Small aircraft on IFR training flight has violent shaking of engine. Emergency landing.

Attributes
ACN	193601
Time
Date	199111
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : c49
State Reference	IL
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : ord tracon : rfd
Operator	general aviation : instructional
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	instruction : instructor
Qualification	pilot : cfi
Experience	flight time last 90 days : 205 flight time total : 828 flight time type : 40
ASRS Report	193601
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other other : unspecified cockpit
Resolutory Action	flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

On IFR training flight in level cruise when aircraft engine started to violently shake. Requested vectors for nearest airport to rockford approach. Rockford then turned us and asked if we could make a frequency change (nearest airport was in chicago's airspace). I contacted chicago, declared an emergency and was vectored to 'case de aeronautical' airport, was unable to find (I believe lights were non on private strip). Proceeded approximately 8 mi to an airport with a beacon, 'lndgs' airport, and was able to make a safe landing.

Original NASA ASRS Text

Title: SMA ON IFR TRAINING FLT HAS VIOLENT SHAKING OF ENG. EMER LNDG.

Narrative: ON IFR TRAINING FLT IN LEVEL CRUISE WHEN ACFT ENG STARTED TO VIOLENTLY SHAKE. REQUESTED VECTORS FOR NEAREST ARPT TO ROCKFORD APCH. ROCKFORD THEN TURNED US AND ASKED IF WE COULD MAKE A FREQ CHANGE (NEAREST ARPT WAS IN CHICAGO'S AIRSPACE). I CONTACTED CHICAGO, DECLARED AN EMER AND WAS VECTORED TO 'CASE DE AERO' ARPT, WAS UNABLE TO FIND (I BELIEVE LIGHTS WERE NON ON PRIVATE STRIP). PROCEEDED APPROX 8 MI TO AN ARPT WITH A BEACON, 'LNDGS' ARPT, AND WAS ABLE TO MAKE A SAFE LNDG.

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.