Cessna 172N N4688D

Summary

On 27 January 1987 at about 00:45 local time, a Cessna 172N registered N4688D, operated by H.f.g., Inc., was involved in an accident near Madison, Indiana, United States. 2 people were on board and nobody was injured. The aircraft was substantially damaged. No probable cause statement is available for this record.

Date

27 January 1987 at 00:45

Classification

Accident

Location

Madison, Indiana, United States

Nearest airport

Madison Municipal (IM5)

Coordinates

38.7509, -85.3791

Aircraft

Cessna 172N

Registration

N4688D

Category

Airplane

Engines

1

Operator

H.f.g., Inc.

Operating rule

Part 91: General Aviation

Purpose of flight

Instructional

Phase of flight

Not recorded

Route

Madison → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Night/Dark

NTSB number

CHI87LA068

Nobody was injured.

The NTSB has not published a probable cause for this record. No probable cause statement is present in the source data.

Nothing about the cause is stated here that is not in the source record.

Read the full NTSB narrative

AT APRX 2500 MSL, THE ENG STOPPED AND ATTEMPTS TO RESTART IT WERE NOT SUCCESSFUL. THE INSTRUCTOR TOOK CONTROL OF THE ACFT AND ATTEMPTED TO LAND ON THE HIGHWAY, BUT THE ACFT STRUCK POWERLINES AND A TELEPHONE POLE BEFORE NOSING OVER AND COMING TO REST. THE ENG WAS REMOVED FROM THE ACFT AND SUBSEQUENT TEARDOWN REVEALED THAT THE CRANKSHAFT GEAR TEETH WERE SHEARED. APRX 140 HRS PRIOR TO THE ACCIDENT, A REPAIR STATION HAD RE-NITRIDED THE CRANKSHAFT FOLLOWING RE-GRINDING OPERATIONS, HOWEVER, THE PRESSED ON TYPE GEAR WAS NOT REMOVED, AS REQUIRED, PRIOR TO RE-NITRIDING. SPECIFICATIONS STATE THAT THE GEAR SHOULD HAVE A MIN ROCKWELL HARDNESS OF 30N-77 AND THAT ANY TEMP IN EXCESS OF 300 DEGREES F WOULD AFFECT THE HARDNESS. WHEN TESTED, THE GEAR EXHIBITED A ROCKWELL HARDNESS OF 30N-39. THE TEMP REQUIRED FOR NITRIDING IS IN EXCESS OF 985 DEGREES F.

Quoted verbatim from the NTSB record.