Medium large transport departs over (maximum gross takeoff weight) maximum takeoff gross weight.

Attributes
ACN	280245
Time
Date	199408
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : lnk
State Reference	NE
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp pilot : cfi
Experience	flight time last 90 days : 230 flight time total : 10400 flight time type : 700
ASRS Report	280245
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument pilot : commercial
Events
Anomaly	non adherence : far non adherence : published procedure other anomaly other
Independent Detector	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:

Maximum allowable gross weight for takeoff is lowest of: structural, runway limit, performance limit, and maximum landing weight plus fuel burnout. This is done by computer and in 9 yrs at my airline I have never seen it in error until now. Early am flight planning for 5 legs showed a maximum takeoff gross weight of 105300 pounds (98,000 landing weight plus 7300 burnout), for leg #3. The day was extended by mechanic delays after a short night and we were tired. The flight plan (from early am) showed the maximum takeoff gross of 105300 pounds but the current weight manifest and performance data, computed and obtained at/near departure time, showed a maximum takeoff gross of 107100 pounds, (performance limited). We took off at 106900 pounds and discovered the error en route. We contacted dispatch and maintenance plus the decision was made to burnoff the excess fuel rather than land overweight. An investigation is underway. Factors: fatigue early flight planning of multiple legs. Dispatcher -- limited maximum takeoff gross's not considered when more current data presented. Too much trust in computer programming: we checked 3 of 4 limiting factors. Discussion with other pilots indicates this is an easy miss. Trust in current data, while ignoring older data. This is usually the correct thing to do.

Original NASA ASRS Text

Title: MLG DEPARTS OVER (MAX GROSS TKOF WT) MAX TKOF GROSS WT.

Narrative: MAX ALLOWABLE GROSS WT FOR TKOF IS LOWEST OF: STRUCTURAL, RWY LIMIT, PERFORMANCE LIMIT, AND MAX LNDG WT PLUS FUEL BURNOUT. THIS IS DONE BY COMPUTER AND IN 9 YRS AT MY AIRLINE I HAVE NEVER SEEN IT IN ERROR UNTIL NOW. EARLY AM FLT PLANNING FOR 5 LEGS SHOWED A MAX TKOF GROSS WT OF 105300 LBS (98,000 LNDG WT PLUS 7300 BURNOUT), FOR LEG #3. THE DAY WAS EXTENDED BY MECH DELAYS AFTER A SHORT NIGHT AND WE WERE TIRED. THE FLT PLAN (FROM EARLY AM) SHOWED THE MAX TKOF GROSS OF 105300 LBS BUT THE CURRENT WT MANIFEST AND PERFORMANCE DATA, COMPUTED AND OBTAINED AT/NEAR DEP TIME, SHOWED A MAX TKOF GROSS OF 107100 LBS, (PERFORMANCE LIMITED). WE TOOK OFF AT 106900 LBS AND DISCOVERED THE ERROR ENRTE. WE CONTACTED DISPATCH AND MAINT PLUS THE DECISION WAS MADE TO BURNOFF THE EXCESS FUEL RATHER THAN LAND OVERWT. AN INVESTIGATION IS UNDERWAY. FACTORS: FATIGUE EARLY FLT PLANNING OF MULTIPLE LEGS. DISPATCHER -- LIMITED MAX TKOF GROSS'S NOT CONSIDERED WHEN MORE CURRENT DATA PRESENTED. TOO MUCH TRUST IN COMPUTER PROGRAMMING: WE CHKED 3 OF 4 LIMITING FACTORS. DISCUSSION WITH OTHER PLTS INDICATES THIS IS AN EASY MISS. TRUST IN CURRENT DATA, WHILE IGNORING OLDER DATA. THIS IS USUALLY THE CORRECT THING TO DO.

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.