Cessna 172R N2103T

Summary

On 2 November 2017 at about 16:30 local time, a Cessna 172R registered N2103T, operated by Iasco Flight Training Inc, was involved in an accident near Redding, California, United States. 3 people were 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

2 November 2017 at 16:30

Classification

Accident

Location

Redding, California, United States

Nearest airport

Redding Municipal Airport (KRDD)

Coordinates

40.5089, -122.2933

Aircraft

Cessna 172R

Registration

N2103T

Category

Airplane

Year built

2004

Engines

1

Operator

Iasco Flight Training Inc

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Redding → Chico

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR18LA039

Nobody was injured.

The fatigue separation of the crankshaft due to a fatigue fracture, which resulted in a total loss of engine power and a subsequent off-airport landing and impact with a fence.

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

Read the full NTSB narrative

Two student pilots and the flight instructor were conducting a cross-country instructional flight. The instructor reported that he told the student who was flying to climb to 3,500 ft above ground level (agl). As the airplane approached 3,100 ft agl, the student began leaning the mixture. Subsequently, the engine began to sputter, followed by a loss of all power. The instructor then saw sparks near the propeller area, took the flight controls, and turned back toward the departure airport. During short final, due to fire near the propeller area and the smell of smoke in the cockpit, the instructor turned the airplane 360° to try to lose altitude; however, the airplane was still too high to safely land on the runway. Subsequently, he conducted a forced landing to a field just past the runway, during which the airplane struck a fence, which resulted in substantial damage to the wing and firewall. Examination of the engine revealed that the crankshaft had separated at the propeller hub assembly and that a portion of it remained in the assembly. No holes were found in the engine case. Metallurgical examination revealed that the crankshaft had fractured into two halves at the main bearing journal’s forward side. The fracture consisted of two primary mating crack faces, one of which was circumferential and the other of which was a spiral through a lubrication hole to the inside of the crankshaft journal. The lubrication hole exhibited crack arrest marks that originated from the inside portion of the hole wall. The mating fracture surfaces of the circumferential and spiral fractures exhibited crack arrest marks consistent with progressive crack growth due to fatigue. The areas outside of the circumferential fracture exhibited features consistent with subsequent overstress fracture. Maintenance records revealed that at the time of the accident the engine had accumulated a total time of 3,907.1 hours and 1,153.7 hours since major overhaul. Based on the evidence, it is likely that the crankshaft fractured due to a fatigue crack that had initiated at a lubrication hole on the main bearing journal and then progressed in an outward spiral direction toward the inside surface of the crankshaft journal. The fatigue crack then progressed circumferentially until the crankshaft fractured into two halves due to overstress, which resulted in a subsequent total loss of engine power and off-airport landing.

Quoted verbatim from the NTSB record.