Encountered strong updraft and penetrated the floor of the TCA.

Attributes
ACN	84633
Time
Date	198803
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : msp airport : mic
State Reference	MN
Altitude	msl bound lower : 2200 msl bound upper : 2400
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tower : stp
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Route In Use	enroute : direct
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 : 130 flight time type : 120
ASRS Report	84633
Person 2
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	inflight encounter : weather other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation

Narrative:

I was flying from minneapolis crystal airport to D97 via stp. After leaving crystal air traffic area I leveled off at 2200' MSL and reported my position to stp and requested transition to fleming. Transition was approved at 2200', which is normal. I then checked the INS and discovered the aircraft was climbing at almost 1000' FPM and my altitude was nearing 2400' MSL. The floor of the TCA is 2300' MSL. My aircraft has a fixed propeller and there was no RPM reduction or reduction in airspeed as in a normal climb. I pushed the nose over and reduced power, eventually to idle stop, but I only could get a 300 FPM descent at cruise airspeed. I believed that I was caught in an updraft and was afraid of diving the aircraft that close to the ground 1500' AGL. I must have flown out of the updraft after a couple of mins because the INS suddenly indicated a very fast descent. I slowed the descent to 500 FPM then leveled at 2200'. I did not report this incident to stop tower. Callback conversation with reporter revealed the following: reporter confirmed conditions were very uncomfortable due to the turbulence and xwinds. Excursion was only momentary and return to altitude was immediate. Had flown this route many times and knew it was the preferred method of flying to fleming. No follow-up by the FAA.

Original NASA ASRS Text

Title: ENCOUNTERED STRONG UPDRAFT AND PENETRATED THE FLOOR OF THE TCA.

Narrative: I WAS FLYING FROM MINNEAPOLIS CRYSTAL ARPT TO D97 VIA STP. AFTER LEAVING CRYSTAL ATA I LEVELED OFF AT 2200' MSL AND RPTED MY POS TO STP AND REQUESTED TRANSITION TO FLEMING. TRANSITION WAS APPROVED AT 2200', WHICH IS NORMAL. I THEN CHKED THE INS AND DISCOVERED THE ACFT WAS CLBING AT ALMOST 1000' FPM AND MY ALT WAS NEARING 2400' MSL. THE FLOOR OF THE TCA IS 2300' MSL. MY ACFT HAS A FIXED PROP AND THERE WAS NO RPM REDUCTION OR REDUCTION IN AIRSPD AS IN A NORMAL CLB. I PUSHED THE NOSE OVER AND REDUCED PWR, EVENTUALLY TO IDLE STOP, BUT I ONLY COULD GET A 300 FPM DSCNT AT CRUISE AIRSPD. I BELIEVED THAT I WAS CAUGHT IN AN UPDRAFT AND WAS AFRAID OF DIVING THE ACFT THAT CLOSE TO THE GND 1500' AGL. I MUST HAVE FLOWN OUT OF THE UPDRAFT AFTER A COUPLE OF MINS BECAUSE THE INS SUDDENLY INDICATED A VERY FAST DSCNT. I SLOWED THE DSCNT TO 500 FPM THEN LEVELED AT 2200'. I DID NOT RPT THIS INCIDENT TO STOP TWR. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR CONFIRMED CONDITIONS WERE VERY UNCOMFORTABLE DUE TO THE TURB AND XWINDS. EXCURSION WAS ONLY MOMENTARY AND RETURN TO ALT WAS IMMEDIATE. HAD FLOWN THIS RTE MANY TIMES AND KNEW IT WAS THE PREFERRED METHOD OF FLYING TO FLEMING. NO FOLLOW-UP BY THE FAA.

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.