Zeke,
The factors that you are talking about in your Jeppesen analysis are extremely basic, from the phrases that you use, I would guess that you are using a standard Airbus takeoff chart? As for the factors which I mentioned.
Slope: The standard way of calculation slope is to take the runway end elevation and divide the different by the runway length; this gives you a mean elevation that works in most cases. But what about the airports where the slope in your accelerate-go portion is greater than the average? Will you reach 35feet?
Runway surface: For years Bombay’s main runway had severe rubber deposits on it, the airport authority even had the audacity of declaring the runway braking action POOR when wet! This basically put the onus on the airline to decide if they wanted to use the runway or not. How many airlines counted for this in their takeoff calculations?
Contaminated runways: It amazes me that there are airlines taking off from wet/contaminated runways without making any corrections! I still haven’t worked out why this is the one case where Boeing actually produces Ops Manual data for ALL ENGINES.
The FMS in a number of our aircraft has a function for calculating wet V-speeds, but the FAR’s don’t require Boeing to certify this data, therefore they refuse to enable this function! (Its there in CAA aircraft)
This is the sort of gray world that I’m talking about!
That’s enough of my gripes……. The information that you are looking for is available, all that you have to do is fly a Boeing aircraft! I believe that Lufthansa give their crews MIN/MAX V1 speeds, the crew then have the option to pick the V1 that suits the present conditions. The Airbus optimized V-speed methodology is pretty complicated and will depend on the speed ratio that was selected by your airline. But there is nothing stopping your ops people from using a lower speed ratio.
In the black and white legal world, your idea of rotating earlier without any SOP for doing so, will backfire on you.
You have given the impression that most aircraft are now certified using worn brakes. I know that the FAR’s have changed, but the ONLY aircraft which I know was certified using worn brakes (2%) is the MD11. (The rules say nothing about the brake temperature.)
Can anyone tell me of any other aircraft certified with worn brakes, this information should be shown on the accelerate stop distance chart in the AFM.
JT, Boeing will argue that their aircraft are built according to the regulations. While history may have shown that 58% of RTO’s were avoidable, Boeing have passed this information on to airlines in the form of the Takeoff Safety Guide, therefore covering their arses.
Slasher, I would have preferred to see the passenger getting fined for endangering the other passengers lives by not taking adequate care to secure herself into the seat!
Night All.
Mutt.
