As captain of a Boeing 747 on a take-off roll I am expecting my co-pilot to call out V1, Rotate, but he does not call out rotate. Do I abort the take-off?
That could end up being a really bad idea if you've accelerated past your V1 speed -- your abort would then put you off the end of the runway, and the consequences from that range from bad to catastrophic.
A much better idea would be to look at the markers on your airspeed indicator, and if you're at/above rotation speed, go ahead and rotate. Then sort out what's up with your copilot.
The worst case is, he's incapacitated, unconscious, experiencing a stroke or heart attack or something similar, and you'll probably end up returning to land as quickly as possible. While the idea of staying on the ground to get him EMS help sooner might seem to be appealing, he'll probably NOT get better attention if your aircraft just ran off the runway, through the airport fence, and into whatever terrain/water/civilization lies beyond, because you didn't start your abort until several seconds after you should have been flying. Better to come back and land with ONE sick person on the airplane, rather than crash, making your copilot now one of potentially MANY injured/scared/incapacitated people on a damaged jet -- and he with the very least ability of any of them to evacuate himself!
Or, maybe he got distracted and he's fine, and after he overcomes his embarrassment for missing the important callouts, the rest of the flight will go fine.
So, no, if the copilot doesn't call "V1, Rotate" I would NOT recommend aborting the takeoff. If you see him slumped over when he should be making an "80 knots" or "airspeed alive" call, that might be a different decision; at that sort of speed you're in no danger of running off the runway & you could probably taxi back to the gate promptly. But if he's missed his calls at significantly higher speeds, aborting is a bad plan.
Very well stated answer and valid common sense reasons not to abort above V1 and on a missed V speed call.
80 kts and 100 kts also serve as incapacitation calls and 100kts caution yu are entering a high energy state in case pf any abort and something to be extra mindful in case of wet/slippery runways.
Here is a good case why not to abort at V1 and above gor a heavy jet
There is a case, exceptionally. When a take off must be aborted after V1 ...when you have no other choice but to.One case might be encounterng flight control failure such as horizontal stabilizer.Another case might be dual/all engines failure case You are not going anywhere with these two scenarios and better salvage a crash close to the runway,stopway and clearway then at height. Another case where it might be tempting to abort a feq seconds after V1 and if particularly second segment limited is encountering a Microburst(ofcourse ypu should not takeoff within sight or radar coverage of any thunderstorm cell..but if a severe speed lag or speed burst occurs close to or at V1 im the given scenario with second segment climb limited case..it might be better to abort if on a dry runway Do expect an overrun and so exert maximum brake energy..and expect a fire in the wheel well or even overrun and crash at the end of an overrun.You have the choice to push throttles to max thrust(Firewall) and totate at a slightly higher speed to countermand the debilitating effects of the microburst during the first and second segment..not forgetting NOT to raise the gear or change any configuration except after flying through the shear..typically past 1500 feet.