B747 Undifferentiated or Other Model
Flight Crew Last 90 Days 190; Flight Crew Total 21850; Flight Crew Type 11000
Situational Awareness; Distraction
Deviation / Discrepancy - Procedural Weight And Balance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Human Factors
Prior to pushback; a pre-departure briefing was accomplished: (Captain) Pilot Flying and (First Officer) Pilot Monitoring. The ATIS report indicated VFR weather with gusty crosswinds 20-25 knots. Even though wind-shear was not being reported; I advocated using Max thrust with Flaps 20. The Captain and I discussed it and agreed it was the best option for takeoff. After pulling up the ACARS Takeoff Data Message for our runway; I gave a performance briefing based on these preferences. The planned TOGW was approximately 854.0; MAX EPR 1.51; and N1 of 98. After pushback and sometime during engine start-up; the final weights were received. Once all engines were started; the Primary Relief Pilot handed me the print out of the final weights. After review; I entered the Final ZFW value into the CDU. I noted a TOW change of (-907 lbs) and verbalized this out loud. The Captain acknowledged the change. I left the CDU on the performance page for final TOGW reference and for the Primary Relief Pilot to call up the ACARS Final Takeoff Data Message based on the final TOGW. During our taxi out; the Primary Relief Pilot handed me the printed Final Takeoff Data. For reasons which I still cannot fully explain; my eyes fell primarily to the Max EPR; N1; and Flap 20 information and not the TOGW and accompanying V-speeds. Because of the slight change in weight (-907 lbs) the best explanation I can offer is that I was not expecting the final performance values and speeds to vary significantly from what I previously briefed. This oversight caused me to fail in discovering that the Primary Relief Pilot had mistakenly used the final ZFW value instead of the final TOGW for the calculation of the Final Takeoff Performance Data. As we continued our taxi out to the runway; I entered the V-speeds for Max EPR without any scrutiny. The V-speeds entered into the CDU were based on the wrong weight. Once the Final Takeoff Data Message was passed forward; I read out loud and briefed the updated data for the Captain and Relief First Officer. After this; I placed the printed data message on the center console for the Captain and relief pilots to re-verify. Remarkably; neither the Captain nor the relief pilots caught any of the errors. As we approached the end of the runway; we ran the before takeoff checklist. The last line on the checklist before Final Items is MCP. Both the Captain and I recalled that V2 response was read at 180 which is a typical value for a heavyweight take-off. I believe the best reason to help explain why the MCP V2 speed was set at this value was again due to my pre-expectation that the final figures would be very close to my earlier performance briefing and also because of the many years of experience on the airplane; intuitively; that value is a normal value to be seen. As we started the takeoff roll and began accelerating; visually; I could see on the ND that V1 and VR were very close together (not typical for a heavyweight takeoff) At that point; I think the Captain and I both instantly detected something was not right about the speeds. Thankfully; instead of forcing the rotation; the Captain allowed the airplane to continue accelerating down the runway developing sufficient speed on the main gear prior to lifting off and becoming airborne. At a safe altitude; we began a review of the Takeoff Data. A conference call with Dispatch and the Duty Manager took place explaining to them the error and the possibility of a tail strike even though the cabin crew; when queried; did not notice or hear anything in the cabin out of the ordinary throughout the takeoff. All aircraft systems appeared normal and after discussion; a collective decision was made to continue. Contributing factor #1 (Dispatch Release): At flight planning in Ops; this particular Captain's routine is to print out and use his own FP (flight plan) for use during the flight instead of using the MFP (Master Flight Plan). What the rest of the crew did not realize anytime duringplanning was that the Captain had FP (release #2) while the rest of the crew was using Master FP (release #1). At the airplane; the First Officer based all FMC and ACARS inputs based on the Master FP (release #1). This created confusion and a distraction during the critical time after pushback and engine start when performance calculations were being performed and the aircraft was being configured for taxi. This diverted my attention and focus away from normal duties and is when the FP release discrepancy was discovered. Contributing factor #2 (Final Weight Manifest): When the final weight manifest figures were received from LP (load planning) the ZFW was loaded into the CDU and I observed that the aircraft gross weight value increased when the Final Weight Manifest indicated that Takeoff Weight Change had dropped (-907 lbs). This inconsistency; which had to be reconciled; caused another distraction and was created by contributing factor #1. Contributing factor #3 (Incorrect Takeoff Performance Data): The Primary Relief Pilot mistakenly used the Final ZFW for the TOGW figure when requesting the Final Takeoff Data Message. The ACARS log reflected that (2) requests were made using the ZFW instead of the TOGW and the error was never caught and corrected. These were the final figures passed forward to be used for takeoff. In all the years that I have been flying the 747; this error has never happened on any of my flights. Contributing factor #4 (Complacency; SOP discipline): I have always prided myself as a professional pilot being vigilant; conscientious; and safe. In retrospect; there were many things that got by me on this flight that I should have caught. I let my guard down and as a result; let myself down; and my crew.
Takeoff with incorrect V speeds. V1-121; VR-124; V2-145 (vs. correct speeds of V1-145; VR-169; V2-180; a difference of 24; 45; and 35 knots low.) During preflight cockpit SOP's; the planned R/W Data message was received and briefed. During taxi out; Relief First Officer 1 received final weight message on ACARS. He then requested the revised/final R/W Data. The first major error was that he entered the actual final ZFW of 498.0 into the request; instead of the correct actual TOG weight of 853.6. He requested this twice using this erroneous weight; once for Flaps 10 and also for Flaps 20 data. Once the R/W Data Weights messages were received; Relief First Officer 1 asked both the flying co-pilot and myself as to which flaps we desired (10 or 20). The Flying First Officer replied 20; and I concurred. We seem to rarely; if ever; be able to use Flaps 10 with the heavy weights of a 13 or 14 hour flight; however; I did not catch the red flag in his query. The second major error occurred when the flying First Officer entered the erroneous V speeds for the underweight R/W Data into the FMC. It is unclear to me whether he entered V1; VR; and V2; or only V1 and VR into the FMC. The MCP V2 speed was never changed from the planned V2 of 180 knots. It is again unclear to me why it was not changed along with the FMC V speeds to reflect the incorrect speeds on the R/W Data message. If the MCP speed window had been changed; it should have been another big red flag. (Afterward; I asked him why he did not change the MCP window too; and he wasn't sure; other than he thought since it's always the same value of 180 knots; he never changes it; so he reflexively didn't this time either.) About at this point; the flying First Officer noted a discrepancy on the final weight/TOG weight change figure. The ACARS final weight message showed a 900 pound TOW decrease; but his numbers from the OFP showed an almost 6;000 pound increase. I inquired which OFP release number he had; and it was determined he had a release 1; while I had a release 2. The numbers on release 2 showed correctly; and that discrepancy was solved; but we neglected to investigate why he had a release 1. I assumed all in the crew had release 2; as I did; so I didn't catch that discrepancy. At least partly because of that distraction; the Flying First Officer laid the R/W Data message down on the pedestal; and it was never verified (or finished being verified) with the Relief First Officer 1 again. This would have been the ideal time for the obviously unreasonable speeds to be discussed and discovered; but this was missed as well. I did not verify the data with the Flying First Officer or the Relief First Officer as I assumed they had accomplished that with each other; as is normal practice with augmented pilots. The before takeoff checklist was accomplished; and at the 'Speeds' prompt; I noted the green speed bug on the PFD; as well as the speeds being 'big' in the CDU Takeoff Ref page. I did not; however; specifically note or question the actual speed values. This should have been another red flag; but all I was verifying was that the final speeds had been entered (which they were; albeit incorrect.) Due to the gusty cross winds and heavy weight for the takeoff; we briefed and planned for a max thrust takeoff. (In retrospect; this one decision may have saved a major incident from occurring; due to the fact that the erroneous weight reduced thrust values could have caused an unacceptably slow takeoff acceleration and a possible runway overrun. As it was; we at least had a normal acceleration.) During the takeoff roll is when I finally realized that something was wrong. On acceleration; the First Officer made the normal V1 call at the normal 5 knots prior to the V1 bug. I felt that the call came pretty early in the takeoff; but quickly reasoned it must be the wind. Almost immediately he called VR (he meant to say 'Rotate'; but VR came out of his mouth; most likely because the two Vspeeds were back to back with each other.) I knew immediately at that point that things were not right. My immediate reaction was to say 'What?!'; and my instincts were to not rotate. I looked at the remaining runway and could see we had a lot remaining (5;000 feet?). I hesitated and delayed the rotation for about another 20 knots. During this delay; the First Officer again called 'Rotate.' I tried to verbalize the problem to the crew; but didn't really know what the problem was yet. I think I said something to the effect; 'Those speeds aren't right.' Once we accelerated approximately 20 knots above the bugged VR speed on the speed tape; I slowly rotated the nose up; but stopped rotation at 10 degrees pitch; until I was certain that we had a positive rate of climb. My instincts were telling me now that those bug speeds were much too slow; and that I didn't want to over rotate into a tail strike; or stall. The airplane lifted off with normal runway remaining as far as I could determine. As soon as we were airborne; I noticed the low speed buffet (red) barber pole hovering at about 160 knots. I'm not sure of the speed at lift off; but I believe it to be over or near 170 knots (near the correct V2 speed) because I noticed we had approximately 20 knots above the low speed buffet indication right after liftoff. Once positive rate was established; the landing gear was retracted; and normal acceleration and flap retraction accomplished. Since the FMC had the correct ZFW; fuel; and Gr. Wt. values entered; the buffet and flap speeds were correct. There was never any stall or stick shaker warning. There was no tail strike (confirmed with mechanics after arrival). There were plenty of errors and red flags to go around here; and even though I didn't start the chain of events; I certainly missed opportunities to identify the errors. I am still relatively new on this aircraft and during the taxi out was focused heavily on the taxiway clearance; taxiing geometry; runway crossing; and thrust and taxi speed limits. I'm sure these gave me my own distractions; and helped keep me out of the loop during the time the first officers were discussing the R/W Data message and speeds. I do not have enough background experience on the aircraft to have noticed the 'red flag' that the V speeds were out of a range of reasonableness. I did not realize that the 2 first officers did not finish or verify the revised R/W Data procedures. The chain of events began with the Relief First Officer 1 entering the wrong weight in the ACARS R/W Data request; but there were ample opportunities for all four of us to catch the errors and rectify them; but we didn't; and they weren't. It's almost impossible to believe that four pilots missed entering incorrect speeds; but we did. I suppose you could point to these long; back sides of the clock; stressful; international flights as a factor; even though we do them every trip. Complacency seems to have played a part. My inexperience on the aircraft also may have contributed. This one definitely snuck up on us for sure; and it's one of those incidents that I would have said; 'That would never happen to me.' But it did.
B747 flight crew describes the circumstances that led up to the entry of incorrect V speeds into the FMC. The ZFW of 498k was used instead of the actual TOGW of 853K for the V speed calculation. The Captain detects the anomaly during the takeoff roll and delays rotation until closer to the actual V2 speed of 180 knots.