Narrative:

While flying a widebody transport aircraft; on the weight and balance form; we are given the fore and aft center of gravity limits for the flight but are not given the lateral limits of the aircraft at all. These limits; which are afm limitations; are not published in any of the pubs that are given to flight crews. On the B747 when in excess of 1.8 units of aileron trim input is used the spoilers are deployed; in conjunction with rudder trim as well. I have no hope of reaching my set performance goals for the flight. So when I have an abnormal fuel burn for the altitude and speed specified for the flight; the only unknowns are the lateral distribution of the load. The greater concern for safety is if we are 30000 pounds over our limit to one side; how does this affect vmcg? Will I be able to keep the aircraft in the clearway ahead due to loss of control effectiveness? Will the abnormal aileron inputs because of this degrade my ability to successfully fly the aircraft? If the aircraft is to make a technical fuel stop; is the aircraft loaded at the point of departure assuming it will be at maximum gross takeoff weight on the second leg with no redistribution of the load? With increasing loads on all our widebody transport aircraft in our fleet; why is this extra crosschk not furnished to the PIC? Boeing; airbus and mcdonnell douglas did not make aircraft without a lateral limit.

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Original NASA ASRS Text

Title: PLT OF B747 IS CONCERNED THAT LACK OF LATERAL CTR OF GRAVITY INFO FOR FLT CREWS MIGHT RESULT IN INABILITY TO CTL ACFT UNDER ASYMMETRICAL THRUST SITS. ALSO FEELS FLT CTL DEFLECTION REQUIRED TO CORRECT FOR LARGE CTR OF GRAVITY VARIATION FROM CTRLINE RESULTS IN INCREASED DRAG WHICH COMPROMISES SPECIFIC FUEL CONSUMPTION PLANNING.

Narrative: WHILE FLYING A WDB ACFT; ON THE WT AND BAL FORM; WE ARE GIVEN THE FORE AND AFT CTR OF GRAVITY LIMITS FOR THE FLT BUT ARE NOT GIVEN THE LATERAL LIMITS OF THE ACFT AT ALL. THESE LIMITS; WHICH ARE AFM LIMITATIONS; ARE NOT PUBLISHED IN ANY OF THE PUBS THAT ARE GIVEN TO FLT CREWS. ON THE B747 WHEN IN EXCESS OF 1.8 UNITS OF AILERON TRIM INPUT IS USED THE SPOILERS ARE DEPLOYED; IN CONJUNCTION WITH RUDDER TRIM AS WELL. I HAVE NO HOPE OF REACHING MY SET PERFORMANCE GOALS FOR THE FLT. SO WHEN I HAVE AN ABNORMAL FUEL BURN FOR THE ALT AND SPD SPECIFIED FOR THE FLT; THE ONLY UNKNOWNS ARE THE LATERAL DISTRIBUTION OF THE LOAD. THE GREATER CONCERN FOR SAFETY IS IF WE ARE 30000 LBS OVER OUR LIMIT TO ONE SIDE; HOW DOES THIS AFFECT VMCG? WILL I BE ABLE TO KEEP THE ACFT IN THE CLEARWAY AHEAD DUE TO LOSS OF CTL EFFECTIVENESS? WILL THE ABNORMAL AILERON INPUTS BECAUSE OF THIS DEGRADE MY ABILITY TO SUCCESSFULLY FLY THE ACFT? IF THE ACFT IS TO MAKE A TECHNICAL FUEL STOP; IS THE ACFT LOADED AT THE POINT OF DEP ASSUMING IT WILL BE AT MAX GROSS TKOF WT ON THE SECOND LEG WITH NO REDISTRIBUTION OF THE LOAD? WITH INCREASING LOADS ON ALL OUR WDB ACFT IN OUR FLEET; WHY IS THIS EXTRA CROSSCHK NOT FURNISHED TO THE PIC? BOEING; AIRBUS AND MCDONNELL DOUGLAS DID NOT MAKE ACFT WITHOUT A LATERAL LIMIT.

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.