A B737-300 climbing out of ord was notified the weights were in error.

Attributes
ACN	707800
Time
Date	200608
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	msl single value : 15000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : c90.tracon
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 225 flight time total : 10000 flight time type : 5000
ASRS Report	707800
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : company policies non adherence : published procedure
Independent Detector	other other : load plan (3)
Resolutory Action	none taken : detected after the fact
Supplementary
Problem Areas	Company
Primary Problem	Company

Narrative:

Shortly after takeoff from runway 22L in ord; we received an ACARS message stating that the final weight manifest we received was 'invalid due to passenger count change. The station has revised the passenger count. Your current weights are now invalid. Please confirm receipt of this message.' the corrected final weight manifest was then sent to our ACARS printer. The passenger count had increased by 6; and our weight correspondingly increased by 1100 pounds! We noted the correction and applied the new zero fuel weight to our FMC and landing weight performance calculations. We continued the flight and landed in phl without further incident. This type of passenger count error from the station should not occur with the new system we're using today.

Original NASA ASRS Text

Title: A B737-300 CLBING OUT OF ORD WAS NOTIFIED THE WTS WERE IN ERROR.

Narrative: SHORTLY AFTER TKOF FROM RWY 22L IN ORD; WE RECEIVED AN ACARS MESSAGE STATING THAT THE FINAL WT MANIFEST WE RECEIVED WAS 'INVALID DUE TO PAX COUNT CHANGE. THE STATION HAS REVISED THE PAX COUNT. YOUR CURRENT WTS ARE NOW INVALID. PLEASE CONFIRM RECEIPT OF THIS MESSAGE.' THE CORRECTED FINAL WT MANIFEST WAS THEN SENT TO OUR ACARS PRINTER. THE PAX COUNT HAD INCREASED BY 6; AND OUR WT CORRESPONDINGLY INCREASED BY 1100 LBS! WE NOTED THE CORRECTION AND APPLIED THE NEW ZERO FUEL WT TO OUR FMC AND LNDG WT PERFORMANCE CALCULATIONS. WE CONTINUED THE FLT AND LANDED IN PHL WITHOUT FURTHER INCIDENT. THIS TYPE OF PAX COUNT ERROR FROM THE STATION SHOULD NOT OCCUR WITH THE NEW SYS WE'RE USING TODAY.

Data retrieved from NASA's ASRS site as of January 2009 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.