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B757 first officer questions takeoff V speeds generated by the FMC and asks dispatch to send new numbers; which are significantly lower. The dispatch numbers are used for takeoff.
| Attributes | |
| ACN | 1060592 |
| Time | |
| Date | 201301 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Make Model Name | B757 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Taxi |
| Flight Plan | IFR |
| Person 1 | |
| Function | Pilot Flying First Officer |
| Experience | Flight Crew Last 90 Days 200 Flight Crew Total 15000 Flight Crew Type 11000 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy |
Narrative:
[There were] two cards. One I requested for runway xx using flaps 5. I looked at the reduced speeds and thought it was high for a 210;000 pounds B757. The [other] card was sent by request from dispatch. The only environmental difference between the two is the new one is for 209;400 pounds vs. My 210;800 pounds card on the left. Vr and V2 are 13 and 12 knots less on the dispatch message. Something is screwed up in some database or in the programming. When I tried to bug the first speeds; the V2 bug was within 13 knots of F5 maneuvering speed. I have never seen V2 that close to F5 maneuver speed. I know there can be differences between reduced and max power numbers; but look at the max numbers at the left card versus the reduced numbers. The fact that dispatch generated more reasonable numbers means the cockpit was accessing something else. Even after getting airborne; I was able to consistently generate unreasonably high reduced v-speeds at all sorts of weights. It shouldn't be 13 or 15 knots high. I'd hate to think of someone doing a high-speed reject at those unusually high numbers.
Original NASA ASRS Text
Title: B757 First Officer questions takeoff V speeds generated by the FMC and asks Dispatch to send new numbers; which are significantly lower. The Dispatch numbers are used for takeoff.
Narrative: [There were] two cards. One I requested for Runway XX using Flaps 5. I looked at the reduced speeds and thought it was high for a 210;000 LBS B757. The [other] card was sent by request from Dispatch. The only environmental difference between the two is the new one is for 209;400 LBS vs. my 210;800 LBS card on the left. Vr and V2 are 13 and 12 knots less on the Dispatch message. Something is screwed up in some database or in the programming. When I tried to bug the first speeds; the V2 bug was within 13 knots of F5 Maneuvering Speed. I have never seen V2 that close to F5 Maneuver speed. I know there can be differences between Reduced and Max Power numbers; but look at the Max numbers at the left card versus the reduced numbers. The fact that Dispatch generated more reasonable numbers means the cockpit was accessing something else. Even after getting airborne; I was able to consistently generate unreasonably high reduced V-speeds at all sorts of weights. It shouldn't be 13 or 15 knots high. I'd hate to think of someone doing a high-speed reject at those unusually high numbers.
Data retrieved from NASA's ASRS site as of July 2013 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.