Narrative:

I had departed humboldt airport, humboldt, ia, VFR to rochester, mn. The total elapsed flight time was now about 15 mins. A smell was noticed in the cabin. I could not identify the source of the smell. I observed the engine instruments. Oil pressure. Oil temperature and ammeter readings were all normal. Suddenly the oil pressure gauge read zero! I had checked the oil prior to takeoff and had 8 qts of oil on the dipstick. I immediately reduced power to idle and started looking for a place to land. I observed the eagle grove airport to the south of my position. The wind is from the south at better than 30 KTS at my altitude. I decided in just a few seconds that it was not possible to make the airport. I noticed a blacktop road with no traffic on it. I could see 2 mi to the town of goldfield and there was no traffic. I shut down the electrical system and left the engine running, in case I would need any power just prior to touching down. When I had the road made, I cut the magneto switch. I checked the dipstick and there was no oil. The engine compartment was full of oil on the left side. The total flight time was 20 mins. I took less than 5 mins from the time of the oil pressure problem to touchdown and rollout. The annual had been completed just a few flight hours prior to the incident. The engine had a total time of 1401.3 hours since overhaul at the time of the annual. The engine had a complete overhaul that was completed in 3/78. The engine oil cooler hoses had been replaced at this overhaul. Apparently the oil cooler hose had aged beyond a service limit. The right oil cooler hose had failed in flight, causing all oil to be pumped overboard. The oil lines did appear to be serviceable at the time of the last annual inspection in 2/89. I would suggest that any oil cooler line that is over 10 yrs old be replaced at the next annual. Apparently the heat that is generated in this installation coupled with the effects of aging had caused the oil cooler line to reach end of life with a resulting catastrophic failure (rupture).

Related reports:

Google
 

Original NASA ASRS Text

Title: GA SMA LOST OIL QUANTITY AND PRESSURE AT CRUISE ALT. PLT MADE AN EMERGENCY LNDG ON A COUNTRY ROAD.

Narrative: I HAD DEPARTED HUMBOLDT ARPT, HUMBOLDT, IA, VFR TO ROCHESTER, MN. THE TOTAL ELAPSED FLT TIME WAS NOW ABOUT 15 MINS. A SMELL WAS NOTICED IN THE CABIN. I COULD NOT IDENT THE SOURCE OF THE SMELL. I OBSERVED THE ENG INSTS. OIL PRESSURE. OIL TEMP AND AMMETER READINGS WERE ALL NORMAL. SUDDENLY THE OIL PRESSURE GAUGE READ ZERO! I HAD CHKED THE OIL PRIOR TO TKOF AND HAD 8 QTS OF OIL ON THE DIPSTICK. I IMMEDIATELY REDUCED PWR TO IDLE AND STARTED LOOKING FOR A PLACE TO LAND. I OBSERVED THE EAGLE GROVE ARPT TO THE S OF MY POS. THE WIND IS FROM THE S AT BETTER THAN 30 KTS AT MY ALT. I DECIDED IN JUST A FEW SECS THAT IT WAS NOT POSSIBLE TO MAKE THE ARPT. I NOTICED A BLACKTOP ROAD WITH NO TFC ON IT. I COULD SEE 2 MI TO THE TOWN OF GOLDFIELD AND THERE WAS NO TFC. I SHUT DOWN THE ELECTRICAL SYS AND LEFT THE ENG RUNNING, IN CASE I WOULD NEED ANY PWR JUST PRIOR TO TOUCHING DOWN. WHEN I HAD THE ROAD MADE, I CUT THE MAGNETO SWITCH. I CHKED THE DIPSTICK AND THERE WAS NO OIL. THE ENG COMPARTMENT WAS FULL OF OIL ON THE L SIDE. THE TOTAL FLT TIME WAS 20 MINS. I TOOK LESS THAN 5 MINS FROM THE TIME OF THE OIL PRESSURE PROB TO TOUCHDOWN AND ROLLOUT. THE ANNUAL HAD BEEN COMPLETED JUST A FEW FLT HRS PRIOR TO THE INCIDENT. THE ENG HAD A TOTAL TIME OF 1401.3 HRS SINCE OVERHAUL AT THE TIME OF THE ANNUAL. THE ENG HAD A COMPLETE OVERHAUL THAT WAS COMPLETED IN 3/78. THE ENG OIL COOLER HOSES HAD BEEN REPLACED AT THIS OVERHAUL. APPARENTLY THE OIL COOLER HOSE HAD AGED BEYOND A SVC LIMIT. THE R OIL COOLER HOSE HAD FAILED IN FLT, CAUSING ALL OIL TO BE PUMPED OVERBOARD. THE OIL LINES DID APPEAR TO BE SERVICEABLE AT THE TIME OF THE LAST ANNUAL INSPECTION IN 2/89. I WOULD SUGGEST THAT ANY OIL COOLER LINE THAT IS OVER 10 YRS OLD BE REPLACED AT THE NEXT ANNUAL. APPARENTLY THE HEAT THAT IS GENERATED IN THIS INSTALLATION COUPLED WITH THE EFFECTS OF AGING HAD CAUSED THE OIL COOLER LINE TO REACH END OF LIFE WITH A RESULTING CATASTROPHIC FAILURE (RUPTURE).

Data retrieved from NASA's ASRS site as of August 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.