Cessna T210N N1925U

Summary

On 28 September 2021 at about 20:08 local time, a Cessna T210N registered N1925U was involved in an accident near East Sparta, Ohio, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

28 September 2021 at 20:08

Classification

Accident

Location

East Sparta, Ohio, United States

Coordinates

40.6900, -81.3500

Aircraft

Cessna T210N

Registration

N1925U

Category

Airplane

Year built

1982

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Wadsworth → Wadsworth

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN21LA472

Nobody was injured.

A total loss of engine power due to a fatigue failure of the No. 2 cylinder exhaust valve.

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

Read the full NTSB narrative

The pilot reported that during cruise flight the engine began to run rough with a sudden decrease in engine manifold pressure and exhaust gas temperature for cylinder Nos. 2 and 4. The engine continued to run erratically for another 100 seconds before it lost total power. The pilot made a forced landing on hilly terrain, during which the nose gear collapsed. The airplane’s engine mount and lower fuselage structure were substantially damaged. Postaccident examination determined that the No. 2 cylinder exhaust valve fractured near the stem-to-fillet transition. The fracture surface exhibited features consistent with a fatigue failure. Additionally, the clearance from the exhaust valve stem to the valve guide exceeded the manufacturer’s service limit. The No. 2 cylinder exhaust valve failed in fatigue likely due to the wear of the valve guide and rocker arm bearing systems. The wear of the guide allowed the exhaust valve to move so that it could no longer consistently contact the valve seat. The asymmetric load induced a bending moment on the exhaust valve stem that eventually resulted in the initiation of a fatigue crack along the stem edge. The wear of the rocker arm shaft and rocker arm bearing likely contributed to the exhaust valve failure by tilting the rocker arm and changing the angle at which it engaged the tip of the exhaust valve stem.

Quoted verbatim from the NTSB record.