War emergency power is recalled as a setting that British pilots were instructed to avoid during training. Spitfires and Hurricanes provide the examples. Extra power could damage an engine or create substantial maintenance work. In a dogfight, the immediate need for performance could justify that cost, so the training rule did not mean the setting was unusable in combat.
Notable Point · 3:48:17-3:48:50
Why war emergency power was restricted in training
Spitfires and Hurricanes illustrate why a training prohibition can coexist with a useful combat capability.