An small aircraft twin shut down an engine due to oil loss. It landed safety en route.

Attributes
ACN	230230
Time
Date	199301
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ski
State Reference	IA
Altitude	msl bound lower : 9000 msl bound upper : 9000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zmp
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 2 Eng, Retractable Gear
Flight Phase	cruise other
Route In Use	enroute : on vectors enroute airway : zmp
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 100 flight time total : 1600
ASRS Report	230230
Person 2
Affiliation	Other
Function	observation : passenger
ASRS Report	230299
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : exited adverse environment flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

During an IFR flight from alliance, northeast, to rockford, il, I experienced loss of oil pressure on the left engine of an small aircraft. I immediately requested vectors to the nearest airport which was sac city (ski). During the descent to landing, the oil pressure dropped to red line on the left engine so I shut it down and feathered the propeller. I experienced no other difficulties during the flight. The next day (I waited for daylight to inspect the cause), the mechanic and I discovered that the throttle cable was resting against the oil filter. It appeared that, over time, engine vibration had caused the throttle cable to rub a hole in the oil filter causing the loss of pressure when it finally broke through. The mechanic replaced the filter and secured the throttle so it wouldn't occur again. This problem could not be seen during a preflight because it requires removing the cowling to see the filter and throttle cable. I believe this problem would never have occurred if the mechanic that performed the previous 100 hour inspection had properly secured the throttle cable instead of allowing it to rest on the oil filter.

Original NASA ASRS Text

Title: AN SMA TWIN SHUT DOWN AN ENG DUE TO OIL LOSS. IT LANDED SAFETY ENRTE.

Narrative: DURING AN IFR FLT FROM ALLIANCE, NE, TO ROCKFORD, IL, I EXPERIENCED LOSS OF OIL PRESSURE ON THE L ENG OF AN SMA. I IMMEDIATELY REQUESTED VECTORS TO THE NEAREST ARPT WHICH WAS SAC CITY (SKI). DURING THE DSCNT TO LNDG, THE OIL PRESSURE DROPPED TO RED LINE ON THE L ENG SO I SHUT IT DOWN AND FEATHERED THE PROP. I EXPERIENCED NO OTHER DIFFICULTIES DURING THE FLT. THE NEXT DAY (I WAITED FOR DAYLIGHT TO INSPECT THE CAUSE), THE MECH AND I DISCOVERED THAT THE THROTTLE CABLE WAS RESTING AGAINST THE OIL FILTER. IT APPEARED THAT, OVER TIME, ENG VIBRATION HAD CAUSED THE THROTTLE CABLE TO RUB A HOLE IN THE OIL FILTER CAUSING THE LOSS OF PRESSURE WHEN IT FINALLY BROKE THROUGH. THE MECH REPLACED THE FILTER AND SECURED THE THROTTLE SO IT WOULDN'T OCCUR AGAIN. THIS PROB COULD NOT BE SEEN DURING A PREFLT BECAUSE IT REQUIRES REMOVING THE COWLING TO SEE THE FILTER AND THROTTLE CABLE. I BELIEVE THIS PROB WOULD NEVER HAVE OCCURRED IF THE MECH THAT PERFORMED THE PREVIOUS 100 HR INSPECTION HAD PROPERLY SECURED THE THROTTLE CABLE INSTEAD OF ALLOWING IT TO REST ON THE OIL FILTER.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.