To solve maximum loadability problem, a population of fireflies of size corresponding to PQ buses is generated. i.e 20 *20. Fitness function for each firefly is evaluated as given in (11) in Section 3.2. The program is run for given number of iterations i.e. 20. The result obtained using firefly algorithm after 20th iteration is considered as input to LIA. A small step size of load is incremented on load buses as explained in Section 3.2 which yields total load of 2.8438 p.u while voltage at all buses is within limits as given below: