Thanks for some of your replies - a couple helpful, others not so much.
Allow me to give some context to the question. I work for an operator of the 737 in Australia - we fly the 738 to a number of ports that have landing distances in the order of 1800m, the shortest one being Hamilton Island with a LDA of 1764m. It is also not uncommon for these places to be wet, and for our landing weight to be fairly close to MLW.
Now, approximately 18 months ago our operator came up with an Operational Landing Solution policy. Essentially this policy REQUIRES us to land with an auto brake selection that ensures that the aircrafts LDR is less than the LDA - which I do not think is an unreasonable policy, given some of the limiting runways we land on.
However the issue arises when landing at Hamilton Island, close to Max Landing Weight on a wet runway. The policy requires us to use auto brake Max - I’m not sure how many of you have landed with Max auto brake in a 738, but it is quite aggressive. Most of the guys will kick the auto brake out fairly soon after touchdown, because if it was left in, you would need to add thrust to roll through to the end of the runway before backtracking, not to mention that all of the passengers are basically thrown forward into the seat in front of them!
So from the research I had done, I was aware that the deceleration rate of AB 3 was in the order of 7 f/s and AB Max was in the order of 14 f/s. The question I posed was to find out whether an operator could request those deceleration rates to be altered - I believe an AB 3 decel of 9-10 f/s and AB 2 decel of 6-7 f/s would be far more suited to my company’s operations.
I’m interested in one posters comments suggesting that changing the deceleration rates would require a heap of flight testing from Boeing. This raises another question I don’t know the answer to, as I would have thought that the landing distances in the QRH would be derived mathematically (but obviously based on a level of flight testing during certification). Am I incorrect in that assumption?
I didn’t mean for this topic to become a debate on levels of automation - I would say at a guess, approximately one third to one half of the Landings I do, I would be overriding the autobrake. It is not uncommon in Sydney when landing on 16R when it’s wet, at high landing weights to override AB 3 in order to make the first high speed taxiway. So I don’t consider myself a ‘child of the magenta line’ - I’m more than happy to over ride AB when needed.
Thanks for all of the replies so far and I appreciate any further detail on the above.
Cheers