There is an interesting comparison in ‘The Berlin Raids’ by Martin Middlebrook between the survival rates of Lancaster crews from number 1 Group and number 5 Group during the Battle of Berlin.

———- Sorties — Shot-Down —- Aborted —– Killed — Baled-Out

1 Group — 2598 — 143 (5.5%) — 207 (8.0%) — 780 — 242 (23.7%)
5 Group — 3002 — 128 (4.3%) — 166 (5.5%) — 750 — 141 (15.8%)

These two groups operated the same aircraft type, in the same operations, but throughout the Battle of Berlin number 1 Group consistently loaded their Lancasters with the maximum possible bomb-load; a sample averaged 9317lb for 1 Group compared to 8986lb for 5 Group during the battle.

Some Lancaster crews took to jettisoning some of their bomb-load (including 4000lb ‘cookie’ bombs which could not be dropped ‘safe’ and therefore could be seen exploding) over the North sea in an effort to regain some of the performance and height of their aircraft.

It also seems that the chances of crew survival were affected by the morale of the crews and their willingness to ‘press-on’.