Originally Posted by Jambo Buana
If you compare my question to, reducing weight to achieve a contaminated RWY takeoff and thereby reducing V1 by 15 to 20 kts, you could reasonably expect, on long runways, that there is bags of extra performance available that would allow operators to reduce V1 by 10 to 20 kts lets say. Now this would provide a real safety benefit as you wouldnt get a really high energy RTO and crews are exposed to less time during which an RTO can be initiated.
2/3 of overruns are rejected unnecessarily in the first place! ref Boeing takeoff safety training guide.
Remember, though, that Vmcg, and the minimum V1 derived from it, are both pretty arbitrary numbers. There's no black/white divide that says that at V1min+1kt you are 'safe' - the wrong combination of circumstances could easily see you in the grass. For example, I just checked one of our test reports for Vmcg testing on a single type. For a speed spread of 1.5 kts the lateral deviation varies between 5ft and 40ft - and pretty randomly at that, the highest deviation is NOT at the lowest speed. If test pilots, briefed as to the test and expecting the failure, have such a wide variation in results, how large would it be applied to service pilots caught unprepared.
So if one were to adopt a policy of
routinely lowering V1 to (near) the minimum value, one would be increasing the risk of runway excursions to side, perhaps as fast as the risk of overruns was r\educed. (It's analagous to the practice of widespread reduced thrust takeoffs, reducing the real margin of takeoff performance)