GA small aircraft made an off airport landing because of a rough running engine and the odor of oil.

Attributes
ACN	171790
Time
Date	199103
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : vgt
State Reference	NV
Altitude	msl bound lower : 3400 msl bound upper : 3400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : vgt
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 18 flight time total : 380 flight time type : 75
ASRS Report	171790
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	aircraft equipment problem : critical other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

I was at 3400' MSL approach altitude, 4 mi west of north las vegas airport, in communication with tower, preparing for a 3 mi straight-in approach to runway, in 3/91. Engine suddenly ran very rough with significant vibration. I told tower I was leaving area of airport traffic and flying north. I wanted to determine extend of problem away from airport traffic. Vibration got progressively worse. I smelled oil and started losing power. I immediately conducted checklist of emergency procedures and a search for any aircraft in area. Chose suitable landing area and landed aircraft in usual, uneventful fashion and shut engine off. On inspection of engine it was found that 2 bolts gear drive unit had failed and that unit was loose and lost oil.

Original NASA ASRS Text

Title: GA SMA MADE AN OFF ARPT LNDG BECAUSE OF A ROUGH RUNNING ENGINE AND THE ODOR OF OIL.

Narrative: I WAS AT 3400' MSL APCH ALT, 4 MI W OF NORTH LAS VEGAS ARPT, IN COM WITH TWR, PREPARING FOR A 3 MI STRAIGHT-IN APCH TO RWY, IN 3/91. ENG SUDDENLY RAN VERY ROUGH WITH SIGNIFICANT VIBRATION. I TOLD TWR I WAS LEAVING AREA OF ARPT TFC AND FLYING N. I WANTED TO DETERMINE EXTEND OF PROB AWAY FROM ARPT TFC. VIBRATION GOT PROGRESSIVELY WORSE. I SMELLED OIL AND STARTED LOSING PWR. I IMMEDIATELY CONDUCTED CHKLIST OF EMER PROCS AND A SEARCH FOR ANY ACFT IN AREA. CHOSE SUITABLE LNDG AREA AND LANDED ACFT IN USUAL, UNEVENTFUL FASHION AND SHUT ENG OFF. ON INSPECTION OF ENG IT WAS FOUND THAT 2 BOLTS GEAR DRIVE UNIT HAD FAILED AND THAT UNIT WAS LOOSE AND LOST OIL.

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.