Afterburner
An afterburner, when ignited, accelerates the fighter, thereby allowing it to reach a higher velocity and escape from capital ship turrets and run away from hostile sentry defences.
The rate of acceleration is dependent on the type of fighter or bombers, each craft has a unique maximal speed, both with or without afterburners. While intercept fighters gain a faster speed using afterburners, bomber engines are less focused on reaching a high maximal speed, due to having more energy required to be diverted to shields and weapons.
Any ship using afterburners can be recognized even by distance without reading the target's speed on your HUD. When the afterburner is used, the engine glow changes color, often to a lighter saturation.
Increasing the energy diverted to engines also make afterburners recharge more quickly, while having no power on engines makes the afterburner not recharge.
The PVF Anubis is the only canon fighter without afterburner capability. However, a number of Shivan Bombers, notably the SB Shaitan, the SB Seraphim, the SB Nephilim and the SB Taurvi, also lack afterburner capacity.
Veteran Comments
A good pilot knows when and how to manage engine power and afterburners. If you meet an ace pilot, do not ever expect to overtake him unless your craft is so much faster.