Narrative:

Climbing out from runway xxl; I noticed oil drops on the windshield. I had just started turning to my vector heading and the controller had just instructed me to contact departure. The oil drops quickly turned into a solid coverage of a circular area of about 8-10 inches in diameter right in front of my viewing area. Since I had added a quart of engine oil before the flight; I immediately assumed it was related. Not knowing the extent of the oil leak; I decided to declare an emergency; which I did on the tower frequency. I was still in VMC; well below the 2300 ft overcast layer at this point. I told the tower I had an engine emergency; but that the engine was still making good power. The tower cleared me to land on runway xxr. I began a turn for a close-in right downwind to runway xxr. However; seeing the 12000 ft long runway right below me; I requested and received clearance to land opposite direction. I landed beyond mid-field and requested clearance to back-taxi to the taxiway which was a few hundred ft behind me. Tower cleared that and I executed the turn and back-taxi. The engine continued to produce normal power throughout the approach; landing; and taxiing. I taxied back to the FBO and was met there by emergency personnel. One of them opened the oil filter access door on the cowling and reported that the oil filler cap had come off in-flight. Upon examination; the oil level was about 1/4 - 1/2 quart lower than it was before the engine was started. I believe the root cause of this emergency was that I failed to securely replace the oil filler cap after adding engine oil during the preflight. Currently; cessna's published preflight procedures call for checking the engine oil level (which is done via a different cowling access door); but the preflight procedures do not call for checking the engine oil filler cap. I will be adding this item to my personal preflight procedures in the future. I have reconsidered whether I should or should not have declared an emergency in this situation. The fact is that I would have been fine had I simply requested an urgent return to the field; flown a full pattern back around and landed. As it was; the runway was closed for several mins while I landed against the flow and emergency crews swept the runway; which resulted in about a 20 min delay for 3-4 airliners waiting at runway xxr. None of that would have happened had I not used the 'east' word. However; I believe I did the best thing by declaring the emergency. At the time; I did not know the root cause of the oil on the windshield and even with the limited oil loss; there still could have been an engine fire. Thinking of other problem in a single engine aircraft is just always an emergency!

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Original NASA ASRS Text

Title: CESSNA PILOT REPORTS OIL ON WINDSCREEN DURING DEPARTURE AND DECLARES EMERGENCY WITH TOWER AND RETURNS FOR SAFE LANDING.

Narrative: CLBING OUT FROM RWY XXL; I NOTICED OIL DROPS ON THE WINDSHIELD. I HAD JUST STARTED TURNING TO MY VECTOR HDG AND THE CTLR HAD JUST INSTRUCTED ME TO CONTACT DEP. THE OIL DROPS QUICKLY TURNED INTO A SOLID COVERAGE OF A CIRCULAR AREA OF ABOUT 8-10 INCHES IN DIAMETER RIGHT IN FRONT OF MY VIEWING AREA. SINCE I HAD ADDED A QUART OF ENG OIL BEFORE THE FLT; I IMMEDIATELY ASSUMED IT WAS RELATED. NOT KNOWING THE EXTENT OF THE OIL LEAK; I DECIDED TO DECLARE AN EMER; WHICH I DID ON THE TWR FREQ. I WAS STILL IN VMC; WELL BELOW THE 2300 FT OVCST LAYER AT THIS POINT. I TOLD THE TWR I HAD AN ENG EMER; BUT THAT THE ENG WAS STILL MAKING GOOD PWR. THE TWR CLRED ME TO LAND ON RWY XXR. I BEGAN A TURN FOR A CLOSE-IN R DOWNWIND TO RWY XXR. HOWEVER; SEEING THE 12000 FT LONG RWY RIGHT BELOW ME; I REQUESTED AND RECEIVED CLRNC TO LAND OPPOSITE DIRECTION. I LANDED BEYOND MID-FIELD AND REQUESTED CLRNC TO BACK-TAXI TO THE TXWY WHICH WAS A FEW HUNDRED FT BEHIND ME. TWR CLRED THAT AND I EXECUTED THE TURN AND BACK-TAXI. THE ENG CONTINUED TO PRODUCE NORMAL PWR THROUGHOUT THE APCH; LNDG; AND TAXIING. I TAXIED BACK TO THE FBO AND WAS MET THERE BY EMER PERSONNEL. ONE OF THEM OPENED THE OIL FILTER ACCESS DOOR ON THE COWLING AND RPTED THAT THE OIL FILLER CAP HAD COME OFF INFLT. UPON EXAM; THE OIL LEVEL WAS ABOUT 1/4 - 1/2 QUART LOWER THAN IT WAS BEFORE THE ENG WAS STARTED. I BELIEVE THE ROOT CAUSE OF THIS EMER WAS THAT I FAILED TO SECURELY REPLACE THE OIL FILLER CAP AFTER ADDING ENG OIL DURING THE PREFLT. CURRENTLY; CESSNA'S PUBLISHED PREFLT PROCS CALL FOR CHKING THE ENG OIL LEVEL (WHICH IS DONE VIA A DIFFERENT COWLING ACCESS DOOR); BUT THE PREFLT PROCS DO NOT CALL FOR CHKING THE ENG OIL FILLER CAP. I WILL BE ADDING THIS ITEM TO MY PERSONAL PREFLT PROCS IN THE FUTURE. I HAVE RECONSIDERED WHETHER I SHOULD OR SHOULD NOT HAVE DECLARED AN EMER IN THIS SITUATION. THE FACT IS THAT I WOULD HAVE BEEN FINE HAD I SIMPLY REQUESTED AN URGENT RETURN TO THE FIELD; FLOWN A FULL PATTERN BACK AROUND AND LANDED. AS IT WAS; THE RWY WAS CLOSED FOR SEVERAL MINS WHILE I LANDED AGAINST THE FLOW AND EMER CREWS SWEPT THE RWY; WHICH RESULTED IN ABOUT A 20 MIN DELAY FOR 3-4 AIRLINERS WAITING AT RWY XXR. NONE OF THAT WOULD HAVE HAPPENED HAD I NOT USED THE 'E' WORD. HOWEVER; I BELIEVE I DID THE BEST THING BY DECLARING THE EMER. AT THE TIME; I DID NOT KNOW THE ROOT CAUSE OF THE OIL ON THE WINDSHIELD AND EVEN WITH THE LIMITED OIL LOSS; THERE STILL COULD HAVE BEEN AN ENG FIRE. THINKING OF OTHER PROB IN A SINGLE ENG ACFT IS JUST ALWAYS AN EMER!

Data retrieved from NASA's ASRS site as of May 2009 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.