C172 pilot had mental confusion and sickness that would indicate carbon monoxide poisoning.

Attributes
ACN	521361
Time
Date	200108
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : s27.airport
State Reference	MT
Altitude	agl single value : 800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme.artcc
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : traffic pattern approach : visual
Flight Plan	None
Aircraft 2
Make Model Name	Skyhawk 172/Cutlass 172
Flight Phase	landing : go around
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 60 flight time total : 390 flight time type : 230
ASRS Report	521361
Person 2
Function	flight crew : single pilot
Events
Anomaly	aircraft equipment problem : critical conflict : airborne less severe inflight encounter : weather non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : landed in emergency condition
Miss Distance	horizontal : 1300 vertical : 0
Supplementary
Problem Areas	Flight Crew Human Performance Aircraft Weather
Primary Problem	Aircraft

Narrative:

I was entering the traffic pattern at (S27). There was a C172 on left downwind for runway 13. I announced on the radio that I was #2 on left downwind for runway 13. Right after making the announcement my engine was sputtering due to lack of fuel caused by a headwind. At that point, I announced on the radio that I had engine emergency and needed to land immediately as I was even with the end of runway 31. The other plane said he would go around. I made a successful landing on runway 31 and cleared the runway. The wind was 180 degrees at 5 mph. The others C172 resumed its pattern and landed safely. I gassed up my plane. It took 38.01 gals on tanks that had 39 gals useable. The problem arose from a headwind occurring during the last leg of 100 mi flight from seely, lake michigan. I also was experiencing light headedness and felt nauseous. These symptoms came on halfway through the leg of the trip. I think these factors led to me choosing to land immediately instead of staying on downwind #2 over the city of kalispell. No one was hurt, no damage, no close encounter (airborne) with other aircraft.

Original NASA ASRS Text

Title: C172 PLT HAD MENTAL CONFUSION AND SICKNESS THAT WOULD INDICATE CARBON MONOXIDE POISONING.

Narrative: I WAS ENTERING THE TFC PATTERN AT (S27). THERE WAS A C172 ON L DOWNWIND FOR RWY 13. I ANNOUNCED ON THE RADIO THAT I WAS #2 ON L DOWNWIND FOR RWY 13. RIGHT AFTER MAKING THE ANNOUNCEMENT MY ENG WAS SPUTTERING DUE TO LACK OF FUEL CAUSED BY A HEADWIND. AT THAT POINT, I ANNOUNCED ON THE RADIO THAT I HAD ENG EMER AND NEEDED TO LAND IMMEDIATELY AS I WAS EVEN WITH THE END OF RWY 31. THE OTHER PLANE SAID HE WOULD GO AROUND. I MADE A SUCCESSFUL LNDG ON RWY 31 AND CLRED THE RWY. THE WIND WAS 180 DEGS AT 5 MPH. THE OTHERS C172 RESUMED ITS PATTERN AND LANDED SAFELY. I GASSED UP MY PLANE. IT TOOK 38.01 GALS ON TANKS THAT HAD 39 GALS USEABLE. THE PROB AROSE FROM A HEADWIND OCCURRING DURING THE LAST LEG OF 100 MI FLT FROM SEELY, LAKE MICHIGAN. I ALSO WAS EXPERIENCING LIGHT HEADEDNESS AND FELT NAUSEOUS. THESE SYMPTOMS CAME ON HALFWAY THROUGH THE LEG OF THE TRIP. I THINK THESE FACTORS LED TO ME CHOOSING TO LAND IMMEDIATELY INSTEAD OF STAYING ON DOWNWIND #2 OVER THE CITY OF KALISPELL. NO ONE WAS HURT, NO DAMAGE, NO CLOSE ENCOUNTER (AIRBORNE) WITH OTHER ACFT.

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.