In the USAF system the first production model in an aircraft series normally has no letter for the model... the second model get the "A"
http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2551
The article itself stated the B-2A is a new model begin flight tests in June 2011 and reach operational status by June 2012...
The USAF plans to begin flight tests on the B-2A starting in June 2011 and reach operational status by June 2012
The B-2 model begin flight tests in 1989 and reach operational status in 1993
http://www.af.mil/information/factsheets/factsheet.asp?id=82
Thanks.
First production model of any aircraft type has the “A” designator under the current MDS (Mission, Design, Series) designation system.
A prototype test and evaluation aircraft would have a “Y” designator before the model type such as the YF-16 for example. When the F-16 was accepted into service, the designation was changed from YF-16 to F-16A.
http://www.designation-systems.net/usmilav/aircraft.html
“(5) Series Letter: Variants of a basic aircraft type are designated by a suffix letter. The first model always receives suffix “A” and subsequent series letters are to be assigned in strict sequence (omitting “I” and “O” to avoid confusion with numerals “1” and “0”). The series letter is actually a mandatory component of a conforming MDS, and therefore “plain” designations like “F-16” always designate the general type of aircraft and never a specific model.”
AIR FORCE JOINT INSTRUCTION 16-401:
http://www.fas.org/man/dod-101/dod/docs/16-401.htm#page1
“A2.7. Series (Required). Identifies the production model of a particular design number and later models representing major modifications that significantly alter the aerospace vehicle systems components or change the logistics support of the vehicle. Consecutive series symbols, starting with “A”, appear to the immediate right of the design number.”