also served to hold down the cylinders. It is likely that when the cylinders were replaced, the through-stud nuts were not properly torqued, which, over time, allowed the case halves to move and led to the bearing spinning and the crankshaft fracturing.
During the accident sequence, the pilot made a right turn in an attempt to return to the airport and did not feather the failed (right) engine's propeller, allowing it to windmill, thereby creating excessive drag. It is likely that the pilot allowed the airspeed to decay below the minimum required for the airplane to remain controllable, which combined with his failure to feather the failed engine's propeller and the turn in the direction of the failed engine resulted in a loss of airplane control.
Probable cause
The loss of right engine power on takeoff due to maintenance personnel's failure to properly tighten the crankcase through-studs during cylinder replacement, which resulted in crankshaft fracture. Also causal were the pilot's failure to feather the propeller on the right engine and his failure to maintain control of the twin-engine airplane while maneuvering to return to the airport.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN16FA013
- Event ID
- 20151015X00706
- Case number
- CEN16FA013
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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: ed22c3c78c25772556c0ba7d8550d769c13471394c9d42156104a8c1c66945c5; retrieved 2026-09-14T21:32:48.203Z.