ATC noted an aircraft 1000 ft lower than cleared. It was discovered that the wrong altimeter was set...

Attributes
ACN	506170
Time
Date	200103
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mht.airport
State Reference	NH
Altitude	msl single value : 14000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : bwi.tracon
Operator	general aviation : personal
Make Model Name	Bonanza 35
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 14.2 flight time total : 2012 flight time type : 466
ASRS Report	506170
Events
Anomaly	airspace violation : entry non adherence : far
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude
Consequence	Other
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Set incorrect altimeter bar press which resulted in aircraft being aprox 1000 ft low in flight. While in contact with manchester approach, they noted my altitude error and cleared me thru their class C airspace. Due to altitude error, I may have passed thru nashua (ash) class D airspace. On landing, the full extent of my error was noted and corrected.

Original NASA ASRS Text

Title: ATC NOTED AN ACFT 1000 FT LOWER THAN CLRED. IT WAS DISCOVERED THAT THE WRONG ALTIMETER WAS SET.

Narrative: SET INCORRECT ALTIMETER BAR PRESS WHICH RESULTED IN ACFT BEING APROX 1000 FT LOW IN FLT. WHILE IN CONTACT WITH MANCHESTER APCH, THEY NOTED MY ALT ERROR AND CLRED ME THRU THEIR CLASS C AIRSPACE. DUE TO ALT ERROR, I MAY HAVE PASSED THRU NASHUA (ASH) CLASS D AIRSPACE. ON LNDG, THE FULL EXTENT OF MY ERROR WAS NOTED AND CORRECTED.

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.