UPDATE 3-Ferrovial's BAA to appeal airports break-up

* BAA to apply to Competition Appeal Tribunal

* Claims ruling was affected by "apparent bias"

* Says report not taking into account economic conditions

(Adds further comment)

By John Bowker

LONDON, May 18 (Reuters) - British airports operator BAA will appeal an order by competition regulators to sell three of its airports, including Gatwick and Stansted in London, saying the ruling was "affected by apparent bias".

BAA, majority owned by Spain's Ferrovial (FER.MC: Quote, Profile, Research), said in a statement on Monday it was also disputing the March ruling to the Competition Appeal Tribunal on the grounds it did not take into account the tough economic conditions.

BAA said one member of the Competition Commission panel was apparently not independent enough to participate in ruling on the break-up of BAA.

The commission ordered BAA to sell Gatwick, Stansted and either Edinburgh or Glasgow airports, in that order, within two years. BAA is in the process of selling Gatwick.