Date: 201206
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: B747 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Mission: Cargo / Freight / Delivery
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Confusion
Anomaly: Deviation / Discrepancy - Procedural Weight And Balance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented
Contributing factors: Procedure; Human Factors
Primary problem: Human Factors

Narrative: We were told it was going to be a light load; somewhere just above 100K LBS; which would allow us to go non-stop to destination. We ferried the aircraft empty and experienced no abnormal fuel problems or performance problems. Upon arriving we were met by the Load Master and informed it was going to be a very light load but it would bulk out. We got minimum crew rest before reporting for duty. Crew was well rested and was showing no signs or reports of fatigue. Load Master picked us up from the hotel. I have worked with this Load Master over many years and know him to be a competent employee. As to be expected; he had completed all paperwork and all required documents were in place. He informed us that it was a lighter load than expected (approximately 55K LBS); and that they had completed loading of the aircraft prior to our arrival. All paperwork was cross referenced by the three crew members as we began preparations for our flight. All numbers from Dispatch as well as the weight and balance were in agreement. On a personal note; I was surprised to see how much freight was on board considering the actual weight. It seemed we had a lot on board considering our light load. We were able to complete our duties and depart just a few minutes ahead of schedule. We were assigned the long runway. For our weight/conditions we were able to use a reduced power setting which we accomplished. In my years of experience you develop a 'feel' for the aircraft performance and as we took off I felt we had used more than normal runway for what should have. Nothing drastic; just out of the norm; there was no undue force on the controls at liftoff; nor was there any excessive pitch change. I commented this concern to my crew after takeoff and the first officer said that he had seen stagnation in the airspeed just before rotate speed and had delayed the rotate callout momentarily and this might have been the reason for the long takeoff.We were cleared right up to FL330 and started struggling to maintain airspeed and rate of climb fairly early. We continued to climb and at approximately 31;500 LBS we were not maintaining airspeed although we were down to 150 FPM climb. We continued to inch the aircraft up to our assigned altitude of FL330. By the time we leveled off we were at max climb power and just a few knots above our low end buffet speed. In level flight aircraft would not accelerate. We were in daytime VMC conditions. I could tell the aircraft was on the verge of a stall so we immediately requested a lower altitude from ATC and descended to FL310. This allowed our airspeed to return to normal but was requiring more than computed power settings to maintain desired airspeed. This aircraft had just undergone a flight spoiler problem on a previous flight so we visually confirmed that no spoilers were deployed. No vibrations were felt in the controls. All flight surfaces were confirmed in the proper position as well as gear and gear doors. At this point all indications were of a weight and balance/loading problem. At this point all loading data forms were reviewed by all crew members trying to ascertain the problem. Fuel consumption was being closely monitored and recorded. A visual inspection of the pallets was performed for any information that could explain our degraded performance. After several position reports and fuel burn calculations were performed we decided to bring Dispatch into this situation. We explained our predicament and told them we thought we had a LBS/kg problem. This radio/phone patch was unfortunately disconnected before Dispatch could suggest a remedy; but we knew they were now informed of out situation. When conditions did not improve; we once again made communication with Dispatch as our concern was we were questionable if: a. the company wanted us to continue on; b. we actually had enough fuel to make our destination. This call was more productive and management was made aware of our problem. We continued meticulouslymonitoring fuel flow/consumption. We were confident that this was a weight problem and were flying the aircraft now at what we now suspected was the proper weight. Communication directly with management put everyone into the loop and a plan of action was agreed upon by all parties. We would continue on; albeit; we would report our status continuously to Dispatch. Aircraft was configured and flown with the new weights. Landing was uneventful and aircraft limitations were not exceeded.The aircraft was loaded with cargo that had been identified as pounds as the unit of measurement; when actually it was measured in kilograms. On U.S. military loads we use pounds. A kilogram is the international standard for commercial freight; although our procedures are to convert this to pounds. This was a commercial load going to a military base and was obviously misinterpreted. Weight units were not clearly defined on the accompanying paperwork. Perhaps larger type could be utilized or a stand alone note that states which unit of measurement is being used; such as: 'ALL WEIGHTS IN KG'; or 'ALL WEIGHTS IN POUNDS'.




Synopsis: B747 Captain reports discovering airborne; that his cargo load of 55;000 pounds is actually 55;000 kilograms while attempting to reach FL330. The flight descends to FL310 and is able to continue to destination.