A 1000 pound addition error allowed a B737-300 to be out of weight and balance limits for flight.

Attributes
ACN	639034
Time
Date	200412
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	ground : takeoff roll ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 240 flight time total : 6700 flight time type : 2800
ASRS Report	639034
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 150 flight time total : 20000 flight time type : 16000
ASRS Report	639035
Events
Anomaly	non adherence : company policies non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted none taken : detected after the fact none taken : unable
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance Company Aircraft
Primary Problem	Company

Narrative:

Upon reaching cruise flight, we noted the autoplt almost continually trimming. I had hand flown through about FL230 and had not noticed any unusual characteristics other than a lot of yoke pull on rotation, which is not uncommon on light takeoffs with very large thrust reductions. Upon inspection of the loading schedule, the captain noticed a 1000 pound error in the zero fuel weight, which in turn put the index balance unit out of limits. The takeoff weight index was within limits with the fuel added. The agent had done a good job at the gate and had done an 18 min turn, but did not seem hurried or rushed. A 1000 pound error is very hard to catch on a cursory math check by the crew. The use of the gate reader terminal for loading schedules should virtually eliminate this type of error.

Original NASA ASRS Text

Title: A 1000 LB ADDITION ERROR ALLOWED A B737-300 TO BE OUT OF WT AND BAL LIMITS FOR FLT.

Narrative: UPON REACHING CRUISE FLT, WE NOTED THE AUTOPLT ALMOST CONTINUALLY TRIMMING. I HAD HAND FLOWN THROUGH ABOUT FL230 AND HAD NOT NOTICED ANY UNUSUAL CHARACTERISTICS OTHER THAN A LOT OF YOKE PULL ON ROTATION, WHICH IS NOT UNCOMMON ON LIGHT TKOFS WITH VERY LARGE THRUST REDUCTIONS. UPON INSPECTION OF THE LOADING SCHEDULE, THE CAPT NOTICED A 1000 LB ERROR IN THE ZERO FUEL WT, WHICH IN TURN PUT THE INDEX BAL UNIT OUT OF LIMITS. THE TKOF WT INDEX WAS WITHIN LIMITS WITH THE FUEL ADDED. THE AGENT HAD DONE A GOOD JOB AT THE GATE AND HAD DONE AN 18 MIN TURN, BUT DID NOT SEEM HURRIED OR RUSHED. A 1000 LB ERROR IS VERY HARD TO CATCH ON A CURSORY MATH CHK BY THE CREW. THE USE OF THE GATE READER TERMINAL FOR LOADING SCHEDULES SHOULD VIRTUALLY ELIMINATE THIS TYPE OF ERROR.

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.