Like I said, "Generally speaking". I also said that depending on the aircraft. My post was meant to be a general post...not a thats not how the 73/75/74 works. Of course a 747 will have a higher speed. The more non-certerline thrust that is generated the higher the speed. I agree. But to quote the 72 Flight Ops Manual, "Eighty knots is the defined point that separates the Low Speed Regime from the High Speed Regime. In the Low Speed regime a takeoff may be rejected for a number of malfunctions. In the High Speed Regime the number of malfunctions that require a reject are dramatically reduced. The Captain must remain "go oriented" in the High Speed regime."

With that said, in a high speed regime it is safer to continue the takeoff than it reject. Below 80 kts (accelerate-stop oriented) it is safer to keep your hands on the tiller for reject purposes.

The bottom line is that above 80 kts you have increased control and reduced runway length/safety margin. Therefore, it is safer to take your hands off the tiller above 80kts than it is to take your hands off below 80kts. It is also safe to assume that if you are using a 80kts call, 80 kts is probably closing on Vmcg. On the C-130J, we use 70kts as the speed to define high speed regime. So for certain malfunctions you would reject prior to 80kts and for others you would not. For malfunctions that are considered critical to safe flight, you would reject in the high speed regime (80kts - V1) b/c it is considered safer to accept the high speed reject on reduced runway margins than it would be to take it airborne.

The original question asked, "He insists that the tiller is used for the first 80 kts on the takeoff roll because there is no rudder steering tied into the nose gear and it's not effective until 80 kts and that's the whole point of the 80 kts callout."

My original attempt to answer the post was probably to vague and general. Each aircraft is going to be different, but the standard operation procedures regarding take-off/reject decisions will be similar.

BTW, does the 73/74/74/76 use a 80kt call out?