Aero Commander 500S N725AC

Summary

On 7 February 1992 at about 02:01 local time, a Aero Commander 500S registered N725AC, operated by Michael Stanton-Hicks, was involved in an accident near Richmond Hts., Ohio, United States. One person was on board and one died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

7 February 1992 at 02:01

Classification

Accident

Location

Richmond Hts., Ohio, United States

Coordinates

41.5492, -81.4795

Aircraft

Aero Commander 500S

Registration

N725AC

Category

Airplane

Engines

2

Operator

Michael Stanton-Hicks

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Aircraft damage

Destroyed

Weather

VMC

Light

Night/Dark

NTSB number

NYC92FA055

1 person died.

THE PILOT'S IMPROPER EMERGENCY PROCEDURES AND FAILURE TO MAINTAIN CONTROL OF THE AIRPLANE, WHICH RESULTED IN AN INADVERTENT SPIN AT TOO LOW AN ALTITUDE TO ALLOW RECOVERY. FACTORS IN THIS ACCIDENT WERE; A POWER LOSS IN THE LEFT ENGINE AS RESULT OF THE EXHAUST VALVE FAILURES IN CYLINDERS #3 AND #5.

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

Read the full NTSB narrative

THE PILOT HAD THE WASTE GATES ON THE TURBOCHARGES ADJUSTED AND WANTED TO TEST FLY THE AIRPLANE AFTER THE WORK WAS COMPLETED. THE AIRPLANE DEPARTED AND HAD REACHED AN ALTITUDE OF ABOUT 1000 FEET WHEN WITNESSES HEARD AN ENGINE SPUTTER. THE AIRPLANE WAS SEEN MAKING A LEFT TURN AND ENTER A NOSE LOW, LEFT SPIN BEFORE IMPACTING THE TERRAIN. A TEAR DOWN OF THE LEFT ENGINE REVEALED THAT THE EXHAUST VALVES IN CYLINDERS #3 AND #5 WERE BURNT THROUGH AT THE VALVE HEAD. THE #5 EXHAUST VALVE HAD A DEEP PREEXISTING DEEP MARK ON THE VALVE STEM. THE FAILURES OF BOTH VALVES WERE SUFFICENT ENOUGH TO CAUSE A POWER FAILURE IN THE LEFT ENGINE.

Quoted verbatim from the NTSB record.