Unauthorized penetration of class C airspace.

Attributes
ACN	272682
Time
Date	199406
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : dsm
State Reference	IA
Altitude	msl bound lower : 2300 msl bound upper : 2300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dsm tower : ptk
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 50 flight time total : 3400 flight time type : 1000
ASRS Report	272682
Events
Anomaly	aircraft equipment problem : critical non adherence : far other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Due to alternator failure (again) was trying to minimize radio and electrical usage and fly by pilotage only so as to have power available to land at rockford, il, and talk to tower there. I was going to skirt the des moines class C space entirely to the north but heavy rain showers there caused me to take a route to the south. Other showers forced me to go to the VOR (and turn on the navigation/communication) and stay below outer space floor of 2200 ft. I was staying at 2000-2100 ft while in the area, but an updraft lifted the aircraft to 2150 ft. Shortly after this it occurred to me that since I had the radio on anyway, I should get the altimeter from ATIS. The altimeter setting was reported as 30.12 while the setting I had been using was 29.98 or 30.00. Thus I had been at approximately 2300 ft when I thought I was still under the airspace floor. Contributing factors: trying to get by without using ATC not getting altimeter setting before negotiating class 'C' space get homeitis. Lesson - - even without charging working, the battery operated the radio for a long time before it was seriously low. Use it to communication and avoid potential problems.

Original NASA ASRS Text

Title: UNAUTH PENETRATION OF CLASS C AIRSPACE.

Narrative: DUE TO ALTERNATOR FAILURE (AGAIN) WAS TRYING TO MINIMIZE RADIO AND ELECTRICAL USAGE AND FLY BY PILOTAGE ONLY SO AS TO HAVE PWR AVAILABLE TO LAND AT ROCKFORD, IL, AND TALK TO TWR THERE. I WAS GOING TO SKIRT THE DES MOINES CLASS C SPACE ENTIRELY TO THE N BUT HVY RAIN SHOWERS THERE CAUSED ME TO TAKE A RTE TO THE S. OTHER SHOWERS FORCED ME TO GO TO THE VOR (AND TURN ON THE NAV/COM) AND STAY BELOW OUTER SPACE FLOOR OF 2200 FT. I WAS STAYING AT 2000-2100 FT WHILE IN THE AREA, BUT AN UPDRAFT LIFTED THE ACFT TO 2150 FT. SHORTLY AFTER THIS IT OCCURRED TO ME THAT SINCE I HAD THE RADIO ON ANYWAY, I SHOULD GET THE ALTIMETER FROM ATIS. THE ALTIMETER SETTING WAS RPTED AS 30.12 WHILE THE SETTING I HAD BEEN USING WAS 29.98 OR 30.00. THUS I HAD BEEN AT APPROX 2300 FT WHEN I THOUGHT I WAS STILL UNDER THE AIRSPACE FLOOR. CONTRIBUTING FACTORS: TRYING TO GET BY WITHOUT USING ATC NOT GETTING ALTIMETER SETTING BEFORE NEGOTIATING CLASS 'C' SPACE GET HOMEITIS. LESSON - - EVEN WITHOUT CHARGING WORKING, THE BATTERY OPERATED THE RADIO FOR A LONG TIME BEFORE IT WAS SERIOUSLY LOW. USE IT TO COM AND AVOID POTENTIAL PROBS.

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.