NORWALK, IA, USA
N67399
CESSNA 152
APPROACHING DES MOINES AIRPORT THE PLT RPTD TO APPROACH CONTROL OF ENG PROBLEMS AND WANTED TO KNOW WHAT AIRPORT WAS CLOSE FOR AN PRECAUTIONARY LANDING. AN ATTEMPT WAS MADE TO LAND AT AN AIRSTRIP 3 MI EAST OF HIS PRESENT POSN. UNABLE TO LAND AT THE AIRSTRIP THE ACFT MADE A LANDING TO A FIELD WHERE IT SUSTAINED SUBSTANTIAL DAMAGE. INSPECTION OF THE ENG REVEALED A BROKEN CRANKSHAFT IDLER GEAR. FATIGUE PROGRESSION WAS EVIDENT ON THE FRACTURE SURFACES EXAMINED. ALSO NOTED WAS AN ELLIPTICAL DEFORMATION OF THE THREADED PORTION OF THE RETAINING BOLT BELOW THE BOLT HEAD. THIS DEFORMATION WAS OF THE SAME THICKNESS AS THE BOLTFLANGE AND LOCKNUT PLATE. VISUAL INSPECTION OF THE FRACTURE SURFACES GAVE NO EVIDENCE OF UNUSUAL CONTACT OR WEAR PATTERN PRIOR TO FAILURE.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
