Hudson - Boulder

During the instructional flight, the instructor shut down the right engine and feathered the propeller. It was subsequently restarted, but the left engine started running rough and began to vibrate. The left engine was shut down and the propeller feathered. Level flight was maintained from power produced by the right engine. The left engine was then restarted but instead of producing thrust, the engine produced more drag so it was secured again. Then the right engine began losing power. Full power was applied but the airplane continued to descend. The instructor lowered the landing gear and while in-transit, the airplane clipped the tops of trees. He was able to guide the airplane between two houses and impacted an open field. The airplane bounced across the road, struck a power pole, and caught fire. The two pilots evacuated the airplane via the main cabin door. Examination at the airport of departure disclosed two pools of oil at the approximate positions of the two engines. There were two trails of oil leading from the parking spot down the taxiway and onto the runway. Both engines were partially disassembled and examined. There was evidence that both engines had failed catastrophically due to oil starvation. The left engine crankshaft was broken and all the piston heads were at the tops of their cylinders. Pieces of metal were recovered from the right engine oil sump. According to the operator, the engine rocker box recovery system must be drained during preflight to avoid hydraulic lock. The instructor stated that when they preflighted the airplane, the drain valves were open (the drained oil is captured and recycled). He thought they had closed both valves. According to the operator, either the pilot's failed to close the drain valves or they were jammed in the open position. The operator said the latter was unlikely "because you can feel it move when you close it."

Flight / Schedule

Hudson - Boulder

Registration

N9562Z

MSN

AF-12

Year of Manufacture

1946

Date

July 19, 2007 at 09:00 AM

Type

CRASH

Flight Type

Training

Flight Phase

Flight

Crash Site

Plain, Valley

Crash Location

Longmont Colorado

Region

North America • United States of America

Coordinates

40.1672°, -105.1019°

Crash Cause

Human factor

Narrative Report

On July 19, 2007 at 09:00 AM, Hudson - Boulder experienced a crash involving Beechcraft C-45 Expeditor, operated by American Airpower Heritage Museum, with the event recorded near Longmont Colorado.

The flight was categorized as training and the reported phase was flight at a plain, valley crash site.

2 people were known to be on board, 0 fatalities were recorded, 2 survivors were identified or estimated. This corresponds to an estimated fatality rate of 0.0%.

Crew on board: 2, crew fatalities: 0, passengers on board: 0, passenger fatalities: 0, other fatalities: 0.

The listed crash cause is human factor. During the instructional flight, the instructor shut down the right engine and feathered the propeller. It was subsequently restarted, but the left engine started running rough and began to vibrate. The left engine was shut down and the propeller feathered. Level flight was maintained from power produced by the right engine. The left engine was then restarted but instead of producing thrust, the engine produced more drag so it was secured again. Then the right engine began losing power. Full power was applied but the airplane continued to descend. The instructor lowered the landing gear and while in-transit, the airplane clipped the tops of trees. He was able to guide the airplane between two houses and impacted an open field. The airplane bounced across the road, struck a power pole, and caught fire. The two pilots evacuated the airplane via the main cabin door. Examination at the airport of departure disclosed two pools of oil at the approximate positions of the two engines. There were two trails of oil leading from the parking spot down the taxiway and onto the runway. Both engines were partially disassembled and examined. There was evidence that both engines had failed catastrophically due to oil starvation. The left engine crankshaft was broken and all the piston heads were at the tops of their cylinders. Pieces of metal were recovered from the right engine oil sump. According to the operator, the engine rocker box recovery system must be drained during preflight to avoid hydraulic lock. The instructor stated that when they preflighted the airplane, the drain valves were open (the drained oil is captured and recycled). He thought they had closed both valves. According to the operator, either the pilot's failed to close the drain valves or they were jammed in the open position. The operator said the latter was unlikely "because you can feel it move when you close it."

Aircraft reference details include registration N9562Z, MSN AF-12, year of manufacture 1946.

Geospatial coordinates for this crash are approximately 40.1672°, -105.1019°.

Fatalities

Total

0

Crew

0

Passengers

0

Other

0

Crash Summary

During the instructional flight, the instructor shut down the right engine and feathered the propeller. It was subsequently restarted, but the left engine started running rough and began to vibrate. The left engine was shut down and the propeller feathered. Level flight was maintained from power produced by the right engine. The left engine was then restarted but instead of producing thrust, the engine produced more drag so it was secured again. Then the right engine began losing power. Full power was applied but the airplane continued to descend. The instructor lowered the landing gear and while in-transit, the airplane clipped the tops of trees. He was able to guide the airplane between two houses and impacted an open field. The airplane bounced across the road, struck a power pole, and caught fire. The two pilots evacuated the airplane via the main cabin door. Examination at the airport of departure disclosed two pools of oil at the approximate positions of the two engines. There were two trails of oil leading from the parking spot down the taxiway and onto the runway. Both engines were partially disassembled and examined. There was evidence that both engines had failed catastrophically due to oil starvation. The left engine crankshaft was broken and all the piston heads were at the tops of their cylinders. Pieces of metal were recovered from the right engine oil sump. According to the operator, the engine rocker box recovery system must be drained during preflight to avoid hydraulic lock. The instructor stated that when they preflighted the airplane, the drain valves were open (the drained oil is captured and recycled). He thought they had closed both valves. According to the operator, either the pilot's failed to close the drain valves or they were jammed in the open position. The operator said the latter was unlikely "because you can feel it move when you close it."

Cause: Human factor

Occupants & Outcome

Crew On Board

2

Passengers On Board

0

Estimated Survivors

2

Fatality Rate

0.0%

Known people on board: 2

Operational Details

Schedule / Flight

Hudson - Boulder

Flight Type

Training

Flight Phase

Flight

Crash Site

Plain, Valley

Region / Country

North America • United States of America

Aircraft Details

Registration

N9562Z

MSN

AF-12

Year of Manufacture

1946