Beechcraft E33 N7011N

Summary

On 16 October 2011 at about 20:56 local time, a Beechcraft E33 registered N7011N, operated by Fly Corona!, was involved in an accident near Daggett, California, United States. 3 people were on board and 3 died. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

16 October 2011 at 20:56

Classification

Accident

Location

Daggett, California, United States

Nearest airport

Daggett-Barstow Airport (KDAG)

Coordinates

34.9356, -116.6644

Aircraft

Beechcraft E33

Registration

N7011N

Category

Airplane

Engines

1

Operator

Fly Corona!

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Las Vegas → Corona

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR12FA012

3 people died.

A loss of engine power due to the separation of a connecting rod, and the pilot's failure to maintain airplane control during a sudden maneuver to avoid power lines during the descent, which resulted in an unrecoverable aerodynamic stall and subsequent spin. Contributing to the accident was noncompliance with the manufacturer-recommended engine overhaul schedule.

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

Read the full NTSB narrative

While in cruise flight, the pilot transmitted that he was in trouble and thought the airplane had experienced a propeller failure. The air traffic controller provided the pilot with instructions to the nearest airport, which was about 21 miles away. The pilot radioed that he thought that he could make it and began a descent toward the airport. A witness near the accident site observed the airplane flying in a southwesterly direction about 500 feet above ground level. As the airplane approached a set of suspended power lines, it pitched up 15 degrees, increased altitude by 100 to 200 feet, yawed to the right, made two 360-degree rotations descending vertically, and impacted terrain, consistent with an aerodynamic stall/spin. Postaccident examination of the engine revealed a 2-inch hole in the top of the crankcase between the Nos. 3 and 4 cylinders. The No. 1 piston connecting rod had separated from the crankshaft, bending the end cap flat with no thermal discoloration evident. Laboratory examination of the bearing insert half identified circumferential wear marks on the back side of the bearing insert. The wear marks on the backside of the intact insert, the lack of heat damage to the connecting rod journal, and the lack of heat damage to the connecting rod and end cap suggest that the bearing began to spin, which led to extrusion/ejection of half of the connecting rod bearing. Once the bearing was free, fragments of bearing material worked their way up between the piston and the cylinder wall causing damage to and embedding in the piston skirt. The increased clearances between the connecting rod end cap and connecting rod journal caused large stress amplitudes that resulted in a fatigue fracture of the connecting rod bolts. In 1998, after 1,002 hours of operation, the engine was top overhauled. A top overhaul does not inspect or replace items inside the crankcase, such as the main bearings or connecting rod bearings. At the time of the accident, the engine had accumulated 2,601 hours. The engine manufacturer recommends that the time between overhaul be 1,500 hours or every 12 years.

Quoted verbatim from the NTSB record.