The IAF will shortly place an order with HAL for eight LCA Tejas twin-seat trainers, powered by the current GE-F404-IN20 engine. Therefore, the force will operate a total of 28 fighters (including the first batch of 20 single-seaters) with the current engine, the one that is unsuitable for any follow-on fighters since it doesn't provide enough thrust. The first twenty fighters will begin delivery by 2011. But following this, the production line will lie vacant for upto 12 months for HAL to re-tool and reconfigure its facilities to produce the LCA with a new and more powerful engine (possible the
Eurojet or another). The IAF's rationale is that it doesn't really need an initial tranche of trainers powered by an uprated engine. Therefore, HAL can use the idling time between the two engine configurations, to build eight trainers powered by the IN20 itself.