NO LAND 3 has the answer if you're operating EFIS with speed trend vector.
No need for a speed / time check on 777 as ASI has a speed trend vector incorporated in its display. Effectively it is an obvious indicator of your level of acceleration during takeoff. On 777 it will usually extend 30 knots.
Correct! And that's because the speed trend vector will usually show predicted airspeed in 10 seconds based on current acceleration! OK, it may vary from type to type, but normally at heavy weights and at about V1, an aircraft is travelling at about 200 to 300 ft per second, so it's therefore accelerating at 3 to 6 knots per second.
Therefore, if the speed trend vector is showing (about) 30 kts predicted speed increase, then acceleration is probably OK and about 3 kts/second.
Remember though, that the above is an 'approximation' only, and to be totally accurate you'd need to get SPECIFIC figures for the type that you operate. However, like all 'rules of thumb', the 'approximation' is probably fairly accurate in practical terms for the purpose of determining whether take-off is 'normal'!