BENGALURU, Aug 27 (Reuters) - Indian shares were largely unchanged in choppy trading on Friday, with banking stocks dropping as investors eyed Federal Reserve Chair Jerome Powell’s speech to get clues on the central bank’s timeline to taper its asset purchase programme. By 0458 GMT, the blue-chip NSE Nifty 50 index was up 0.02% at 16,649.55, while the benchmark S&P BSE Sensex fell 0.07% to 55,939.36. Main indexes in India’s liquidity-abundant market hit all-time highs earlier this week as the country authorised more COVID-19 vaccines to ramp up its immunisation program, setting up the Nifty 50 for a weekly gain. “The uncertainty over the Fed’s speech is keeping investors cautious. If the Fed comes up with a clear roadmap with respect to the rate regime that it is planning to follow, it could help markets gain some stability next week”, said Gaurav Garg, head of research at CapitalVia Global Research, said. The rate-sensitive Nifty Bank index fell as much as 0.73%. Budget airline SpiceJet Ltd jumped nearly 4% after the country’s air safety regulator cleared Boeing’s 737 MAX aircraft to fly with immediate effect on Thursday. The Nifty Metal index rose as much as 1.74%, boosted by aluminium stocks. Vedanta Ltd, Hindalco Industries Ltd and National Aluminium Co were up between 1.5% and 5.7% after China’s Xinjiang region imposed output limits on five aluminium smelters. Among broader markets, Asian shares were mixed as slight gains in China were balanced by declines elsewhere and investors globally turned cautious ahead of Powell’s speech. A deadly attack in Afghanistan on Thursday, which killed scores of civilians and at least 13 U.S. troops, also dented global sentiment. (Reporting by Shivani Singh in Bengaluru; editing by Uttaresh.V) Our Standards: The Thomson Reuters Trust Principles.