MD-11
Flight Crew Air Transport Pilot (ATP)
Workload; Time Pressure; Fatigue; Distraction; Situational Awareness
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Weight And Balance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented; Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action
Chart Or Publication; Human Factors; Procedure
We operated a two leg trip with a short stop in ZZZZ before continuing on to our final destination. The first flight was uneventful. The flight to our final destination was uneventful until we were on the glideslope for the ILS approach to runway. At about 1000 feet I noticed that the airspeed on the PFD would turn amber if it went below the approach speed at all. I looked at the pitch attitude of the airplane on my PFD and noticed it was 7.5 degrees. I asked the Captain to check the AOA reading in the HUD. He said it was at the top of the approach reference band and maybe a little outside. I told him that something is wrong we are at too high a pitch attitude. I also said that at 7.5 deg he would have little or no ability to flare the airplane without a tailstrike. I suggested we bug the speed up some and he agreed. I set the bug up 5K above approach speed and I noticed our pitch dropped to about 5 deg. We were at 500 feet. We continued on to landing and both of us paid very close attention to the aircraft pitch during the flare. Landing was uneventful and we taxied back in. The post flight readout for the landing showed 1.3 G and 8 deg pitch.As we were taxiing to our parking spot I asked the captain if he had noticed anything about our previous airport approach being different. I was thinking that if we had a Freight misloading problem then it would have been an issue on approach there too. He said that he had not noticed anything out the ordinary on the previous airport approach. We looked at the FMS landing weight and noticed it was saying about 295;000 LBS. Which seemed to be too light based upon our fuel and payload. Once we got in the chocks we pulled out the weight and balance paperwork to check it over. The stop at the previous airport requires that we do a contingency weight and balance and I had run the module on the performance computer and entered the data onto the form. I quickly discovered that I had entered the wrong number for the Zero Fuel Weight (ZFW) onto the contingency weight and balance form. The number I entered on the form was 96;000 LBS less than our actual ZFW. The captain missed this when he reviewed the form and entered the incorrect number into the FMS. We also forgot to check the form against what was loaded in the FMS which might have been another opportunity to catch the mistake. (Although; there would have been no difference between the numbers on the form and what was in the FMS.) I needed to pay closer attention to the contingency weight and balance form. I was entering data and recording numbers on the form without asking myself if the numbers made sense. In hindsight; I probably entered a bad number in the computer which caused the error and I just recorded it right on to the contingency weight and balance form. I did not review it to double check all the numbers. I had done this flight a number of times in the past so I was comfortable with how to do the form but it had been 10 months or more since I had been in that airport. I was not looking at the task as high threat but as a relatively routine thing that I had done many times before. That was a mistake that allowed an error to go undetected.Forgetting to do the W+B check was also factor here (but as I said previously the check may not have caught the bad number on the form). Since the contingency weight and balance process is different than what we normally do; that may have contributed to breaking the habit pattern of remembering to do the check. This was our 4th flight together on this trip and we had accomplished the check on all previous flights. As a suggestion; maybe we should consider making it a checklist item instead of a memory item?I will also mention that this pairing is a disputed pairing and while I did get some rest prior to the flight; the time of day of the flight combined with the 2 legs and 24 hr layover makes it a difficult day. I know I was tired and I believe the captain was too. The last thing I want to mention is that although we made a mistake today that could have had grave consequences; we discovered that something was wrong and took the correct action to fix the problem. I firmly believe that catching this on final was as a result of the training we received on the annual simulator. Had I not seen this very scenario in the simulator; I do not think I would have caught it in the airplane before we landed. The result could have been very different. The training is very valuable and we should keep doing it.
Departing manual weight and balance was completed incorrectly and verified incorrectly by crew resulting in an inputted ZFW 96;000 LBS below actual. As a result approach speed were low and a check of the AOA at 1000 feet AGL was outside brackets at approximately 10.2. 5 knots was added to approach speed resulting in a better configuration for landing. Aircraft landed with 7.5 - 8.0 pitch up attitude with very little flare.Fatigue; Rushing; A non-standard procedure not practiced with any regularity by crew; Human Error.Slower pace; better attention and awareness of non-standard procedures involved. Crew awareness and situational awareness on approach; along with training probably mitigated the resulting possibility of aircraft damage.
A MD-11 First Officer's manual weight calculation was based on a very low Zero Fuel Weight which resulted in a low speed; high angle of attack approach. The high angle of attack was corrected preventing a tail strike; but the computation error was only discovered during post flight.