Motor racing-F1 teams call for return to 2015 qualifying

LONDON, April 7 (Reuters) - Formula One teams have called for a return to last year's qualifying format after rejecting a proposal backed by the governing FIA to switch to an aggregate format, team sources said on Thursday. The teams stated their united position in a letter to commercial supremo Bernie Ecclestone and International Automobile Federation (FIA) head Jean Todt who have both said there can be no going back. The impasse is likely to mean a new elimination format introduced this season, widely condemned by fans and teams as a failure, will remain in place for at least next week's Chinese Grand Prix in Shanghai. Any change to the 2016 regulations requires the unanimous approval of the FIA's F1 commission which groups the teams and governing body as well as other stakeholders. Teams agreed at last weekend's Bahrain Grand Prix to vote by Thursday on the compromise solution which would see each driver do at least two laps in each of the three phases of qualifying with the times aggregated. (Reporting by Alan Baldwin, editing by Tony Jimenez)