aardvark2zz wrote: The on board computer, with a very simple software, could warn them of serious danger ahead as they are accelerating.
THIS - real-time acceleration analysis during each and every departure roll - is the 21'st century way to solve the problem, even if weighbridges and other passive controls are added as a further means to assure load limits.
The informal discussion here has clearly pointed out that quite a number of factors can influence the ability of the bird to depart her runway in the time and space available. Weight, elevation, temperature, humidity, thrust, wheel friction, winds, turbulence, runway surface contamination, etcetera. A large number of variable but potentially decisive factors affect the launch outcome. Most are hard to know precisely and uncontrollable once the roll begins. The choices mid-roll devolve to power, airfoils, and reject/braking.
Departure performance is pre-calculated with an expected weight, thrust, slope, winds, temps, etc. The calculation, as done manually, creates a few numbers such as MTOW and V-speeds. But the same information and the same calculation can just as easily create a complete moment-by moment profile curve, expressed as speed vs distance or acceleration vs time or roll distance vs time from throttle up.
Having this computed curve of expected performance at hand, it is the most natural thing in the world for a little bit of electronics to compute a moment-by moment 'actual performance' during the roll from airspeed, surface radar, gps, wheel spin, acceleration, or all of the above. By continuously comparing the projected performance with the observed values, the resulting real-time all-encompassing magical performance number would provide a very true comparison of expected versus actual progress in safely unsticking from mother earth. And the information - at least for gross deviations in performance - would be available and useful early in the roll, making an informed take-off abort possible before the uncertainty of stopping makes scrubbing the takeoff a terribly hard decision.
This evolving launch data could be plotted in detail on the FE console, if present, but a few lights would probably serve the purpose up front. Green, amber, red and brown might be appropriate.
What this bit of kit would do is add method and precision to just what a pilot does now: monitor the progress of the takeoff run and determine whether it "feels" right or not. The difference is that it would add a degree of accountable precision to a seat-of-the-pants process and work just as well in cold dark places, in rain and snow and other cases where crew sensory perception is constrained.
In an era where good electronics can be created cheaper and easier than good plumbing, this is not an expensive thing to do.. in comparison to the cost of a tragically failed departure. Certainly it can be integrated into aircraft electronic systems, but that is a long-cycle evolution. For sooner availability, the necessary bits could be made fairly cheap and reliable as an add-on black box or even as a portable unit for application on all those ageing airframes hauling heavy stuff in the night.
The history of aviation is trial and error. The best monument to those lost in the process is to SOLVE the problems that tragedy reveals. RIP.