Actuarial estimates are closely guarded figures, for obvious reasons. BUT, guestimates (and that's all they are) are that pilots who retire at 55 live to an average of 78. Pilots who retire at 60 live to an average of 74 and the pension hole virtually disappears , only 14 years of payouts as against 23. So if you work until 65 and the average age of shuffling off this mortal coil is then lowered even further to say, 72, then the pension fund will be overflowing.
It is in the company interest to get you to work as long as possible as their liability to you in pension payouts decreases expotentially.