Cessna T210L N1631X

Summary

On 3 April 2014 at about 20:30 local time, a Cessna T210L registered N1631X, operated by Southern Aerial Images Inc, was involved in an accident near Clayton, Alabama, United States. 2 people were on board and one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

3 April 2014 at 20:30

Classification

Accident

Location

Clayton, Alabama, United States

Coordinates

31.9103, -85.3708

Aircraft

Cessna T210L

Registration

N1631X

Category

Airplane

Year built

1975

Engines

1

Operator

Southern Aerial Images Inc

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Valdosta → Tuscaloosa

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ERA14LA179

1 person had minor injuries.

Maintenance personnel’s failure to properly torque the engine case through bolts, which resulted in the fatigue fracture of the crankshaft and subsequent total loss of engine power.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The pilot receiving instruction reported that, about 1 hour into the flight, the engine "clunked and shuddered" and then lost total power. The flight instructor assumed control of the airplane and maneuvered it toward a nearby airport, and the pilot receiving instruction initiated an unsuccessful restart of the engine. After determining that the airplane was not going to reach the airport, the flight instructor executed a forced landing to a road, which resulted in substantial damage to the wings and firewall. Examination of the engine crankshaft revealed that it had fractured at the No. 2 main bearing journal; the fracture surface exhibited evidence consistent with fatigue crack propagation. The adjacent bearing materials had deformed and disintegrated. The failure of these components likely preceded the final fracture of the crankshaft. The bearing components from this section were generally too damaged to conclude the mode of failure. However, examination of the No. 6 bearing components and connecting rod bearing journal exhibited wear patterns and damage consistent with oil starvation; the oil starvation likely resulted from bearing movement, which can result from inadequate torque on the engine case through bolts. Although the torque values on the through bolts could not be determined, the failure of the engine's internal components and the oil starvation were consistent with the through bolts not being torqued properly. Further, the damage was also consistent with damage found on another airplane engine that had experienced a crankshaft failure and oil starvation, which was determined to had been caused by the engine through bolts not being properly torqued (NTSB accident number ERA14LA193). A review of maintenance records revealed that maintenance personnel had replaced the Nos. 2, 3, and 6 engine cylinders about 3 months before the accident. It is likely that maintenance personnel did not torque the through bolts in accordance with the manufacturer's specifications during this maintenance and that this led to the eventual fracture of the crankshaft. Further, during postaccident engine examination, metal particles were found in the oil sump. The maintenance records indicated that the engine oil was changed the day before the accident. However, the entry did not indicate that the oil filter was dissected or that the filter element was examined. It is likely that maintenance personnel did not examine the oil filter after the oil change and that, if they had examined the oil filter element, they would have detected the metal particles, which would have indicated an impending failure of an internal engine component.

Quoted verbatim from the NTSB record.